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Sample records for plethodontid salamander mitochondrial

  1. Molecular mechanisms of extensive mitochondrial gene rearrangementin plethodontid salamanders

    SciTech Connect

    Mueller, Rachel Lockridge; Boore, Jeffrey L.

    2005-06-01

    Extensive gene rearrangement is reported in the mitochondrial genomes of lungless salamanders (Plethodontidae). In each genome with a novel gene order, there is evidence that the rearrangement was mediated by duplication of part of the mitochondrial genome, including the presence of both pseudogenes and additional, presumably functional, copies of duplicated genes. All rearrangement-mediating duplications include either the origin of light strand replication and the nearby tRNA genes or the regions flanking the origin of heavy strand replication. The latter regions comprise nad6, trnE, cob, trnT, an intergenic spacer between trnT and trnP and, in some genomes, trnP, the control region, trnF, rrnS, trnV, rrnL, trnL1, and nad1. In some cases, two copies of duplicated genes, presumptive regulatory regions, and/or sequences with no assignable function have been retained in the genome following the initial duplication; in other genomes, only one of the duplicated copies has been retained. Both tandem and non-tandem duplications are present in these genomes, suggesting different duplication mechanisms. In some of these mtDNAs, up to 25 percent of the total length is composed of tandem duplications of non-coding sequence that includes putative regulatory regions and/or pseudogenes of tRNAs and protein-coding genes along with otherwise unassignable sequences. These data indicate that imprecise initiation and termination of replication, slipped-strand mispairing, and intra-molecular recombination may all have played a role in generating repeats during the evolutionary history of plethodontid mitochondrial genomes.

  2. Plethodontid salamander mitochondrial genomics: A parsimonyevaluation of character conflict and implications for historicalbiogeography

    SciTech Connect

    Macey, J. Robert

    2005-01-19

    A new parsimony analysis of 27 complete mitochondrial genomic sequences is conducted to investigate the phylogenetic relationships of plethodontid salamanders. This analysis focuses on the amount of character conflict between phylogenetic trees recovered from newly conducted parsimony searches and the Bayesian and maximum likelihood topology reported by Mueller et al. (2004, PNAS, 101, 13820-13825). Strong support for Hemidactylium as the sister taxon to all other plethodontids is recovered from parsimony analyses. Plotting area relationships on the most parsimonious phylogenetic tree suggests that eastern North America is the origin of the family Plethodontidae supporting the ''Out of Appalachia'' hypothesis. A new taxonomy that recognizes clades recovered from phylogenetic analyses is proposed.

  3. Morphological homoplasy, life history evolution, and historical biogeography of plethodontid salamanders inferred from complete mitochondrial genomes

    SciTech Connect

    Mueller, Rachel Lockridge; Macey, J. Robert; Jaekel, Martin; Wake, David B.; Boore, Jeffrey L.

    2004-08-01

    The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an independent, molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, ML, and MP phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (PP > 0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three out of four major groups is rejected. Reanalysis of current hypotheses in light of these new evolutionary relationships suggests that (1) a larval life history stage re-evolved from a direct-developing ancestor multiple times, (2) there is no phylogenetic support for the ''Out of Appalachia'' hypothesis of plethodontid origins, and (3) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these novel scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative.

  4. Prey detection by vomeronasal chemoreception in a plethodontid salamander.

    PubMed

    Placyk, John S; Graves, Brent M

    2002-05-01

    While chemoreception is involved in a wide variety of salamander behaviors, the chemosensory system that mediates specific behaviors is rarely known. We investigated the role of the vomeronasal system (VNS) in foraging behavior of the red-backed salamander (Plethodon cinereus) by manipulating salamanders' abilities to detect nonvolatile chemical cues emitted by potential prey. Subjects received one of three treatments: (1) impaired vomeronasal system, (2) sham manipulation, and (3) no manipulation. The role of the VNS in mediating foraging on motile prey (Drosophila melanogaster) was investigated under three light conditions (bright, dim, dark). Salamanders with impaired VNSs foraged less efficiently than either of the other experimental groups by displaying the longest latency to attack and the lowest rate of prey capture, especially in the absence of visual cues. A second experiment utilized freshly killed prey to determine whether the VNS takes on added importance in the absence of visual or tactile cues associated with moving prey. Animals with impaired VNSs showed a decreased foraging efficiency on stationary prey under both dark and light conditions. In addition, a mark-recapture study of VNS-impaired and sham salamanders in the field also indicated that salamanders with impaired VNSs consumed fewer stationary prey compared to shams. The study indicates that the VNS plays a substantial role in the foraging behavior of the plethodontid salamander, P. cinereus.

  5. Detection of an enigmatic plethodontid Salamander using Environmental DNA

    USGS Publications Warehouse

    Pierson, Todd W.; Mckee, Anna; Spear, Stephen F.; Maerz, John C.; Camp, Carlos D.; Glenn, Travis C.

    2016-01-01

    The isolation and identification of environmental DNA (eDNA) offers a non-invasive and efficient method for the detection of rare and secretive aquatic wildlife, and it is being widely integrated into inventory and monitoring efforts. The Patch-Nosed Salamander (Urspelerpes brucei) is a tiny, recently discovered species of plethodontid salamander known only from headwater streams in a small region of Georgia and South Carolina. Here, we present results of a quantitative PCR-based eDNA assay capable of detecting Urspelerpes in more than 75% of 33 samples from five confirmed streams. We deployed the method at 31 additional streams and located three previously undocumented populations of Urspelerpes. We compare the results of our eDNA assay with our attempt to use aquatic leaf litterbags for the rapid detection of Urspelerpes and demonstrate the relative efficacy of the eDNA assay. We suggest that eDNA offers great potential for use in detecting other aquatic and semi-aquatic plethodontid salamanders.

  6. Comparing population size estimators for plethodontid salamanders

    USGS Publications Warehouse

    Bailey, L.L.; Simons, T.R.; Pollock, K.H.

    2004-01-01

    Despite concern over amphibian declines, few studies estimate absolute abundances because of logistic and economic constraints and previously poor estimator performance. Two estimation approaches recommended for amphibian studies are mark-recapture and depletion (or removal) sampling. We compared abundance estimation via various mark-recapture and depletion methods, using data from a three-year study of terrestrial salamanders in Great Smoky Mountains National Park. Our results indicate that short-term closed-population, robust design, and depletion methods estimate surface population of salamanders (i.e., those near the surface and available for capture during a given sampling occasion). In longer duration studies, temporary emigration violates assumptions of both open- and closed-population mark-recapture estimation models. However, if the temporary emigration is completely random, these models should yield unbiased estimates of the total population (superpopulation) of salamanders in the sampled area. We recommend using Pollock's robust design in mark-recapture studies because of its flexibility to incorporate variation in capture probabilities and to estimate temporary emigration probabilities.

  7. Spermatogenic cycle of a plethodontid salamander, Eurycea longicauda (Amphibia, Urodela)

    PubMed Central

    Siegel, Dustin S; Alvino, Sam; Trauth, Stanley E; Sever, David M; Gribbins, Kevin M

    2014-01-01

    Previous investigators have described the spermatogenic cycles of numerous species of plethodontid salamanders. Most studies describe a fairly stereotypical cycle with meiotic divisions of spermatogenesis commencing in the spring/summer. However, many studies lack details obtainable from histological examination and/or testicular squashes and, instead, provide only mensural data from the testes. Studies that lacked microscopic evaluation often revealed spermatogenic cycles that varied greatly from that of the stereotypical cycle with meiotic divisions commencing in the fall/winter. Those studies hamper comparisons between the spermatogenic cycles of different species and their environments, as they do not provide a correlation between testicular size and any aspect of the spermatogenic cycle. In the following manuscript, we elucidate the spermatogenic cycle of Eurycea longicauda longicauda in an effort to outline an appropriate protocol for analyzing spermatogenesis in salamanders that will facilitate future comparative studies. Like many Nearctic plethodontids, E. l. longicauda exhibits a meiotic wave that travels through the testes during the summer; this process is followed by spermiogenesis, spermiation, and recrudescence in the fall, winter, and spring. PMID:26413402

  8. A case for using Plethodontid salamanders for monitoring biodiversity and ecosystem integrity of North American forests

    USGS Publications Warehouse

    Welsh, H.H.; Droege, S.

    2001-01-01

    Terrestrial salamanders of the family P!ethodontidae have unique attributes that make them excellent indicators of biodiversity and ecosystem integrity in forested habitats. Their longevity, small territory size, site fidelity, sensitivity to natural and anthropogenic perturbations, tendency to occur in high densities, and low sampling costs mean that counts of plethodontid salamanders provide numerous advantages over counts of other North American forest organisms for indicating environmental change. Furthermore, they are tightly linked physiologically to microclimatic and successional processes that influence the distribution and abundance of numerous other hydrophilic but difficult-to-study forest-dwelling plants and animals. Ecosystem processes such as moisture cycling, food-web dynamics, and succession, with their related structural and microclimatic variability, all affect forest biodiversity and have been shown to affect salamander populations as well. We determined the variability associated with sampling for plethodontid salamanders by estimating the coefficient of variation (CV) from available time-series data. The median coefficient of variation indicated that variation in counts of individuals among studies was much lower in plethodonticis (27%) than in lepidoptera (93%), passerine birds (57%), small mammals (69%), or other amphibians (37-46%), which means plethodontid salamanders provide an important statistical advantage over other species for monitoring long-term forest health.

  9. Rapid diversification and dispersal during periods of global warming by plethodontid salamanders.

    PubMed

    Vieites, David R; Min, Mi-Sook; Wake, David B

    2007-12-11

    A phylogeny and timescale derived from analyses of multilocus nuclear DNA sequences for Holarctic genera of plethodontid salamanders reveal them to be an old radiation whose common ancestor diverged from sister taxa in the late Jurassic and underwent rapid diversification during the late Cretaceous. A North American origin of plethodontids was followed by a continental-wide diversification, not necessarily centered only in the Appalachian region. The colonization of Eurasia by plethodontids most likely occurred once, by dispersal during the late Cretaceous. Subsequent diversification in Asia led to the origin of Hydromantes and Karsenia, with the former then dispersing both to Europe and back to North America. Salamanders underwent rapid episodes of diversification and dispersal that coincided with major global warming events during the late Cretaceous and again during the Paleocene-Eocene thermal optimum. The major clades of plethodontids were established during these episodes, contemporaneously with similar phenomena in angiosperms, arthropods, birds, and mammals. Periods of global warming may have promoted diversification and both inter- and transcontinental dispersal in northern hemisphere salamanders by making available terrain that shortened dispersal routes and offered new opportunities for adaptive and vicariant evolution.

  10. Rapid diversification and dispersal during periods of global warming by plethodontid salamanders

    PubMed Central

    Vieites, David R.; Min, Mi-Sook; Wake, David B.

    2007-01-01

    A phylogeny and timescale derived from analyses of multilocus nuclear DNA sequences for Holarctic genera of plethodontid salamanders reveal them to be an old radiation whose common ancestor diverged from sister taxa in the late Jurassic and underwent rapid diversification during the late Cretaceous. A North American origin of plethodontids was followed by a continental-wide diversification, not necessarily centered only in the Appalachian region. The colonization of Eurasia by plethodontids most likely occurred once, by dispersal during the late Cretaceous. Subsequent diversification in Asia led to the origin of Hydromantes and Karsenia, with the former then dispersing both to Europe and back to North America. Salamanders underwent rapid episodes of diversification and dispersal that coincided with major global warming events during the late Cretaceous and again during the Paleocene–Eocene thermal optimum. The major clades of plethodontids were established during these episodes, contemporaneously with similar phenomena in angiosperms, arthropods, birds, and mammals. Periods of global warming may have promoted diversification and both inter- and transcontinental dispersal in northern hemisphere salamanders by making available terrain that shortened dispersal routes and offered new opportunities for adaptive and vicariant evolution. PMID:18077422

  11. Climate change and shrinking salamanders: alternative mechanisms for changes in plethodontid salamander body size.

    PubMed

    Connette, Grant M; Crawford, John A; Peterman, William E

    2015-08-01

    An increasing number of studies have demonstrated relationships between climate trends and body size change of organisms. In many cases, climate might be expected to influence body size by altering thermoregulation, energetics or food availability. However, observed body size change can result from a variety of ecological processes (e.g. growth, selection, population dynamics) or imperfect observation of biological systems. We used two extensive datasets to evaluate alternative mechanisms for recently reported changes in the observed body size of plethodontid salamanders. We found that mean adult body size of salamanders can be highly sensitive to survey conditions, particularly rainfall. This systematic bias in the detection of larger or smaller individuals could result in a signature of body size change in relation to reported climate trends when it is simply observation error. We also identify considerable variability in body size distributions among years and find that individual growth rates can be strongly influenced by weather. Finally, our study demonstrates that measures of mean adult body size can be highly variable among surveys and that large sample sizes may be required to make reliable inferences. Identifying the effects of climate change is a critical area of research in ecology and conservation. Researchers should be aware that observed changes in certain organisms can result from multiple ecological processes or systematic bias due to nonrandom sampling of populations.

  12. Climate change and shrinking salamanders: alternative mechanisms for changes in plethodontid salamander body size.

    PubMed

    Connette, Grant M; Crawford, John A; Peterman, William E

    2015-08-01

    An increasing number of studies have demonstrated relationships between climate trends and body size change of organisms. In many cases, climate might be expected to influence body size by altering thermoregulation, energetics or food availability. However, observed body size change can result from a variety of ecological processes (e.g. growth, selection, population dynamics) or imperfect observation of biological systems. We used two extensive datasets to evaluate alternative mechanisms for recently reported changes in the observed body size of plethodontid salamanders. We found that mean adult body size of salamanders can be highly sensitive to survey conditions, particularly rainfall. This systematic bias in the detection of larger or smaller individuals could result in a signature of body size change in relation to reported climate trends when it is simply observation error. We also identify considerable variability in body size distributions among years and find that individual growth rates can be strongly influenced by weather. Finally, our study demonstrates that measures of mean adult body size can be highly variable among surveys and that large sample sizes may be required to make reliable inferences. Identifying the effects of climate change is a critical area of research in ecology and conservation. Researchers should be aware that observed changes in certain organisms can result from multiple ecological processes or systematic bias due to nonrandom sampling of populations. PMID:25641384

  13. Endoparasites of plethodontid salamanders from Paradise Brook, New Hampshire.

    PubMed

    Muzzall, P M; Peebles, C R; Burton, T M

    1997-12-01

    Totals of 52 dusky salamanders Desmognathus fuscus, 51 two-lined salamanders Eurycea bislineata, 54 red-backed salamanders Plethodon cinereus, and 3 spring salamanders Gyrinophilus porphyriticus (Plethodontidae) collected in June and August 1995 from Paradise Brook, a tributary to Hubbard Brook, New Hampshire, were examined for parasites. Parasites found were Brachycoelium storeriae, Brachycoelium sp., Bothriocephalus rarus, Falcaustra sp., Omeia sp., Batracholandros magnavulvaris, and Cepedietta michiganensis. Eighty-six percent of the red-backed salamanders, a terrestrial species, harbored 1 or more parasites. Among the aquatic and semiaquatic species, 27% of the dusky and 45% of the two-lined salamanders were infected with 1 or more parasites.

  14. Evaluating multi-level models to test occupancy state responses of Plethodontid salamanders

    USGS Publications Warehouse

    Kroll, Andrew J.; Garcia, Tiffany S.; Jones, Jay E.; Dugger, Catherine; Murden, Blake; Johnson, Josh; Peerman, Summer; Brintz, Ben; Rochelle, Michael

    2015-01-01

    Plethodontid salamanders are diverse and widely distributed taxa and play critical roles in ecosystem processes. Due to salamander use of structurally complex habitats, and because only a portion of a population is available for sampling, evaluation of sampling designs and estimators is critical to provide strong inference about Plethodontid ecology and responses to conservation and management activities. We conducted a simulation study to evaluate the effectiveness of multi-scale and hierarchical single-scale occupancy models in the context of a Before-After Control-Impact (BACI) experimental design with multiple levels of sampling. Also, we fit the hierarchical single-scale model to empirical data collected for Oregon slender and Ensatina salamanders across two years on 66 forest stands in the Cascade Range, Oregon, USA. All models were fit within a Bayesian framework. Estimator precision in both models improved with increasing numbers of primary and secondary sampling units, underscoring the potential gains accrued when adding secondary sampling units. Both models showed evidence of estimator bias at low detection probabilities and low sample sizes; this problem was particularly acute for the multi-scale model. Our results suggested that sufficient sample sizes at both the primary and secondary sampling levels could ameliorate this issue. Empirical data indicated Oregon slender salamander occupancy was associated strongly with the amount of coarse woody debris (posterior mean = 0.74; SD = 0.24); Ensatina occupancy was not associated with amount of coarse woody debris (posterior mean = -0.01; SD = 0.29). Our simulation results indicate that either model is suitable for use in an experimental study of Plethodontid salamanders provided that sample sizes are sufficiently large. However, hierarchical single-scale and multi-scale models describe different processes and estimate different parameters. As a result, we recommend careful consideration of study questions

  15. Heterochrony repolarized: a phylogenetic analysis of developmental timing in plethodontid salamanders

    PubMed Central

    2014-01-01

    Background Disentangling evolutionary shifts in developmental timing (heterochony) is dependent upon accurate estimates of ancestral patterns. However, many classic assessments of heterochronic patterns predate robust phylogenetic hypotheses and methods for trait reconstruction, and therefore may have been polarized with untested ‘primitive’ conditions. Here we revisit the heterochronic modes of development that underlie the evolution of metamorphosis, maturation, and paedomorphosis in plethodontid salamanders. We focus on the tribe Spelerpini, which is a diverse clade that exhibits tremendous variation in timing of metamorphosis and maturation, as well as multiple independent instances of larval form paedomorphosis. Based on morphology and biogeography, early investigators concluded that the most recent common ancestors of plethodontids, and also spelerpines, were large salamanders, with very long larval periods and late maturation times. This prevailing assumption influenced subsequent heterochronic assessments, which concluded that most modern spelerpines (with shorter larval periods) were derived through multiple independent accelerations in larval development. It was also concluded that most occurrences of larval form paedomorphosis in this clade resulted from progenesis (acceleration of gonadal development relative to metamorphosis). Results By reconstructing the time to metamorphosis on a molecular-based phylogeny of plethodontids, we find that ancestral spelerpines likely had relatively shorter larval periods than previously proposed. Taken together with the credibility interval from our ancestral state estimation we show that very long larval periods are likely derived decelerations, only a few lineages have undergone appreciable accelerations in metamorphic timing, and the remaining taxa have lower probabilities of being different than the ancestral condition (possibly due to stasis). Reconstructing maturation age across nodes concomitant with the

  16. Rapid evolution of plethodontid modulating factor, a hypervariable salamander courtship pheromone, is driven by positive selection.

    PubMed

    Palmer, Catherine A; Watts, Richard A; Hastings, Amy P; Houck, Lynne D; Arnold, Stevan J

    2010-05-01

    Sexual communication in plethodontid salamanders is mediated by a proteinaceous pheromone that a male delivers to a female during courtship, boosting her receptivity. The pheromone consists of three proteins from three unrelated protein families. These proteins are among a small group of pheromones known to affect female receptivity in vertebrates. Previously, we showed that the genes of two of these proteins (PRF and SPF) are prone to incessant evolution driven by positive selection, presumably as a consequence of coevolution with female receptors. In this report, we focus on the evolution of the third pheromone protein gene family, plethodontid modulating factor (PMF), to determine whether it shows the same pattern of diversification. We used RT-PCR in mental gland cDNA to survey PMF sequences from three genera of plethodontid salamanders (27 spp.) to measure rates of evolution, level of gene diversification, modes of selection, and types of amino acid substitution. Like PRF and SPF, PMF is produced by a multigene family characterized by gene duplication and high levels of polymorphism. PMF evolution is rapid, incessant, and driven by positive selection. PMF is more extreme in these dimensions than both PRF and SPF. Nestled within this extraordinary variation, however, is a signature of purifying selection, acting to preserve important structural and biochemical features of the PMF protein (i.e., secretion signal, cysteine residues, and pI). Although a pattern of persistent diversification exists at the molecular level, the morphological and behavioral aspects of the pheromone delivery system show evolutionary stasis over millions of years.

  17. Rapid evolution of plethodontid modulating factor, a hypervariable salamander courtship pheromone, is driven by positive selection.

    PubMed

    Palmer, Catherine A; Watts, Richard A; Hastings, Amy P; Houck, Lynne D; Arnold, Stevan J

    2010-05-01

    Sexual communication in plethodontid salamanders is mediated by a proteinaceous pheromone that a male delivers to a female during courtship, boosting her receptivity. The pheromone consists of three proteins from three unrelated protein families. These proteins are among a small group of pheromones known to affect female receptivity in vertebrates. Previously, we showed that the genes of two of these proteins (PRF and SPF) are prone to incessant evolution driven by positive selection, presumably as a consequence of coevolution with female receptors. In this report, we focus on the evolution of the third pheromone protein gene family, plethodontid modulating factor (PMF), to determine whether it shows the same pattern of diversification. We used RT-PCR in mental gland cDNA to survey PMF sequences from three genera of plethodontid salamanders (27 spp.) to measure rates of evolution, level of gene diversification, modes of selection, and types of amino acid substitution. Like PRF and SPF, PMF is produced by a multigene family characterized by gene duplication and high levels of polymorphism. PMF evolution is rapid, incessant, and driven by positive selection. PMF is more extreme in these dimensions than both PRF and SPF. Nestled within this extraordinary variation, however, is a signature of purifying selection, acting to preserve important structural and biochemical features of the PMF protein (i.e., secretion signal, cysteine residues, and pI). Although a pattern of persistent diversification exists at the molecular level, the morphological and behavioral aspects of the pheromone delivery system show evolutionary stasis over millions of years. PMID:20407892

  18. Trends in Ranavirus Prevalence Among Plethodontid Salamanders in the Great Smoky Mountains National Park.

    PubMed

    Sutton, William B; Gray, Matthew J; Hoverman, Jason T; Secrist, Richard G; Super, Paul E; Hardman, Rebecca H; Tucker, Jennifer L; Miller, Debra L

    2015-06-01

    Emerging pathogens are a potential contributor to global amphibian declines. Ranaviruses, which infect ectothermic vertebrates and are common in aquatic environments, have been implicated in die-offs of at least 72 amphibian species worldwide. Most studies on the subject have focused on pool-breeding amphibians, and infection trends in other amphibian species assemblages have been understudied. Our primary study objective was to evaluate hypotheses explaining ranavirus prevalence within a lungless salamander assemblage (Family Plethodontidae) in the Great Smoky Mountains National Park, USA. We sampled 566 total plethodontid salamanders representing 14 species at five sites over a 6-year period (2007-2012). We identified ranavirus-positive individuals in 11 of the 14 (78.6%) sampled species, with salamanders in the genus Desmognathus having greatest infection prevalence. Overall, we found the greatest support for site elevation and sampling year determining infection prevalence. We detected the greatest number of infections in 2007 with 82.5% of sampled individuals testing positive for ranavirus, which we attribute to record drought during this year. Infection prevalence remained relatively high in low-elevation sites in 2008 and 2009. Neither body condition nor aquatic dependence was a significant predictor of ranavirus prevalence. Overall, our results indicate that life history differences among species play a minor role determining ranavirus prevalence compared to the larger effects of site elevation and yearly fluctuations (likely due to environmental stressors) during sampling years. PMID:25537630

  19. Trends in Ranavirus Prevalence Among Plethodontid Salamanders in the Great Smoky Mountains National Park.

    PubMed

    Sutton, William B; Gray, Matthew J; Hoverman, Jason T; Secrist, Richard G; Super, Paul E; Hardman, Rebecca H; Tucker, Jennifer L; Miller, Debra L

    2015-06-01

    Emerging pathogens are a potential contributor to global amphibian declines. Ranaviruses, which infect ectothermic vertebrates and are common in aquatic environments, have been implicated in die-offs of at least 72 amphibian species worldwide. Most studies on the subject have focused on pool-breeding amphibians, and infection trends in other amphibian species assemblages have been understudied. Our primary study objective was to evaluate hypotheses explaining ranavirus prevalence within a lungless salamander assemblage (Family Plethodontidae) in the Great Smoky Mountains National Park, USA. We sampled 566 total plethodontid salamanders representing 14 species at five sites over a 6-year period (2007-2012). We identified ranavirus-positive individuals in 11 of the 14 (78.6%) sampled species, with salamanders in the genus Desmognathus having greatest infection prevalence. Overall, we found the greatest support for site elevation and sampling year determining infection prevalence. We detected the greatest number of infections in 2007 with 82.5% of sampled individuals testing positive for ranavirus, which we attribute to record drought during this year. Infection prevalence remained relatively high in low-elevation sites in 2008 and 2009. Neither body condition nor aquatic dependence was a significant predictor of ranavirus prevalence. Overall, our results indicate that life history differences among species play a minor role determining ranavirus prevalence compared to the larger effects of site elevation and yearly fluctuations (likely due to environmental stressors) during sampling years.

  20. Effect of acute low body temperature on predatory behavior and prey-capture efficiency in a plethodontid salamander.

    PubMed

    Marvin, Glenn A; Davis, Kayla; Dawson, Jacob

    2016-05-01

    The low-temperature limit for feeding in some salamander species (Desmognathus, Plethodontidae) has been inferred from field studies of seasonal variation in salamander activity and gut contents, which could not determine whether feeding is more dependent on environmental conditions influencing salamander foraging behavior or prey availability and movement. We performed two controlled laboratory experiments to examine the effect of short-term (acute) low body temperature on predatory behavior and prey-capture efficiency in a semiaquatic plethodontid salamander (Desmognathus conanti). In the first experiment, we quantified variation in the feeding responses of cold salamanders (at 1, 3, 5 and 7°C) to a video recording of a walking, warm (15°C) cricket to determine the lower thermal limit for predatory behavior, independent of any temperature effect on movement of prey. Experimental-group salamanders exhibited vigorous feeding responses at 5 and 7°C, large variation in feeding responses both among and within individuals (over time) at 3°C, and little to no feeding response at 1°C. Feeding responses at both 1 and 3°C were significantly less than at each higher temperature, whereas responses of control-group individuals at 15°C did not vary over time. In the second experiment, we quantified feeding by cold salamanders (at 3, 5, 7 and 11°C) on live, warm crickets to examine thermal effects on prey-capture ability. The mean feeding response to live crickets was significantly less at 3°C than at higher temperatures; however, 50% of salamanders captured and ingested prey with high efficiency at this temperature. We conclude that many individuals stalk and capture prey at very low temperatures (down to 3°C). Our results support a growing body of data that indicate many plethodontid salamanders feed at temperatures only a few degrees above freezing.

  1. Effect of acute low body temperature on predatory behavior and prey-capture efficiency in a plethodontid salamander.

    PubMed

    Marvin, Glenn A; Davis, Kayla; Dawson, Jacob

    2016-05-01

    The low-temperature limit for feeding in some salamander species (Desmognathus, Plethodontidae) has been inferred from field studies of seasonal variation in salamander activity and gut contents, which could not determine whether feeding is more dependent on environmental conditions influencing salamander foraging behavior or prey availability and movement. We performed two controlled laboratory experiments to examine the effect of short-term (acute) low body temperature on predatory behavior and prey-capture efficiency in a semiaquatic plethodontid salamander (Desmognathus conanti). In the first experiment, we quantified variation in the feeding responses of cold salamanders (at 1, 3, 5 and 7°C) to a video recording of a walking, warm (15°C) cricket to determine the lower thermal limit for predatory behavior, independent of any temperature effect on movement of prey. Experimental-group salamanders exhibited vigorous feeding responses at 5 and 7°C, large variation in feeding responses both among and within individuals (over time) at 3°C, and little to no feeding response at 1°C. Feeding responses at both 1 and 3°C were significantly less than at each higher temperature, whereas responses of control-group individuals at 15°C did not vary over time. In the second experiment, we quantified feeding by cold salamanders (at 3, 5, 7 and 11°C) on live, warm crickets to examine thermal effects on prey-capture ability. The mean feeding response to live crickets was significantly less at 3°C than at higher temperatures; however, 50% of salamanders captured and ingested prey with high efficiency at this temperature. We conclude that many individuals stalk and capture prey at very low temperatures (down to 3°C). Our results support a growing body of data that indicate many plethodontid salamanders feed at temperatures only a few degrees above freezing. PMID:26939728

  2. Reduced effects of thyroid hormone on gene expression and metamorphosis in a paedomorphic plethodontid salamander.

    PubMed

    Aran, Robert P; Steffen, Michael A; Martin, Samuel D; Lopez, Olivia I; Bonett, Ronald M

    2014-07-01

    It has been over a century since Gudernatsch (1912, Wilhelm Roux Arch Entwickl Mech Org 35:457-483) demonstrated that mammalian thyroid gland extracts can stimulate tadpole metamorphosis. Despite the tremendous developmental diversity of amphibians, mechanisms of metamorphosis have mostly been studied in a few model systems. This limits our understanding of the processes that influence the evolution of developmental aberrations. Here we isolated thyroid hormone receptors alpha (TRα) and beta (TRβ) from Oklahoma salamanders (Eurycea tynerensis), which exhibit permanently aquatic (paedomorphic) or biphasic (metamorphic) developmental modes in different populations. We found that TRα and TRβ were upregulated by thyroid hormone (T3 ) in tail tissues of larvae from metamorphic populations, but basal levels of TR expression and T3 responsiveness were reduced in larvae from paedomorphic populations. Likewise, we found that T3 treatment resulted in complete loss of larval epibranchials in larvae from metamorphic populations, but little to no epibranchial remodeling occurred in larvae from paedomorphic populations over the same duration. This is the first study to directly demonstrate reduced gene expression and metamorphic responses to T3 in a paedomorphic plethodontid compared to metamorphic conspecifics, and the first salamander system to show differential expression of thyroid hormone receptors associated with alternative developmental patterns.

  3. Three new helminth species from two endemic plethodontid salamanders, Typhlomolge rathbuni and Eurycea nana, in central Texas.

    PubMed

    Moravec, F; Huffman, D G

    2000-01-01

    Helminthological examination of two rare, endemic species of plethodontid salamanders, the Texas blind salamander (Typhlomolge rathbuni Stejneger) and the San Marcos dwarf salamander (Eurycea nana Bishop), from the subterranean waters and springs in San Marcos, Hays County, central Texas, USA revealed the presence of three new, previously undescribed species of intestinal helminths: Brachycoelium longleyi sp. n. (Trematoda) from T. rathbuni (type host) and E. nana, Dendronucleata americana sp. n. (Acanthocephala) from T. rathbuni, and Amphibiocapillaria texensis sp. n. (Nematoda) from T. rathbuni; nematode larvae probably belonging to the last named species were recorded from E. nana. Brachycoelium longleyi can be distinguished from all congeners primarily by its conspicuously small eggs among other features, whereas A. texensis differs from its closest congeneric species A. tritonispiunctati mainly in the structure of mature eggs and a markedly shorter spicule. Dendronucleata americana is the first species of the family Dendronucleatidae from the New World, differing from its Asian congeners mainly in the number and arrangement of proboscis hooks, number of giant hypodermic nuclei and in the position of testes.

  4. Thermal equilibrium and temperature differences among body regions in European plethodontid salamanders.

    PubMed

    Lunghi, Enrico; Manenti, Raoul; Canciani, Giancarlo; Scarì, Giorgio; Pennati, Roberta; Ficetola, Gentile Francesco

    2016-08-01

    Information on species thermal physiology is extremely important to understand species responses to environmental heterogeneity and changes. Thermography is an emerging technology that allows high resolution and accurate measurement of body temperature, but until now it has not been used to study thermal physiology of amphibians in the wild. Hydromantes terrestrial salamanders are strongly depending on ambient temperature for their activity and gas exchanges, but information on their body temperature is extremely limited. In this study we tested if Hydromantes salamanders are thermoconform, we assessed whether there are temperature differences among body regions, and evaluated the time required to reach the thermal equilibrium. During summers of 2014 and 2015 we analysed 56 salamanders (Hydromantes ambrosii and Hydromantes italicus) using infrared thermocamera. We photographed salamanders at the moment in which we found them and 1, 2, 3, 4, 5 and 15min after having kept them in the hands. Body temperature was equal to air temperature; salamanders attained the equilibrium with air temperature in about 8min, the time required to reach equilibrium was longer in individuals with large body size. We detected small temperature differences between body parts, the head being slightly warmer than the body and the tail (mean difference: 0.05°C). These salamanders quickly reach the equilibrium with the environment, thus microhabitat measurement allows obtaining accurate information on their tolerance limits. PMID:27503719

  5. Thermal equilibrium and temperature differences among body regions in European plethodontid salamanders.

    PubMed

    Lunghi, Enrico; Manenti, Raoul; Canciani, Giancarlo; Scarì, Giorgio; Pennati, Roberta; Ficetola, Gentile Francesco

    2016-08-01

    Information on species thermal physiology is extremely important to understand species responses to environmental heterogeneity and changes. Thermography is an emerging technology that allows high resolution and accurate measurement of body temperature, but until now it has not been used to study thermal physiology of amphibians in the wild. Hydromantes terrestrial salamanders are strongly depending on ambient temperature for their activity and gas exchanges, but information on their body temperature is extremely limited. In this study we tested if Hydromantes salamanders are thermoconform, we assessed whether there are temperature differences among body regions, and evaluated the time required to reach the thermal equilibrium. During summers of 2014 and 2015 we analysed 56 salamanders (Hydromantes ambrosii and Hydromantes italicus) using infrared thermocamera. We photographed salamanders at the moment in which we found them and 1, 2, 3, 4, 5 and 15min after having kept them in the hands. Body temperature was equal to air temperature; salamanders attained the equilibrium with air temperature in about 8min, the time required to reach equilibrium was longer in individuals with large body size. We detected small temperature differences between body parts, the head being slightly warmer than the body and the tail (mean difference: 0.05°C). These salamanders quickly reach the equilibrium with the environment, thus microhabitat measurement allows obtaining accurate information on their tolerance limits.

  6. Potential rapid evolution of foot morphology in Italian plethodontid salamanders (Hydromantes strinatii) following the colonization of an artificial cave.

    PubMed

    Salvidio, S; Crovetto, F; Adams, D C

    2015-07-01

    How organisms respond to environmental change is a long-standing question in evolutionary biology. Species invading novel habitats provide an opportunity to examine contemporary evolution in action and decipher the pace of evolutionary change over short timescales. Here, we characterized phenotypic evolution in the Italian plethodontid salamander, Hydromantes strinatii, following the recent colonization of an artificial cave by a forest floor population. When compared with a nearby and genetically related population in the natural forest floor and a nearby cave population, the artificial cave population displayed significant differences in overall foot shape, with more interdigital webbing relative to the other populations. Further, this population evolved significantly larger feet, which corresponded more closely to those found in other cave populations than to forest floor populations to which the cave population is closely related. Finally, we quantified the rate of evolution for both foot shape and foot area, and found that both traits displayed large and significant evolutionary rates, at levels corresponding to other classic cases of rapid evolution in vertebrates. Together, these findings reveal that the response to novel environmental pressures can be large and rapid and that the anatomical shifts observed in the artificial cave population of H. strinatii may represent a case of rapid evolution in response to novel environmental pressures.

  7. Stoichiometry of a semi-aquatic plethodontid salamander: intraspecific variation due to location, size and diet.

    PubMed

    Milanovich, Joseph R; Hopton, Matthew E

    2014-11-01

    Ecological stoichiometry provides a framework to investigate an organism's relationship to nutrient cycles. An organism's stoichiometry is thought to constrain its contribution to nutrient cycles (recycling or storage), and to limit its growth and reproduction. Factors that influence the stoichiometry of a consumer are largely unstudied, but what is known is that consumer stoichiometry is influenced by the elemental requirements of the consumer (e.g. for growth, reproduction and cell maintenance) and the availability of elements. We examined whole-body stoichiometry of larval southern two-lined salamanders (Eurycea cirrigera) and described the influence of location, body size, stoichiometry of diet items, and environmental nutrient supply on whole-body stoichiometry. Mean composition of phosphorous was 2.6%, nitrogen was 11.3%, and carbon was 39.6%, which are similar for other aquatic vertebrate taxa. The most significant predictor of whole-body stoichiometry was the site where the samples were collected, which was significant for each nutrient and nutrient ratio. Body size and stoichiometry of diet items were also predictors of Eurycea cirrigera stoichiometry. Our study suggests that spatial differences in environmental nutrient supply have a stronger influence on consumer whole-body stoichiometry among similar-sized larvae compared to life history traits, such as body size or diet.

  8. Larval masquerade: a new species of paedomorphic salamander (Caudata: Plethodontidae: Eurycea) from the Ouachita Mountains of North America.

    PubMed

    Steffen, Michael A; Irwin, Kelly J; Blair, Andrea L; Bonett, Ronald M

    2014-04-11

    Species with truncated developmental patterns may go undetected if they resemble the juveniles of their close relatives. Herein we present an example of this phenomenon with the description of a highly divergent, relict species of stream-dwelling plethodontid salamander from the Ouachita Mountains of North America. Both mitochondrial and nuclear sequence data show that this new species is most closely related to its syntopic relative, Eurycea multiplicata. Interestingly, E. multiplicata exhibits the ancestral biphasic (metamorphic) life cycle, whereas the new species maintains an aquatic larval form throughout life (paedomorphic) and superficially resembles larval E. multiplicata. The new species is the first known paedomorphic plethodontid from the Ouachita Mountains, and the most divergent paedomorphic salamander discovered in over seventy years. This species represents an independent instance of the evolution of paedomorphosis associated with a porous streambed, which may facilitate vertical seasonal movements. This new species currently has an extremely limited known distribution and is of immediate conservation concern.

  9. Larval masquerade: a new species of paedomorphic salamander (Caudata: Plethodontidae: Eurycea) from the Ouachita Mountains of North America.

    PubMed

    Steffen, Michael A; Irwin, Kelly J; Blair, Andrea L; Bonett, Ronald M

    2014-01-01

    Species with truncated developmental patterns may go undetected if they resemble the juveniles of their close relatives. Herein we present an example of this phenomenon with the description of a highly divergent, relict species of stream-dwelling plethodontid salamander from the Ouachita Mountains of North America. Both mitochondrial and nuclear sequence data show that this new species is most closely related to its syntopic relative, Eurycea multiplicata. Interestingly, E. multiplicata exhibits the ancestral biphasic (metamorphic) life cycle, whereas the new species maintains an aquatic larval form throughout life (paedomorphic) and superficially resembles larval E. multiplicata. The new species is the first known paedomorphic plethodontid from the Ouachita Mountains, and the most divergent paedomorphic salamander discovered in over seventy years. This species represents an independent instance of the evolution of paedomorphosis associated with a porous streambed, which may facilitate vertical seasonal movements. This new species currently has an extremely limited known distribution and is of immediate conservation concern. PMID:24869544

  10. Conflicting patterns of genetic structure produced by nuclear and mitochondrial markers in the Oregon Slender Salamander (Batrachoseps wrighti): implications for conservation efforts and species management

    USGS Publications Warehouse

    Miller, Mark; Haig, Susan M.; Wagner, R.S.

    2005-01-01

    Endemic to Oregon in the northwestern US, the Oregon slender salamander (Batrachoseps wrighti) is a terrestrial plethodontid found associated with late successional mesic forests. Consequently, forest management practices such as timber harvesting may impact their persistence. Therefore, to infer possible future effects of these practices on population structure and differentiation, we used mitochondrial DNA sequences (cytochrome b) and RAPD markers to analyze 22 populations across their range. Phylogenetic analyses of sequence data (774 bp) revealed two historical lineages corresponding to northern and southern-distributed populations. Relationships among haplotypes and haplotype diversity within lineages suggested that the northern region may have more recently been colonized compared to the southern region. In contrast to the mitochondrial data, analyses of 46 RAPD loci suggested an overall pattern of isolation-by-distance in the set of populations examined and no particularly strong clustering of populations based on genetic distances. We propose two non-exclusive hypotheses to account for discrepancies between mitochondrial and nuclear data sets. First, our data may reflect an overall ancestral pattern of isolation-by-distance that has subsequently been influenced by vicariance. Alternately, our analyses may suggest that male-mediated gene flow and female philopatry are important contributors to the pattern of genetic diversity. We discuss the importance of distinguishing between these two hypotheses for the purposes of identifying conservation units and note that, regardless of the relative contribution of each mechanism towards the observed pattern of diversity, protection of habitat will likely prove critical for the long-term persistence of this species.

  11. Complete nucleotide sequence of the mitochondrial genome of a salamander, Mertensiella luschani.

    PubMed

    Zardoya, Rafael; Malaga-Trillo, Edward; Veith, Michael; Meyer, Axel

    2003-10-23

    The complete nucleotide sequence (16,650 bp) of the mitochondrial genome of the salamander Mertensiella luschani (Caudata, Amphibia) was determined. This molecule conforms to the consensus vertebrate mitochondrial gene order. However, it is characterized by a long non-coding intervening sequence with two 124-bp repeats between the tRNA(Thr) and tRNA(Pro) genes. The new sequence data were used to reconstruct a phylogeny of jawed vertebrates. Phylogenetic analyses of all mitochondrial protein-coding genes at the amino acid level recovered a robust vertebrate tree in which lungfishes are the closest living relatives of tetrapods, salamanders and frogs are grouped together to the exclusion of caecilians (the Batrachia hypothesis) in a monophyletic amphibian clade, turtles show diapsid affinities and are placed as sister group of crocodiles+birds, and the marsupials are grouped together with monotremes and basal to placental mammals. The deduced phylogeny was used to characterize the molecular evolution of vertebrate mitochondrial proteins. Amino acid frequencies were analyzed across the main lineages of jawed vertebrates, and leucine and cysteine were found to be the most and least abundant amino acids in mitochondrial proteins, respectively. Patterns of amino acid replacements were conserved among vertebrates. Overall, cartilaginous fishes showed the least variation in amino acid frequencies and replacements. Constancy of rates of evolution among the main lineages of jawed vertebrates was rejected.

  12. Complete nucleotide sequence of the mitochondrial genome of a salamander, Mertensiella luschani.

    PubMed

    Zardoya, Rafael; Malaga-Trillo, Edward; Veith, Michael; Meyer, Axel

    2003-10-23

    The complete nucleotide sequence (16,650 bp) of the mitochondrial genome of the salamander Mertensiella luschani (Caudata, Amphibia) was determined. This molecule conforms to the consensus vertebrate mitochondrial gene order. However, it is characterized by a long non-coding intervening sequence with two 124-bp repeats between the tRNA(Thr) and tRNA(Pro) genes. The new sequence data were used to reconstruct a phylogeny of jawed vertebrates. Phylogenetic analyses of all mitochondrial protein-coding genes at the amino acid level recovered a robust vertebrate tree in which lungfishes are the closest living relatives of tetrapods, salamanders and frogs are grouped together to the exclusion of caecilians (the Batrachia hypothesis) in a monophyletic amphibian clade, turtles show diapsid affinities and are placed as sister group of crocodiles+birds, and the marsupials are grouped together with monotremes and basal to placental mammals. The deduced phylogeny was used to characterize the molecular evolution of vertebrate mitochondrial proteins. Amino acid frequencies were analyzed across the main lineages of jawed vertebrates, and leucine and cysteine were found to be the most and least abundant amino acids in mitochondrial proteins, respectively. Patterns of amino acid replacements were conserved among vertebrates. Overall, cartilaginous fishes showed the least variation in amino acid frequencies and replacements. Constancy of rates of evolution among the main lineages of jawed vertebrates was rejected. PMID:14604788

  13. Phylogeny and genetic history of the Siberian salamander (Salamandrella keyserlingii, Dybowski, 1870) inferred from complete mitochondrial genomes.

    PubMed

    Malyarchuk, Boris; Derenko, Miroslava; Denisova, Galina

    2013-05-01

    We assessed phylogeny of the Siberian salamander (Salamandrella keyserlingii, Dybowski, 1870), the most northern ectothermic, terrestrial vertebrate in Eurasia, by sequence analysis of complete mitochondrial genomes in 26 specimens from different localities (China, Khabarovsk region, Sakhalin, Yakutia, Magadan region, Chukotka, Kamchatka, Ural, European part of Russia). In addition, a complete mitochondrial genome of the Schrenck salamander, Salamandrella schrenckii, was determined for the first time. Bayesian phylogenetic analysis of the entire mtDNA genomes of S. keyserlingii demonstrates that two haplotype clades, AB and C, radiated about 1.4 million years ago (Mya). Bayesian skyline plots of population size change through time show an expansion around 250 thousand years ago (kya) and then a decline around the Last Glacial Maximum (25 kya) with subsequent restoration of population size. Climatic changes during the Quaternary period have dramatically affected the population genetic structure of the Siberian salamanders. In addition, complete mtDNA sequence analysis allowed us to recognize that the vast area of Northern Eurasia was colonized only by the Siberian salamander clade C1b during the last 150 kya. Meanwhile, we were unable to find evidence of molecular adaptation in this clade by analyzing the whole mitochondrial genomes of the Siberian salamanders.

  14. Phylogeny and genetic history of the Siberian salamander (Salamandrella keyserlingii, Dybowski, 1870) inferred from complete mitochondrial genomes.

    PubMed

    Malyarchuk, Boris; Derenko, Miroslava; Denisova, Galina

    2013-05-01

    We assessed phylogeny of the Siberian salamander (Salamandrella keyserlingii, Dybowski, 1870), the most northern ectothermic, terrestrial vertebrate in Eurasia, by sequence analysis of complete mitochondrial genomes in 26 specimens from different localities (China, Khabarovsk region, Sakhalin, Yakutia, Magadan region, Chukotka, Kamchatka, Ural, European part of Russia). In addition, a complete mitochondrial genome of the Schrenck salamander, Salamandrella schrenckii, was determined for the first time. Bayesian phylogenetic analysis of the entire mtDNA genomes of S. keyserlingii demonstrates that two haplotype clades, AB and C, radiated about 1.4 million years ago (Mya). Bayesian skyline plots of population size change through time show an expansion around 250 thousand years ago (kya) and then a decline around the Last Glacial Maximum (25 kya) with subsequent restoration of population size. Climatic changes during the Quaternary period have dramatically affected the population genetic structure of the Siberian salamanders. In addition, complete mtDNA sequence analysis allowed us to recognize that the vast area of Northern Eurasia was colonized only by the Siberian salamander clade C1b during the last 150 kya. Meanwhile, we were unable to find evidence of molecular adaptation in this clade by analyzing the whole mitochondrial genomes of the Siberian salamanders. PMID:23415986

  15. [Episodes of adaptive evolution of mitochondrial genome in Asiatic salamanders (Amphibia, Caudata, Hynobiidae)].

    PubMed

    Maliarchuk, B A; Derenko, M V; Denisova, G A

    2014-02-01

    To elucidate the effect of natural selection on the evolution of mitochondrial DNA (mtDNA) in Asiatic salamanders of the family Hynobiidae, nucleotide sequences of 12 protein-coding genes were analyzed. Using a mixed effects model of evolution, it was found that, in spite of the pronounced effect of negative selection on the mtDNA evolution in Hynobiidae (which is typical for the animals in general), two phylogenetic clusters, the West Asian one, represented by the genera Ranodon and Paradactylodon, and North Eurasian one, represented by the genus Salamandrella, were formed under the influence of episodic positive selection. Analysis of protein sequences encoded by the mitochondrial genome also supported the influence of positive selection on the evolution of Hynobiidae at some stages of their cladogenesis. It is suggested that the signatures of adaptive evolution detected in the mtDNA of Hynobiidae were determined by the complex and long-lasting history of their formation, accompanied by adaptation to the changing environment. PMID:25711027

  16. Ecological radiation with limited morphological diversification in salamanders.

    PubMed

    Blankers, Thomas; Adams, D C; Wiens, J J

    2012-04-01

    A major goal of evolutionary biology is to explain morphological diversity among species. Many studies suggest that much morphological variation is explained by adaptation to different microhabitats. Here, we test whether morphology and microhabitat use are related in plethodontid salamanders, which contain the majority of salamander species, and have radiated into a striking diversity of microhabitats. We obtained microhabitat data for 189 species that also had both morphometric and phylogenetic data. We then tested for associations between morphology and microhabitat categories using phylogenetic comparative methods. Associations between morphology and ecology in plethodontids are largely confined to a single clade within one subfamily (Bolitoglossinae), whereas variation in morphology across other plethodontids is unrelated to microhabitat categories. These results demonstrate that ecological radiation and morphological evolution can be largely decoupled in a major clade. The results also offer a striking contrast to lizards, which typically show close relationships between morphology and microhabitat.

  17. Ecological radiation with limited morphological diversification in salamanders.

    PubMed

    Blankers, Thomas; Adams, D C; Wiens, J J

    2012-04-01

    A major goal of evolutionary biology is to explain morphological diversity among species. Many studies suggest that much morphological variation is explained by adaptation to different microhabitats. Here, we test whether morphology and microhabitat use are related in plethodontid salamanders, which contain the majority of salamander species, and have radiated into a striking diversity of microhabitats. We obtained microhabitat data for 189 species that also had both morphometric and phylogenetic data. We then tested for associations between morphology and microhabitat categories using phylogenetic comparative methods. Associations between morphology and ecology in plethodontids are largely confined to a single clade within one subfamily (Bolitoglossinae), whereas variation in morphology across other plethodontids is unrelated to microhabitat categories. These results demonstrate that ecological radiation and morphological evolution can be largely decoupled in a major clade. The results also offer a striking contrast to lizards, which typically show close relationships between morphology and microhabitat. PMID:22268991

  18. Nuclear and mitochondrial multilocus phylogeny and survey of alkaloid content in true salamanders of the genus Salamandra (Salamandridae).

    PubMed

    Vences, Miguel; Sanchez, Eugenia; Hauswaldt, J Susanne; Eikelmann, Daniel; Rodríguez, Ariel; Carranza, Salvador; Donaire, David; Gehara, Marcelo; Helfer, Véronique; Lötters, Stefan; Werner, Philine; Schulz, Stefan; Steinfartz, Sebastian

    2014-04-01

    The genus Salamandra represents a clade of six species of Palearctic salamanders of either contrasted black-yellow, or uniformly black coloration, known to contain steroidal alkaloid toxins in high concentrations in their skin secretions. This study reconstructs the phylogeny of the genus Salamandra based on DNA sequences of segments of 10 mitochondrial and 13 nuclear genes from 31 individual samples representing all Salamandra species and most of the commonly recognized subspecies. The concatenated analysis of the complete dataset produced a fully resolved tree with most nodes strongly supported, suggesting that a clade composed of the Alpine salamander (S. atra) and the Corsican fire salamander (S. corsica) is the sister taxon to a clade containing the remaining species, among which S. algira and S. salamandra are sister species. Separate analyses of mitochondrial and nuclear data partitions disagreed regarding basal nodes and in the position of the root but concordantly recovered the S. atra/S. corsica as well as the S. salamandra/S. algira relationship. A species-tree analysis suggested almost simultaneous temporal splits between these pairs of species, which we hypothesize was caused by vicariance events after the Messinian salinity crisis (from late Miocene to early Pliocene). A survey of toxins with combined gas chromatography/mass spectroscopy confirmed the presence of samandarine and/or samandarone steroidal alkaloids in all species of Salamandra as well as in representatives of their sister group, Lyciasalamandra. Samandarone was also detected in lower concentrations in other salamandrids including Calotriton, Euproctus, Lissotriton, and Triturus, suggesting that the presence and possible biosynthesis of this alkaloid is plesiomorphic within the Salamandridae.

  19. Detecting cryptic species in phylogeographic studies: speciation in the California Slender Salamander, Batrachoseps attenuatus.

    PubMed

    Highton, Richard

    2014-02-01

    A study of DNA sequence variation in the plethodontid salamander Batrachoseps attenuatus by Martínez-Solano et al. (2007) revealed more species than acknowledged by the authors. They sequenced 677 base pairs of the cytochrome-b mitochondrial gene in 178 individuals from 123 populations of the currently recognized species B. attenuatus from throughout most of its known range in southwestern Oregon and northern and central California. Their data show that the common ancestor of the species diverged into five clades during the late Miocene Epoch, an estimated 9.2-5.5 mya, with subsequent divergences producing at least 39 living lineages that replace each other geographically. These groups have been diverging independently from each other throughout the Pleistocene Epoch and many of them have probably reached the species level of divergence.

  20. Spatial variation in water loss predicts terrestrial salamander distribution and population dynamics.

    PubMed

    Peterman, W E; Semlitsch, R D

    2014-10-01

    Many patterns observed in ecology, such as species richness, life history variation, habitat use, and distribution, have physiological underpinnings. For many ectothermic organisms, temperature relationships shape these patterns, but for terrestrial amphibians, water balance may supersede temperature as the most critical physiologically limiting factor. Many amphibian species have little resistance to water loss, which restricts them to moist microhabitats, and may significantly affect foraging, dispersal, and courtship. Using plaster models as surrogates for terrestrial plethodontid salamanders (Plethodon albagula), we measured water loss under ecologically relevant field conditions to estimate the duration of surface activity time across the landscape. Surface activity time was significantly affected by topography, solar exposure, canopy cover, maximum air temperature, and time since rain. Spatially, surface activity times were highest in ravine habitats and lowest on ridges. Surface activity time was a significant predictor of salamander abundance, as well as a predictor of successful recruitment; the probability of a juvenile salamander occupying an area with high surface activity time was two times greater than an area with limited predicted surface activity. Our results suggest that survival, recruitment, or both are demographic processes that are affected by water loss and the ability of salamanders to be surface-active. Results from our study extend our understanding of plethodontid salamander ecology, emphasize the limitations imposed by their unique physiology, and highlight the importance of water loss to spatial population dynamics. These findings are timely for understanding the effects that fluctuating temperature and moisture conditions predicted for future climates will have on plethodontid salamanders.

  1. Enlarged Multilocus Data set Provides Surprisingly Younger Time of Origin for the Plethodontidae, the Largest Family of Salamanders.

    PubMed

    Shen, Xing-Xing; Liang, Dan; Chen, Meng-Yun; Mao, Rong-Li; Wake, David B; Zhang, Peng

    2016-01-01

    Deep phylogenetic relationships of the largest salamander family Plethodontidae have been difficult to resolve, probably reflecting a rapid diversification early in their evolutionary history. Here, data from 50 independent nuclear markers (total 48,582 bp) are used to reconstruct the phylogeny and divergence times for plethodontid salamanders, using both concatenation and coalescence-based species tree analyses. Our results robustly resolve the position of the enigmatic eastern North American four-toed salamander (Hemidactylium) as the sister taxon of Batrachoseps + Tribe Bolitoglossini, thus settling a long-standing question. Furthermore, we statistically reject sister taxon status of Karsenia and Hydromantes, the only plethodontids to occur outside the Americas, leading us to new biogeographic hypotheses. Contrary to previous long-standing arguments that plethodontid salamanders are an old lineage originating in the Cretaceous (more than 90 Ma), our analyses lead to the hypothesis that these salamanders are much younger, arising close to the K-T boundary (~66 Ma). These time estimates are highly stable using alternative calibration schemes and dating methods. Our data simulation highlights the potential risk of making strong arguments about phylogenetic timing based on inferences from a handful of nuclear genes, a common practice. Based on the newly obtained timetree and ancestral area reconstruction results, we argue that (i) the classic "Out of Appalachia" hypothesis of plethodontid origins is problematic; (ii) the common ancestor of extant plethodontids may have originated in northwestern North America in the early Paleocene; (iii) origins of Eurasian plethodontids likely result from two separate dispersal events from western North America via Beringia in the late Eocene (~42 Ma) and the early Miocene (~23 Ma), respectively. PMID:26385618

  2. Gene lineages and eastern North American palaeodrainage basins: phylogeography and speciation in salamanders of the Eurycea bislineata species complex.

    PubMed

    Kozak, Kenneth H; Blaine, Russell A; Larson, Allan

    2006-01-01

    Contemporary North American drainage basins are composites of formerly isolated drainages, suggesting that fragmentation and fusion of palaeodrainage systems may have been an important factor generating current patterns of genetic and species diversity in stream-associated organisms. Here, we combine traditional molecular-phylogenetic, multiple-regression, nested clade, and molecular-demographic analyses to investigate the relationship between phylogeographic variation and the hydrogeological history of eastern North American drainage basins in semiaquatic plethodontid salamanders of the Eurycea bislineata species complex. Four hundred forty-two sequences representing 1108 aligned bases from the mitochondrial genome are reported for the five formally recognized species of the E. bislineata complex and three outgroup taxa. Within the in-group, 270 haplotypes are recovered from 144 sampling locations. Geographic patterns of mtDNA-haplotype coalescence identify 13 putatively independent population-level lineages, suggesting that the current taxonomy of the group underestimates species-level diversity. Spatial and temporal patterns of phylogeographic divergence are strongly associated with historical rather than modern drainage connections, indicating that shifts in major drainage patterns played a pivotal role in the allopatric fragmentation of populations and build-up of lineage diversity in these stream-associated salamanders. More generally, our molecular genetic results corroborate geological and faunistic evidence suggesting that palaeodrainage connections altered by glacial advances and headwater erosion occurring between the mid-Miocene and Pleistocene epochs explain regional patterns of biodiversity in eastern North American streams.

  3. Hellbender genome sequences shed light on genomic expansion at the base of crown salamanders.

    PubMed

    Sun, Cheng; Mueller, Rachel Lockridge

    2014-07-01

    Among animals, genome sizes range from 20 Mb to 130 Gb, with 380-fold variation across vertebrates. Most of the largest vertebrate genomes are found in salamanders, an amphibian clade of 660 species. Thus, salamanders are an important system for studying causes and consequences of genomic gigantism. Previously, we showed that plethodontid salamander genomes accumulate higher levels of long terminal repeat (LTR) retrotransposons than do other vertebrates, although the evolutionary origins of such sequences remained unexplored. We also showed that some salamanders in the family Plethodontidae have relatively slow rates of DNA loss through small insertions and deletions. Here, we present new data from Cryptobranchus alleganiensis, the hellbender. Cryptobranchus and Plethodontidae span the basal phylogenetic split within salamanders; thus, analyses incorporating these taxa can shed light on the genome of the ancestral crown salamander lineage, which underwent expansion. We show that high levels of LTR retrotransposons likely characterize all crown salamanders, suggesting that disproportionate expansion of this transposable element (TE) class contributed to genomic expansion. Phylogenetic and age distribution analyses of salamander LTR retrotransposons indicate that salamanders' high TE levels reflect persistence and diversification of ancestral TEs rather than horizontal transfer events. Finally, we show that relatively slow DNA loss rates through small indels likely characterize all crown salamanders, suggesting that a decreased DNA loss rate contributed to genomic expansion at the clade's base. Our identification of shared genomic features across phylogenetically distant salamanders is a first step toward identifying the evolutionary processes underlying accumulation and persistence of high levels of repetitive sequence in salamander genomes. PMID:25115007

  4. Separating Population Structure from Population History: A Cladistic Analysis of the Geographical Distribution of Mitochondrial DNA Haplotypes in the Tiger Salamander, Ambystoma Tigrinum

    PubMed Central

    Templeton, A. R.; Routman, E.; Phillips, C. A.

    1995-01-01

    Nonrandom associations of alleles or haplotypes with geographical location can arise from restricted gene flow, historical events (fragmentation, range expansion, colonization), or any mixture of these factors. In this paper, we show how a nested cladistic analysis of geographical distances can be used to test the null hypothesis of no geographical association of haplotypes, test the hypothesis that significant associations are due to restricted gene flow, and identify patterns of significant association that are due to historical events. In this last case, criteria are given to discriminate among contiguous range expansion, long-distance colonization, and population fragmentation. The ability to make these discriminations depends critically upon an adequate geographical sampling design. These points are illustrated with a worked example: mitochondrial DNA haplotypes in the salamander Ambystoma tigrinum. For this example, prior information exists about restricted gene flow and likely historical events, and the nested cladistic analyses were completely concordant with this prior information. This concordance establishes the plausibility of this nested cladistic approach, but much future work will be necessary to demonstrate robustness and to explore the power and accuracy of this procedure. PMID:7498753

  5. Hellbender Genome Sequences Shed Light on Genomic Expansion at the Base of Crown Salamanders

    PubMed Central

    Sun, Cheng; Mueller, Rachel Lockridge

    2014-01-01

    Among animals, genome sizes range from 20 Mb to 130 Gb, with 380-fold variation across vertebrates. Most of the largest vertebrate genomes are found in salamanders, an amphibian clade of 660 species. Thus, salamanders are an important system for studying causes and consequences of genomic gigantism. Previously, we showed that plethodontid salamander genomes accumulate higher levels of long terminal repeat (LTR) retrotransposons than do other vertebrates, although the evolutionary origins of such sequences remained unexplored. We also showed that some salamanders in the family Plethodontidae have relatively slow rates of DNA loss through small insertions and deletions. Here, we present new data from Cryptobranchus alleganiensis, the hellbender. Cryptobranchus and Plethodontidae span the basal phylogenetic split within salamanders; thus, analyses incorporating these taxa can shed light on the genome of the ancestral crown salamander lineage, which underwent expansion. We show that high levels of LTR retrotransposons likely characterize all crown salamanders, suggesting that disproportionate expansion of this transposable element (TE) class contributed to genomic expansion. Phylogenetic and age distribution analyses of salamander LTR retrotransposons indicate that salamanders’ high TE levels reflect persistence and diversification of ancestral TEs rather than horizontal transfer events. Finally, we show that relatively slow DNA loss rates through small indels likely characterize all crown salamanders, suggesting that a decreased DNA loss rate contributed to genomic expansion at the clade’s base. Our identification of shared genomic features across phylogenetically distant salamanders is a first step toward identifying the evolutionary processes underlying accumulation and persistence of high levels of repetitive sequence in salamander genomes. PMID:25115007

  6. Context-dependent movement behavior of woodland salamanders (Plethodon) in two habitat types.

    PubMed

    Connette, Grant M; Semlitsch, Raymond D

    2013-12-01

    Animal movement is critical to the maintenance of functional connectivity at the landscape scale and can play a key role in population persistence and metapopulation dynamics. The permeability of habitat to animal movement may vary as a result of either differential mortality, physical resistance, or simply the behavioral responses of organisms to perceived habitat quality. Understanding how and when animal movement behavior varies among habitat types is critical for identifying barriers to dispersal and predicting species distributions in relation to landscape features. We conducted an experimental translocation study and compared the movement success and behavioral strategies of plethodontid salamanders in both forest and open-canopy habitat. We found that individuals in closed-canopy forest oriented more strongly towards their home ranges and moved significantly farther on their release night. In spite of the clear differences in movement paths, the ultimate movement success of homing salamanders did not appear to vary with habitat type. Our study contributes to a growing body of literature suggesting the importance of recognizing the context dependence of animal movement behavior. Because the movement rates of displaced salamanders were significantly reduced in open-canopy, dispersal rates of plethodontid salamanders in open-canopy habitat are likely lower than in control forest. Further mechanistic studies focusing on habitat-specific movement behavior and survival costs will be valuable for effectively identifying and mitigating barriers to animal movement.

  7. Do larval traits re-evolve? Evidence from the embryogenesis of a direct-developing salamander, Plethodon cinereus.

    PubMed

    Kerney, Ryan R; Blackburn, David C; Müller, Hendrik; Hanken, James

    2012-01-01

    Recent molecular phylogenies suggest the surprising reacquisition of posthatching metamorphosis within an otherwise direct-developing clade of lungless salamanders (family Plethodontidae). Metamorphosis was long regarded as plesiomorphic for plethodontids, yet the genus Desmognathus, which primarily includes metamorphosing species, is now nested within a much larger clade of direct-developing species. The extent to which the putative reacquisition of metamorphosis in Desmognathus represents a true evolutionary reversal is contingent upon the extent to which both larva-specific features and metamorphosis were actually lost during the evolution of direct development. In this study we analyze development of the hyobranchial skeleton, which is dramatically remodeled during salamander metamorphosis, in the direct-developing red-backed salamander, Plethodon cinereus. We find dramatic remodeling of the hyobranchial skeleton during embryogenesis in P. cinereus and the transient appearance of larva-specific cartilages. Hyobranchial development in this direct-developing plethodontid is highly similar to that in metamorphosing plethodontids (e.g., Desmognathus). The proposed reacquisition of hyobranchial metamorphosis within Desmognathus does not represent the "re-evolution" of a lost phenotype, but instead the elaboration of an existing developmental sequence.

  8. Phylogeography and evolution of the Red Salamander (Pseudotriton ruber).

    PubMed

    Folt, Brian; Garrison, Nicole; Guyer, Craig; Rodriguez, Juanita; Bond, Jason E

    2016-05-01

    Phylogeographic studies frequently result in the elevation of subspecific taxa to species given monophyly, or the synonymy of subspecies that are not monophyletic. However, given limited or incongruent datasets, retention of subspecies can be useful to describe hypothesized incipient species or to illustrate interesting biological phenomena driving morphological diversity. Four subspecific taxa have been used to describe largely allopatric geographic variation within the species Pseudotriton ruber, a plethodontid salamander occupying stream and spring habitats across eastern North America: P. r. vioscai occurs in lowland Coastal Plain habitats, while P. r. ruber, P. r. nitidus, and P. r. schencki occupy upland regions in and around the Appalachian Mountains. Pseudotriton ruber co-occurs through its distribution with the aposematic newt Notophthalmus viridescens, and both species are hypothesized to be part of a Müllerian mimicry complex. In this study, we sequenced regions of two mitochondrial (cytochrome b, NADH dehydrogenase subunit 2) and one single copy nuclear protein-coding gene (pro-opiomelanocortin) from individuals sampled across much of the distribution of P. ruber and then used maximum-likelihood and Bayesian phylogenetic inference to test the monophyly of subspecies, reconstruct biogeographic history, and make inferences about morphological evolution. Phylogeographic hypotheses from mitochondrial and nuclear datasets described structure among populations of P. ruber which separated Coastal Plain and upland Appalachian populations, but subspecies were not monophyletic. Biogeographic reconstruction estimated the ancestor of all populations to have occupied and initially diverged in the Coastal Plain during the Pliocene (∼3.6mya), before one lineage subsequently invaded upland areas of Appalachia. Bold bright coloration of high elevation subspecies P. r. nitidus and P. r. schencki appears to have evolved twice. We hypothesize that the Müllerian mimicry

  9. Phylogeography and evolution of the Red Salamander (Pseudotriton ruber).

    PubMed

    Folt, Brian; Garrison, Nicole; Guyer, Craig; Rodriguez, Juanita; Bond, Jason E

    2016-05-01

    Phylogeographic studies frequently result in the elevation of subspecific taxa to species given monophyly, or the synonymy of subspecies that are not monophyletic. However, given limited or incongruent datasets, retention of subspecies can be useful to describe hypothesized incipient species or to illustrate interesting biological phenomena driving morphological diversity. Four subspecific taxa have been used to describe largely allopatric geographic variation within the species Pseudotriton ruber, a plethodontid salamander occupying stream and spring habitats across eastern North America: P. r. vioscai occurs in lowland Coastal Plain habitats, while P. r. ruber, P. r. nitidus, and P. r. schencki occupy upland regions in and around the Appalachian Mountains. Pseudotriton ruber co-occurs through its distribution with the aposematic newt Notophthalmus viridescens, and both species are hypothesized to be part of a Müllerian mimicry complex. In this study, we sequenced regions of two mitochondrial (cytochrome b, NADH dehydrogenase subunit 2) and one single copy nuclear protein-coding gene (pro-opiomelanocortin) from individuals sampled across much of the distribution of P. ruber and then used maximum-likelihood and Bayesian phylogenetic inference to test the monophyly of subspecies, reconstruct biogeographic history, and make inferences about morphological evolution. Phylogeographic hypotheses from mitochondrial and nuclear datasets described structure among populations of P. ruber which separated Coastal Plain and upland Appalachian populations, but subspecies were not monophyletic. Biogeographic reconstruction estimated the ancestor of all populations to have occupied and initially diverged in the Coastal Plain during the Pliocene (∼3.6mya), before one lineage subsequently invaded upland areas of Appalachia. Bold bright coloration of high elevation subspecies P. r. nitidus and P. r. schencki appears to have evolved twice. We hypothesize that the Müllerian mimicry

  10. What are the consequences of combining nuclear and mitochondrial data for phylogenetic analysis? Lessons from Plethodon salamanders and 13 other vertebrate clades

    PubMed Central

    2011-01-01

    Background The use of mitochondrial DNA data in phylogenetics is controversial, yet studies that combine mitochondrial and nuclear DNA data (mtDNA and nucDNA) to estimate phylogeny are common, especially in vertebrates. Surprisingly, the consequences of combining these data types are largely unexplored, and many fundamental questions remain unaddressed in the literature. For example, how much do trees from mtDNA and nucDNA differ? How are topological conflicts between these data types typically resolved in the combined-data tree? What determines whether a node will be resolved in favor of mtDNA or nucDNA, and are there any generalities that can be made regarding resolution of mtDNA-nucDNA conflicts in combined-data trees? Here, we address these and related questions using new and published nucDNA and mtDNA data for Plethodon salamanders and published data from 13 other vertebrate clades (including fish, frogs, lizards, birds, turtles, and mammals). Results We find widespread discordance between trees from mtDNA and nucDNA (30-70% of nodes disagree per clade), but this discordance is typically not strongly supported. Despite often having larger numbers of variable characters, mtDNA data do not typically dominate combined-data analyses, and combined-data trees often share more nodes with trees from nucDNA alone. There is no relationship between the proportion of nodes shared between combined-data and mtDNA trees and relative numbers of variable characters or levels of homoplasy in the mtDNA and nucDNA data sets. Congruence between trees from mtDNA and nucDNA is higher on branches that are longer and deeper in the combined-data tree, but whether a conflicting node will be resolved in favor mtDNA or nucDNA is unrelated to branch length. Conflicts that are resolved in favor of nucDNA tend to occur at deeper nodes in the combined-data tree. In contrast to these overall trends, we find that Plethodon have an unusually large number of strongly supported conflicts between

  11. Dramatic declines in neotropical salamander populations are an important part of the global amphibian crisis

    PubMed Central

    Rovito, Sean M.; Parra-Olea, Gabriela; Vásquez-Almazán, Carlos R.; Papenfuss, Theodore J.; Wake, David B.

    2009-01-01

    We document major declines of many species of salamanders at several sites in Central America and Mexico, with emphasis on the San Marcos region of Guatemala, one of the best studied and most diverse salamander communities in the Neotropics. Profound declines of several formerly abundant species, including 2 apparent extinctions, are revealed. Terrestrial microhabitat specialists at mid- to high elevations have declined more than microhabitat generalists. These terrestrial microhabitat specialists have largely disappeared from multiple sites in western Guatemala, including in well-protected areas, suggesting that the phenomenon cannot be explained solely by localized habitat destruction. Major declines in southern Mexican plethodontid salamanders occurred in the late 1970s to early 1980s, concurrent with or preceding many reported frog declines. The species in decline comprise several major evolutionary lineages of tropical salamanders, underscoring that significant portions of the phylogenetic diversity of Neotropical salamanders are at risk. Our results highlight the urgent need to document and understand Neotropical salamander declines as part of the larger effort to conserve global amphibian diversity. PMID:19204286

  12. A re-examination and re-evaluation of salamander orbital glands.

    PubMed

    Rehorek, Susan J; Grand-Pierre, Alix E; Cummings, Joshua R; Jewell, Bridgette; Constantine, Julieanne; Hillenius, W Jaap

    2013-11-01

    The amphibian integument contains numerous multicellular glands. Although two of these, the nasolabial and orbital glands and the associated nasolacrimal duct (NLD), have historically received considerable attention, interpretation of the original observations can be problematic in the context of current literature. Salamanders, in particular, are frequently regarded as at least indicative of aspects of the morphology of the common ancestor to all extant tetrapods; hence, an understanding of these glands in salamanders might prove to be informative about their evolution. For this study, the orbitonasal region of salamanders from three families was histologically examined. Three themes emerged: (1) examination of the effect of phylogeny on the nasolabial gland and NLD revealed a combination of features that may be unique to plethodontid salamanders, and may be correlated to their nose-tapping behavior by which substances are moved into the vomeronasal organ; (2) ecology appears to impact the relative development of the orbital glands, but not necessarily the nasolabial gland, with smaller glands being present in the aquatic species; (3) the nomenclature of the salamander orbital gland remains problematic, especially in light of comparative studies, as several alternate possibilities are viable. From this nomenclatural conundrum, however, it could be concluded that there may be a global pattern in the location of tetrapod orbital gland development. Molecular questions in terms of ontogeny and genetic homology affect the nature of the debate on orbital gland nomenclature. These observations suggest that rather than reflecting an ancestral condition, salamanders may instead represent a case of specialized, convergent evolution.

  13. Variable infection of stream salamanders in the southern Appalachians by the trematode Metagonimoides oregonensis (family: Heterophyidae).

    PubMed

    Wyderko, Jennie A; Benfield, Ernest F; Maerz, John C; Cecala, Kristen C; Belden, Lisa K

    2015-08-01

    Many factors contribute to parasites varying in host specificity and distribution among potential hosts. Metagonimoides oregonensis is a digenetic trematode that uses stream-dwelling plethodontid salamanders as second intermediate hosts in the Eastern US. We completed a field survey to identify which stream salamander species, at a regional level, are most likely to be important for transmission to raccoon definitive hosts. We surveyed six plethodontid species (N = 289 salamanders) from 23 Appalachian headwater sites in North Carolina: Desmognathus quadramaculatus (n = 69), Eurycea wilderae (n = 160), Desmognathus ocoee (n = 31), Desmognathus monticola (n = 3), Eurycea guttolineata (n = 7), and Gyrinophilus porphyriticus (n = 19). We found infection in all species except D. monticola. Further analysis focused on comparing infection in the two most abundant species, D. quadramaculatus and E. wilderae. We found that D. quadramaculatus had significantly higher infection prevalence and intensity, probably due to a longer aquatic larval period and larger body sizes and thus greater cumulative exposure to the parasite. PMID:26026670

  14. New species of salamander (Caudata: Plethodontidae: Cryptotriton) from Quebrada Cataguana, Francisco Morazán, Honduras, with comments on the taxonomic status of Cryptotriton wakei.

    PubMed

    Mccranie, James R; Rovito, Sean M

    2014-05-09

    We describe a new species of the plethodontid salamander genus Cryptotriton from Honduras after comparing morphological, molecular, and osteological data from the holotype to that of the other nominal forms of the genus. The new species differs from all of the known species of Cryptotriton in at least one character from all three datasets. We also suggest placing C. wakei in the synonymy of C. nasalis after examining the morphological and osteological characters of the single known specimen of C. wakei.

  15. Digits Lost or Gained? Evidence for Pedal Evolution in the Dwarf Salamander Complex (Eurycea, Plethodontidae)

    PubMed Central

    2012-01-01

    Change in digit number, particularly digit loss, has occurred repeatedly over the evolutionary history of tetrapods. Although digit loss has been documented among distantly related species of salamanders, it is relatively uncommon in this amphibian order. For example, reduction from five to four toes appears to have evolved just three times in the morphologically and ecologically diverse family Plethodontidae. Here we report a molecular phylogenetic analysis for one of these four-toed lineages – the Eurycea quadridigitata complex (dwarf salamanders) – emphasizing relationships to other species in the genus. A multilocus phylogeny reveals that dwarf salamanders are paraphyletic with respect to a complex of five-toed, paedomorphic Eurycea from the Edwards Plateau in Texas. We use this phylogeny to examine evolution of digit number within the dwarf−Edwards Plateau clade, testing contrasting hypotheses of digit loss (parallelism among dwarf salamanders) versus digit gain (re-evolution in the Edwards Plateau complex). Bayes factors analysis provides statistical support for a five-toed common ancestor at the dwarf-Edwards node, favoring, slightly, the parallelism hypothesis for digit loss. More importantly, our phylogenetic results pinpoint a rare event in the pedal evolution of plethodontid salamanders. PMID:22649536

  16. Stoichiometry of a semi-aquatic plethodontid salamander: Intraspecific variation due to location, size and diet

    EPA Science Inventory

    Ecological stoichiometry provides a framework to investigate an organism's relationship to nutrient cycles. An organism's stoichiometry is thought to constrain its contribution to nutrient cycles (recycling or storage), and to limit its growth and reproduction. Factors that influ...

  17. Decline of disjunct green salamander (Aneides aeneus) populations in the southern appalachians

    USGS Publications Warehouse

    Corser, J.D.

    2001-01-01

    Coincident with other amphibians around the world Aneides aeneus, a terrestrial plethodontid salamander, suffered a population collapse in a disjunct portion of its range in the mid-late 1970s. Long-term monitoring of seven historical green salamander populations throughout the 1990s showed a 98% decline in relative abundance since 1970. Three out of six populations first discovered in 1991 also crashed in 1996-1997. The synchronized suddenness of the declines, their region-wide impact, and effects on both small and larger populations, suggest the role of a novel agent of mortality beginning in the mid-late 1970s. Acting alone, but more likely in concert, habitat loss, overcollecting, epidemic disease and climate change could account for this region-wide decline.

  18. Survey for the pathogenic chytrid fungus Batrachochytrium dendrobatidis in southwestern North Carolina salamander populations.

    PubMed

    Keitzer, S Conor; Goforth, Reuben; Pessier, Allan P; Johnson, April J

    2011-04-01

    Batrachochytrium dendrobatidis is a fungal pathogen responsible for a potentially fatal disease of amphibians. We conducted a survey for B. dendrobatidis in the Appalachian Mountains of southwestern North Carolina, USA, from 10 June to 23 July 23 2009. Ventral skin swabs were collected from plethodontid salamanders (n=278) and real-time PCR was performed to test for the presence of B. dendrobatidis. We found no evidence of B. dendrobatidis, suggesting that B. dendrobatidis is absent or present in such low levels that it was undetected. If B. dendrobatidis was present at the time of our sampling, this survey supports evidence of low prevalence of B. dendrobatidis in North American headwater stream salamander populations. PMID:21441199

  19. Osteological Variation among Extreme Morphological Forms in the Mexican Salamander Genus Chiropterotriton (Amphibia: Plethodontidae): Morphological Evolution And Homoplasy

    PubMed Central

    Darda, David M.; Wake, David B.

    2015-01-01

    Osteological variation is recorded among and within four of the most distinctive species of the Mexican salamander genus Chiropterotriton. Analysis of the data is consistent with the monophyletic status of the genus and documents previously unrecorded intraspecific and interspecific variation. Most of the recorded variation involves qualitative and quantitative proportional differences, but four fixed differences constitute autapomorphic states that affirm and diagnose some species (C. dimidiatus, C. magnipes). Osteological variation in 15 characters is analyzed with respect to predictions generated from four hypotheses: 1) phylogeny, 2) adaptation to specific habitats (the four species include cave-dwelling, terrestrial, and arboreal forms), 3) size-free shape, and 4) size. High levels of intraspecific variation suggest that the characters studied are not subject to rigid functional constraints in salamanders, regardless of size. The pattern predicted by the hypothesis based on size differences seen among these four Chiropterotriton species matches most closely the observed pattern of relative skull robustness. Since size change and heterochrony are often associated in plethodontid evolution, it is likely that changes in developmental timing play a role in the morphological transitions among these morphologically diverse taxa. Webbed feet, miniaturization, body shape, and an unusual tarsal arrangement are morphologies exhibited in species of Chiropterotrition that are shown to be homoplastic with other clades of tropical plethodontids. Although extensive homoplasy in salamanders might be seen as a roadblock to unraveling phylogenetic hypotheses, the homologous developmental systems that appear to underlie such homoplasy may reveal common and consistent evolutionary processes at work. PMID:26060996

  20. Osteological Variation among Extreme Morphological Forms in the Mexican Salamander Genus Chiropterotriton (Amphibia: Plethodontidae): Morphological Evolution And Homoplasy.

    PubMed

    Darda, David M; Wake, David B

    2015-01-01

    Osteological variation is recorded among and within four of the most distinctive species of the Mexican salamander genus Chiropterotriton. Analysis of the data is consistent with the monophyletic status of the genus and documents previously unrecorded intraspecific and interspecific variation. Most of the recorded variation involves qualitative and quantitative proportional differences, but four fixed differences constitute autapomorphic states that affirm and diagnose some species (C. dimidiatus, C. magnipes). Osteological variation in 15 characters is analyzed with respect to predictions generated from four hypotheses: 1) phylogeny, 2) adaptation to specific habitats (the four species include cave-dwelling, terrestrial, and arboreal forms), 3) size-free shape, and 4) size. High levels of intraspecific variation suggest that the characters studied are not subject to rigid functional constraints in salamanders, regardless of size. The pattern predicted by the hypothesis based on size differences seen among these four Chiropterotriton species matches most closely the observed pattern of relative skull robustness. Since size change and heterochrony are often associated in plethodontid evolution, it is likely that changes in developmental timing play a role in the morphological transitions among these morphologically diverse taxa. Webbed feet, miniaturization, body shape, and an unusual tarsal arrangement are morphologies exhibited in species of Chiropterotrition that are shown to be homoplastic with other clades of tropical plethodontids. Although extensive homoplasy in salamanders might be seen as a roadblock to unraveling phylogenetic hypotheses, the homologous developmental systems that appear to underlie such homoplasy may reveal common and consistent evolutionary processes at work.

  1. Lagged influence of North Atlantic Oscillation on population dynamics of a Mediterranean terrestrial salamander

    NASA Astrophysics Data System (ADS)

    Salvidio, Sebastiano; Oneto, Fabrizio; Ottonello, Dario; Pastorino, Mauro V.

    2016-04-01

    The North Atlantic Oscillation (NAO) is a large-scale climatic pattern that strongly influences the atmospheric circulation in the northern Hemisphere and by consequence the long-term variability of marine and terrestrial ecosystem over great part of northern Europe and western Mediterranean. In the Mediterranean, the effects of the NAO on vertebrates has been studied mainly on bird populations but was rarely analysed in ectothermic animals, and in particular in amphibians. In this study, we investigated the relationships between winter, spring and summer NAO indexes and the long-term population dynamics of the plethodontid salamander Speleomantes strinatii. This terrestrial salamander was monitored inside an artificial cave in NW Italy for 24 consecutive years. The relationships between seasonal NAO indexes and the salamander dynamics were assessed by cross-correlation function (CCF) analysis, after prewhitening the time series by autoregressive moving average statistical modelling. Results of CCF analyses indicated that the salamander abundance varied in relation to the one-year ahead winter NAO ( P = 0.018), while no relationships were found with spring and summer indexes. These results strengthen some previous findings that suggested a high sensitivity of temperate terrestrial amphibians to wintertime climatic conditions.

  2. Embryonic staging table for a direct-developing salamander, Plethodon cinereus (Plethodontidae).

    PubMed

    Kerney, Ryan

    2011-11-01

    This work presents a refined staging table for the direct-developing red-backed salamander Plethodon cinereus, which is based on the incomplete staging system of James Norman Dent (J Morphol 1942; 71:577-601). This common species from eastern North America is a member of the species-rich lungless salamander family Plethodontidae. The staging table presented here covers several stages omitted by Dent and reveals novel developmental features of P. cinereus embryos. These include putative Leydig cells and open gill clefts, which are found in larvae of metamorphosing species but were previously reported as absent in direct-developing Plethodon. Other features found in larvae of metamorphosing salamander species, such as the palatopterygoid bone and lateral line neuromasts, were not observed in this material. The occurrence of larval and metamorphic features in these embryos has direct bearing on the patterns of life history evolution within the plethodontidae family. This study emphasizes the degree to which typically larval structures are retained in this direct-developing species and provides a staging table for further investigations into the development and evolution of plethodontid salamanders.

  3. Population dynamics and regulation in the cave salamander Speleomantes strinatii

    NASA Astrophysics Data System (ADS)

    Salvidio, Sebastiano

    2007-05-01

    Time series analysis has been used to evaluate the mechanisms regulating population dynamics of mammals and insects, but has been rarely applied to amphibian populations. In this study, the influence of endogenous (density-dependent) and exogenous (density-independent) factors regulating population dynamics of the terrestrial plethodontid salamander Speleomantes strinatii was analysed by means of time series and multiple regression analyses. During the period 1993 2005, S. strinatii population abundance, estimated by a standardised temporary removal method, displayed relatively low fluctuations, and the autocorrelation function (ACF) analysis showed that the time series had a noncyclic structure. The partial rate correlation function (PRCF) indicated that a strong first-order negative feedback dominated the endogenous dynamics. Stepwise multiple regression analysis showed that the only climatic factor influencing population growth rate was the minimum winter temperature. Thus, at least during the study period, endogenous, density-dependent negative feedback was the main factor affecting the growth rate of the salamander population, whereas stochastic environmental variables, such as temperature and rainfall, seemed to play a minor role in regulation. These results stress the importance of considering both exogenous and endogenous factors when analysing amphibian long-term population dynamics.

  4. Acute toxicity of acidity in larvae and adults of four stream salamander species (Plethodontidae).

    PubMed

    Green, Linda E; Peloquin, Jennifer E

    2008-11-01

    High levels of acid deposition have severely affected streamwater chemistry in the southern Appalachians. Plethodontid stream salamanders living in and around headwater streams rely on cutaneous respiration and are highly susceptible to changes in water quality. We examined the sensitivity to low pH conditions in four stream salamanders by monitoring the response to six pH treatments ranging from pH 2.75 to 6.5. To quantify acid tolerance, we determined median lethal concentrations (LC50) in 96-h laboratory bioassays. This is the first study to quantify the level of sensitivity of stream salamanders to acidic conditions, indicating that stream salamanders are acid tolerant compared with many other lotic organisms. We found that acid tolerance is a species-specific trait with intraspecific variation shaped by life stage and body size. Mortality occurred at pH levels less than 4.2. The acid sensitivity of Desmognathus quadramaculatus larvae (LC50 = pH 3.95) was highest compared to sensitivity of Eurycea cirrigera larvae (LC50 = 3.6), Gyrinophilus porphyriticus larvae (LC50 = 3.5), and Pseudotriton ruber larvae (LC50 = 3.5). Larval survival was lower than adult survival in low pH treatments for E. cirrigera (adult LC50 = 3.1) and D. quadramaculatus (adult LC50 = 3.5). Salamanders responded to sublethal exposure to acidity with lethargic movements and decreased swimming speed. These results suggest that episodic acid events that cause streamwater pH to drop near 4.2 may cause mortality or induce sublethal effects, such as slower swimming speed. Because salamander larvae are more sensitive to acidic conditions than adults, we recommend that population monitoring programs extend methodology to include reliable estimates of larval population sizes.

  5. Histology and ultrastructure of the caudal courtship glands of the red-backed salamander, Plethodon cinereus (Amphibia: Plethodontidae).

    PubMed

    Sever, David M; Siegel, Dustin S

    2015-03-01

    Caudal courtship glands (CCGs) are sexually dimorphic glands described in the skin of the dorsal tail base of some male salamanders in the genera Desmognathus, Eurycea, and Plethodon in the family Plethodontidae. These glands are believed to deliver pheromones to females during courtship, when the female rests her chin on the dorsal tail base during the stereotypic tail straddling walk unique to plethodontids. Although CCGs have been studied histologically, no investigations of their ultrastructure have been made. This article presents the first study on the fine structure and seasonal variation of CCGs, using the plethodontid Plethodon cinereus. The CCGs vary seasonally in height and secretory activity. The mature secretory granules observed in males collected in October and April consist of oval, biphasic granules that are eosinophilic and give positive reactions to periodic acid-Schiff for neutral carbohydrates but do not stain for acidic mucosusbtances or proteins with alcian blue and bromphenol blue, respectively. Granular glands, some of which contain mucous demilunes, are twice as large as CCGs, are syncytial (unlike CCGs), and stain for proteins. Mucous glands are similar in size to CCGs, but are basophilic, show no seasonal variation in secretory activity, and stain positive for acidic mucosubstances. CCGs do not resemble cytologically the sexually dimorphic mental glands of some plethodontids, which contain round or oval granules filled with an electron-dense amorphous substance. The CCGs are similar histologically to sexually dimorphic skin glands described in some anurans, but more comparative work is needed.

  6. Laser vibrometric studies of sound-induced motion of the body walls and lungs of salamanders and lizards: implications for lung-based hearing.

    PubMed

    Hetherington, T E

    2001-09-01

    A laser Doppler vibrometer was used to measure the acoustic responses of different body surfaces of several species of salamanders and lizards. The lateral body wall over the lung displayed sound-induced motion up to 30 dB greater than the lateral head surface from 300-1,000 Hz in salamanders and from 200-2,500 Hz in lizards. The lateral body wall of lungless plethodontid salamanders showed no such enhanced motion to sound. The lateral body wall of lizards was more responsive than their tympanum to sound frequencies below about 1,250-2,000 Hz. The frequency of the peak response of lizard body walls matched the resonant frequency of a Helmholtz resonator with the volume and dimensions of their lungs. In contrast, the frequency of peak response of salamander body walls was well below the resonant frequencies calculated for both Helmholtz resonators and closed tubes with the dimensions and volumes of their lungs. Nonetheless, filling the lungs with saline dramatically reduced the responsiveness of the lateral body walls of both the lunged salamanders and the lizards. As previously demonstrated in anuran amphibians, the lateral body wall and lungs of salamanders and lizards may function in sound reception, especially at relatively low frequencies.

  7. Fluctuations in a metapopulation of nesting four-toed salamanders, Hemidactylium scutatum, in the Great Smoky Mountains National Park, USA, 1999-2003

    USGS Publications Warehouse

    Corser, J.D.; Dodd, C.K.

    2004-01-01

    We tested two predictions associated with the hypothesis that certain populations of pond-breeding amphibians are structured into metapopulations using minimum relative abundance estimates of nesting four-toed salamanders (Hemidactylium scutatum Schlegel) from 11 different ponds in the Great Smoky Mountains National Park. Coefficients of variation (CV) for counts at individual ponds ranged from 0.25 to 1.26, and the overall mean CV at all 11 ponds was 0.34. Many pairs of ponds had negative correlations in abundance from 1999-2003, whereas others had various degrees of positive correlation (mean r = 0.29). Thus, nesting population size fluctuated semi-independently among the ponds from year to year, inferring the existence of inter-pond dispersal. The mean number of nesting females at a pond was negatively, but non-significantly, correlated (r = -0.27; P = 0.40; 10 d.f.) to the pond's isolation. Owing to physiological constraints on plethodontid salamander energetics, precipitation during the nesting season (February and March) appeared to play an important role (r = 0.78; P = 0.12; 4 d.f.) in the number of nesting females we observed. Unlike some other plethodontid salamander populations in more fragmented southern Appalachian forest ecosystems, this (meta)population within Great Smoky Mountains National Park does not appear to be declining.

  8. Unexpected rarity of the pathogen Batrachochytrium dendrobatidis in Appalachian Plethodon Salamanders: 1957-2011.

    PubMed

    Muletz, Carly; Caruso, Nicholas M; Fleischer, Robert C; McDiarmid, Roy W; Lips, Karen R

    2014-01-01

    Widespread population declines in terrestrial Plethodon salamanders occurred by the 1980s throughout the Appalachian Mountains, the center of global salamander diversity, with no evident recovery. We tested the hypothesis that the historic introduction and spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd) into the eastern US was followed by Plethodon population declines. We expected to detect elevated prevalence of Bd prior to population declines as observed for Central American plethodontids. We tested 1,498 Plethodon salamanders of 12 species (892 museum specimens, 606 wild individuals) for the presence of Bd, and tested 94 of those for Batrachochytrium salamandrivorans (Bs) and for ranavirus. Field samples were collected in 2011 from 48 field sites across a 767 km transect. Historic samples from museum specimens were collected at five sites with the greatest number and longest duration of collection (1957-987), four of which were sampled in the field in 2011. None of the museum specimens were positive for Bd, but four P. cinereus from field surveys were positive. The overall Bd prevalence from 1957-2011 for 12 Plethodon species sampled across a 757 km transect was 0.2% (95% CI 0.1-0.7%). All 94 samples were negative for Bs and ranavirus. We conclude that known amphibian pathogens are unlikely causes for declines in these Plethodon populations. Furthermore, these exceptionally low levels of Bd, in a region known to harbor Bd, may indicate that Plethodon specific traits limit Bd infection. PMID:25084159

  9. Unexpected Rarity of the Pathogen Batrachochytrium dendrobatidis in Appalachian Plethodon Salamanders: 1957–2011

    PubMed Central

    Muletz, Carly; Caruso, Nicholas M.; Fleischer, Robert C.; McDiarmid, Roy W.; Lips, Karen R.

    2014-01-01

    Widespread population declines in terrestrial Plethodon salamanders occurred by the 1980s throughout the Appalachian Mountains, the center of global salamander diversity, with no evident recovery. We tested the hypothesis that the historic introduction and spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd) into the eastern US was followed by Plethodon population declines. We expected to detect elevated prevalence of Bd prior to population declines as observed for Central American plethodontids. We tested 1,498 Plethodon salamanders of 12 species (892 museum specimens, 606 wild individuals) for the presence of Bd, and tested 94 of those for Batrachochytrium salamandrivorans (Bs) and for ranavirus. Field samples were collected in 2011 from 48 field sites across a 767 km transect. Historic samples from museum specimens were collected at five sites with the greatest number and longest duration of collection (1957–987), four of which were sampled in the field in 2011. None of the museum specimens were positive for Bd, but four P. cinereus from field surveys were positive. The overall Bd prevalence from 1957–2011 for 12 Plethodon species sampled across a 757 km transect was 0.2% (95% CI 0.1–0.7%). All 94 samples were negative for Bs and ranavirus. We conclude that known amphibian pathogens are unlikely causes for declines in these Plethodon populations. Furthermore, these exceptionally low levels of Bd, in a region known to harbor Bd, may indicate that Plethodon specific traits limit Bd infection. PMID:25084159

  10. Unexpected rarity of the pathogen Batrachochytrium dendrobatidis in Appalachian Plethodon Salamanders: 1957-2011.

    PubMed

    Muletz, Carly; Caruso, Nicholas M; Fleischer, Robert C; McDiarmid, Roy W; Lips, Karen R

    2014-01-01

    Widespread population declines in terrestrial Plethodon salamanders occurred by the 1980s throughout the Appalachian Mountains, the center of global salamander diversity, with no evident recovery. We tested the hypothesis that the historic introduction and spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd) into the eastern US was followed by Plethodon population declines. We expected to detect elevated prevalence of Bd prior to population declines as observed for Central American plethodontids. We tested 1,498 Plethodon salamanders of 12 species (892 museum specimens, 606 wild individuals) for the presence of Bd, and tested 94 of those for Batrachochytrium salamandrivorans (Bs) and for ranavirus. Field samples were collected in 2011 from 48 field sites across a 767 km transect. Historic samples from museum specimens were collected at five sites with the greatest number and longest duration of collection (1957-987), four of which were sampled in the field in 2011. None of the museum specimens were positive for Bd, but four P. cinereus from field surveys were positive. The overall Bd prevalence from 1957-2011 for 12 Plethodon species sampled across a 757 km transect was 0.2% (95% CI 0.1-0.7%). All 94 samples were negative for Bs and ranavirus. We conclude that known amphibian pathogens are unlikely causes for declines in these Plethodon populations. Furthermore, these exceptionally low levels of Bd, in a region known to harbor Bd, may indicate that Plethodon specific traits limit Bd infection.

  11. Potential reduction in terrestrial salamander ranges associated with Marcellus shale development

    USGS Publications Warehouse

    Brand, Adrianne; Wiewel, Amber N. M.; Grant, Evan H. Campbell

    2014-01-01

    Natural gas production from the Marcellus shale is rapidly increasing in the northeastern United States. Most of the endemic terrestrial salamander species in the region are classified as ‘globally secure’ by the IUCN, primarily because much of their ranges include state- and federally protected lands, which have been presumed to be free from habitat loss. However, the proposed and ongoing development of the Marcellus gas resources may result in significant range restrictions for these and other terrestrial forest salamanders. To begin to address the gaps in our knowledge of the direct impacts of shale gas development, we developed occurrence models for five species of terrestrial plethodontid salamanders found largely within the Marcellus shale play. We predicted future Marcellus shale development under several scenarios. Under scenarios of 10,000, 20,000, and 50,000 new gas wells, we predict 4%, 8%, and 20% forest loss, respectively, within the play. Predictions of habitat loss vary among species, but in general, Plethodon electromorphus and Plethodonwehrlei are predicted to lose the greatest proportion of forested habitat within their ranges if future Marcellus development is based on characteristics of the shale play. If development is based on current well locations,Plethodonrichmondi is predicted to lose the greatest proportion of habitat. Models showed high uncertainty in species’ ranges and emphasize the need for distribution data collected by widespread and repeated, randomized surveys.

  12. Conservation genetics of extremely isolated urban populations of the northern dusky salamander (Desmognathus fuscus) in New York City

    PubMed Central

    Zak, Yana; Pehek, Ellen

    2013-01-01

    Urbanization is a major cause of amphibian decline. Stream-dwelling plethodontid salamanders are particularly susceptible to urbanization due to declining water quality and hydrological changes, but few studies have examined these taxa in cities. The northern dusky salamander (Desmognathus fuscus) was once common in the New York City metropolitan area, but has substantially declined throughout the region in recent decades. We used five tetranucleotide microsatellite loci to examine population differentiation, genetic variation, and bottlenecks among five remnant urban populations of dusky salamanders in NYC. These genetic measures provide information on isolation, prevalence of inbreeding, long-term prospects for population persistence, and potential for evolutionary responses to future environmental change. All populations were genetically differentiated from each other, and the most isolated populations in Manhattan have maintained very little genetic variation (i.e. <20% heterozygosity). A majority of the populations also exhibited evidence of genetic bottlenecks. These findings contrast with published estimates of high genetic variation within and lack of structure between populations of other desmognathine salamanders sampled over similar or larger spatial scales. Declines in genetic variation likely resulted from population extirpations and the degradation of stream and terrestrial paths for dispersal in NYC. Loss of genetic variability in populations isolated by human development may be an underappreciated cause and/or consequence of the decline of this species in urbanized areas of the northeast USA. PMID:23646283

  13. Conservation genetics of extremely isolated urban populations of the northern dusky salamander (Desmognathus fuscus) in New York City.

    PubMed

    Munshi-South, Jason; Zak, Yana; Pehek, Ellen

    2013-01-01

    Urbanization is a major cause of amphibian decline. Stream-dwelling plethodontid salamanders are particularly susceptible to urbanization due to declining water quality and hydrological changes, but few studies have examined these taxa in cities. The northern dusky salamander (Desmognathus fuscus) was once common in the New York City metropolitan area, but has substantially declined throughout the region in recent decades. We used five tetranucleotide microsatellite loci to examine population differentiation, genetic variation, and bottlenecks among five remnant urban populations of dusky salamanders in NYC. These genetic measures provide information on isolation, prevalence of inbreeding, long-term prospects for population persistence, and potential for evolutionary responses to future environmental change. All populations were genetically differentiated from each other, and the most isolated populations in Manhattan have maintained very little genetic variation (i.e. <20% heterozygosity). A majority of the populations also exhibited evidence of genetic bottlenecks. These findings contrast with published estimates of high genetic variation within and lack of structure between populations of other desmognathine salamanders sampled over similar or larger spatial scales. Declines in genetic variation likely resulted from population extirpations and the degradation of stream and terrestrial paths for dispersal in NYC. Loss of genetic variability in populations isolated by human development may be an underappreciated cause and/or consequence of the decline of this species in urbanized areas of the northeast USA.

  14. Phylogenetic history underlies elevational biodiversity patterns in tropical salamanders

    PubMed Central

    Wiens, John J; Parra-Olea, Gabriela; García-París, Mario; Wake, David B

    2007-01-01

    Elevational variation in species richness is ubiquitous and important for conservation, but remains poorly explained. Numerous studies have documented higher species richness at mid-elevations, but none have addressed the underlying evolutionary and biogeographic processes that ultimately explain this pattern (i.e. speciation, extinction and dispersal). Here, we address the evolutionary causes of the mid-elevational diversity hump in the most species-rich clade of salamanders, the tropical bolitoglossine plethodontids. We present a new phylogeny for the group based on DNA sequences from all 13 genera and 137 species. Using this phylogeny, we find no relationship between rates of diversification of clades and their elevational distribution, and no evidence for a rapid ‘species pump’ in tropical montane regions. Instead, we find a strong relationship between the number of species in each elevational zone and the estimated time when each elevational band was first colonized. Mid-elevation habitats were colonized early in the phylogenetic history of bolitoglossines, and given similar rates of diversification across elevations, more species have accumulated in the elevational zones that were inhabited the longest. This pattern may be widespread and suggests that mid-elevation habitats may not only harbour more species, but may also contain more phylogenetic diversity than other habitats within a region. PMID:17284409

  15. What explains patterns of species richness? The relative importance of climatic-niche evolution, morphological evolution, and ecological limits in salamanders.

    PubMed

    Kozak, Kenneth H; Wiens, John J

    2016-08-01

    A major goal of evolutionary biology and ecology is to understand why species richness varies among clades. Previous studies have suggested that variation in richness among clades might be related to variation in rates of morphological evolution among clades (e.g., body size and shape). Other studies have suggested that richness patterns might be related to variation in rates of climatic-niche evolution. However, few studies, if any, have tested the relative importance of these variables in explaining patterns of richness among clades. Here, we test their relative importance among major clades of Plethodontidae, the most species-rich family of salamanders. Earlier studies have suggested that climatic-niche evolution explains patterns of diversification among plethodontid clades, whereas rates of morphological evolution do not. A subsequent study stated that rates of morphological evolution instead explained patterns of species richness among plethodontid clades (along with "ecological limits" on richness of clades, leading to saturation of clades with species, given limited resources). However, they did not consider climatic-niche evolution. Using phylogenetic multiple regression, we show that rates of climatic-niche evolution explain most variation in richness among plethodontid clades, whereas rates of morphological evolution do not. We find little evidence that ecological limits explain patterns of richness among plethodontid clades. We also test whether rates of morphological and climatic-niche evolution are correlated, and find that they are not. Overall, our results help explain richness patterns in a major amphibian group and provide possibly the first test of the relative importance of climatic niches and morphological evolution in explaining diversity patterns.

  16. What explains patterns of species richness? The relative importance of climatic-niche evolution, morphological evolution, and ecological limits in salamanders.

    PubMed

    Kozak, Kenneth H; Wiens, John J

    2016-08-01

    A major goal of evolutionary biology and ecology is to understand why species richness varies among clades. Previous studies have suggested that variation in richness among clades might be related to variation in rates of morphological evolution among clades (e.g., body size and shape). Other studies have suggested that richness patterns might be related to variation in rates of climatic-niche evolution. However, few studies, if any, have tested the relative importance of these variables in explaining patterns of richness among clades. Here, we test their relative importance among major clades of Plethodontidae, the most species-rich family of salamanders. Earlier studies have suggested that climatic-niche evolution explains patterns of diversification among plethodontid clades, whereas rates of morphological evolution do not. A subsequent study stated that rates of morphological evolution instead explained patterns of species richness among plethodontid clades (along with "ecological limits" on richness of clades, leading to saturation of clades with species, given limited resources). However, they did not consider climatic-niche evolution. Using phylogenetic multiple regression, we show that rates of climatic-niche evolution explain most variation in richness among plethodontid clades, whereas rates of morphological evolution do not. We find little evidence that ecological limits explain patterns of richness among plethodontid clades. We also test whether rates of morphological and climatic-niche evolution are correlated, and find that they are not. Overall, our results help explain richness patterns in a major amphibian group and provide possibly the first test of the relative importance of climatic niches and morphological evolution in explaining diversity patterns. PMID:27547367

  17. Identification of conservation units of the hynobiid salamander Pachyhynobius shangchengensis.

    PubMed

    Su, L-N; Zhao, Y-Y; Wu, X-M; Zhang, H-F; Li, X-C

    2015-08-19

    The evolutionary significant units (ESUs) of the salamander Pachyhynobius shangchengensis (Hynobiidae) in the Dabieshan mountains, southeastern China, were identified based on mitochondrial DNA data. We used methods for detecting cryptic species, such as the minimum spanning tree, the automatic barcode gap discovery, and the generalized mixed Yule-coalescent model; geographical partitioning was also used to identify the ESUs. A total of four ESUs were identified.

  18. Cold-blooded snipers: thermal independence of ballistic tongue projection in the salamander Hydromantes platycephalus.

    PubMed

    Deban, Stephen M; Richardson, Jason C

    2011-12-01

    Plethodontid salamanders of the genus Hydromantes capture prey using the most extreme tongue projection among salamanders, and can shoot the tongue a distance of 80% of body length in less than 20 msec. The tongue skeleton is projected from the body via an elastic-recoil mechanism that decouples muscle contraction from tongue projection, amplifying muscle power tenfold. We tested the hypothesis that the elastic-recoil mechanism also endows tongue projection with low thermal dependence by examining the kinematics and dynamics of tongue projection in Hydromantes platycephalus over a range of body temperatures (2-24°C). We found that H. platycephalus maintained tongue-projection performance over the tested temperature range and that tongue projection showed thermal independence (Q(10) values of 0.94-1.04) of all performance parameters including projection distance, average velocity, and peak instantaneous values of velocity, acceleration, and power. Nonelastic, muscle-powered tongue retraction, in contrast, responded to temperature changes significantly differently than elastic tongue projection; performance parameters of retraction displayed thermal dependence typical of muscle-powered movement (Q(10) values of 1.63-4.97). These results reveal that the elastic-recoil mechanism liberates tongue projection from the effects of temperature on muscle contractile rates. We suggest that relative thermal independence is a general characteristic of elastic-recoil mechanisms and may promote the evolution of these mechanisms in ectothermic animals.

  19. Cold-blooded snipers: thermal independence of ballistic tongue projection in the salamander Hydromantes platycephalus.

    PubMed

    Deban, Stephen M; Richardson, Jason C

    2011-12-01

    Plethodontid salamanders of the genus Hydromantes capture prey using the most extreme tongue projection among salamanders, and can shoot the tongue a distance of 80% of body length in less than 20 msec. The tongue skeleton is projected from the body via an elastic-recoil mechanism that decouples muscle contraction from tongue projection, amplifying muscle power tenfold. We tested the hypothesis that the elastic-recoil mechanism also endows tongue projection with low thermal dependence by examining the kinematics and dynamics of tongue projection in Hydromantes platycephalus over a range of body temperatures (2-24°C). We found that H. platycephalus maintained tongue-projection performance over the tested temperature range and that tongue projection showed thermal independence (Q(10) values of 0.94-1.04) of all performance parameters including projection distance, average velocity, and peak instantaneous values of velocity, acceleration, and power. Nonelastic, muscle-powered tongue retraction, in contrast, responded to temperature changes significantly differently than elastic tongue projection; performance parameters of retraction displayed thermal dependence typical of muscle-powered movement (Q(10) values of 1.63-4.97). These results reveal that the elastic-recoil mechanism liberates tongue projection from the effects of temperature on muscle contractile rates. We suggest that relative thermal independence is a general characteristic of elastic-recoil mechanisms and may promote the evolution of these mechanisms in ectothermic animals. PMID:21953778

  20. Side-by-side secretion of Late Palaeozoic diverged courtship pheromones in an aquatic salamander.

    PubMed

    Van Bocxlaer, Ines; Treer, Dag; Maex, Margo; Vandebergh, Wim; Janssenswillen, Sunita; Stegen, Gwij; Kok, Philippe; Willaert, Bert; Matthijs, Severine; Martens, Erik; Mortier, Anneleen; de Greve, Henri; Proost, Paul; Bossuyt, Franky

    2015-03-22

    Males of the advanced salamanders (Salamandroidea) attain internal fertilization without a copulatory organ by depositing a spermatophore on the substrate in the environment, which females subsequently take up with their cloaca. The aquatically reproducing modern Eurasian newts (Salamandridae) have taken this to extremes, because most species do not display close physical contact during courtship, but instead largely rely on females following the male track at spermatophore deposition. Although pheromones have been widely assumed to represent an important aspect of male courtship, molecules able to induce the female following behaviour that is the prelude for successful insemination have not yet been identified. Here, we show that uncleaved sodefrin precursor-like factor (SPF) protein pheromones are sufficient to elicit such behaviour in female palmate newts (Lissotriton helveticus). Combined transcriptomic and proteomic evidence shows that males simultaneously tail-fan multiple ca 20 kDa glycosylated SPF proteins during courtship. Notably, molecular dating estimates show that the diversification of these proteins already started in the late Palaeozoic, about 300 million years ago. Our study thus not only extends the use of uncleaved SPF proteins outside terrestrially reproducing plethodontid salamanders, but also reveals one of the oldest vertebrate pheromone systems.

  1. Plethodon cinereus (Redback Salamander) predation

    USGS Publications Warehouse

    Jung, R.E.; Ward, W.L.; Kings, C.O.; Weir, L.A.

    2000-01-01

    In 1999 at the Patuxent Research Refuge, we observed a large rove beetle (Staphylinus maculosus) consuming an eviscerated redback salamander (Plethodon cinereus) underneath a coverboard. Rove beetles typically eat invertebrates.

  2. Landmark learning by juvenile salamanders (Ambystoma maculatum).

    PubMed

    Heuring, Whitney L; Mathis, Alicia

    2014-10-01

    Learning to use a landmark as a beacon to locate resources is one of the simplest forms of spatial learning. We tested whether landmark learning occurs in a semifossorial salamander that migrates annually to breeding ponds as adults. Juvenile spotted salamanders (Ambystoma maculatum) were tested in square containers with a plastic feeding dish in each corner, and a piece of earthworm was placed in one randomly-chosen dish. For landmark-trained salamanders, a rock was placed beside the dish containing the prey. For control salamanders, the rock was placed beside a randomly selected feeding dish. Each salamander was trained once every 2 days for 30 days. Significantly more landmark-trained salamanders than control salamanders entered the landmark area first, and landmark-trained individuals had faster latencies to enter the landmark area and longer stay-times. These results suggest that spotted salamanders are able to locate resources by associating their positions with landmarks.

  3. Landmark learning by juvenile salamanders (Ambystoma maculatum).

    PubMed

    Heuring, Whitney L; Mathis, Alicia

    2014-10-01

    Learning to use a landmark as a beacon to locate resources is one of the simplest forms of spatial learning. We tested whether landmark learning occurs in a semifossorial salamander that migrates annually to breeding ponds as adults. Juvenile spotted salamanders (Ambystoma maculatum) were tested in square containers with a plastic feeding dish in each corner, and a piece of earthworm was placed in one randomly-chosen dish. For landmark-trained salamanders, a rock was placed beside the dish containing the prey. For control salamanders, the rock was placed beside a randomly selected feeding dish. Each salamander was trained once every 2 days for 30 days. Significantly more landmark-trained salamanders than control salamanders entered the landmark area first, and landmark-trained individuals had faster latencies to enter the landmark area and longer stay-times. These results suggest that spotted salamanders are able to locate resources by associating their positions with landmarks. PMID:25444775

  4. Fine-Scale Habitat Associations of a Terrestrial Salamander: The Role of Environmental Gradients and Implications for Population Dynamics

    PubMed Central

    Peterman, William E.; Semlitsch, Raymond D.

    2013-01-01

    Environmental gradients are instrumental in shaping the distribution and local abundance of species because at the most fundamental level, an organism’s performance is constrained by the environment it inhabits. In topographically complex landscapes, slope, aspect, and vegetative cover interact to affect solar exposure, creating temperature-moisture gradients and unique microclimates. The significance of the interaction of abiotic gradients and biotic factors such as competition, movement, or physiology has long been recognized, but the scale at which these factors vary on the landscape has generally precluded their inclusion in spatial abundance models. We used fine-scale spatial data relating to surface-soil moisture, temperature, and canopy cover to describe the spatial distribution of abundance of a terrestrial salamander, Plethodon albagula, across the landscape. Abundance was greatest in dense-canopy ravine habitats with high moisture and low solar exposure, resulting in a patchy distribution of abundance. We hypothesize that these patterns reflect the physiological constraints of Plethodontid salamanders. Furthermore, demographic cohorts were not uniformly distributed among occupied plots on the landscape. The probability of gravid female occurrence was nearly uniform among occupied plots, but juveniles were much more likely to occur on plots with lower surface temperatures. The disconnect between reproductive effort and recruitment suggests that survival differs across the landscape and that local population dynamics vary spatially. Our study demonstrates a connection between abundance, fine-scale environmental gradients, and population dynamics, providing a foundation for future research concerning movement, population connectivity, and physiology. PMID:23671586

  5. 'Salamander plague' on Britain's doorstep.

    PubMed

    Mills, Georgina

    2015-01-24

    Chytridiomycosis can cause mass declines in amphibians, and the chytrid fungus Batrachochytrium dendrobatidis is the classic cause of this disease. However, recently, a second strain of chytrid fungus has emerged in Europe, resulting in major declines in fire salamanders. The Zoological Society of London (ZSL) discussed this, and the implications for the UK, at a meeting in December in London. Georgina Mills reports.

  6. Early Miocene origin and cryptic diversification of South American salamanders

    PubMed Central

    2013-01-01

    Background The currently recognized species richness of South American salamanders is surprisingly low compared to North and Central America. In part, this low richness may be due to the salamanders being a recent arrival to South America. Additionally, the number of South American salamander species may be underestimated because of cryptic diversity. The aims of our present study were to infer evolutionary relationships, lineage diversity, and timing of divergence of the South American Bolitoglossa using mitochondrial and nuclear sequence data from specimens primarily from localities in the Andes and upper Amazon Basin. We also estimated time of colonization of South America to test whether it is consistent with arrival via the Panamanian Isthmus, or land bridge connection, at its traditionally assumed age of 3 million years. Results Divergence time estimates suggest that Bolitoglossa arrived in South America from Central America by at least the Early Miocene, ca. 23.6 MYA (95% HPD 15.9-30.3 MYA), and subsequently diversified. South American salamanders of the genus Bolitoglossa show strong phylogeographic structure at fine geographic scales and deep divergences at the mitochondrial gene cytochrome b (Cytb) and high diversity at the nuclear recombination activating gene-1 (Rag1). Species often contain multiple genetically divergent lineages that are occasionally geographically overlapping. Single specimens from two southeastern localities in Ecuador are sister to the equatoriana-peruviana clade and genetically distinct from all other species investigated to date. Another single exemplar from the Andes of northwestern Ecuador is highly divergent from all other specimens and is sister to all newly studied samples. Nevertheless, all sampled species of South American Bolitoglossa are members of a single clade that is one of several constituting the subgenus Eladinea, one of seven subgenera in this large genus. Conclusions The ancestors of South American salamanders

  7. 'Salamander plague' on Britain's doorstep.

    PubMed

    Mills, Georgina

    2015-01-24

    Chytridiomycosis can cause mass declines in amphibians, and the chytrid fungus Batrachochytrium dendrobatidis is the classic cause of this disease. However, recently, a second strain of chytrid fungus has emerged in Europe, resulting in major declines in fire salamanders. The Zoological Society of London (ZSL) discussed this, and the implications for the UK, at a meeting in December in London. Georgina Mills reports. PMID:25614547

  8. Earliest known crown-group salamanders.

    PubMed

    Gao, Ke-Qin; Shubin, Neil H

    2003-03-27

    Salamanders are a model system for studying the rates and patterns of the evolution of new anatomical structures. Recent discoveries of abundant Late Jurassic and Early Cretaceous salamanders are helping to address these issues. Here we report the discovery of well-preserved Middle Jurassic salamanders from China, which constitutes the earliest known record of crown-group urodeles (living salamanders and their closest relatives). The new specimens are from the volcanic deposits of the Jiulongshan Formation (Bathonian), Inner Mongolia, China, and represent basal members of the Cryptobranchidae, a family that includes the endangered Asian giant salamander (Andrias) and the North American hellbender (Cryptobranchus). These fossils document a Mesozoic record of the Cryptobranchidae, predating the previous record of the group by some 100 million years. This discovery provides evidence to support the hypothesis that the divergence of the Cryptobranchidae from the Hynobiidae had taken place in Asia before the Middle Jurassic period.

  9. Earliest known crown-group salamanders.

    PubMed

    Gao, Ke-Qin; Shubin, Neil H

    2003-03-27

    Salamanders are a model system for studying the rates and patterns of the evolution of new anatomical structures. Recent discoveries of abundant Late Jurassic and Early Cretaceous salamanders are helping to address these issues. Here we report the discovery of well-preserved Middle Jurassic salamanders from China, which constitutes the earliest known record of crown-group urodeles (living salamanders and their closest relatives). The new specimens are from the volcanic deposits of the Jiulongshan Formation (Bathonian), Inner Mongolia, China, and represent basal members of the Cryptobranchidae, a family that includes the endangered Asian giant salamander (Andrias) and the North American hellbender (Cryptobranchus). These fossils document a Mesozoic record of the Cryptobranchidae, predating the previous record of the group by some 100 million years. This discovery provides evidence to support the hypothesis that the divergence of the Cryptobranchidae from the Hynobiidae had taken place in Asia before the Middle Jurassic period. PMID:12660782

  10. A little bit is better than nothing: the incomplete parthenogenesis of salamanders, frogs and fish

    PubMed Central

    2010-01-01

    A re-examination of the mitochondrial genomes of unisexual salamander lineages, published in BMC Evolutionary Biology, shows them to be the oldest unisexual vertebrates known, having been around for 5 million years. This presents a challenge to the prediction that lack of genetic recombination is a fast track to extinction. See research article http://www.biomedcentral.com/1471-2148/10/238 PMID:20687905

  11. Ambystoma maculatum (spotted salamander). Reproduction

    USGS Publications Warehouse

    Glorioso, Brad M.; Waddle, Hardin; Hefner, Jeromi

    2012-01-01

    The Spotted Salamander is a wide-ranging salamander of the eastern United States that typically breeds in winter or early spring in ephemeral pools in lowland forests. Ambystoma maculatum is known to deposit 2-4 egg masses per year, each containing 1-250 eggs. As part of ongoing research into the ecology and reproductive biology of Spotted Salamanders in the Kisatchie District of Kisatchie National Forest in Natchitoches Parish, Louisiana, USA, we have been counting the number of embryos per egg mass. We captured seven female A. maculatum in a small pool, six of which were still gravid. We took standard measurements, including SVL, and then implanted a Passive Integrated Transponder (PIT tag) into each adult female as was the protocol. About an hour after processing these animals we marked new A. maculatum egg masses found in the same small pool using PVC pin flags pushed carefully through the outer jelly. We did not have enough time to process them that evening, and it was not until a few days later that we photographed those masses. We discovered that one of the masses contained a PIT tag in the outer jelly that corresponded to one of the six gravid females that were marked that same evening. To our knowledge, this is the first report of PIT tags being the means, albeit coincidentally, by which a particular egg mass of Ambystoma maculatum has been assigned to a particular female. For our purposes, losing the PIT tag from the adult female is counter to the goals of our study of this population, and we will no longer be implanting PIT tags into gravid females.

  12. Late Jurassic salamanders from northern China.

    PubMed

    Gao, K Q; Shubin, N H

    2001-03-29

    With ten extant families, salamanders (urodeles) are one of the three major groups of modern amphibians (lissamphibians). Extant salamanders are often used as a model system to assess fundamental issues of developmental, morphological and biogeographical evolution. Unfortunately, our understanding of these issues has been hampered by the paucity of fossil evidence available to assess the early history of the group. Here we report the discovery of an extraordinary sample of salamander fossils, some with rare soft-tissue impressions, from the Upper Jurassic of China. With over 500 articulated specimens, this assemblage documents the morphological diversity of early urodeles and includes larvae and adults of both neotenic and metamorphosed taxa. Phylogenetic analysis confirms that these salamanders are primitive, and reveals that all basal salamander clades have Asian distributions. This is compelling evidence for an Asian origin of Recent salamanders, as well as for an extensive and early radiation of several major lineages. These discoveries show that the evolution of salamanders has involved phylogenetic and ecological diversification around a body plan that has remained fundamentally stable for over 150 million years. PMID:11279493

  13. Late Jurassic salamanders from northern China.

    PubMed

    Gao, K Q; Shubin, N H

    2001-03-29

    With ten extant families, salamanders (urodeles) are one of the three major groups of modern amphibians (lissamphibians). Extant salamanders are often used as a model system to assess fundamental issues of developmental, morphological and biogeographical evolution. Unfortunately, our understanding of these issues has been hampered by the paucity of fossil evidence available to assess the early history of the group. Here we report the discovery of an extraordinary sample of salamander fossils, some with rare soft-tissue impressions, from the Upper Jurassic of China. With over 500 articulated specimens, this assemblage documents the morphological diversity of early urodeles and includes larvae and adults of both neotenic and metamorphosed taxa. Phylogenetic analysis confirms that these salamanders are primitive, and reveals that all basal salamander clades have Asian distributions. This is compelling evidence for an Asian origin of Recent salamanders, as well as for an extensive and early radiation of several major lineages. These discoveries show that the evolution of salamanders has involved phylogenetic and ecological diversification around a body plan that has remained fundamentally stable for over 150 million years.

  14. Phylogeny, evolution, and biogeography of Asiatic Salamanders (Hynobiidae).

    PubMed

    Zhang, Peng; Chen, Yue-Qin; Zhou, Hui; Liu, Yi-Fei; Wang, Xiu-Ling; Papenfuss, Theodore J; Wake, David B; Qu, Liang-Hu

    2006-05-01

    We sequenced 15 complete mitochondrial genomes and performed comprehensive molecular phylogenetic analyses to study the origin and phylogeny of the Hynobiidae, an ancient lineage of living salamanders. Our phylogenetic analyses show that the Hynobiidae is a clade with well resolved relationships, and our results contrast with a morphology-based phylogenetic hypothesis. These salamanders have low vagility and are limited in their distribution primarily by deserts, mountains, and oceans. Our analysis suggests that the relationships among living hynobiids have been shaped primarily by geography. We show that four-toed species assigned to Batrachuperus do not form a monophyletic group, and those that occur in Afghanistan and Iran are transferred to the resurrected Paradactylodon. Convergent morphological characters in different hynobiid lineages are likely produced by similar environmental selective pressures. Clock-independent molecular dating suggests that hynobiids originated in the Middle Cretaceous [ approximately 110 million years ago (Mya)]. We propose an "out of North China" hypothesis for hynobiid origins and hypothesize an ancestral stream-adapted form. Given the particular distributional patterns and our molecular dating estimates, we hypothesize that: (i) the interior desertification from Mongolia to Western Asia began approximately 50 Mya; (ii) the Tibetan plateau (at least on the eastern fringe) experienced rapid uplift approximately 40 Mya and reached an altitude of at least 2,500 m; and (iii) the Ailao-Red River shear zone underwent the most intense orogenic movement approximately 24 Mya.

  15. Phylogenetic relationships of the endangered Shenandoah salamander (Plethodon shenandoah) and other salamanders of the Plethodon cinereus group (Caudata : Plethodontidae)

    USGS Publications Warehouse

    Sites, J.W.; Morando, M.; Highton, R.; Huber, F.; Jung, R.E.

    2004-01-01

    The Shenandoah salamander (Plethodon shenandoah), known from isolated talus slopes on three of the highest mountains in Shenandoah National Park, is listed as state-endangered in Virginia and federally endangered under the U.S. Endangered Species Act. A 1999 paper by G. R. Thurow described P. shenandoah-like salamanders from three localities further south in the Blue Ridge Physiographic Province, which, if confirmed, would represent a range extension for P. shenandoah of approximately 90 km from its nearest known locality. Samples collected from two of these three localities were included in a molecular phylogenetic study of the known populations of P. shenandoah, and all other recognized species in the Plethodon cinereus group, using a 792 bp region of the mitochondrial cytochrome-b gene. Phylogenetic estimates were based on Bayesian, maximum likelihood, and maximum parsimony methods and topologies examined for placement of the new P. shenandoah-like samples relative to all others. All topologies recovered all haplotypes of the P. shenandoah-like animals nested within P. cinereus, and a statistical comparison of the best likelihood tree topology with one with an enforced (Thurow + Shenandoah P. shenandoah) clade revealed that the unconstrained tree had a significantly lower -In L score (P < 0.05, using the Shimodaira-Hasegawa test) than the constraint tree. This result and other anecdotal information give us no solid reason to consider the Thurow report valid. The current recovery program for P. shenandoah should remain focused on populations in Shenandoah National Park.

  16. Conservation assessment for the Siskiyou Mountains salamander and Scott Bar salamander in northern California.

    SciTech Connect

    Vinikour, W. S.; LaGory, K. E.; Adduci, J. J.; Environmental Science Division

    2006-10-20

    The purpose of this conservation assessment is to summarize existing knowledge regarding the biology and ecology of the Siskiyou Mountains salamander and Scott Bar salamander, identify threats to the two species, and identify conservation considerations to aid federal management for persistence of the species. The conservation assessment will serve as the basis for a conservation strategy for the species.

  17. ARE SALAMANDERS USEFUL INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS?

    EPA Science Inventory

    Regulatory agencies need appropriate indicators of stream permanence to aid in jurisdictional determinations for headwater streams. We evaluated salamanders as permanence indicators because they are often abundant in fishless headwaters. Salamander and habitat data were collect...

  18. Dynamics and thermal sensitivity of ballistic and non-ballistic feeding in salamanders.

    PubMed

    Deban, Stephen M; Scales, Jeffrey A

    2016-02-01

    Low temperature reduces the performance of muscle-powered movements, but in movements powered by elastic recoil mechanisms, this effect can be mitigated and performance can be increased. To better understand the morphological basis of high performance and thermal robustness of elastically powered movements, we compared feeding dynamics at a range of temperatures (5-25°C) in two species of terrestrial plethodontid salamanders, Plethodon metcalfi and Ensatina eschscholtzii, which differ in tongue muscle architecture and the mechanism of tongue projection. We found that Ensatina is capable of ballistic projection with a mean muscle mass-specific power of 2100 W kg(-1), revealing an elastic mechanism. Plethodon, in contrast, projected its tongue non-ballistically with a mean power of only 18 W kg(-1), indicating it is muscle powered. Ensatina projected its tongue significantly farther than Plethodon and with dynamics that had significantly lower thermal sensitivity at temperatures below 15°C. These performance differences were correlated with morphological differences, namely elongated collagenous aponeuroses in the projector muscle of Ensatina as compared with Plethodon, which are likely the site of energy storage, and the absence in Ensatina of projector muscle fibers attaching to the tongue skeleton that allows projection to be truly ballistic. These findings demonstrate that, in these otherwise similar species, the presence in one species of elaborated connective tissue in series with myofibers confers not only 10-fold greater absolute performance but also greater thermal robustness of performance. We conclude that changes in muscle and connective tissue architecture are sufficient to alter significantly the mechanics, performance and thermal robustness of musculoskeletal systems.

  19. Biodiversity of Costa Rican salamanders: Implications of high levels of genetic differentiation and phylogeographic structure for species formation

    PubMed Central

    García-París, Mario; Good, David A.; Parra-Olea, Gabriela; Wake, David B.

    2000-01-01

    Although salamanders are characteristic amphibians in Holarctic temperate habitats, in tropical regions they have diversified evolutionarily only in tropical America. An adaptive radiation centered in Middle America occurred late in the history of a single clade, the supergenus Bolitoglossa (Plethodontidae), and large numbers of species now occur in diverse habitats. Sublineages within this clade decrease in number from the northern to southern parts of Middle America, and in Costa Rica, there are but three. Despite this phylogenetic constraint, Costa Rica has many species; the number of salamander species on one local elevational transect in the Cordillera de Talamanca may be the largest for any such transect in the world. Extraordinary variation in sequences of the mitochondrial gene cytochrome b within a clade of the genus Bolitoglossa in Costa Rica reveals strong phylogeographic structure within a single species, Bolitoglossa pesrubra. Allozymic variation in 19 proteins reveals a pattern largely concordant with the mitochondrial DNA phylogeography. More species exist than are currently recognized. Diversification occurs in restricted geographic areas and involves sharp geographic and elevational differentiation and zonation. In their degree of genetic differentiation at a local scale, these species of the deep tropics exceed the known variation of extratropical salamanders, which also differ in being less restricted in elevational range. Salamanders display “tropicality” in that although speciose, they are usually local in distribution and rare. They display strong ecological and physiological differentiation that may contribute importantly to morphological divergence and species formation. PMID:10677512

  20. [Peculiarities of phosphoglycerate kinase-1 pseudogene evolution in Schrenck salamander (Salamandrella schrenckii Strauch, 1870)].

    PubMed

    Malyarchuk, B A; Denisova, G A; Derenko, M V

    2013-07-01

    Processed copies of genes generally evolve in neutral mode as pseudogenes, however, some of them might be important sources of new functional genes. The psiPGK1 pseudogene has been discovered in Schrenck salamander (Salamandrella schrenckii, Amphibia, Caudata, Hynobiidae) via polymerase chain reaction used to amplify the phosphoglycerate kinase 1 gene (PGK1). This pseudogene is an intronless copy of PGK1 gene absent of exon 6. Analysis of psiPGK1 pseudogene polymorphism has demonstrated that it lacks mutations, which results in shifts in the stop codons and reading frames, as well as that the interspecies variation of this pseudogene was inconsistent with the neutral model of evolution. In addition, the pattern of phylogeographic differentiation of the psiPGK1 variants mainly coincides with that observed in mitochondrial DNA. These observations allow it to be suggested that the psiPGK1 pseudogene is a new functional gene in the Schrenck salamander. PMID:24450152

  1. Salamander occupancy in headwater stream networks

    USGS Publications Warehouse

    Grant, E.H.C.; Green, L.E.; Lowe, W.H.

    2009-01-01

    1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

  2. Data congruence, paedomorphosis and salamanders

    PubMed Central

    Struck, Torsten H

    2007-01-01

    Background The retention of ancestral juvenile characters by adult stages of descendants is called paedomorphosis. However, this process can mislead phylogenetic analyses based on morphological data, even in combination with molecular data, because the assessment if a character is primary absent or secondary lost is difficult. Thus, the detection of incongruence between morphological and molecular data is necessary to investigate the reliability of simultaneous analyses. Different methods have been proposed to detect data congruence or incongruence. Five of them (PABA, PBS, NDI, LILD, DRI) are used herein to assess incongruence between morphological and molecular data in a case study addressing salamander phylogeny, which comprises several supposedly paedomorphic taxa. Therefore, previously published data sets were compiled herein. Furthermore, two strategies ameliorating effects of paedomorphosis on phylogenetic studies were tested herein using a statistical rigor. Additionally, efficiency of the different methods to assess incongruence was analyzed using this empirical data set. Finally, a test statistic is presented for all these methods except DRI. Results The addition of morphological data to molecular data results in both different positions of three of the four paedomorphic taxa and strong incongruence, but treating the morphological data using different strategies ameliorating the negative impact of paedomorphosis revokes these changes and minimizes the conflict. Of these strategies the strategy to just exclude paedomorphic character traits seem to be most beneficial. Of the three molecular partitions analyzed herein the RAG1 partition seems to be the most suitable to resolve deep salamander phylogeny. The rRNA and mtDNA partition are either too conserved or too variable, respectively. Of the different methods to detect incongruence, the NDI and PABA approaches are more conservative in the indication of incongruence than LILD and PBS. Conclusion

  3. Invasive Asian Earthworms Negatively Impact Keystone Terrestrial Salamanders

    PubMed Central

    Ziemba, Julie L.

    2016-01-01

    Asian pheretimoid earthworms (e.g. Amynthas and Metaphire spp.) are invading North American forests and consuming the vital detrital layer that forest floor biota [including the keystone species Plethodon cinereus (Eastern Red-backed Salamander)], rely on for protection, food, and habitat. Plethodon cinereus population declines have been associated with leaf litter loss following the invasion of several exotic earthworm species, but there have been few studies on the specific interactions between pheretimoid earthworms and P. cinereus. Since some species of large and active pheretimoids spatially overlap with salamanders beneath natural cover objects and in detritus, they may distinctively compound the negative consequences of earthworm-mediated resource degradation by physically disturbing important salamander activities (foraging, mating, and egg brooding). We predicted that earthworms would exclude salamanders from high quality microhabitat, reduce foraging efficiency, and negatively affect salamander fitness. In laboratory trials, salamanders used lower quality microhabitat and consumed fewer flies in the presence of earthworms. In a natural field experiment, conducted on salamander populations from “non-invaded” and “pheretimoid invaded” sites in Ohio, salamanders and earthworms shared cover objects ~60% less than expected. Earthworm abundance was negatively associated with juvenile and male salamander abundance, but had no relationship with female salamander abundance. There was no effect of pheretimoid invasion on salamander body condition. Juvenile and non-resident male salamanders do not hold stable territories centered beneath cover objects such as rocks or logs, which results in reduced access to prey, greater risk of desiccation, and dispersal pressure. Habitat degradation and physical exclusion of salamanders from cover objects may hinder juvenile and male salamander performance, ultimately reducing recruitment and salamander abundance

  4. Invasive Asian Earthworms Negatively Impact Keystone Terrestrial Salamanders.

    PubMed

    Ziemba, Julie L; Hickerson, Cari-Ann M; Anthony, Carl D

    2016-01-01

    Asian pheretimoid earthworms (e.g. Amynthas and Metaphire spp.) are invading North American forests and consuming the vital detrital layer that forest floor biota [including the keystone species Plethodon cinereus (Eastern Red-backed Salamander)], rely on for protection, food, and habitat. Plethodon cinereus population declines have been associated with leaf litter loss following the invasion of several exotic earthworm species, but there have been few studies on the specific interactions between pheretimoid earthworms and P. cinereus. Since some species of large and active pheretimoids spatially overlap with salamanders beneath natural cover objects and in detritus, they may distinctively compound the negative consequences of earthworm-mediated resource degradation by physically disturbing important salamander activities (foraging, mating, and egg brooding). We predicted that earthworms would exclude salamanders from high quality microhabitat, reduce foraging efficiency, and negatively affect salamander fitness. In laboratory trials, salamanders used lower quality microhabitat and consumed fewer flies in the presence of earthworms. In a natural field experiment, conducted on salamander populations from "non-invaded" and "pheretimoid invaded" sites in Ohio, salamanders and earthworms shared cover objects ~60% less than expected. Earthworm abundance was negatively associated with juvenile and male salamander abundance, but had no relationship with female salamander abundance. There was no effect of pheretimoid invasion on salamander body condition. Juvenile and non-resident male salamanders do not hold stable territories centered beneath cover objects such as rocks or logs, which results in reduced access to prey, greater risk of desiccation, and dispersal pressure. Habitat degradation and physical exclusion of salamanders from cover objects may hinder juvenile and male salamander performance, ultimately reducing recruitment and salamander abundance following Asian

  5. Invasive Asian Earthworms Negatively Impact Keystone Terrestrial Salamanders.

    PubMed

    Ziemba, Julie L; Hickerson, Cari-Ann M; Anthony, Carl D

    2016-01-01

    Asian pheretimoid earthworms (e.g. Amynthas and Metaphire spp.) are invading North American forests and consuming the vital detrital layer that forest floor biota [including the keystone species Plethodon cinereus (Eastern Red-backed Salamander)], rely on for protection, food, and habitat. Plethodon cinereus population declines have been associated with leaf litter loss following the invasion of several exotic earthworm species, but there have been few studies on the specific interactions between pheretimoid earthworms and P. cinereus. Since some species of large and active pheretimoids spatially overlap with salamanders beneath natural cover objects and in detritus, they may distinctively compound the negative consequences of earthworm-mediated resource degradation by physically disturbing important salamander activities (foraging, mating, and egg brooding). We predicted that earthworms would exclude salamanders from high quality microhabitat, reduce foraging efficiency, and negatively affect salamander fitness. In laboratory trials, salamanders used lower quality microhabitat and consumed fewer flies in the presence of earthworms. In a natural field experiment, conducted on salamander populations from "non-invaded" and "pheretimoid invaded" sites in Ohio, salamanders and earthworms shared cover objects ~60% less than expected. Earthworm abundance was negatively associated with juvenile and male salamander abundance, but had no relationship with female salamander abundance. There was no effect of pheretimoid invasion on salamander body condition. Juvenile and non-resident male salamanders do not hold stable territories centered beneath cover objects such as rocks or logs, which results in reduced access to prey, greater risk of desiccation, and dispersal pressure. Habitat degradation and physical exclusion of salamanders from cover objects may hinder juvenile and male salamander performance, ultimately reducing recruitment and salamander abundance following Asian

  6. Social monogamy in a territorial salamander.

    PubMed

    Gillette; Jaeger; Peterson

    2000-06-01

    Social monogamy, which does not necessarily imply mating or genetic monogamy, is important in the formation of male-female pair associations. We operationally define social monogamy as occurring when two heterosexual adults, exclusive of kin-directed behaviour, direct significantly less aggression and significantly more submission towards each other, and/or spend significantly more time associating with each other relative to other adult heterosexual conspecifics. Long-term pair associations (i.e. those lasting through a lengthy breeding season) that are characteristic of social monogamy are common in some taxa but are virtually unknown in amphibians. Recent studies, however, have suggested that red-backed salamanders, Plethodon cinereus, have complex (for amphibians) social systems. Our laboratory experiments tested the hypothesis that red-backed salamanders found in pairs in the forest display behaviours consistent with social monogamy. During the summer noncourtship season, newly collected male-females pairs showed no preference to associate with their partners more than with a novel conspecific of the opposite sex. However, during the autumn courtship season, paired males and females significantly directed preferential behaviours towards their partners rather than towards a surrogate or a novel paired salamander. Focal animals showed no significant preferences when presented with their partner and a novel single salamander, but they never directed preferential behaviours towards a novel salamander (whether paired or single) or a surrogate. These results are the first to suggest that a salamander species engages in social monogamy. Furthermore, our results suggest that social monogamy may not inhibit paired males and females from displaying alternative strategies: preferring partners when extrapair associations may be disadvantageous (i.e. the extrapair animal is already paired) but not preferring partners when extrapair associations may be advantageous (i

  7. Effects of timber harvests and silvicultural edges on terrestrial salamanders.

    PubMed

    MacNeil, Jami E; Williams, Rod N

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years

  8. Effects of Timber Harvests and Silvicultural Edges on Terrestrial Salamanders

    PubMed Central

    MacNeil, Jami E.; Williams, Rod N.

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years

  9. Effects of timber harvests and silvicultural edges on terrestrial salamanders.

    PubMed

    MacNeil, Jami E; Williams, Rod N

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years

  10. Asymmetric Introgression in a Spotted Salamander Hybrid Zone.

    PubMed

    Johnson, Benjamin B; White, Thomas A; Phillips, Christopher A; Zamudio, Kelly R

    2015-01-01

    Before the establishment of reproductive isolation, deeply diverged intraspecific lineages can experience complex genetic and behavioral interactions as they come into secondary contact. Divergent selective and demographic processes mediate gene flow among lineages, resulting in hybrid zones with complex biogeographic structure. Discordance in the biogeographic patterns of autosomal and maternally inherited loci provides a useful window to infer the processes mediating admixture and introgression across hybrid zones. Here, we sampled 489 genotypes across a hybrid zone between 2 phylogeographic lineages of the spotted salamander, Ambystoma maculatum, and characterize discordant patterns of nuclear and mitochondrial introgression across the contact boundary. Our results indicate asymmetric introgression of nuclear DNA beyond the contact boundary from the western to eastern lineage, with introgression of eastern mitochondrial DNA into the western lineage. We discuss alternative mechanisms for this pattern and attribute this result to neutral patterns of population expansion of the western lineage into the east in combination with female mate choice for larger-bodied western males. Our results underscore the complexity of interacting mechanisms that give rise to reproductive asymmetries in the earliest stages of the speciation process. PMID:26136297

  11. Evolving possibilities: Post-embryonic axial elongation in salamanders with biphasic (Eurcyea cirrigera, E. longicauda, E. quadridigitata) and paedomorphic life cycles (Eurycea nana and Ambystoma mexicanum). Submitted Acta Zoologica

    PubMed Central

    Vaglia, Janet L.; White, Kurt; Case, Alison

    2014-01-01

    Typically the number of vertebrae an organism will have post-embryonically is determined during embryogenesis via the development of paired somites. Our research investigates the phenomenon of post-embryonic vertebral addition in salamander tails. We describe body and tail growth, and patterns of postsacral vertebral addition and elongation in context with caudal morphology for four plethodontids (Eurycea), and one ambystomatid. Eurycea nana and A. mexicanum have paedomorphic life cycles; E. cirrigera, E. longicauda and E. quadridigitata are biphasic. Specimens were collected, borrowed and/or purchased, and cleared and stained for bone and cartilage. Data collected include snout-vent length (SVL), tail length (TL), vertebral counts and centrum lengths. Eurycea species with biphasic life cycles had TLs that surpassed SVL following metamorphosis. Tails in paedomorphic species elongated but rarely exceeded body length. Larger TLs were associated with more vertebrae and longer vertebrae in all species. We observed that rates of postsacral vertebral addition varied little amongst species. Regional variation along the tail becomes prominent following metamorphosis in biphasic developers. In all species vertebrae in the posterior one-half of the tail taper towards the tip. We suggest a developmental link might exist between the ability to continually add vertebrae and regeneration in salamanders. PMID:24790225

  12. Phylogeography of Sardinian Cave Salamanders (Genus Hydromantes) Is Mainly Determined by Geomorphology

    PubMed Central

    Chiari, Ylenia; van der Meijden, Arie; Mucedda, Mauro; Lourenço, João M.; Hochkirch, Axel; Veith, Michael

    2012-01-01

    Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems. PMID:22427830

  13. Phylogeography of Sardinian cave salamanders (genus Hydromantes) is mainly determined by geomorphology.

    PubMed

    Chiari, Ylenia; van der Meijden, Arie; Mucedda, Mauro; Lourenço, João M; Hochkirch, Axel; Veith, Michael

    2012-01-01

    Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems.

  14. Phylogeography of Sardinian cave salamanders (genus Hydromantes) is mainly determined by geomorphology.

    PubMed

    Chiari, Ylenia; van der Meijden, Arie; Mucedda, Mauro; Lourenço, João M; Hochkirch, Axel; Veith, Michael

    2012-01-01

    Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems. PMID:22427830

  15. Sex in unisexual salamanders: discovery of a new sperm donor with ancient affinities.

    PubMed

    Bogart, J P; Bartoszek, J; Noble, D W A; Bi, K

    2009-12-01

    Although bisexual reproduction has considerable evolutionary benefits, several all-female vertebrates exist. Unisexual salamanders in the genus Ambystoma are common around the Great Lakes region in eastern North America. They originated from a hybridization event that involved a female that shared a common ancestor with Ambystoma barbouri 2.4 to 3.9 million years ago but, unexpectedly, A. barbouri nuclear genomes were unknown in unisexuals. Unisexual salamanders steal sperm from donors of normally bisexual species, so their reproductive mode is described as kleptogenesis. Most known unisexuals are polyploid and they all possess at least one A. laterale genome. One or more other genomes are taken from sperm donors that may include A. jeffersonianum, A. laterale, A. texanum and A. tigrinum. We examined unisexual adults and larvae in a southern Ohio pond where unisexual individuals coexist with male A. barbouri. This population provided an opportunity to test hypotheses pertaining to the role of A. barbouri in the evolution of the disparate cytoplasmic and nuclear genomes in unisexual salamanders. Microsatellite DNA loci, mitochondrial DNA sequences and genomic in situ hybridization were used to identify the genomic constitution of individuals. A. barbouri was found to be an acceptable sperm donor for unisexuals but only contributed genomes in ploidy-elevated individuals. In the absence of A. jeffersonianum, this Ohio population is likely experiencing a recent switch in sperm donors from A. jeffersonianum to A. barbouri and demonstrates the evolutionary flexibility and dynamics of kleptogenesis. PMID:19639004

  16. Structural Insights into the Evolution of a Sexy Protein: Novel Topology and Restricted Backbone Flexibility in a Hypervariable Pheromone from the Red-Legged Salamander, Plethodon shermani

    PubMed Central

    Wilburn, Damien B.; Bowen, Kathleen E.; Doty, Kari A.; Arumugam, Sengodagounder; Lane, Andrew N.; Feldhoff, Pamela W.; Feldhoff, Richard C.

    2014-01-01

    In response to pervasive sexual selection, protein sex pheromones often display rapid mutation and accelerated evolution of corresponding gene sequences. For proteins, the general dogma is that structure is maintained even as sequence or function may rapidly change. This phenomenon is well exemplified by the three-finger protein (TFP) superfamily: a diverse class of vertebrate proteins co-opted for many biological functions – such as components of snake venoms, regulators of the complement system, and coordinators of amphibian limb regeneration. All of the >200 structurally characterized TFPs adopt the namesake “three-finger” topology. In male red-legged salamanders, the TFP pheromone Plethodontid Modulating Factor (PMF) is a hypervariable protein such that, through extensive gene duplication and pervasive sexual selection, individual male salamanders express more than 30 unique isoforms. However, it remained unclear how this accelerated evolution affected the protein structure of PMF. Using LC/MS-MS and multidimensional NMR, we report the 3D structure of the most abundant PMF isoform, PMF-G. The high resolution structural ensemble revealed a highly modified TFP structure, including a unique disulfide bonding pattern and loss of secondary structure, that define a novel protein topology with greater backbone flexibility in the third peptide finger. Sequence comparison, models of molecular evolution, and homology modeling together support that this flexible third finger is the most rapidly evolving segment of PMF. Combined with PMF sequence hypervariability, this structural flexibility may enhance the plasticity of PMF as a chemical signal by permitting potentially thousands of structural conformers. We propose that the flexible third finger plays a critical role in PMF:receptor interactions. As female receptors co-evolve, this flexibility may allow PMF to still bind its receptor(s) without the immediate need for complementary mutations. Consequently, this

  17. Structural insights into the evolution of a sexy protein: novel topology and restricted backbone flexibility in a hypervariable pheromone from the red-legged salamander, Plethodon shermani.

    PubMed

    Wilburn, Damien B; Bowen, Kathleen E; Doty, Kari A; Arumugam, Sengodagounder; Lane, Andrew N; Feldhoff, Pamela W; Feldhoff, Richard C

    2014-01-01

    In response to pervasive sexual selection, protein sex pheromones often display rapid mutation and accelerated evolution of corresponding gene sequences. For proteins, the general dogma is that structure is maintained even as sequence or function may rapidly change. This phenomenon is well exemplified by the three-finger protein (TFP) superfamily: a diverse class of vertebrate proteins co-opted for many biological functions - such as components of snake venoms, regulators of the complement system, and coordinators of amphibian limb regeneration. All of the >200 structurally characterized TFPs adopt the namesake "three-finger" topology. In male red-legged salamanders, the TFP pheromone Plethodontid Modulating Factor (PMF) is a hypervariable protein such that, through extensive gene duplication and pervasive sexual selection, individual male salamanders express more than 30 unique isoforms. However, it remained unclear how this accelerated evolution affected the protein structure of PMF. Using LC/MS-MS and multidimensional NMR, we report the 3D structure of the most abundant PMF isoform, PMF-G. The high resolution structural ensemble revealed a highly modified TFP structure, including a unique disulfide bonding pattern and loss of secondary structure, that define a novel protein topology with greater backbone flexibility in the third peptide finger. Sequence comparison, models of molecular evolution, and homology modeling together support that this flexible third finger is the most rapidly evolving segment of PMF. Combined with PMF sequence hypervariability, this structural flexibility may enhance the plasticity of PMF as a chemical signal by permitting potentially thousands of structural conformers. We propose that the flexible third finger plays a critical role in PMF:receptor interactions. As female receptors co-evolve, this flexibility may allow PMF to still bind its receptor(s) without the immediate need for complementary mutations. Consequently, this unique

  18. Structural insights into the evolution of a sexy protein: novel topology and restricted backbone flexibility in a hypervariable pheromone from the red-legged salamander, Plethodon shermani.

    PubMed

    Wilburn, Damien B; Bowen, Kathleen E; Doty, Kari A; Arumugam, Sengodagounder; Lane, Andrew N; Feldhoff, Pamela W; Feldhoff, Richard C

    2014-01-01

    In response to pervasive sexual selection, protein sex pheromones often display rapid mutation and accelerated evolution of corresponding gene sequences. For proteins, the general dogma is that structure is maintained even as sequence or function may rapidly change. This phenomenon is well exemplified by the three-finger protein (TFP) superfamily: a diverse class of vertebrate proteins co-opted for many biological functions - such as components of snake venoms, regulators of the complement system, and coordinators of amphibian limb regeneration. All of the >200 structurally characterized TFPs adopt the namesake "three-finger" topology. In male red-legged salamanders, the TFP pheromone Plethodontid Modulating Factor (PMF) is a hypervariable protein such that, through extensive gene duplication and pervasive sexual selection, individual male salamanders express more than 30 unique isoforms. However, it remained unclear how this accelerated evolution affected the protein structure of PMF. Using LC/MS-MS and multidimensional NMR, we report the 3D structure of the most abundant PMF isoform, PMF-G. The high resolution structural ensemble revealed a highly modified TFP structure, including a unique disulfide bonding pattern and loss of secondary structure, that define a novel protein topology with greater backbone flexibility in the third peptide finger. Sequence comparison, models of molecular evolution, and homology modeling together support that this flexible third finger is the most rapidly evolving segment of PMF. Combined with PMF sequence hypervariability, this structural flexibility may enhance the plasticity of PMF as a chemical signal by permitting potentially thousands of structural conformers. We propose that the flexible third finger plays a critical role in PMF:receptor interactions. As female receptors co-evolve, this flexibility may allow PMF to still bind its receptor(s) without the immediate need for complementary mutations. Consequently, this unique

  19. Homing orientation in salamanders: A mechanism involving chemical cues

    NASA Technical Reports Server (NTRS)

    Madison, D. M.

    1972-01-01

    A detailed description is given of experiments made to determine the senses and chemical cues used by salamanders for homing orientation. Sensory impairment and cue manipulative techniques were used in the investigation. All experiments were carried out at night. Results show that sense impaired animals did not home as readily as those who were blind but retained their sensory mechanism. This fact suggests that the olfactory mechanism is necessary for homing in the salamander. It was determined that after the impaired salamander regenerated its sensory mechanism it too returned home. It was concluded that homing ability in salamanders is direction independent, distant dependent, and vision independent.

  20. Stream salamanders as indicators of stream quality in Maryland, USA

    USGS Publications Warehouse

    Southerland, M.T.; Jung, R.E.; Baxter, D.P.; Chellman, I.C.; Mercurio, G.; Volstad, J.H.

    2004-01-01

    Biological indicators are critical to the protection of small, headwater streams and the ecological values they provide. Maryland and other state monitoring programs have determined that fish indicators are ineffective in small streams, where stream salamanders may replace fish as top predators. Because of their life history, physiology, abundance, and ubiquity, stream salamanders are likely representative of biological integrity in these streams. The goal of this study was to determine whether stream salamanders are effective indicators of ecological conditions across biogeographic regions and gradients of human disturbance. During the summers of 2001 and 2002, we intensively surveyed for stream salamanders at 76 stream sites located west of the Maryland Coastal Plain, sites also monitored by the Maryland Biological Stream Survey (MBSS) and City of Gaithersburg. We found 1,584 stream salamanders, including all eight species known in Maryland, using two 15 ? 2 m transects and two 4 m2 quadrats that spanned both stream bank and channel. We performed removal sampling on transects to estimate salamander species detection probabilities, which ranged from 0.67-0.85. Stepwise regressions identified 15 of 52 non-salamander variables, representing water quality, physical habitat, land use, and biological conditions, which best predicted salamander metrics. Indicator development involved (1) identifying reference (non-degraded) and degraded sites (using percent forest, shading, riparian buffer width, aesthetic rating, and benthic macroinvertebrate and fish indices of biotic integrity); (2) testing 12 candidate salamander metrics (representing species richness and composition, abundance, species tolerance, and reproductive function) for their ability to distinguish reference from degraded sites; and (3) combining metrics into an index that effectively discriminated sites according to known stream conditions. Final indices for Highlands, Piedmont, and Non-Coastal Plain

  1. Reproductive biology of Ambystoma salamanders in the southeastern United States

    USGS Publications Warehouse

    Glorioso, Brad M.; Waddle, J. Hardin; Hefner, Jeromi M.

    2015-01-01

    Reproductive aspects of Ambystoma salamanders were investigated at sites in Louisiana (2010–12) and Mississippi (2013). Three species occurred at the Louisiana site, Spotted Salamander (A. maculatum), Marbled Salamander (A. opacum), and Mole Salamander (A. talpoideum), whereas only Spotted Salamanders were studied at the Mississippi site. A total of 162 and 71 egg masses of Spotted Salamanders were examined at the Louisiana and Mississippi sites, respectively. Significantly more Spotted Salamander eggs per egg mass were observed at the Mississippi site (x̄ = 78.2) than the Louisiana site (x̄ = 53.8; P < 0.001). The mean snout–vent length of female Spotted Salamanders at the Mississippi site (82.9 mm) was significantly larger than the Louisiana site (76.1 mm; P < 0.001). Opaque Spotted Salamander egg masses were not found at the Mississippi site, but accounted for 11% of examined egg masses at the Louisiana site. The mean number of eggs per egg mass at the Louisiana site did not differ between opaque (47.3) and clear (54.6) egg masses (P = 0.21). A total of 47 egg masses of the Mole Salamander were examined, with a mean number of 6.7 embryos per mass. Twenty-three individual nests of the Marbled Salamander were found either under or in decaying logs in the dry pond basins. There was no difference between the mean numbers of eggs per mass of attended nests (93.0) versus those that were discovered unattended (86.6; P = 0.67). Females tended to place their nests at intermediate heights within the pond basin.

  2. Bromeliad selection by two salamander species in a harsh environment.

    PubMed

    Ruano-Fajardo, Gustavo; Rovito, Sean M; Ladle, Richard J

    2014-01-01

    Bromeliad phytotelmata are frequently used by several Neotropical amphibian taxa, possibly due to their high humidity, microclimatic stability, and role as a refuge from predators. Indeed, the ability of phytotelmata to buffer against adverse environmental conditions may be instrumental in allowing some amphibian species to survive during periods of environmental change or to colonize sub-optimal habitats. Association between bromeliad traits and salamanders has not been studied at a fine scale, despite the intimate association of many salamander species with bromeliads. Here, we identify microhabitat characteristics of epiphytic bromeliads used by two species of the Bolitoglossa morio group (B. morio and B. pacaya) in forest disturbed by volcanic activity in Guatemala. Specifically, we measured multiple variables for bromeliads (height and position in tree, phytotelma water temperature and pH, canopy cover, phytotelma size, leaf size, and tree diameter at breast height), as well as salamander size. We employed a DNA barcoding approach to identify salamanders. We found that B. morio and B. pacaya occurred in microsympatry in bromeliads and that phytotelmata size and temperature of bromeliad microhabitat were the most important factors associated with the presence of salamanders. Moreover, phytotelmata with higher pH contained larger salamanders, suggesting that larger salamanders or aggregated individuals might modify pH. These results show that bromeliad selection is nonrandom with respect to microhabitat characteristics, and provide insight into the relationship between salamanders and this unique arboreal environment.

  3. Bromeliad Selection by Two Salamander Species in a Harsh Environment

    PubMed Central

    Ruano-Fajardo, Gustavo; Rovito, Sean M.; Ladle, Richard J.

    2014-01-01

    Bromeliad phytotelmata are frequently used by several Neotropical amphibian taxa, possibly due to their high humidity, microclimatic stability, and role as a refuge from predators. Indeed, the ability of phytotelmata to buffer against adverse environmental conditions may be instrumental in allowing some amphibian species to survive during periods of environmental change or to colonize sub-optimal habitats. Association between bromeliad traits and salamanders has not been studied at a fine scale, despite the intimate association of many salamander species with bromeliads. Here, we identify microhabitat characteristics of epiphytic bromeliads used by two species of the Bolitoglossa morio group (B. morio and B. pacaya) in forest disturbed by volcanic activity in Guatemala. Specifically, we measured multiple variables for bromeliads (height and position in tree, phytotelma water temperature and pH, canopy cover, phytotelma size, leaf size, and tree diameter at breast height), as well as salamander size. We employed a DNA barcoding approach to identify salamanders. We found that B. morio and B. pacaya occurred in microsympatry in bromeliads and that phytotelmata size and temperature of bromeliad microhabitat were the most important factors associated with the presence of salamanders. Moreover, phytotelmata with higher pH contained larger salamanders, suggesting that larger salamanders or aggregated individuals might modify pH. These results show that bromeliad selection is nonrandom with respect to microhabitat characteristics, and provide insight into the relationship between salamanders and this unique arboreal environment. PMID:24892414

  4. Bromeliad selection by two salamander species in a harsh environment.

    PubMed

    Ruano-Fajardo, Gustavo; Rovito, Sean M; Ladle, Richard J

    2014-01-01

    Bromeliad phytotelmata are frequently used by several Neotropical amphibian taxa, possibly due to their high humidity, microclimatic stability, and role as a refuge from predators. Indeed, the ability of phytotelmata to buffer against adverse environmental conditions may be instrumental in allowing some amphibian species to survive during periods of environmental change or to colonize sub-optimal habitats. Association between bromeliad traits and salamanders has not been studied at a fine scale, despite the intimate association of many salamander species with bromeliads. Here, we identify microhabitat characteristics of epiphytic bromeliads used by two species of the Bolitoglossa morio group (B. morio and B. pacaya) in forest disturbed by volcanic activity in Guatemala. Specifically, we measured multiple variables for bromeliads (height and position in tree, phytotelma water temperature and pH, canopy cover, phytotelma size, leaf size, and tree diameter at breast height), as well as salamander size. We employed a DNA barcoding approach to identify salamanders. We found that B. morio and B. pacaya occurred in microsympatry in bromeliads and that phytotelmata size and temperature of bromeliad microhabitat were the most important factors associated with the presence of salamanders. Moreover, phytotelmata with higher pH contained larger salamanders, suggesting that larger salamanders or aggregated individuals might modify pH. These results show that bromeliad selection is nonrandom with respect to microhabitat characteristics, and provide insight into the relationship between salamanders and this unique arboreal environment. PMID:24892414

  5. Northwestern salamanders Ambystoma gracile in mountain lakes: record oviposition depths among salamanders

    USGS Publications Warehouse

    Hoffman, R.; Pearl, C.A.; Larson, G.L.; Samora, B.

    2012-01-01

    Oviposition timing, behaviors, and microhabitats of ambystomatid salamanders vary considerably (Egan and Paton 2004; Figiel and Semlitsch 1995; Howard and Wallace 1985; Mac-Cracken 2007). Regardless of species, however, females typically oviposit using sites conducive to embryo development and survival. For example, the results of an experiment by Figiel and Semlitsch (1995) on Ambystoma opacum (Marbled Salamander) oviposition indicated that females actively selected sites that were under grass clumps in wet versus dry treatments, and surmised that environmental conditions such as humidity, moisture, and temperature contributed to their results. Other factors associated with ambystomatid oviposition and embryo survival include water temperature (Anderson 1972; Brown 1976), dissolved oxygen concentration (Petranka et al. 1982; Sacerdote and King 2009), oviposition depth (Dougherty et al. 2005; Egan and Paton 2004), and oviposition attachment structures such as woody vegetation (McCracken 2007; Nussbaum et al. 1983). Resetarits (1996), in creating a model of oviposition site selection for anuran amphibians, hypothesized that oviparous organisms were also capable of modifying oviposition behavior and site selection to accommodate varying habitat conditions and to minimize potential negative effects of environmental stressors. Kats and Sih (1992), investigating the oviposition of Ambystoma barbouri (Streamside Salamander) in pools of a Kentucky stream, found that females preferred pools without predatory Lepomis cyanellus (Green Sunfish), and that the number of egg masses present in a pool historically containing fish increased significantly the year after fish had been extirpated from the pool. Palen et al. (2005) determined that Ambystoma gracile (Northwestern Salamander) and Ambystoma macrodactylum (Longtoed Salamander) eggs were deposited either at increased depth or in full shaded habitats, respectively, as water transperancy to UV-B radiation increased.

  6. Ecological separation in a polymorphic terrestrial salamander.

    PubMed

    Anthony, Carl D; Venesky, Matthew D; Hickerson, Cari-Ann M

    2008-07-01

    1. When studying speciation, researchers commonly examine reproductive isolation in recently diverged populations. Polymorphic species provide an opportunity to examine the role of reproductive isolation in populations that may be in the process of divergence. 2. We examined a polymorphic population of Plethodon cinereus (red-backed salamanders) for evidence of sympatric ecological separation by colour morphology. Recent studies have correlated temperature and climate with colour morphology in this species, but no studies have looked at differences in diet or mate choice between colour morphs. We used artificial cover objects to assess salamander diet, mating preference and surface activity over a 2-year period at a field site in north-eastern Ohio. 3. We detected differences in diet between two colour morphs, striped and unstriped. The diets of striped individuals were significantly more diverse and were made up of more profitable prey than the diets of unstriped salamanders. 4. Opposite sex pairs were made up of individuals of the same colour morph and striped males were found more often with larger females than were unstriped males. 5. We corroborate findings of earlier studies suggesting that the unstriped form is adapted to warmer conditions. Unstriped individuals were the first to withdraw from the forest floor as temperatures fell in the late fall. We found no evidence that the colour morphs responded differently to abiotic factors such as soil moisture and relative humidity, and responses to surface temperatures were also equivocal. 6. We conclude that the two colour morphs exhibit some degree of ecological separation and tend to mate assortatively, but are unlikely to be undergoing divergence given the observed frequency of intermorph pairings.

  7. Effects of red-backed salamanders on ecosystem functions.

    PubMed

    Hocking, Daniel J; Babbitt, Kimberly J

    2014-01-01

    Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp.) likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus) on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2) plots) and small-scale enclosures (2 m(2)) where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2)). In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders). Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

  8. Effects of Red-Backed Salamanders on Ecosystem Functions

    PubMed Central

    Hocking, Daniel J.; Babbitt, Kimberly J.

    2014-01-01

    Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp.) likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus) on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m2 plots) and small-scale enclosures (2 m2) where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m−2). In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders). Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types. PMID:24466269

  9. Effects of red-backed salamanders on ecosystem functions.

    PubMed

    Hocking, Daniel J; Babbitt, Kimberly J

    2014-01-01

    Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp.) likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus) on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2) plots) and small-scale enclosures (2 m(2)) where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2)). In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders). Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types. PMID:24466269

  10. Effects of urbanization on occupancy of stream salamanders.

    PubMed

    Price, Steven J; Cecala, Kristen K; Browne, Robert A; Dorcas, Michael E

    2011-06-01

    Urban development is the most common form of land conversion in the United States. Using a before-after control-impact study design, we investigated the effects of urbanization on larval and adult stages of southern two-lined salamanders (Eurycea cirrigera) and northern dusky salamanders (Desmognathus fuscus). Over 5 years, we estimated changes in occupancy and probabilities of colonization and survival in 13 stream catchments after urbanization and in 17 catchments that were not urbanized. We also examined effects of proportion of urbanized area in a catchment and distance of the salamander population to the nearest stream on probabilities of colonization and survival. Before urbanization, adult and larval stages of the two salamander species occupied nearly all surveyed streams, with occupancy estimates ranging from 1.0 to 0.78. Four years after urbanization mean occupancy of larval and adult two-lined salamanders had decreased from 0.87 and 0.78 to 0.57 and 0.39, respectively. Estimates of mean occupancy of larval northern dusky salamanders decreased from 1.0 to 0.57 in urban streams 4 years after urbanization; however, adult northern dusky salamander occupancy remained close to 1.0 in urban streams over 5 years. Occupancy estimates in control streams were similar for each species and stage over 5 years. Urbanization was associated with decreases in survival probabilities of adult and larval two-lined salamanders and decreases in colonization probabilities of larval dusky salamanders. Nevertheless, proportion of impervious surface and distance to nearest stream had little effect on probabilities of survival and colonization. Our results imply that in the evaluation of the effects of urbanization on species, such as amphibians, with complex life cycles, consideration of the effects of urbanization on both adult and larval stages is required.

  11. Paedomorphosis and simplification in the nervous system of salamanders.

    PubMed

    Roth, G; Nishikawa, K C; Naujoks-Manteuffel, C; Schmidt, A; Wake, D B

    1993-01-01

    Comparative neuroanatomists since Herrick [1914] have been aware of the paradox that the brain of amphibians, especially salamanders, is less complex than one would expect based on their phylogenetic position among the Tetrapoda. Many features of the brain are less differentiated in salamanders than in tetrapod outgroups, including chondrichthyans and bony fishes, and for some brain characters, the salamander brain is even more simple than that of the agnathans. Here, we perform a cladistic analysis on 23 characters of four sensory systems (visual, auditory, lateral line and olfactory) and the brain. Our taxa include myxinoids, lampreys, chondrichthyans, actinopterygians, Latimeria, Neoceratodus and the lepidosirenid lungfishes, amniotes, frogs, caecilians, salamanders and bolitoglossine salamanders. Of the 23 characters we examined, 19 are most parsimoniously interpreted as secondarily simplified in salamanders from a more complex ancestral state, two characters are equally parsimonious under both hypotheses, one character (well developed ipsilateral retinotectal projections) is more complex in bolitoglossine salamanders than in vertebrates generally, and only one character (migration of neurons in the medial pallium) is most parsimoniously interpreted as retention of the plesiomorphically simple condition. Secondary simplification of the salamander brain appears to result from paedomorphosis, or retention of juvenile or embryonic morphology into adulthood. Paedomorphosis is correlated with an increase in genome size, which in turn is positively correlated with cell size, but negatively correlated with cell proliferation and differentiation rates. Available data suggest that, although increasing genome size and paedomorphosis tend to compromise the function of the salamander brain, compensating mechanisms have evolved that may restore or even enhance brain function. PMID:8364715

  12. Locomotion and visually guided behavior in salamander: a neuromechanical study

    NASA Astrophysics Data System (ADS)

    Ijspeert, Auke J.; Arbib, Michael A.

    2000-10-01

    This article investigates the neural mechanisms underlying locomotion and visually-guided behavior in a lower vertebrate: the salamander. We develop connectionist models of the salamander's locomotor circuitry and visual system, and analyze their functioning by embedding them into a biomechanical simulation of the salamander's body. This work is therefore an experiment in computational neuroethology which aims at investigating how behavior results from the coupling of a central nervous system (CNS) and a body, and from the interactions of the CNS-body pair with the environment. We believe that understanding these mechanisms is not only relevant for neurobiology but also for potential applications in robotics.

  13. Generation of aneurogenic larvae by parabiosis of salamander embryos.

    PubMed

    Kumar, Anoop; Delgado, Jean Paul

    2015-01-01

    Limb regeneration of salamanders is nerve dependent, and the removal of the nerves in early stages of limb regeneration severely curtails the proliferation of the blastemal cells and growth of the regenerate. The removal of the neural tube from a developing salamander embryo results in an aneurogenic larva and the aneurogenic limb (ANL) develops independently without innervation. Paradoxically, the limb in an ANL is capable of regeneration in a nerve-independent manner. Here, we describe a detailed method for the generation of ANL in the spotted salamander, Ambystoma maculatum, for regeneration studies.

  14. Could we also be regenerative superheroes, like salamanders?

    PubMed

    Dall'Agnese, Alessandra; Puri, Pier Lorenzo

    2016-09-01

    Development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. While most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. Studies in newts and axolotls, two salamander models, have provided significant knowledge about adult limb regeneration. In this review, we present a comparative analysis of salamander and mammalian regeneration and discuss how evolutionarily altered properties of the regenerative environment can be exploited to restore full regenerative potential in the human body. PMID:27338874

  15. Could we also be regenerative superheroes, like salamanders?

    PubMed

    Dall'Agnese, Alessandra; Puri, Pier Lorenzo

    2016-09-01

    Development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. While most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. Studies in newts and axolotls, two salamander models, have provided significant knowledge about adult limb regeneration. In this review, we present a comparative analysis of salamander and mammalian regeneration and discuss how evolutionarily altered properties of the regenerative environment can be exploited to restore full regenerative potential in the human body.

  16. Ancient DNA assessment of tiger salamander population in Yellowstone National Park.

    PubMed

    McMenamin, Sarah K; Hadly, Elizabeth A

    2012-01-01

    Recent data indicates that blotched tiger salamanders (Ambystoma tigrinum melanostictum) in northern regions of Yellowstone National Park are declining due to climate-related habitat changes. In this study, we used ancient and modern mitochondrial haplotype diversity to model the effective size of this amphibian population through recent geological time and to assess past responses to climatic changes in the region. Using subfossils collected from a cave in northern Yellowstone, we analyzed >700 base pairs of mitochondrial sequence from 16 samples ranging in age from 100 to 3300 years old and found that all shared an identical haplotype. Although mitochondrial diversity was extremely low within the living population, we still were able to detect geographic subdivision within the local area. Using serial coalescent modelling with Bayesian priors from both modern and ancient genetic data we simulated a range of probable population sizes and mutation rates through time. Our simulations suggest that regional mitochondrial diversity has remained relatively constant even through climatic fluctuations of recent millennia.

  17. Reduced genetic variation in the Japanese giant salamander, Andrias japonicus (Amphibia: Caudata).

    PubMed

    Matsui, Masafumi; Tominaga, Atsushi; Liu, Wan-zhao; Tanaka-Ueno, Tomoko

    2008-10-01

    The phylogenetic relationships among 46 samples from 27 populations of the Japanese giant salamander, Andriasjaponicus and its congener, A. davidianus from China was investigated, using 3664 bp sequences of the mitochondrial genes NADH1, NADH3, cyt b and CR, partial NADH6 and intervening genes. In phylogenetic trees constructed by MP, ML, and Bayesian methods, the family Cryptobranchidae and the genus Andrias both form monophyletic groups. Japanese A. japonicus and Chinese A. davidianus are sister taxa and can be regarded as separate species despite a small degree of genetic differentiation. Andriasjaponicus is divided into central and western clades, but the phylogenetic relationships within the latter clade are unresolved. As previously reported from allozyme analyses, A. japonicus exhibits little genetic differentiation, in strong contrast to salamanders of the genus Hynobius with which their distributions overlap. This reduced genetic variability in A. japonicus is attributable to a unique mating system of polygyny, delayed sexual maturity, notable longevity, life in a stable aquatic environment, and gigantism, as well as bottleneck effects following habitat fragmentation and extinction of local populations during Quaternary glaciations. The species is thus susceptible to extinction by potential environmental fluctuations, and requires extensive conservation measures. PMID:18723097

  18. Salamander-like development in a seymouriamorph revealed by palaeohistology.

    PubMed

    Sanchez, Sophie; Klembara, Jozef; Castanet, Jacques; Steyer, J Sébastien

    2008-08-23

    The amniotes generally lay eggs on land and are thereby differentiated from lissamphibians (salamanders, frogs and caecilians) by their developmental pattern. Although a number of 330-300-Myr old fossils are regarded as early tetrapods placed close to amniotes on the basis of anatomical data, we still do not know whether their developmental pattern was more similar to those of lissamphibians or amniotes. Here we report palaeohistological and skeletochronological evidence supporting a salamander-like development in the seymouriamorph Discosauriscus. Its long-bone growth pattern, slow diaphyseal growth rate and delayed sexual maturity (at more than 10 years old) are more comparable with growth features of extant salamanders rather than extant amniotes, even though they are mostly hypothesized to be phylogenetically closer to living amniotes than salamanders.

  19. Habitat requirements of New Mexico’s endangered salamanders

    USGS Publications Warehouse

    Ramotnik, Cindy A.; Scott, N.J.

    1988-01-01

    We measured habitat components for two state-listed endangered salamanders in New Mexico in 1986 and 1987. Both species are restricted to mesic environments within high-elevation, mixed coniferous forests. Steep slope and high elevation were the most useful variables for predicting the occurrence of Jemez Mountains salamanders and Sacramento Mountain salamanders, respectively. Although the discriminant models show some predictive value in detecting salamanders based on habitat variables, we believe that the best survey technique is ground-truth surveys in wet weather. A better fit of the discriminant models might be obtained by including variables not measured e.g., fire and logging history, and soil characteristics. We offer interim management guidelines as a result of our analysis.

  20. Salamander-like development in a seymouriamorph revealed by palaeohistology.

    PubMed

    Sanchez, Sophie; Klembara, Jozef; Castanet, Jacques; Steyer, J Sébastien

    2008-08-23

    The amniotes generally lay eggs on land and are thereby differentiated from lissamphibians (salamanders, frogs and caecilians) by their developmental pattern. Although a number of 330-300-Myr old fossils are regarded as early tetrapods placed close to amniotes on the basis of anatomical data, we still do not know whether their developmental pattern was more similar to those of lissamphibians or amniotes. Here we report palaeohistological and skeletochronological evidence supporting a salamander-like development in the seymouriamorph Discosauriscus. Its long-bone growth pattern, slow diaphyseal growth rate and delayed sexual maturity (at more than 10 years old) are more comparable with growth features of extant salamanders rather than extant amniotes, even though they are mostly hypothesized to be phylogenetically closer to living amniotes than salamanders. PMID:18460423

  1. Escape to Alcatraz: evolutionary history of slender salamanders (Batrachoseps) on the islands of San Francisco Bay

    PubMed Central

    Martínez-Solano, Iñigo; Lawson, Robin

    2009-01-01

    Background Island populations are excellent model systems for studies of phenotypic, ecological and molecular evolution. In this study, molecular markers of mitochondrial and nuclear derivation were used to investigate the evolution, structure and origin of populations of the California slender salamander (Batrachoseps attenuatus) inhabiting the six major islands of San Francisco Bay, formed following the rising of sea level around 9,000 years ago. Results There was a high degree of congruence in the results of analyses of nucleotide and allozyme data, both of which strongly support the hypothesis that, for the majority of the islands, salamanders are descended from hilltop populations that became isolated with the formation of the Bay ca. 9,000 years ago. There are two exceptions (Alcatraz and Yerba Buena) where the evidence suggests that salamander populations are wholly or in part, the result of anthropogenic introductions. Comparison of the molecular data and the interpretations drawn therefrom with an earlier morphological study of many of the same salamander populations show some of the same evolutionary trends. Conclusion In spite of marked differences between the evolutionary rates of the two kinds of molecular markers, both indicate distinctive and similar patterns of population structure for B. attenuatus in the San Francisco Bay Area and its islands. With the two noted exceptions, it is clear that most island populations were established prior to the 9,000 years since the formation of the Bay. Results of coalescence-based analyses suggest that for most island populations the mtDNA lineages from which they were derived date from the Pleistocene. It can be said that, based on observed values of genetic diversity, the last 9,000 years of evolution on these islands have been characterized by relative stability, with the occasional extinction of some haplotypes or alleles that were formerly shared between island and mainland populations but overall

  2. Terrestrial salamander abundance on reclaimed mountaintop removal mines

    USGS Publications Warehouse

    Wood, Petra Bohall; Williams, Jennifer M.

    2013-01-01

    Mountaintop removal mining, a large-scale disturbance affecting vegetation, soil structure, and topography, converts landscapes from mature forests to extensive grassland and shrubland habitats. We sampled salamanders using drift-fence arrays and coverboard transects on and near mountaintop removal mines in southern West Virginia, USA, during 2000–2002. We compared terrestrial salamander relative abundance and species richness of un-mined, intact forest with habitats on reclaimed mountaintop removal mines (reclaimed grassland, reclaimed shrubland, and fragmented forest). Salamanders within forests increased in relative abundance with increasing distance from reclaimed mine edge. Reclaimed grassland and shrubland habitats had lower relative abundance and species richness than forests. Characteristics of reclaimed habitats that likely contributed to lower salamander abundance included poor soils (dry, compacted, little organic matter, high rock content), reduced vertical structure of vegetation and little tree cover, and low litter and woody debris cover. Past research has shown that salamander populations reduced by clearcutting may rebound in 15–24 years. Time since disturbance was 7–28 years in reclaimed habitats on our study areas and salamander populations had not reached levels found in adjacent mature forests.

  3. Defining evolutionary boundaries across parapatric ecomorphs of Black Salamanders (Aneides flavipunctatus) with conservation implications.

    PubMed

    Reilly, Sean B; Marks, Sharyn B; Jennings, W Bryan

    2012-12-01

    The accurate delimitation of evolutionary population units represents an important component in phylogeographic and conservation genetic studies. Here, we used a combined population assignment and historical demographic approach to study a complex of ecomorphologically distinctive populations of Black Salamanders (Aneides flavipunctatus) that are parapatrically distributed and meet at a three-way contact zone in north-western California. We used mitochondrial tree-based and multilocus clustering methods to evaluate a priori two- (Northern and Southern) and three (Northern, Coast and Inland) population hypotheses derived from previous studies. Mitochondrial results were consistent with the two- and three-population hypotheses, while the nDNA clustering results supported only the two-population hypothesis. Historical demographic analyses and mtDNA gene divergence estimates revealed that the Northern and Southern populations split during the Pliocene (2-5 Ma). Subdivision of the Southern population into Coast and Inland populations was estimated to be late Pleistocene (0.24 Ma), although our mtDNA results suggested a Pliocene divergence. Effective gene flow estimates (2N(e)m) suggest that either the two- or three-population hypotheses remain valid. However, our results unexpectedly revealed that the Northern population might instead represent two parapatric populations that separated nearly 4 Ma. These results are surprising because the Pliocene divergence between these ecomorphologically conservative forms is similar or older than for the ecomorphologically divergent Coast and Inland sister populations. We conclude that Black Salamanders in north-western California belong to at least three or four populations or species, and these all meet criteria for being Evolutionary Significant Units or 'ESUs' and therefore warrant conservation consideration.

  4. Phylogeography of the Alpine salamander, Salamandra atra (Salamandridae) and the influence of the Pleistocene climatic oscillations on population divergence.

    PubMed

    Riberon, A; Miaud, C; Grossenbacher, K; Taberlet, P

    2001-10-01

    Fifty individuals of the endemic Alpine salamander, Salamandra atra, representing 13 populations throughout the range of the two currently recognized subspecies, atra and aurorae, were examined for sequence variation in a large portion (1050 bp) of the mitochondrial cytochrome b gene. We revealed a large number of mitochondrial DNA (mtDNA) haplotypes (10). Interpopulation sequence divergence was very low, ranging from 0 to 3.1%. The relationships among haplotypes were poorly resolved. The divergence time estimate between several mtDNA haplotypes suggested a pre-Pleistocene differentiation approximately 3 million years ago. Moreover, the impact of the Pleistocene glaciations on the phylogeographical patterns appears to have been secondary, although a somewhat reduced genetic variability was found in populations living in areas that were directly affected by the glaciation.

  5. A potential wound-healing-promoting peptide from salamander skin.

    PubMed

    Mu, Lixian; Tang, Jing; Liu, Han; Shen, Chuanbin; Rong, Mingqiang; Zhang, Zhiye; Lai, Ren

    2014-09-01

    Although it is well known that wound healing proceeds incredibly quickly in urodele amphibians, such as newts and salamanders, little is known about skin-wound healing, and no bioactive/effector substance that contributes to wound healing has been identified from these animals. As a step toward understanding salamander wound healing and skin regeneration, a potential wound-healing-promoting peptide (tylotoin; KCVRQNNKRVCK) was identified from salamander skin of Tylototriton verrucosus. It shows comparable wound-healing-promoting ability (EC50=11.14 μg/ml) with epidermal growth factor (EGF; NSDSECPLSHDGYCLHDGVCMYIEALDKYACNCVVGYIGERCQYRDLKWWELR) in a murine model of full-thickness dermal wound. Tylotoin directly enhances the motility and proliferation of keratinocytes, vascular endothelial cells, and fibroblasts, resulting in accelerated reepithelialization and granulation tissue formation in the wound site. Tylotoin also promotes the release of transforming growth factor β1 (TGF-β1) and interleukin 6 (IL-6), which are essential in the wound healing response. Gene-encoded tylotoin secreted in salamander skin is possibly an effector molecule for skin wound healing. This study may facilitate understanding of the cellular and molecular events that underlie quick wound healing in salamanders.

  6. Are Salamanders Useful Indicators of Hydrologic Permanence in Headwater Streams?

    NASA Astrophysics Data System (ADS)

    Johnson, B.; Fritz, K.

    2005-05-01

    Regulatory agencies need appropriate indicators of stream permanence to aid in jurisdictional determinations for headwater streams. We evaluated salamanders as permanence indicators because they are often abundant in fishless headwaters. Salamander and habitat data were collected in spring and summer 2003 from 59 sites located longitudinally along 17 forested streams in KY, IN, and OH. Larval Eurycea bislineata/cirrigera dominated all forests, and their abundances were highly correlated with drainage areas and channel dimensions. Appalachian streams were more diverse and had intermittent sites with more Desmognathus and Gyrinophilus spp. Of 22 sites where larvae were collected in spring, 9 sites subsequently dried in summer, suggesting salamanders either emigrated or died. We therefore only used taxa with multi-year larval stages as indicators of perennial water. Salamander larvae >1 yr old were collected from each locality in drainage areas <0.17 km2. However, these older larvae were often found in isolated pools that serve as refugia during dry periods. Findings suggest salamanders with multi-year larval periods can indicate perennial waters and that their use is more effective in Appalachia where abundance and diversity are high. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

  7. Thyroid hormone responsive QTL and the evolution of paedomorphic salamanders

    PubMed Central

    Voss, S R; Kump, D K; Walker, J A; Shaffer, H B; Voss, G J

    2012-01-01

    The transformation of ancestral phenotypes into novel traits is poorly understood for many examples of evolutionary novelty. Ancestrally, salamanders have a biphasic life cycle with an aquatic larval stage, a brief and pronounced metamorphosis, followed by a terrestrial adult stage. Repeatedly during evolution, metamorphic timing has been delayed to exploit growth-permissive environments, resulting in paedomorphic salamanders that retain larval traits as adults. We used thyroid hormone (TH) to rescue metamorphic phenotypes in paedomorphic salamanders and then identified quantitative trait loci (QTL) for life history traits that are associated with amphibian life cycle evolution: metamorphic timing and adult body size. We demonstrate that paedomorphic tiger salamanders (Ambystoma tigrinum complex) carry alleles at three moderate effect QTL (met1–3) that vary in responsiveness to TH and additively affect metamorphic timing. Salamanders that delay metamorphosis attain significantly larger body sizes as adults and met2 explains a significant portion of this variation. Thus, substitution of alleles at TH-responsive loci suggests an adaptive pleiotropic basis for two key life-history traits in amphibians: body size and metamorphic timing. Our study demonstrates a likely pathway for the evolution of novel paedomorphic species from metamorphic ancestors via selection of TH-response alleles that delay metamorphic timing and increase adult body size. PMID:22850698

  8. From lamprey to salamander: an exploratory modeling study on the architecture of the spinal locomotor networks in the salamander.

    PubMed

    Bicanski, Andrej; Ryczko, Dimitri; Cabelguen, Jean-Marie; Ijspeert, Auke Jan

    2013-10-01

    The evolutionary transition from water to land required new locomotor modes and corresponding adjustments of the spinal "central pattern generators" for locomotion. Salamanders resemble the first terrestrial tetrapods and represent a key animal for the study of these changes. Based on recent physiological data from salamanders, and previous work on the swimming, limbless lamprey, we present a model of the basic oscillatory network in the salamander spinal cord, the spinal segment. Model neurons are of the Hodgkin-Huxley type. Spinal hemisegments contain sparsely connected excitatory and inhibitory neuron populations, and are coupled to a contralateral hemisegment. The model yields a large range of experimental findings, especially the NMDA-induced oscillations observed in isolated axial hemisegments and segments of the salamander Pleurodeles waltlii. The model reproduces most of the effects of the blockade of AMPA synapses, glycinergic synapses, calcium-activated potassium current, persistent sodium current, and [Formula: see text]-current. Driving segments with a population of brainstem neurons yields fast oscillations in the in vivo swimming frequency range. A minimal modification to the conductances involved in burst-termination yields the slower stepping frequency range. Slow oscillators can impose their frequency on fast oscillators, as is likely the case during gait transitions from swimming to stepping. Our study shows that a lamprey-like network can potentially serve as a building block of axial and limb oscillators for swimming and stepping in salamanders.

  9. Spontaneous nephroblastoma in a Japanese giant salamander (Andrias japonicus).

    PubMed

    Kawasumi, Taiga; Kudo, Tomoo; Une, Yumi

    2012-05-01

    An adult male Japanese giant salamander (Andrias japonicus) died accidentally, and necropsy showed a white mass (23 × 15 mm) in the left kidney and hepatorrhexis with hemoperitoneum. Histologically, the renal mass was mainly composed of immature nephroblastic tumor cells. In the tumor tissue, a trabecular pattern lined by oval to polygonal tumor cells with a rich interstitium, solid growth and a few tubular structures was observed. Nephroblastic tumor cells were strongly positive for vimentin and weakly positive, and epithelium-like tumor cells were strongly positive for cytokeratin. However, antibody for Wilms' tumor protein 1 did not react with the salamander's cells. On electron microscopy, a desmosome junction was observed between tumor cells. This is the first report of nephroblastoma in a Japanese giant salamander.

  10. Ecological implications of metabolic compensation at low temperatures in salamanders

    PubMed Central

    2016-01-01

    Global warming is influencing the biology of the world’s biota. Temperature increases are occurring at a faster pace than that experienced by organisms in their evolutionary histories, limiting the organisms’ response to new conditions. Mechanistic models that include physiological traits can help predict species’ responses to warming. Changes in metabolism at high temperatures are often examined; yet many species are behaviorally shielded from high temperatures. Salamanders generally favor cold temperatures and are one of few groups of metazoans to be most species-rich in temperate regions. I examined variation in body temperature, behavioral activity, and temperature dependence of resting heart rate, used as a proxy for standard metabolic rate, in fire salamanders (Salamandra salamandra). Over 26 years, I found that salamanders are behaviorally active at temperatures as low as 1 °C, and aestivate at temperatures above 16 °C. Infrared thermography indicates limited thermoregulation opportunities for these nocturnal amphibians. Temperature affects resting heart rate, causing metabolic depression above 11 °C, and metabolic compensation below 8 °C: heart rate at 3 °C is 224% the expected heart rate. Thus, salamanders operating at low temperatures during periods of peak behavioral activity are able to maintain a higher metabolic rate than the rate expected in absence of compensation. This compensatory mechanism has important ecological implications, because it increases estimated seasonal heart rates. Increased heart rate, and thus metabolism, will require higher caloric intake for field-active salamanders. Thus, it is important to consider a species performance breadth over the entire temperature range, and particularly low temperatures that are ecologically relevant for cold tolerant species such as salamanders. PMID:27257549

  11. Ecological implications of metabolic compensation at low temperatures in salamanders.

    PubMed

    Catenazzi, Alessandro

    2016-01-01

    Global warming is influencing the biology of the world's biota. Temperature increases are occurring at a faster pace than that experienced by organisms in their evolutionary histories, limiting the organisms' response to new conditions. Mechanistic models that include physiological traits can help predict species' responses to warming. Changes in metabolism at high temperatures are often examined; yet many species are behaviorally shielded from high temperatures. Salamanders generally favor cold temperatures and are one of few groups of metazoans to be most species-rich in temperate regions. I examined variation in body temperature, behavioral activity, and temperature dependence of resting heart rate, used as a proxy for standard metabolic rate, in fire salamanders (Salamandra salamandra). Over 26 years, I found that salamanders are behaviorally active at temperatures as low as 1 °C, and aestivate at temperatures above 16 °C. Infrared thermography indicates limited thermoregulation opportunities for these nocturnal amphibians. Temperature affects resting heart rate, causing metabolic depression above 11 °C, and metabolic compensation below 8 °C: heart rate at 3 °C is 224% the expected heart rate. Thus, salamanders operating at low temperatures during periods of peak behavioral activity are able to maintain a higher metabolic rate than the rate expected in absence of compensation. This compensatory mechanism has important ecological implications, because it increases estimated seasonal heart rates. Increased heart rate, and thus metabolism, will require higher caloric intake for field-active salamanders. Thus, it is important to consider a species performance breadth over the entire temperature range, and particularly low temperatures that are ecologically relevant for cold tolerant species such as salamanders. PMID:27257549

  12. Ontogenetic evidence for the Paleozoic ancestry of salamanders.

    PubMed

    Schoch, Rainer R; Carroll, Robert L

    2003-01-01

    The phylogenetic positions of frogs, salamanders, and caecilians have been difficult to establish. Data matrices based primarily on Paleozoic taxa support a monophyletic origin of all Lissamphibia but have resulted in widely divergent hypotheses of the nature of their common ancestor. Analysis that concentrates on the character states of the stem taxa of the extant orders, in contrast, suggests a polyphyletic origin from divergent Paleozoic clades. Comparison of patterns of larval development in Paleozoic and modern amphibians provides a means to test previous phylogenies based primarily on adult characteristics. This proves to be highly informative in the case of the origin of salamanders. Putative ancestors of salamanders are recognized from the Permo-Carboniferous boundary of Germany on the basis of ontogenetic changes observed in fossil remains of larval growth series. The entire developmental sequence from hatching to metamorphosis is revealed in an assemblage of over 600 specimens from a single locality, all belonging to the genus Apateon. Apateon forms the most speciose genus of the neotenic temnospondyl family Branchiosauridae. The sequence of ossification of individual bones and the changing configuration of the skull closely parallel those observed in the development of primitive living salamanders. These fossils provide a model of how derived features of the salamander skull may have evolved in the context of feeding specializations that appeared in early larval stages of members of the Branchiosauridae. Larvae of Apateon share many unique derived characters with salamanders of the families Hynobiidae, Salamandridae, and Ambystomatidae, which have not been recognized in any other group of Paleozoic amphibians. PMID:12752770

  13. Modular functional organisation of the axial locomotor system in salamanders.

    PubMed

    Cabelguen, Jean-Marie; Charrier, Vanessa; Mathou, Alexia

    2014-02-01

    Most investigations on tetrapod locomotion have been concerned with limb movements. However, there is compelling evidence that the axial musculoskeletal system contributes to important functions during locomotion. Adult salamanders offer a remarkable opportunity to examine these functions because these amphibians use axial undulations to propel themselves in both aquatic and terrestrial environments. In this article, we review the currently available biological data on axial functions during various locomotor modes in salamanders. We also present data showing the modular organisation of the neural networks that generate axial synergies during locomotion. The functional implication of this modular organisation is discussed.

  14. Perceived predation risk as a function of predator dietary cues in terrestrial salamanders.

    PubMed

    Murray; Jenkins

    1999-01-01

    Prey often avoid predator chemical cues, and in aquatic systems, prey may even appraise predation risk via cues associated with the predator's diet. However, this relationship has not been shown for terrestrial predator-prey systems, where the proximity of predators and prey, and the intensity of predator chemical cues in the environment, may be less than in aquatic systems. In the laboratory, we tested behavioural responses (avoidance, habituation and activity) of terrestrial red-backed salamanders, Plethodon cinereus, to chemical cues from garter snakes, Thamnophis sirtalis, fed either red-backed salamanders or earthworms (Lumbricus spp.). We placed salamanders in arenas lined with paper towels pretreated with snake chemicals, and monitored salamander movements during 120 min. Salamanders avoided substrates preconditioned by earthworm-fed (avoidanceX+/-SE=91.1+/-2.5%, N=25) and salamander-fed (95.2+/-2.5%, N=25) snakes, when tested against untreated substrate (control). Salamanders avoided cues from salamander-fed snakes more strongly (75.2+/-5.5%, N=25) than earthworm-fed snakes when subjected to both treatments simultaneously, implying that salamanders were sensitive to predator diet. Salamanders tended to avoid snake substrate more strongly during the last 60 min of a trial, but activity patterns were similar between salamanders exposed exclusively to control substrate versus those subject to snake cues. In another experiment, salamanders failed to avoid cues from dead conspecifics, suggesting that the stronger avoidance of salamander-fed snakes in the previous experiment was not directly due to chemical cues emitted by predator-killed salamanders. Salamanders also did not discriminate between cues from a salamander-fed snake versus a salamander-fed snake that was recently switched (i.e. <14 days) to an earthworm diet. Our results imply that terrestrial salamanders are sensitive to perceived predation risk via by-products of predator diet, and that snake

  15. Perceived predation risk as a function of predator dietary cues in terrestrial salamanders.

    PubMed

    Murray; Jenkins

    1999-01-01

    Prey often avoid predator chemical cues, and in aquatic systems, prey may even appraise predation risk via cues associated with the predator's diet. However, this relationship has not been shown for terrestrial predator-prey systems, where the proximity of predators and prey, and the intensity of predator chemical cues in the environment, may be less than in aquatic systems. In the laboratory, we tested behavioural responses (avoidance, habituation and activity) of terrestrial red-backed salamanders, Plethodon cinereus, to chemical cues from garter snakes, Thamnophis sirtalis, fed either red-backed salamanders or earthworms (Lumbricus spp.). We placed salamanders in arenas lined with paper towels pretreated with snake chemicals, and monitored salamander movements during 120 min. Salamanders avoided substrates preconditioned by earthworm-fed (avoidanceX+/-SE=91.1+/-2.5%, N=25) and salamander-fed (95.2+/-2.5%, N=25) snakes, when tested against untreated substrate (control). Salamanders avoided cues from salamander-fed snakes more strongly (75.2+/-5.5%, N=25) than earthworm-fed snakes when subjected to both treatments simultaneously, implying that salamanders were sensitive to predator diet. Salamanders tended to avoid snake substrate more strongly during the last 60 min of a trial, but activity patterns were similar between salamanders exposed exclusively to control substrate versus those subject to snake cues. In another experiment, salamanders failed to avoid cues from dead conspecifics, suggesting that the stronger avoidance of salamander-fed snakes in the previous experiment was not directly due to chemical cues emitted by predator-killed salamanders. Salamanders also did not discriminate between cues from a salamander-fed snake versus a salamander-fed snake that was recently switched (i.e. <14 days) to an earthworm diet. Our results imply that terrestrial salamanders are sensitive to perceived predation risk via by-products of predator diet, and that snake

  16. Cyto-nuclear discordance suggests complex evolutionary history in the cave-dwelling salamander, Eurycea lucifuga.

    PubMed

    Edgington, Hilary A; Ingram, Colleen M; Taylor, Douglas R

    2016-09-01

    Our understanding of the evolutionary history and ecology of cave-associated species has been driven historically by studies of morphologically adapted cave-restricted species. Our understanding of the evolutionary history and ecology of nonrestricted cave species, troglophiles, is limited to a few studies, which present differing accounts of troglophiles' relationship with the cave habitat, and its impact on population dynamics. Here, we used phylogenetics, demographic statistics, and population genetic methods to study lineage divergence, dates of divergence, and population structure in the Cave Salamander, Eurycea lucifuga, across its range. In order to perform these analyses, we sampled 233 individuals from 49 populations, using sequence data from three gene loci as well as genotyping data from 19 newly designed microsatellite markers. We find, as in many other species studied in a phylogeographic context, discordance between patterns inferred from mitochondrial relationships and those inferred by nuclear markers indicating a complicated evolutionary history in this species. Our results suggest Pleistocene-based divergence among three main lineages within E. lucifuga corresponding to the western, central, and eastern regions of the range, similar to patterns seen in species separated in multiple refugia during climatic shifts. The conflict between mitochondrial and nuclear patterns is consistent with what we would expect from secondary contact between regional populations following expansion from multiple refugia. PMID:27648230

  17. Intracellular invasion of green algae in a salamander host

    PubMed Central

    Kerney, Ryan; Kim, Eunsoo; Hangarter, Roger P.; Heiss, Aaron A.; Bishop, Cory D.; Hall, Brian K.

    2011-01-01

    The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell–cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures. PMID:21464324

  18. Slow DNA loss in the gigantic genomes of salamanders.

    PubMed

    Sun, Cheng; López Arriaza, José R; Mueller, Rachel Lockridge

    2012-01-01

    Evolutionary changes in genome size result from the combined effects of mutation, natural selection, and genetic drift. Insertion and deletion mutations (indels) directly impact genome size by adding or removing sequences. Most species lose more DNA through small indels (i.e., ~1-30 bp) than they gain, which can result in genome reduction over time. Because this rate of DNA loss varies across species, small indel dynamics have been suggested to contribute to genome size evolution. Species with extremely large genomes provide interesting test cases for exploring the link between small indels and genome size; however, most large genomes remain relatively unexplored. Here, we examine rates of DNA loss in the tetrapods with the largest genomes-the salamanders. We used low-coverage genomic shotgun sequence data from four salamander species to examine patterns of insertion, deletion, and substitution in neutrally evolving non-long terminal repeat (LTR) retrotransposon sequences. For comparison, we estimated genome-wide DNA loss rates in non-LTR retrotransposon sequences from five other vertebrate genomes: Anolis carolinensis, Danio rerio, Gallus gallus, Homo sapiens, and Xenopus tropicalis. Our results show that salamanders have significantly lower rates of DNA loss than do other vertebrates. More specifically, salamanders experience lower numbers of deletions relative to insertions, and both deletions and insertions are skewed toward smaller sizes. On the basis of these patterns, we conclude that slow DNA loss contributes to genomic gigantism in salamanders. We also identify candidate molecular mechanisms underlying these differences and suggest that natural variation in indel dynamics provides a unique opportunity to study the basis of genome stability. PMID:23175715

  19. The molecular phylogenetics of endangerment: cryptic variation and historical phylogeography of the California tiger salamander, Ambystoma californiense.

    PubMed

    Shaffer, H Bradley; Pauly, Gregory B; Oliver, Jeffrey C; Trenham, Peter C

    2004-10-01

    A primary goal of conservation genetics is the discovery, delimitation and protection of phylogenetic lineages within sensitive or endangered taxa. Given the importance of lineage protection, a combination of phylogeography, historical geology and molecular clock analyses can provide an important historical context for overall species conservation. We present the results of a range-wide survey of genetic variation in the California tiger salamander, Ambystoma californiense, as well as a summary of the past several million years of inundation and isolation of the Great Central Valley and surrounding uplands that constitute its limited range. A combination of population genetic and phylogenetic analyses of mitochondrial DNA variation among 696 samples from 84 populations revealed six well-supported genetic units that are geographically discrete and characterized by nonoverlapping haplotype distributions. Populations from Santa Barbara and Sonoma Counties are particularly well differentiated and geographically isolated from all others. The remaining units in the Southern San Joaquin Valley, Central Coast Range, Central Valley and Bay Area are separated by geological features, ecological zone boundaries, or both. The geological history of the California landscape is consistent with molecular clock evidence suggesting that the Santa Barbara unit has been isolated for at least 0.74-0.92 Myr, and the Sonoma clade is equally ancient. Our work places patterns of genetic differentiation into both temporal- and landscape-level contexts, providing important insights into the conservation genetics of the California tiger salamander.

  20. Genealogical relationships of southern Ontario polyploid unisexual salamanders (genus Ambystoma) inferred from intergenomic exchanges and major rDNA cytotypes.

    PubMed

    Bi, Ke; Bogart, James P; Fu, Jinzhong

    2008-01-01

    North American unisexual salamanders in the genus Ambystoma are common around the Great Lakes region of North America. They contain an almost identical mitochondrial genome across their distribution that is unlike that of any of the four species whose genomes may be included in their nuclei. Thus, sequence-based phylogenies of unisexual populations are confusing. We used chromosomal intergenomic exchanges and major rDNA cytotypes as combined cytogenetic markers to tentatively construct a genealogy of unisexual Ambystoma in southern Ontario. We employed GISH and sequential/simultaneous GISH/FISH-rDNA to reveal intergenomic exchanges and rDNA cytotypes in unisexual A. laterale--2 jeffersonianum (LJJ) triploids and their tetraploid derivative A. laterale--3 jeffersonianum (LJJJ). We identified 10 different patterns of intergenomic exchanges from 18 isolated populations and used them as primary cytogenetic markers. Major rDNA cytotypes served as independent and supplementary markers. Our results suggest that current LJJ and LJJJ populations in southern Ontario are likely derived from a few unisexual individuals. Intergenomic exchanges are common phenomena and widely distributed in the salamanders of the A. laterale--A. jeffersonianum unisexual complex. Integration of GISH and FISH can exhibit multiple unrelated chromosomal markers on the same chromosome spread and demonstrate lineage relationships in unisexual populations. Similar methods may be applied for studying the molecular cytogenetics of other unisexuals to improve our understanding of their genealogical relationships and historical dispersal. PMID:18175200

  1. Mitochondrial evidence on the phylogenetic position of caecilians (Amphibia: Gymnophiona).

    PubMed Central

    Zardoya, R; Meyer, A

    2000-01-01

    The complete nucleotide sequence (17,005 bp) of the mitochondrial genome of the caecilian Typhlonectes natans (Gymnophiona, Amphibia) was determined. This molecule is characterized by two distinctive genomic features: there are seven large 109-bp tandem repeats in the control region, and the sequence for the putative origin of replication of the L strand can potentially fold into two alternative secondary structures (one including part of the tRNA(Cys)). The new sequence data were used to assess the phylogenetic position of caecilians and to gain insights into the origin of living amphibians (frogs, salamanders, and caecilians). Phylogenetic analyses of two data sets-one combining protein-coding genes and the other combining tRNA genes-strongly supported a caecilian + frog clade and, hence, monophyly of modern amphibians. These two data sets could not further resolve relationships among the coelacanth, lungfishes, and tetrapods, but strongly supported diapsid affinities of turtles. Phylogenetic relationships among a larger set of species of frogs, salamanders, and caecilians were estimated with a mitochondrial rRNA data set. Maximum parsimony analysis of this latter data set also recovered monophyly of living amphibians and favored a frog + salamander (Batrachia) relationship. However, bootstrap support was only moderate at these nodes. This is likely due to an extensive among-site rate heterogeneity in the rRNA data set and the narrow window of time in which the three main groups of living amphibians were originated. PMID:10835397

  2. Mitochondrial evidence on the phylogenetic position of caecilians (Amphibia: Gymnophiona).

    PubMed

    Zardoya, R; Meyer, A

    2000-06-01

    The complete nucleotide sequence (17,005 bp) of the mitochondrial genome of the caecilian Typhlonectes natans (Gymnophiona, Amphibia) was determined. This molecule is characterized by two distinctive genomic features: there are seven large 109-bp tandem repeats in the control region, and the sequence for the putative origin of replication of the L strand can potentially fold into two alternative secondary structures (one including part of the tRNA(Cys)). The new sequence data were used to assess the phylogenetic position of caecilians and to gain insights into the origin of living amphibians (frogs, salamanders, and caecilians). Phylogenetic analyses of two data sets-one combining protein-coding genes and the other combining tRNA genes-strongly supported a caecilian + frog clade and, hence, monophyly of modern amphibians. These two data sets could not further resolve relationships among the coelacanth, lungfishes, and tetrapods, but strongly supported diapsid affinities of turtles. Phylogenetic relationships among a larger set of species of frogs, salamanders, and caecilians were estimated with a mitochondrial rRNA data set. Maximum parsimony analysis of this latter data set also recovered monophyly of living amphibians and favored a frog + salamander (Batrachia) relationship. However, bootstrap support was only moderate at these nodes. This is likely due to an extensive among-site rate heterogeneity in the rRNA data set and the narrow window of time in which the three main groups of living amphibians were originated.

  3. Mitochondrial evidence on the phylogenetic position of caecilians (Amphibia: Gymnophiona).

    PubMed

    Zardoya, R; Meyer, A

    2000-06-01

    The complete nucleotide sequence (17,005 bp) of the mitochondrial genome of the caecilian Typhlonectes natans (Gymnophiona, Amphibia) was determined. This molecule is characterized by two distinctive genomic features: there are seven large 109-bp tandem repeats in the control region, and the sequence for the putative origin of replication of the L strand can potentially fold into two alternative secondary structures (one including part of the tRNA(Cys)). The new sequence data were used to assess the phylogenetic position of caecilians and to gain insights into the origin of living amphibians (frogs, salamanders, and caecilians). Phylogenetic analyses of two data sets-one combining protein-coding genes and the other combining tRNA genes-strongly supported a caecilian + frog clade and, hence, monophyly of modern amphibians. These two data sets could not further resolve relationships among the coelacanth, lungfishes, and tetrapods, but strongly supported diapsid affinities of turtles. Phylogenetic relationships among a larger set of species of frogs, salamanders, and caecilians were estimated with a mitochondrial rRNA data set. Maximum parsimony analysis of this latter data set also recovered monophyly of living amphibians and favored a frog + salamander (Batrachia) relationship. However, bootstrap support was only moderate at these nodes. This is likely due to an extensive among-site rate heterogeneity in the rRNA data set and the narrow window of time in which the three main groups of living amphibians were originated. PMID:10835397

  4. Effects of predator chemical cues and behavioral biorhythms on foraging activity of terrestrial salamanders.

    PubMed

    Maerz, J C; Panebianco, N L; Madison, D M

    2001-07-01

    Red-backed salamanders, Plethodon cinereus, show a variety of alarm responses to chemical cues from eastern garter snakes, Thamnophis sirtalis. We measured the foraging activity of red-backed salamanders exposed to water soiled by a garter snake (fed P. cinereus) or to unsoiled water. Salamanders exposed to snake-soiled water showed less foraging activity than salamanders exposed to unsoiled water; therefore, predators could have nonlethal effects on salamander populations. Our results also show additional factors influenced salamander foraging activity. Salamander foraging activity and responsiveness to chemical cues do not appear to have been affected by sex or food deprivation. Salamander foraging activity does appear to have been influenced by activity biorhythms. Foraging activity of animals in both treatments showed a bimodal periodicity that is consistent with natural activity patterns controlled by internal biorhythms. Exposure to snake-soiled water significantly reduced foraging activity during periods of peak foraging activity, but had a subtler effect on foraging activity during natural lulls in activity. We suggest that both activity biorhythms and exposure to chemical cues are important factors affecting salamander foraging behavior.

  5. High occupancy of stream salamanders despite high ranavirus prevalence in a southern appalachians watershed.

    PubMed

    Rothermel, Betsie B; Travis, Emilie R; Miller, Debra L; Hill, Robert L; McGuire, Jessica L; Yabsley, Michael J

    2013-06-01

    The interactive effects of environmental stressors and emerging infectious disease pose potential threats to stream salamander communities and their headwater stream ecosystems. To begin assessing these threats, we conducted occupancy surveys and pathogen screening of stream salamanders (Family Plethodontidae) in a protected southern Appalachians watershed in Georgia and North Carolina, USA. Of the 101 salamanders screened for both chytrid fungus (Batrachochytrium dendrobatidis) and Ranavirus, only two exhibited low-level chytrid infections. Prevalence of Ranavirus was much higher (30.4% among five species of Desmognathus). Despite the ubiquity of ranaviral infections, we found high probabilities of site occupancy (≥0.60) for all stream salamander species.

  6. Impact of valley fills on streamside salamanders in southern West Virginia

    USGS Publications Warehouse

    Wood, Petra Bohall; Williams, Jennifer M.

    2013-01-01

    Valley fills associated with mountaintop-removal mining bury stream headwaters and affect water quality and ecological function of reaches below fills. We quantified relative abundance of streamside salamanders in southern West Virginia during 2002 in three streams below valley fills (VFS) and in three reference streams (RS). We surveyed 36 10- × 2-m stream transects, once in summer and fall, paired by order and structure. Of 2,343 salamanders captured, 66.7% were from RS. Total salamanders (adults plus larvae) were more abundant in RS than VFS for first-order and second-order reaches. Adult salamanders had greater abundance in first-order reaches of RS than VFS. Larval salamanders were more abundant in second-order reaches of RS than VFS. No stream width or mesohabitat variables differed between VFS and RS. Only two cover variables differed. Silt cover, greater in VFS than RS first-order reaches, is a likely contributor to reduced abundance of salamanders in VFS. Second-order RS had more boulder cover than second-order VFS, which may have contributed to the higher total and larval salamander abundance in RS. Water chemistry assessments of our VFS and RS reported elevated levels of metal and ion concentrations in VFS, which can depress macroinvertebrate populations and likely affect salamander abundance. Valley fills appear to have significant negative effects on stream salamander abundance due to alterations in habitat structure, water quality and chemistry, and macroinvertebrate communities in streams below fills.

  7. Salamander Blue-sensitive Cones Lost During Metamorphosis†

    PubMed Central

    Chen, Ying; Znoiko, Sergey; DeGrip, Willem J.; Crouch, Rosalie K.; Ma, Jian-xing

    2009-01-01

    The tiger salamander lives in shallow water with bright light in the aquatic phase, and in dim tunnels or caves in the terrestrial phase. In the aquatic phase, there are five types of photoreceptors—two types of rods and three types of cones. Our previous studies showed that the green rods and blue-sensitive cones contain the same visual pigment and have the same absorbance spectra; however, the green rods have a larger photon-catch area and thus have higher light sensitivity than the blue-sensitive cones. Here we show that after metamorphosis, the terrestrial salamander looses the blue-sensitive cones, while the density of the green rods increases. Moreover, the size of the green rod outer segments is increased in the terrestrial phase, compared to that in the aquatic phase. This switch from the blue-sensitive cones to the green rods may represent an adaptation to the dim light environment of the terrestrial phase. PMID:18331398

  8. Salamander growth rates increase along an experimental stream phosphorus gradient.

    PubMed

    Bumpers, Phillip M; Maerz, John C; Rosemond, Amy D; Benstead, Jonathan P

    2015-11-01

    Nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two-year whole-stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P = 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free-roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40% and 60%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free-roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem-level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus-based food webs.

  9. Salamander growth rates increase along an experimental stream phosphorus gradient.

    PubMed

    Bumpers, Phillip M; Maerz, John C; Rosemond, Amy D; Benstead, Jonathan P

    2015-11-01

    Nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two-year whole-stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P = 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free-roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40% and 60%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free-roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem-level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus-based food webs. PMID:27070018

  10. Apparent predation by Gray Jays, Perisoreus canadensis, on Long-toed Salamanders, Ambystoma macrodactylum, in the Oregon Cascade Range

    USGS Publications Warehouse

    Murray, M.P.; Pearl, C.A.; Bury, R.B.

    2005-01-01

    We report observations of Gray Jays (Perisoreus canadensis) appearing to consume larval Long-toed Salamanders (Ambystoma macrodactylum) in a drying subalpine pond in Oregon, USA. Corvids are known to prey upon a variety of anuran amphibians, but to our knowledge, this is the first report of predation by any corvid on aquatic salamanders. Long-toed Salamanders appear palatable to Gray Jays, and may provide a food resource to Gray Jays when salamander larvae are concentrated in drying temporary ponds.

  11. Mitochondrial Diseases

    MedlinePlus

    ... disorder, something goes wrong with this process. Mitochondrial diseases are a group of metabolic disorders. Mitochondria are ... cells and cause damage. The symptoms of mitochondrial disease can vary. It depends on how many mitochondria ...

  12. Better than fish on land? Hearing across metamorphosis in salamanders

    PubMed Central

    Christensen, Christian Bech; Lauridsen, Henrik; Christensen-Dalsgaard, Jakob; Pedersen, Michael; Madsen, Peter Teglberg

    2015-01-01

    Early tetrapods faced an auditory challenge from the impedance mismatch between air and tissue in the transition from aquatic to terrestrial lifestyles during the Early Carboniferous (350 Ma). Consequently, tetrapods may have been deaf to airborne sounds for up to 100 Myr until tympanic middle ears evolved during the Triassic. The middle ear morphology of recent urodeles is similar to that of early ‘lepospondyl’ microsaur tetrapods, and experimental studies on their hearing capabilities are therefore useful to understand the evolutionary and functional drivers behind the shift from aquatic to aerial hearing in early tetrapods. Here, we combine imaging techniques with neurophysiological measurements to resolve how the change from aquatic larvae to terrestrial adult affects the ear morphology and sensory capabilities of salamanders. We show that air-induced pressure detection enhances underwater hearing sensitivity of salamanders at frequencies above 120 Hz, and that both terrestrial adults and fully aquatic juvenile salamanders can detect airborne sound. Collectively, these findings suggest that early atympanic tetrapods may have been pre-equipped to aerial hearing and are able to hear airborne sound better than fish on land. When selected for, this rudimentary hearing could have led to the evolution of tympanic middle ears. PMID:25652830

  13. Effects of hatching time for larval ambystomatid salamanders

    USGS Publications Warehouse

    Boone, M.D.; Scott, D.E.; Niewiarowski, P.H.

    2002-01-01

    In aquatic communities, the phenology of breeding may influence species interactions. In the early-breeding marbled salamander, Ambystoma opacum, timing of pond filling may determine whether interactions among larvae are competitive or predatory. The objectives of our studies were to determine how time of egg hatching affected size, larval period, and survival to metamorphosis in A. opacum, and if early-hatching in A. opacum influenced the competitive and predator-prey relationships with smaller larvae of the mole salamander, Ambystoma talpoideum. Salamander larvae were reared from hatching through metamorphosis in large, outdoor enclosures located in a natural temporary pond in Aiken County, South Carolina, in two experiments. In study 1, we reared early- and late-hatching A. opacum larvae separately from hatching through metamorphosis. In study 2, we examined how early- versus late-hatching A. opacum affected a syntopic species, A. talpoideum. In general, early-hatching A. opacum were larger and older at metamorphosis, had greater survival, and left the pond earlier than late-hatching larvae. Ambystoma talpoideum reared in the presence of early-hatching A. opacum had lower survival than in controls, suggesting that A. opacum may predate upon A. talpoideum when they gain a growth advantage over later-hatching larvae. Our studies demonstrate that time of pond filling and phenology of breeding may influence population dynamics and alter the nature of relationships that develop among species.

  14. Cannibalistic-morph Tiger Salamanders in unexpected ecological contexts

    USGS Publications Warehouse

    McLean, Kyle I.; Stockwell, Craig A.; Mushet, David M.

    2016-01-01

    Barred tiger salamanders [Ambystoma mavortium (Baird, 1850)] exhibit two trophic morphologies; a typical and a cannibalistic morph. Cannibalistic morphs, distinguished by enlarged vomerine teeth, wide heads, slender bodies, and cannibalistic tendencies, are often found where conspecifics occur at high density. During 2012 and 2013, 162 North Dakota wetlands and lakes were sampled for salamanders. Fifty-one contained A. mavortium populations; four of these contained cannibalistic morph individuals. Two populations with cannibalistic morphs occurred at sites with high abundances of conspecifics. However, the other two populations occurred at sites with unexpectedly low conspecific but high fathead minnow [Pimephales promelas (Rafinesque, 1820)] abundances. Further, no typical morphs were observed in either of these later two populations, contrasting with earlier research suggesting cannibalistic morphs only occur at low frequencies in salamander populations. Another anomaly of all four populations was the occurrence of cannibalistic morphs in permanent water sites, suggesting their presence was due to factors other than faster growth allowing them to occupy ephemeral habitats. Therefore, our findings suggest environmental factors inducing the cannibalistic morphism may be more complex than previously thought.

  15. Mechanisms underlying vertebrate limb regeneration: lessons from the salamander.

    PubMed

    Brockes, Jeremy P; Gates, Phillip B

    2014-06-01

    Limb regeneration in adult salamanders proceeds by formation of a mound of progenitor cells called the limb blastema. It provides several pointers for regenerative medicine. These include the role of differentiated cells in the origin of the blastema, the role of regenerating axons of peripheral nerves and the importance of cell specification in conferring morphogenetic autonomy on the blastema. One aspect of regeneration that has received less attention is the ability to undergo multiple episodes without detectable change in the outcome, and with minimal effect of aging. We suggest that, although such pointers are valuable, it is important to understand why salamanders are the only adult tetrapod vertebrates able to regenerate their limbs. Although this remains a controversial issue, the existence of salamander-specific genes that play a significant role in the mechanism of regeneration provides evidence for the importance of local evolution, rather than a purely ancestral mechanism. The three-finger protein called Prod1 is discussed in the present article as an exemplar of this approach.

  16. Origin and diversification of a salamander sex pheromone system.

    PubMed

    Janssenswillen, Sunita; Vandebergh, Wim; Treer, Dag; Willaert, Bert; Maex, Margo; Van Bocxlaer, Ines; Bossuyt, Franky

    2015-02-01

    Sex pheromones form an important facet of reproductive strategies in many organisms throughout the Animal Kingdom. One of the oldest known sex pheromones in vertebrates are proteins of the Sodefrin Precursor-like Factor (SPF) system, which already had a courtship function in early salamanders. The subsequent evolution of salamanders is characterized by a diversification in courtship and reproduction, but little is known on how the SPF pheromone system diversified in relation to changing courtship strategies. Here, we combined transcriptomic, genomic, and phylogenetic analyses to investigate the evolution of the SPF pheromone system in nine salamandrid species with distinct courtship displays. First, we show that SPF originated from vertebrate three-finger proteins and diversified through multiple gene duplications in salamanders, while remaining a single copy in frogs. Next, we demonstrate that tail-fanning newts have retained a high phylogenetic diversity of SPFs, whereas loss of tail-fanning has been associated with a reduced importance or loss of SPF expression in the cloacal region. Finally, we show that the attractant decapeptide sodefrin is cleaved from larger SPF precursors that originated by a 62 bp insertion and consequent frameshift in an ancestral Cynops lineage. This led to the birth of a new decapeptide that rapidly evolved a pheromone function independently from uncleaved proteins.

  17. Extreme morphological and ecological homoplasy in tropical salamanders

    PubMed Central

    Parra-Olea, Gabriela; Wake, David B.

    2001-01-01

    Fossorial salamanders typically have elongate and attenuated heads and bodies, diminutive limbs, hands and feet, and extremely elongate tails. Batrachoseps from California, Lineatriton from eastern México, and Oedipina from southern México to Ecuador, all members of the family Plethodontidae, tribe Bolitoglossini, resemble one another in external morphology, which has evolved independently. Whereas Oedipina and Batrachoseps are elongate because there are more trunk vertebrae, a widespread homoplasy (parallelism) in salamanders, the genus Lineatriton is unique in having evolved convergently by an alternate “giraffe-neck” developmental program. Lineatriton has the same number of trunk vertebrae as related, nonelongated taxa, but individual trunk vertebrae are elongated. A robust phylogenetic hypothesis, based on sequences of three mtDNA genes, finds Lineatriton to be deeply nested within a clade characterized by generalized ecology and morphology. Lineatriton lineolus, the only currently recognized taxon in the genus, shows unanticipated genetic diversity. Surprisingly, geographically separated populations of L. lineolus are not monophyletic, but are sister taxa of different species of the morphologically generalized genus Pseudoeurycea. Lineatriton, long thought to be a unique monospecific lineage, is polyphyletic. Accordingly, the specialized morphology of Lineatriton displays homoplasy at two hierarchical levels: (i) with respect to other elongate lineages in the family (convergence), and (ii) within what is currently recognized as a single taxon (parallelism). These evolutionary events are of adaptive significance because to invade the lowland tropics salamanders must be either arboreal or fossorial; the repeated evolution of elongation and attenuation has led to multiple lowland invasions. PMID:11427707

  18. Better than fish on land? Hearing across metamorphosis in salamanders.

    PubMed

    Christensen, Christian Bech; Lauridsen, Henrik; Christensen-Dalsgaard, Jakob; Pedersen, Michael; Madsen, Peter Teglberg

    2015-03-01

    Early tetrapods faced an auditory challenge from the impedance mismatch between air and tissue in the transition from aquatic to terrestrial lifestyles during the Early Carboniferous (350 Ma). Consequently, tetrapods may have been deaf to airborne sounds for up to 100 Myr until tympanic middle ears evolved during the Triassic. The middle ear morphology of recent urodeles is similar to that of early 'lepospondyl' microsaur tetrapods, and experimental studies on their hearing capabilities are therefore useful to understand the evolutionary and functional drivers behind the shift from aquatic to aerial hearing in early tetrapods. Here, we combine imaging techniques with neurophysiological measurements to resolve how the change from aquatic larvae to terrestrial adult affects the ear morphology and sensory capabilities of salamanders. We show that air-induced pressure detection enhances underwater hearing sensitivity of salamanders at frequencies above 120 Hz, and that both terrestrial adults and fully aquatic juvenile salamanders can detect airborne sound. Collectively, these findings suggest that early atympanic tetrapods may have been pre-equipped to aerial hearing and are able to hear airborne sound better than fish on land. When selected for, this rudimentary hearing could have led to the evolution of tympanic middle ears.

  19. Predator perception of Batesian mimicry and conspicuousness in a salamander.

    PubMed

    Kraemer, Andrew C; Adams, Dean C

    2014-04-01

    In Batesian mimicry a palatable mimic deceives predators by resembling an unpalatable model. The evolution of Batesian mimicry relies on the visual capabilities of the potential predators, as prey detection provides the selective force driving evolutionary change. We compared the visual capabilities of several potential predators to test predictions stemming from the hypothesis of Batesian mimicry between two salamanders: the model species Notophthalmus viridescens, and polymorphic mimic, Plethodon cinereus. First, we found mimicry to be restricted to coloration, but not brightness. Second, only bird predators appeared able to discriminate between the colors of models and nonmimic P. cinereus. Third, estimates of salamander conspicuousness were background dependent, corresponding to predictions only for backgrounds against which salamanders are most active. These results support the hypothesis that birds influence the evolution of Batesian mimicry in P. cinereus, as they are the only group examined capable of differentiating N. viridescens and nonmimetic P. cinereus. Additionally, patterns of conspicuousness suggest that selection from predators may drive the evolution of conspicuousness in this system. This study confirms the expectation that the visual abilities of predators may influence the evolution of Batesian mimicry, but the role of conspicuousness may be more complex than previously thought.

  20. Extensive unidirectional introgression between two salamander lineages of ancient divergence and its evolutionary implications.

    PubMed

    Canestrelli, Daniele; Bisconti, Roberta; Nascetti, Giuseppe

    2014-10-01

    Hybridization and introgression, contrary to previous beliefs, are now considered to be widespread processes even among animal species. Nonetheless, the range of their possible outcomes and roles in moulding biodiversity patterns are still far from being fully appraised. Here we investigated the pattern of hybridization and introgression between Salamandrina perspicillata and S. terdigitata, two salamanders endemic to the Italian peninsula. Using a set of diagnostic or differentiated genetic markers (9 nuclear and 1 mitochondrial), we documented extensive unidirectional introgression of S. terdigitata alleles into the S. perspicillata gene pool in central Italy, indicating that barriers against hybridization were permeable when they came into secondary contact, and despite their ancient divergence. Nonetheless, purebred S. terdigitata, as well as F1, F2, and backcrosses were not found within the hybrid zone. Moreover, Bayesian analyses of population structure identified admixed populations belonging to a differentiated gene pool with respect to both parental populations. Overall, the observed genetic structure, together with their geographic pattern of distribution, suggests that Salamandrina populations in central Italy could have entered a distinct evolutionary pathway. How far they have gone along this pathway will deserve future investigation.

  1. 77 FR 36287 - Proposed Low-Effect Habitat Conservation Plan for the California Tiger Salamander, Calaveras...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ... Fish and Wildlife Service Proposed Low-Effect Habitat Conservation Plan for the California Tiger... listed animal, the threatened Central California Distinct Population Segment of the California tiger salamander (tiger salamander). The applicant would implement a conservation program to minimize and...

  2. Habitat relationships of eastern red-backed salamanders (Plethodon cinereus) in Appalachian grazing systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Altered microclimates and vegetation structure after timber harvest can result in longterm population declines of some Appalachian salamanders. If changes in forest structure following harvest alter woodland salamander habitat quality, conversion of forests to pastures or meadows is believed to resu...

  3. Deep divergences and extensive phylogeographic structure in a clade of lowland tropical salamanders

    PubMed Central

    2012-01-01

    Background The complex geological history of Mesoamerica provides the opportunity to study the impact of multiple biogeographic barriers on population differentiation. We examine phylogeographic patterns in a clade of lowland salamanders (Bolitoglossa subgenus Nanotriton) using two mitochondrial genes and one nuclear gene. We use several phylogeographic analyses to infer the history of this clade and test hypotheses regarding the geographic origin of species and location of genetic breaks within species. We compare our results to those for other taxa to determine if historical events impacted different species in a similar manner. Results Deep genetic divergence between species indicates that they are relatively old, and two of the three widespread species show strong phylogeographic structure. Comparison of mtDNA and nuclear gene trees shows no evidence of hybridization or introgression between species. Isolated populations of Bolitoglossa rufescens from Los Tuxtlas region constitute a separate lineage based on molecular data and morphology, and divergence between Los Tuxtlas and other areas appears to predate the arrival of B. rufescens in other areas west of the Isthmus of Tehuantepec. The Isthmus appears responsible for Pliocene vicariance within B. rufescens, as has been shown for other taxa. The Motagua-Polochic fault system does not appear to have caused population vicariance, unlike in other systems. Conclusions Species of Nanotriton have responded to some major geological events in the same manner as other taxa, particularly in the case of the Isthmus of Tehuantepec. The deep divergence of the Los Tuxtlas populations of B. rufescens from other populations highlights the contribution of this volcanic system to patterns of regional endemism, and morphological differences observed in the Los Tuxtlas populations suggests that they may represent an undescribed species of Bolitoglossa. The absence of phylogeographic structure in B. nympha, in contrast to the

  4. Mitochondrial Cardiomyopathies

    PubMed Central

    El-Hattab, Ayman W.; Scaglia, Fernando

    2016-01-01

    Mitochondria are found in all nucleated human cells and perform various essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA), whereas more than 99% of them are encoded by nuclear DNA (nDNA). Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs for various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20–40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular non-compaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain complexes subunits and their assembly factors, mitochondrial transfer RNAs, ribosomal RNAs, ribosomal proteins, translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia. PMID:27504452

  5. Mitochondrial Cardiomyopathies.

    PubMed

    El-Hattab, Ayman W; Scaglia, Fernando

    2016-01-01

    Mitochondria are found in all nucleated human cells and perform various essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA), whereas more than 99% of them are encoded by nuclear DNA (nDNA). Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs for various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20-40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular non-compaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain complexes subunits and their assembly factors, mitochondrial transfer RNAs, ribosomal RNAs, ribosomal proteins, translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia. PMID:27504452

  6. Mitochondrial vasculopathy

    PubMed Central

    Finsterer, Josef; Zarrouk-Mahjoub, Sinda

    2016-01-01

    Mitochondrial disorders (MIDs) are usually multisystem disorders (mitochondrial multiorgan disorder syndrome) either on from onset or starting at a point during the disease course. Most frequently affected tissues are those with a high oxygen demand such as the central nervous system, the muscle, endocrine glands, or the myocardium. Recently, it has been shown that rarely also the arteries may be affected (mitochondrial arteriopathy). This review focuses on the type, diagnosis, and treatment of mitochondrial vasculopathy in MID patients. A literature search using appropriate search terms was carried out. Mitochondrial vasculopathy manifests as either microangiopathy or macroangiopathy. Clinical manifestations of mitochondrial microangiopathy include leukoencephalopathy, migraine-like headache, stroke-like episodes, or peripheral retinopathy. Mitochondrial macroangiopathy manifests as atherosclerosis, ectasia of arteries, aneurysm formation, dissection, or spontaneous rupture of arteries. The diagnosis relies on the documentation and confirmation of the mitochondrial metabolic defect or the genetic cause after exclusion of non-MID causes. Treatment is not at variance compared to treatment of vasculopathy due to non-MID causes. Mitochondrial vasculopathy exists and manifests as micro- or macroangiopathy. Diagnosing mitochondrial vasculopathy is crucial since appropriate treatment may prevent from severe complications. PMID:27231520

  7. Axial dynamics during locomotion in vertebrates lesson from the salamander.

    PubMed

    Cabelguen, Jean-Marie; Ijspeert, Auke; Lamarque, Stéphanie; Ryczko, Dimitri

    2010-01-01

    Much of what we know about the flexibility of the locomotor networks in vertebrates is derived from studies examining the adaptation of limb movements during stepping in various conditions. However, the body movements play important roles during locomotion: they produce the thrust during undulatory locomotion and they help to increase the stride length during legged locomotion. In this chapter, we review our current knowledge about the flexibility in the neuronal circuits controlling the body musculature during locomotion. We focus especially on salamander because, as an amphibian, this animal is able to display a rich repertoire of aquatic and terrestrial locomotor modes.

  8. Acid precipitation and embryonic mortality of spotted salamanders, Ambystoma maculatum.

    PubMed

    Pough, F H

    1976-04-01

    Spotted salamanders breed in temporary pools formed in early spring by melted snow and rain. Many of these pools reflect the low pH of precipitation in the northeastern United States. Egg mortality is low (less than 1 percent) in pools near neutrality, but high (greater than 60 percent) in pools more acid than pH 6. Developmental anomalies and the embryonic stage at which death occurs are the same in field situations as at corresponding pH's in laboratory experiments.

  9. Telocytes in ileum of the Chinese giant salamander: ultrastructural evidence.

    PubMed

    Zhang, Hui; Zhong, Shengwei; Ge, Tingting; Peng, Shasha; Yu, Pengcheng; Zhou, Zuohong; Guo, Xiaoquan

    2016-03-01

    Telocytes (TCs) and their telopodes (Tps) have been found in various organs of many mammals, including in lower animals. However, knowledge of TCs in lower animals is still very limited. This study identified TCs and their Tps in the ileum of the Chinese giant salamander, Andrias davidianus (Amphibia: Caudata), by transmission electron microscopy. The TCs/Tps were found near epithelial cells, glandular cells and unmyelinated nerve fibres. Moreover, exosomes were also found to be present in between TCs/Tps and these cells. PMID:26805522

  10. Significance of pre-Quaternary climate change for montane species diversity: insights from Asian salamanders (Salamandridae: Pachytriton).

    PubMed

    Wu, Yunke; Wang, Yuezhao; Jiang, Ke; Hanken, James

    2013-01-01

    Despite extensive focus on the genetic legacy of Pleistocene glaciation, impacts of earlier climatic change on biodiversity are poorly understood. Because amphibians are highly sensitive to variations in precipitation and temperature, we use a genus of Chinese montane salamanders (Salamandridae: Pachytriton) to study paleoclimatic change in East Asia, which experienced intensification of its monsoon circulation in the late Miocene associated with subsequent Pliocene warming. Using both nuclear and mitochondrial DNA sequences, we reconstruct the species tree under a coalescent model and demonstrate that all major lineages originated before the Quaternary. Initial speciation within the genus occurred after the summer monsoon entered a stage of substantial intensification. Heavy summer precipitation established temporary water connectivity through overflows between adjacent stream systems, which may facilitate geographic range expansion by aquatic species such as Pachytriton. Species were formed in allopatry likely through vicariant isolation during or after range expansion. To evaluate the influence of Pliocene warming on these cold-adapted salamanders, we construct a novel temperature buffer-zone model, which suggests widespread physiological stress or even extinction during the warming period. A significant deceleration of species accumulation rate is consistent with Pliocene range contraction, which affected P. granulosus and P. archospotus the most because they lack large temperature buffer zones. In contrast, demographic growth occurred in species for which refugia persist. The buffer-zone model reveals the Huangshan Mountain as a potential climatic refugium, which is similar to that found for other East Asian organisms. Our approach can incorporate future climatic data to evaluate the potential impact of ongoing global warming on montane species (particularly amphibians) and to predict possible population declines.

  11. Earthworms, as ecosystem engineers, influence multiple aspects of a salamander's ecology.

    PubMed

    Ransom, Tami S

    2011-03-01

    Ecosystem engineers create habitat that can be used by other species in multiple ways, such as refugees from predators, places to breed, or areas with increased prey resources. I conducted a series of enclosure experiments to: (1) determine if salamanders use earthworm burrows, and (2) examine the potential influence of earthworm burrow use and indirect effects on salamander intra- and interspecific competition, predator avoidance, and seasonal performance. I found that one species of woodland salamander, Plethodon cinereus, used earthworm burrows 50% of the time when burrows were present. Neither adults nor juveniles of the congeneric P. glutinosus used earthworm burrows. Intraspecific, but not interspecific, competition by P. cinereus affected salamander behavior when earthworms were absent, with P. cinereus found under cover objects >70% of the time when alone or with a P. glutinosus, but only 40% of the time when with another P. cinereus. When earthworms were present, the behavior of P. cinereus was similar across salamander treatments. Earthworms decreased the amount of leaf litter and microinvertebrates, although this did not affect salamander mass. In subsequent experiments using only P. cinereus, the refuge provided by earthworm burrows increased the survival of P. cinereus over the winter and allowed P. cinereus to avoid being consumed by the common garter snake (Thamnophis sirtalis). Because earthworm burrows provide a refuge for P. cinereus during intraspecific encounters, in the presence of a predator and over the winter, they may serve as an important belowground-aboveground linkage in eastern forests where salamanders are common.

  12. Science Review for the Scott Bar Salamander (Plethodon asupak) and the Siskiyou Mountains Salamander (P. stormi): Biology, Taxonomy, Habitat, and Detection Probabilities/Occupancy

    USGS Publications Warehouse

    DeGross, Douglas J.; Bury, R. Bruce

    2007-01-01

    The Plethodon elongatus Complex in the Klamath-Siskiyou Ecoregion of southern Oregon and northern California includes three species: the Del Norte salamander, Plethodon elongatus; the Siskiyou Mountains salamander, P. stormi; and the Scott Bar salamander, P. asupak. This review aims to summarize the current literature and information available on select topics for P. stormi and P. asupak. These are both terrestrial salamanders belonging to the Family Plethodontidae, which contains more species and has a wider geographic distribution than any other family of salamanders (Wake 1966, 2006; Pough 1989). The genera of this family have greatly diversified ecologically across North America, Central America, northern South America, Sardinia, southeastern France and northwestern Italy, and have recently been discovered on the Korean peninsula (Min et al. 2005). The genus Plethodon is found exclusively in North America and is split into three distinct clades, based upon morphology and phylogenetics (Highton and Larson 1979): eastern small Plethodon, eastern large Plethodon, and the western Plethodon. The western Plethodon are the greatest representation of Plethodontidae in the Pacific Northwest, with 8 species. The two species with the most restricted ranges of these regional congeners are the Siskiyou Mountains and Scott Bar salamanders. These salamanders occupy the interior of the Klamath-Siskiyou Ecoregion which straddles the California and Oregon state lines, between Siskiyou County (CA) and Jackson and Josephine Counties (OR). The relatively recent discovery of P. asupak (Mead et al. 2005) and the limited range of both species have created an environment of uncertain conservation status for these species. This review will focus on four central topics of concern for land and resource managers: Biology; Taxonomy; Habitat; and Detection Probabilities/Occupancy.

  13. A new species of salamander (Caudata: Plethodontidae, Bolitoglossa) from Sierra Nevada de Mérida, Venezuela.

    PubMed

    García-Gutiérrez, Javier; Escalona, Moisés; Mora, Andrés; Díaz De Pascual, Amelia; Fermin, Gustavo

    2013-01-01

    In this article, a new species of salamander of the genus Bolitoglossa (Eladinea) from the cloud forest near La Mucuy in Sierra Nevada de Mérida, Venezuelan Andes, is described. Bolitoglossa mucuyensis sp. nov. differs from all Venezuelan salamanders, except B. orestes, by a larger SVL/TL ratio, and from La Culata salamander B. orestes by a reduced webbing extension of the front and hind limbs. Additionally, B. mucuyensis sp. nov. and B. orestes diverge 3.12% in terms of the nucleotide sequence of the 16S rRNA gene, as previously reported, and in 8.1% for the cytb gene as shown in this study.

  14. A field test of the effect of acidic rain on ion balance in a woodland salamander

    SciTech Connect

    Frisbie, M.P.; Wyman, R.L. )

    1994-06-01

    Earlier laboratory studies demonstrated that red-backed salamanders, Plethodon cinereus, are susceptible to osmotic disruption by low pH substrates. In natural systems, however, acidic input from precipitation may be mediated by soils before it impacts salamanders. We tested the effect of acidic rain on sodium balance in salamanders by confining individuals in enclosure in two forest types (hemlock, beech) for 34 d. Enclosures received artificial rain of either pH 3 or 5 every 3-4 d. Soils inside enclosures in the hemlock forest were more acidic than those in the beech forest at the outset. At termination, [H[sup +

  15. Extreme negative temperatures and body mass loss in the Siberian salamander (Salamandrella keyserlingii, amphibia, hynobiidae).

    PubMed

    Berman, D I; Meshcheryakova, E N; Bulakhova, N A

    2016-05-01

    Frozen Siberian salamander safely tolerates long (45 days) stay at-35°C. Short-term (3 days) cooling down to-50°C was tolerable for 40% of adult individuals; down to-55°C, for 80% of the underyearlings. Generally, the salamanders lose about 28% of the body mass during the pre-hibernating period (before winter, at temperatures as low as 0°C) and during the process of freezing (as low as-5°C). The body weight remained constant upon further cooling (to-35°C). The frozen salamanders have no physiological mechanisms protecting from sublimation. PMID:27411827

  16. Iteroparity in the variable environment of the salamander Ambystoma tigrinum

    USGS Publications Warehouse

    Church, D.R.; Bailey, L.L.; Wilbur, H.M.; Kendall, W.L.; Hines, J.E.

    2007-01-01

    Simultaneous estimation of survival, reproduction, and movement is essential to understanding how species maximize lifetime reproduction in environments that vary across space and time. We conducted a four-year, capture–recapture study of three populations of eastern tiger salamanders (Ambystoma tigrinum tigrinum) and used multistate mark–recapture statistical methods to estimate the manner in which movement, survival, and breeding probabilities vary under different environmental conditions across years and among populations and habitats. We inferred how individuals may mitigate risks of mortality and reproductive failure by deferring breeding or by moving among populations. Movement probabilities among populations were extremely low despite high spatiotemporal variation in reproductive success and survival, suggesting possible costs to movements among breeding ponds. Breeding probabilities varied between wet and dry years and according to whether or not breeding was attempted in the previous year. Estimates of survival in the nonbreeding, forest habitat varied among populations but were consistent across time. Survival in breeding ponds was generally high in years with average or high precipitation, except for males in an especially ephemeral pond. A drought year incurred severe survival costs in all ponds to animals that attempted breeding. Female salamanders appear to defer these episodic survival costs of breeding by choosing not to breed in years when the risk of adult mortality is high. Using stochastic simulations of survival and breeding under historical climate conditions, we found that an interaction between breeding probabilities and mortality limits the probability of multiple breeding attempts differently between the sexes and among populations.

  17. Conservation genetics of the endangered Shenandoah salamander (Plethodon shenandoah, Plethodontidae)

    USGS Publications Warehouse

    Carpenter, D.W.; Jung, R.E.; Sites, J.W.

    2001-01-01

    The Shenandoah salamander (Plethodon shenandoah) is restricted to three isolated talus outcrops in Shenandoah National Park, VA, USA and has one of the smallest ranges of any tetrapod vertebrate. This species was listed as endangered under the US Endangered Species Act in 1989 over concern that direct competition with the red-backed salamander (Plethodon cinereus), successional habitat changes, and human impacts may cause its decline and possible extinction. We address two issues herein: (1) whether extensive introgression (through long-term hybridization) is present between the two species and threatens the survival of P. shenandoah, and (2) the level of population structure within P. shenandoah. We provide evidence from mtDNA haplotypes that shows no genetic differentiation among the three isolates of P. shenandoah, suggesting that their fragmentation is a geologically recent event, and/or that the isolates are still connected by occasional gene flow. There is also no evidence for extensive introgression of alleles in either direction between P. cinereus and P. shenandoah, which suggests that P. shenandoah may not be in danger of being genetically swamped out through hybridization with P. cinereus.

  18. Evidence for Sex Chromosome Turnover in Proteid Salamanders.

    PubMed

    Sessions, Stanley K; Bizjak Mali, Lilijana; Green, David M; Trifonov, Vladimir; Ferguson-Smith, Malcolm

    2016-01-01

    A major goal of genomic and reproductive biology is to understand the evolution of sex determination and sex chromosomes. Species of the 2 genera of the Salamander family Proteidae - Necturus of eastern North America, and Proteus of Southern Europe - have similar-looking karyotypes with the same chromosome number (2n = 38), which differentiates them from all other salamanders. However, Necturus possesses strongly heteromorphic X and Y sex chromosomes that Proteus lacks. Since the heteromorphic sex chromosomes of Necturus were detectable only with C-banding, we hypothesized that we could use C-banding to find sex chromosomes in Proteus. We examined mitotic material from colchicine-treated intestinal epithelium, and meiotic material from testes in specimens of Proteus, representing 3 genetically distinct populations in Slovenia. We compared these results with those from Necturus. We performed FISH to visualize telomeric sequences in meiotic bivalents. Our results provide evidence that Proteus represents an example of sex chromosome turnover in which a Necturus-like Y-chromosome has become permanently translocated to another chromosome converting heteromorphic sex chromosomes to homomorphic sex chromosomes. These results may be key to understanding some unusual aspects of demographics and reproductive biology of Proteus, and are discussed in the context of models of the evolution of sex chromosomes in amphibians. PMID:27351721

  19. Sensitivity of two salamander (Ambystoma) species to ultraviolet radiation

    USGS Publications Warehouse

    Calfee, R.D.; Bridges, C.M.; Little, E.E.

    2006-01-01

    Increased ultraviolet-B (UV-B) radiation reaching the Earth's surface has been implicated in amphibian declines. Recent studies have shown that many amphibian species have differences in sensitivity depending on developmental stage. Embryos and larvae of Ambystoma maculatum (Spotted Salamander) and larvae of Ambystoma talpoideum (Mole Salamander) were exposed to five simulated UV-B treatments in controlled laboratory experiments to determine the relative sensitivity of different lifestages. Hatching success of the embryos exceeded 95% in all treatments; however, the larvae of both species exhibited greater sensitivity to UV-B exposure. Older larvae of A. maculatum that were not exposed to UV-B as embryos were more sensitive than larvae that had hatched during exposure to UV-B. Growth of surviving larvae of A. maculatum was significantly reduced as UV-B intensity increased, whereas growth of A. talpoideum was unaffected. These results were compared to ambient UV-B conditions in natural environments. It appears that the embryo stage is relatively unaffected by UV-B levels observed in natural habitats, probably because of protection from vegetation, organic matter in the water column, oviposition depth, and egg jelly. The larval stage of these species may be at greater risk, particularly if there is an increase in UV-B radiation exposure caused by increases in water clarity and/or decreases in dissolved organic carbon.

  20. Iteroparity in the variable environment of the salamander Ambystoma tigrinum.

    PubMed

    Church, Don R; Bailey, Larissa L; Wilbur, Henry M; Kendall, William L; Hines, James E

    2007-04-01

    Simultaneous estimation of survival, reproduction, and movement is essential to understanding how species maximize lifetime reproduction in environments that vary across space and time. We conducted a four-year, capture-recapture study of three populations of eastern tiger salamanders (Ambystoma tigrinum tigrinum) and used multistate mark-recapture statistical methods to estimate the manner in which movement, survival, and breeding probabilities vary under different environmental conditions across years and among populations and habitats. We inferred how individuals may mitigate risks of mortality and reproductive failure by deferring breeding or by moving among populations. Movement probabilities among populations were extremely low despite high spatiotemporal variation in reproductive success and survival, suggesting possible costs to movements among breeding ponds. Breeding probabilities varied between wet and dry years and according to whether or not breeding was attempted in the previous year. Estimates of survival in the nonbreeding, forest habitat varied among populations but were consistent across time. Survival in breeding ponds was generally high in years with average or high precipitation, except for males in an especially ephemeral pond. A drought year incurred severe survival costs in all ponds to animals that attempted breeding. Female salamanders appear to defer these episodic survival costs of breeding by choosing not to breed in years when the risk of adult mortality is high. Using stochastic simulations of survival and breeding under historical climate conditions, we found that an interaction between breeding probabilities and mortality limits the probability of multiple breeding attempts differently between the sexes and among populations. PMID:17536706

  1. Mitochondrial cytopathies.

    PubMed

    El-Hattab, Ayman W; Scaglia, Fernando

    2016-09-01

    Mitochondria are found in all nucleated human cells and perform a variety of essential functions, including the generation of cellular energy. Most of mitochondrial proteins are encoded by the nuclear DNA (nDNA) whereas a very small fraction is encoded by the mitochondrial DNA (mtDNA). Mutations in mtDNA or mitochondria-related nDNA genes can result in mitochondrial dysfunction which leads to a wide range of cellular perturbations including aberrant calcium homeostasis, excessive reactive oxygen species production, dysregulated apoptosis, and insufficient energy generation to meet the needs of various organs, particularly those with high energy demand. Impaired mitochondrial function in various tissues and organs results in the multi-organ manifestations of mitochondrial diseases including epilepsy, intellectual disability, skeletal and cardiac myopathies, hepatopathies, endocrinopathies, and nephropathies. Defects in nDNA genes can be inherited in an autosomal or X-linked manners, whereas, mtDNA is maternally inherited. Mitochondrial diseases can result from mutations of nDNA genes encoding subunits of the electron transport chain complexes or their assembly factors, proteins associated with the mitochondrial import or networking, mitochondrial translation factors, or proteins involved in mtDNA maintenance. MtDNA defects can be either point mutations or rearrangements. The diagnosis of mitochondrial disorders can be challenging in many cases and is based on clinical recognition, biochemical screening, histopathological studies, functional studies, and molecular genetic testing. Currently, there are no satisfactory therapies available for mitochondrial disorders that significantly alter the course of the disease. Therapeutic options include symptomatic treatment, cofactor supplementation, and exercise. PMID:26996063

  2. Phylogeography of the Brownback Salamander reveals patterns of local endemism in Southern Appalachian springs.

    PubMed

    Timpe, Elizabeth K; Graham, Sean P; Bonett, Ronald M

    2009-08-01

    The Appalachian Mountains of eastern North America are characterized by high faunal diversity and many endemic species, especially in the unglaciated southern latitudes where lineages have been accumulating for tens of millions of years. The Brownback Salamander, Eurycea aquatica, is an enigmatic species that dwells in isolated springs in southeastern North America. Eurycea aquatica have often been dismissed as simply robust spring-adapted ecomorphs of the widespread and more gracile species Eurycea cirrigera. We sequenced the mitochondrial gene encoding NADH dehydrogenase subunit-2 (ND2; 753 bp) and the nuclear recombination activating gene-1 (Rag1; 1201 bp) for E. aquatica (ND2 n = 72; Rag1 n = 17) from across their presumed distribution and compared them to E. cirrigera (ND2 n = 23; Rag1 n = 10) from nearby populations. Using phylogenetic and morphological analyses we explicitly test if E. aquatica in the Southern Appalachians is simply a local spring-adapted ecomorph of E. cirrigera or a single lineage that resulted from fragmentation of (or dispersal to) spring habitats. We found that E. aquatica from isolated springs form a well-supported monophyletic group that is nested among E. cirrigera, E. wilderae, and E. junaluska. Furthermore, we uncovered three very divergent lineages of E. aquatica that we estimate have been isolated from each another since the early Pliocene to late Miocene (2.5-6.1 Myr) and may each represent distinct species. The distribution of these lineages is coincident with the distribution of other endemic spring-dwelling vertebrates, and suggests that this region may be a relictual habitat for an unexpected diversity of unrecognized endemics. PMID:19345271

  3. Unisexual salamanders (genus Ambystoma) present a new reproductive mode for eukaryotes.

    PubMed

    Bogart, James P; Bi, Ke; Fu, Jinzong; Noble, Daniel W A; Niedzwiecki, John

    2007-02-01

    To persist, unisexual and asexual eukaryotes must have reproductive modes that circumvent normal bisexual reproduction. Parthenogenesis, gynogenesis, and hybridogenesis are the modes that have generally been ascribed to various unisexuals. Unisexual Ambystoma are abundant around the Great Lakes region of North America, and have variously been described as having all 3 reproductive modes. Diploid and polyploid unisexuals have nuclear genomes that combine the haploid genomes of 2 to 4 distinct sexual species, but the mtDNA is unlike any of those 4 species and is similar to another species, Ambystoma barbouri. To obtain better resolution of the reproductive mode used by unisexual Ambystoma and to explore the relationship of A. barbouri to the unisexuals, we sequenced the mitochondrial control and highly variable intergenic spacer region of 48 ambystomatids, which included 28 unisexuals, representatives of the 4 sexual species and A. barbouri. The unisexuals have similar sequences over most of their range, and form a close sister group to A. barbouri, with an estimated time of divergence of 2.4-3.9 million years ago. Individuals from the Lake Erie Islands (Kelleys, Pelee, North Bass) have a haplotype that demonstrates an isolation event. We examined highly variable microsatellite loci, and found that the genetic makeup of the unisexuals is highly variable and that unisexual individuals share microsatellite alleles with sexual individuals within populations. Although many progeny from the same female had the same genotype for 5 microsatellite DNA loci, there was no indication that any particular genome is consistently inherited in a clonal fashion in a population. The reproductive mode used by unisexual Ambystoma appears to be unique; we suggest kleptogenesis as a new unisexual reproductive mode that is used by these salamanders. PMID:17546077

  4. SPATIALLY AUTOCORRELATED DEMOGRAPHY AND INTERPOND MIGRATION IN THE CALIFORNIA TIGER SALAMANDER (AMBYSTOME CALIFORNIENSE)

    EPA Science Inventory

    We investigated the metapopulation structure of the California tiger salamander (Ambystoma californiense) using a combination of indirect and direct methods to evaluate two key requirements of modern metapopulation models: 1) that patches support somewhat independent populations ...

  5. Overwintered Bullfrog tadpoles negatively affect Salamanders and Anurans in native amphibian communities

    USGS Publications Warehouse

    Boone, M.D.; Little, E.E.; Semlitsch, R.D.

    2004-01-01

    We examined the interactive effects of overwintered Bullfrog (Rana catesbeiana) tadpoles and pond hydroperiod on a community of larval amphibians in outdoor mesocosms including American Toads (Bufo americanus), Southern Leopard Frogs (Rana sphenocephala), and Spotted Salamanders (Ambystoma maculatum) - species within the native range of Bullfrogs. Spotted Salamanders and Southern Leopard Frogs were negatively influenced by the presence of overwintered Bullfrogs. Spotted Salamanders had shorter larval periods and slightly smaller masses at metamorphosis, and Southern Leopard Frogs had smaller masses at metamorphosis when reared with Bullfrogs than without. Presence of overwintered Bullfrogs, however, did not significantly affect American Toads. Longer pond hydroperiods resulted in greater survival, greater size at metamorphosis, longer larval periods, and later time until emergence of the first metamorphs for Southern Leopard Frog tadpoles and Spotted Salamander larvae. Our study demonstrated that overwintered Bullfrog tadpoles can respond to changing pond hydroperiods and can negatively impact metamorphosis of native amphibians.

  6. Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

    EPA Science Inventory

    Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

  7. [Phylogenetic relationships among Asiatic salamanders of the genus Salamandrella based on variability of nuclear genes].

    PubMed

    Maliarchuk, B A; Derenko, M V; Denisova, G A

    2015-01-01

    Based on sequence variation of three nuclear genome genes (BDNF, POMC, and RAG1), the phylogenetic relationships among Asiatic salamanders of the genus Salamandrella, Siberian salamander (S. keyserlingii) and Schrenk salamander (S. schrenkii), were examined. Both species demonstrated high levels of heterozygosity determined by intraspecific polymorphism. Fixed interspecific differences were revealed at one nucleotide position of the RAG1 gene, and thus the level of interspecific divergence over the three genes constituted only 0.04%. Analysis of the RAG1 polymorphism across the whole range of S. keyserlingii showed that only one gene variant, encoding for modified RAG1 recombinase, had the highest distribution to the north of the Amur region (west and northeast of Siberia). It is possible that the changes in the RAG1 gene in Siberian salamander are of an adaptive nature. However, cases of interspecific hybridization were identified in Jewish autonomous oblast (JAO), which contains one of the range borders between the two Salamandrella species. PMID:25857197

  8. Reintroduction and Post-Release Survival of a Living Fossil: The Chinese Giant Salamander

    PubMed Central

    Zhang, Lu; Jiang, Wei; Wang, Qi-Jun; Zhao, Hu; Zhang, Hong-Xing; Marcec, Ruth M.; Willard, Scott T.; Kouba, Andrew J.

    2016-01-01

    Captive rearing and reintroduction / translocation are increasingly used as tools to supplement wild populations of threatened species. Reintroducing captive-reared Chinese giant salamanders may help to augment the declining wild populations and conserve this critically endangered amphibian. We released 31 captive-reared juvenile giant salamanders implanted with VHF radio transmitters at the Heihe River (n = 15) and the Donghe River (n = 16) in the Qinling Mountains of central China. Salamanders were monitored every day for survival from April 28th 2013 to September 3rd 2014. We attempted to recapture all living individuals by the end of the study, measured their body mass and total body length, and checked for abnormalities and presence of external parasites. Two salamanders at the Heihe River and 10 animals at the Donghe River survived through the project timeline. Nine salamanders were confirmed dead, while the status of the other 10 animals was undetermined. The annual survival rate of giant salamanders at the Donghe River (0.702) was 1.7-fold higher than that at the Heihe River (0.405). Survival increased as individuals were held longer following surgery, whereas body mass did not have a significant impact on survival rate. All salamanders recaptured from the Donghe River (n = 8) increased in mass (0.50 ± 0.13 kg) and length (5.5 ± 1.5 cm) after approximately 11 months in the wild, and they were only 7% lighter than wild animals of the same length (mean residual = -0.033 ± 0.025). Our results indicate that captive-reared Chinese giant salamanders can survive in the wild one year after release and adequate surgical recovery time is extremely important to post-release survival. Future projects may reintroduce older juveniles to achieve better survival and longer monitoring duration. PMID:27258650

  9. Diagnostic and molecular evaluation of three iridovirus-associated salamander mortality events

    USGS Publications Warehouse

    Docherty, D.E.; Meteyer, C.U.; Wang, Jingyuan; Mao, J.; Case, S.T.; Chinchar, V.G.

    2003-01-01

    In 1998 viruses were isolated from tiger salamander larvae (Ambystoma tigrinum diaboli and A. tigrinum melanostictum) involved in North Dakota and Utah (USA) mortality events and spotted salamander (A. maculatum) larvae in a third event in Maine (USA). Although sympatric caudates and anurans were present at all three sites only ambystomid larvae appeared to be affected. Mortality at the North Dakota site was in the thousands while at the Utah and Maine sites mortality was in the hundreds. Sick larvae were lethargic and slow moving. They swam in circles with obvious buoyancy problems and were unable to remain upright. On the ventral surface, near the gills and hind limbs, red spots or swollen areas were noted. Necropsy findings included: hemorrhages and ulceration of the skin, subcutaneous and intramuscular edema, swollen and pale livers with multifocal hemorrhage, and distended fluid-filled intestines with areas of hemorrhage. Light microscopy revealed intracytoplasmic inclusions, suggestive of a viral infection, in a variety of organs. Electron microscopy of ultra thin sections of the same tissues revealed iridovirus-like particles within the inclusions. These viruses were isolated from a variety of organs, indicating a systemic infection. Representative viral isolates from the three mortality events were characterized using molecular assays. Characterization confirmed that the viral isolates were iridoviruses and that the two tiger salamander isolates were similar and could be distinguished from the spotted salamander isolate. The spotted salamander isolate was similar to frog virus 3, the type species of the genus Ranavirus, while the tiger salamander isolates were not. These data indicate that different species of salamanders can become infected and die in association with different iridoviruses. Challenge assays are required to determine the fish and amphibian host range of these isolates and to assess the susceptibility of tiger and spotted salamanders to

  10. Estimation of stream salamander (Plethodontidae, Desmognathinae and Plethodontinae) populations in Shenandoah National Park, Virginia, USA

    USGS Publications Warehouse

    Jung, R.E.; Royle, J. Andrew; Sauer, J.R.; Addison, C.; Rau, R.D.; Shirk, J.L.; Whissel, J.C.

    2005-01-01

    Stream salamanders in the family Plethodontidae constitute a large biomass in and near headwater streams in the eastern United States and are promising indicators of stream ecosystem health. Many studies of stream salamanders have relied on population indices based on counts rather than population estimates based on techniques such as capture-recapture and removal. Application of estimation procedures allows the calculation of detection probabilities (the proportion of total animals present that are detected during a survey) and their associated sampling error, and may be essential for determining salamander population sizes and trends. In 1999, we conducted capture-recapture and removal population estimation methods for Desmognathus salamanders at six streams in Shenandoah National Park, Virginia, USA. Removal sampling appeared more efficient and detection probabilities from removal data were higher than those from capture-recapture. During 2001-2004, we used removal estimation at eight streams in the park to assess the usefulness of this technique for long-term monitoring of stream salamanders. Removal detection probabilities ranged from 0.39 to 0.96 for Desmognathus, 0.27 to 0.89 for Eurycea and 0.27 to 0.75 for northern spring (Gyrinophilus porphyriticus) and northern red (Pseudotriton ruber) salamanders across stream transects. Detection probabilities did not differ across years for Desmognathus and Eurycea, but did differ among streams for Desmognathus. Population estimates of Desmognathus decreased between 2001-2002 and 2003-2004 which may be related to changes in stream flow conditions. Removal-based procedures may be a feasible approach for population estimation of salamanders, but field methods should be designed to meet the assumptions of the sampling procedures. New approaches to estimating stream salamander populations are discussed.

  11. Tiger salamanders' (Ambystoma tigrinum) response learning and usage of visual cues.

    PubMed

    Kundey, Shannon M A; Millar, Roberto; McPherson, Justin; Gonzalez, Maya; Fitz, Aleyna; Allen, Chadbourne

    2016-05-01

    We explored tiger salamanders' (Ambystoma tigrinum) learning to execute a response within a maze as proximal visual cue conditions varied. In Experiment 1, salamanders learned to turn consistently in a T-maze for reinforcement before the maze was rotated. All learned the initial task and executed the trained turn during test, suggesting that they learned to demonstrate the reinforced response during training and continued to perform it during test. In a second experiment utilizing a similar procedure, two visual cues were placed consistently at the maze junction. Salamanders were reinforced for turning towards one cue. Cue placement was reversed during test. All learned the initial task, but executed the trained turn rather than turning towards the visual cue during test, evidencing response learning. In Experiment 3, we investigated whether a compound visual cue could control salamanders' behaviour when it was the only cue predictive of reinforcement in a cross-maze by varying start position and cue placement. All learned to turn in the direction indicated by the compound visual cue, indicating that visual cues can come to control their behaviour. Following training, testing revealed that salamanders attended to stimuli foreground over background features. Overall, these results suggest that salamanders learn to execute responses over learning to use visual cues but can use visual cues if required. Our success with this paradigm offers the potential in future studies to explore salamanders' cognition further, as well as to shed light on how features of the tiger salamanders' life history (e.g. hibernation and metamorphosis) impact cognition. PMID:26796198

  12. Reintroduction and Post-Release Survival of a Living Fossil: The Chinese Giant Salamander.

    PubMed

    Zhang, Lu; Jiang, Wei; Wang, Qi-Jun; Zhao, Hu; Zhang, Hong-Xing; Marcec, Ruth M; Willard, Scott T; Kouba, Andrew J

    2016-01-01

    Captive rearing and reintroduction / translocation are increasingly used as tools to supplement wild populations of threatened species. Reintroducing captive-reared Chinese giant salamanders may help to augment the declining wild populations and conserve this critically endangered amphibian. We released 31 captive-reared juvenile giant salamanders implanted with VHF radio transmitters at the Heihe River (n = 15) and the Donghe River (n = 16) in the Qinling Mountains of central China. Salamanders were monitored every day for survival from April 28th 2013 to September 3rd 2014. We attempted to recapture all living individuals by the end of the study, measured their body mass and total body length, and checked for abnormalities and presence of external parasites. Two salamanders at the Heihe River and 10 animals at the Donghe River survived through the project timeline. Nine salamanders were confirmed dead, while the status of the other 10 animals was undetermined. The annual survival rate of giant salamanders at the Donghe River (0.702) was 1.7-fold higher than that at the Heihe River (0.405). Survival increased as individuals were held longer following surgery, whereas body mass did not have a significant impact on survival rate. All salamanders recaptured from the Donghe River (n = 8) increased in mass (0.50 ± 0.13 kg) and length (5.5 ± 1.5 cm) after approximately 11 months in the wild, and they were only 7% lighter than wild animals of the same length (mean residual = -0.033 ± 0.025). Our results indicate that captive-reared Chinese giant salamanders can survive in the wild one year after release and adequate surgical recovery time is extremely important to post-release survival. Future projects may reintroduce older juveniles to achieve better survival and longer monitoring duration. PMID:27258650

  13. Using a GIS model to assess terrestrial salamander response to alternative forest management plans.

    PubMed

    Gustafson, E J; Murphy, N L; Crow, T R

    2001-11-01

    A GIS model predicting the spatial distribution of terrestrial salamander abundance based on topography and forest age was developed using parameters derived from the literature. The model was tested by sampling salamander abundance across the full range of site conditions used in the model. A regression of the predictions of our GIS model against these sample data showed that the model has a modest but significant ability to predict both salamander abundance and mass per unit area. The model was used to assess the impacts of alternative management plans for the Hoosier National Forest (Indiana, USA) on salamanders. These plans differed in the spatial delineation of management areas where timber harvest was permitted, and the intensity of timber harvest within those management areas. The spatial pattern of forest openings produced by alternative forest management scenarios based on these plans was projected over 150 years using a timber-harvest simulator (HARVEST). We generated a predictive map of salamander abundance for each scenario over time, and summarized each map by calculating mean salamander abundance and the mean colonization distance (average distance from map cells with low predicted abundance to those with relatively high abundance). Projected salamander abundance was affected more by harvest rate (area harvested each decade) than by the management area boundaries. The alternatives had a varying effect on the mean distance salamanders would have to travel to colonize regenerating stands. Our GIS modeling approach is an example of a spatial analytical tool that could help resource management planners to evaluate the potential ecological impact of management alternatives. PMID:11775500

  14. Evaluation of terrestrial and streamside salamander monitoring techniques at Shenandoah National Park

    USGS Publications Warehouse

    Jung, R.E.; Droege, S.; Sauer, J.R.; Landy, R.B.

    2000-01-01

    In response to concerns about amphibian declines, a study evaluating and validating amphibian monitoring techniques was initiated in Shenandoah and Big Bend National Parks in the spring of 1998. We evaluate precision, bias, and efficiency of several sampling methods for terrestrial and streamside salamanders in Shenandoah National Park and assess salamander abundance in relation to environmental variables, notably soil and water pH. Terrestrial salamanders, primarily redback salamanders (Plethodon cinereus), were sampled by searching under cover objects during the day in square plots (10 to 35 m2). We compared population indices (mean daily and total counts) with adjusted population estimates from capture-recapture. Analyses suggested that the proportion of salamanders detected (p) during sampling varied among plots, necessitating the use of adjusted population estimates. However, adjusted population estimates were less precise than population indices, and may not be efficient in relating salamander populations to environmental variables. In future sampling, strategic use of capture-recapture to verify consistency of p's among sites may be a reasonable compromise between the possibility of bias in estimation of population size and deficiencies due to inefficiency associated with the estimation of p. The streamside two-lined salamander (Eurycea bislineata) was surveyed using four methods: leaf litter refugia bags, 1 m2 quadrats, 50 x 1 m visual encounter transects, and electric shocking. Comparison of survey methods at nine streams revealed congruent patterns of abundance among sites, suggesting that relative bias among the methods is similar, and that choice of survey method should be based on precision and logistical efficiency. Redback and two-lined salamander abundance were not significantly related to soil or water pH, respectively.

  15. Reintroduction and Post-Release Survival of a Living Fossil: The Chinese Giant Salamander.

    PubMed

    Zhang, Lu; Jiang, Wei; Wang, Qi-Jun; Zhao, Hu; Zhang, Hong-Xing; Marcec, Ruth M; Willard, Scott T; Kouba, Andrew J

    2016-01-01

    Captive rearing and reintroduction / translocation are increasingly used as tools to supplement wild populations of threatened species. Reintroducing captive-reared Chinese giant salamanders may help to augment the declining wild populations and conserve this critically endangered amphibian. We released 31 captive-reared juvenile giant salamanders implanted with VHF radio transmitters at the Heihe River (n = 15) and the Donghe River (n = 16) in the Qinling Mountains of central China. Salamanders were monitored every day for survival from April 28th 2013 to September 3rd 2014. We attempted to recapture all living individuals by the end of the study, measured their body mass and total body length, and checked for abnormalities and presence of external parasites. Two salamanders at the Heihe River and 10 animals at the Donghe River survived through the project timeline. Nine salamanders were confirmed dead, while the status of the other 10 animals was undetermined. The annual survival rate of giant salamanders at the Donghe River (0.702) was 1.7-fold higher than that at the Heihe River (0.405). Survival increased as individuals were held longer following surgery, whereas body mass did not have a significant impact on survival rate. All salamanders recaptured from the Donghe River (n = 8) increased in mass (0.50 ± 0.13 kg) and length (5.5 ± 1.5 cm) after approximately 11 months in the wild, and they were only 7% lighter than wild animals of the same length (mean residual = -0.033 ± 0.025). Our results indicate that captive-reared Chinese giant salamanders can survive in the wild one year after release and adequate surgical recovery time is extremely important to post-release survival. Future projects may reintroduce older juveniles to achieve better survival and longer monitoring duration.

  16. Plethodon cinerius (eastern red-backed salamander) movement

    USGS Publications Warehouse

    Sterrett, Sean; Brand, Adrianne; Fields, William R.; Katz, Rachel A.; Grant, Evan H. Campbell

    2015-01-01

    Lungless salamanders (family Plethodontidae) are relatively sedentary and are presumed to have limited dispersal ability (Marsh et al. 2004. Ecology 85:3396–3405). Site fidelity in Plethodontidae is high, and individuals displaced 90 m return to home territories (Kleeberger and Werner 1982. Copeia 1982:409–415). Individuals defend territories (Jaeger et al. 1982. Anim. Behav. 30:490–496) and female home ranges have been estimated to be 24.34 m2 (Kleeberger and Werner 1982, op. cit.). Females may seek out suitable subsurface habitat to oviposit eggs, yet little is known about their maximum movement distances (Petranka 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington. 587 pp.).On 18 September 2014, a female P. cinereus (lead back morphotype; SVL = 44.68 mm; 0.89 g) was found under a coverboard during a standard sampling event and uniquely marked using visual implant elastomer at the S.O. Conte Anadromous Fish Research Center, Massachusetts, USA (42.59280°N, 72.58070°W, datum WGS84; elev. 74 m). This individual was subsequently recaptured at ~1500 h on 8 October 2014 under a coverboard within 3 m of the original capture location and then again ~1430 h on 16 October 2014 under a log, within the same forest patch, though in a 50 x 150 m area adjacent to the original study area. Because we found the marked salamander while collecting multiple individuals for a laboratory study, the exact recapture location of the marked individual is not known. However, the distance between the 8 October capture location and the nearest edge of the 16 October search area (i.e. 50 x 150 m) was 143 m, indicating a minimum movement distance. As far as we are aware, this is the longest recorded movement for P. cinereus by more than 53 m (Kleeberger and Werner 1982, op. cit.). This finding followed a rain event of 1.63 cm within 24 h and the second largest sustained rain event during October. The movement we observed may have been due to

  17. Leaf litter bags as an index to populations of northern two-lined salamanders (Eurycea bislineata)

    USGS Publications Warehouse

    Chalmers, R.J.; Droege, S.

    2002-01-01

    Concern about recent amphibian declines has led to research on amphibian populations, but few statistically tested, standardized methods of counting amphibians exist. We tested whether counts of northern two-lined salamander larvae (Eurycea bislineata) sheltered in leaf litter bags--a relatively new, easily replicable survey technique--had a linear correlation to total number of larvae. Using experimental enclosures placed in streams, we compared number of salamanders found in artificial habitat (leaf litter bags) with total number of salamanders in each enclosure. Low numbers of the animals were found in leaf litter bags, and the relative amount of variation in the index (number of animals in leaf litter bags compared to total number of animals in stream enclosures) was high. The index of salamanders in leaf litter bags was not significantly related to total number of salamanders in enclosures for two-thirds of the replicates or with pooled replicates (P= 0.066). Consequently, we cannot recommend using leaf litter bags to index populations of northern two-lined salamanders.

  18. Organisation of the spinal central pattern generators for locomotion in the salamander: biology and modelling.

    PubMed

    Chevallier, Stéphanie; Jan Ijspeert, Auke; Ryczko, Dimitri; Nagy, Frédéric; Cabelguen, Jean-Marie

    2008-01-01

    Among living tetrapods, salamanders are regarded as most closely resembling the first terrestrial vertebrates, and are therefore an interesting group in which the evolutionary changes in the locomotor behaviour from aquatic to terrestrial habitats can be inferred. Salamanders exhibit two locomotor modes: swimming and terrestrial stepping. The swimming is anguilliform and resembles closely that of the lamprey. On the ground, the salamander switches to a stepping gait with axial undulations that is also observed in many reptiles. The salamander is therefore ideally suited for examining the neural mechanisms for the generation of these two locomotor modes, as well as the neural mechanisms of gait transition. In the present paper, we describe the kinematics and patterns of activation of axial and limb muscles during stepping and swimming in adult salamanders. We then review the current neurobiological data about the organisation of the spinal networks underlying swimming and stepping, and the mechanisms of gait transition. Finally we report modelling studies aimed at understanding the organisation and operation of the salamander locomotor circuits. Altogether, the neurobiological and the modelling data support the hypothesis of a phylogenetic conservatism from agnathians to amphibians of the spinal locomotor networks generating axial motor patterns.

  19. Mercury bioaccumulation in northern two-lined salamanders from streams in the northeastern United States

    USGS Publications Warehouse

    Bank, M.S.; Loftin, C.S.; Jung, R.E.

    2005-01-01

    Mercury (Hg) bioaccumulation in salamanders has received little attention despite widespread Hg contamination of aquatic ecosystems and worldwide amphibian declines. Here we report concentrations of methyl Hg (MeHg) and total Hg in larval northern two-lined salamanders (Eurycea bislineata bislineata) collected from streams in Acadia National Park (ANP), Maine, and Bear Brook Watershed, Maine (BBWM; a paired, gauged watershed treated with bimonthly applications (25 kg/ha/yr) of ammonium sulfate [(NH4)(2)SO4]) since 1989), and Shenandoah National Park (SNP), Virginia. MeHg comprised 73-97% of total Hg in the larval salamander composite samples from ANP. At BBWM we detected significantly higher total Hg levels in larvae from the (NH4)(2)SO4 treatment watershed. At ANP total Hg concentrations in salamander larvae were significantly higher from streams in unburned watersheds in contrast with larval samples collected from streams located in watersheds burned by the 1947 Bar Harbor fire. Additionally, total Hg levels were significantly higher in salamander larvae collected at ANP in contrast with SNP. Our results suggest that watershed-scale attributes including. re history, whole-catchment (NH4)(2)SO4 additions, wetland extent, and forest cover type influence mercury bioaccumulation in salamanders inhabiting lotic environments. We also discuss the use of this species as an indicator of Hg bioaccumulation in stream ecosystems.

  20. Three decades of urbanization: Estimating the impact of land-cover change on stream salamander populations

    USGS Publications Warehouse

    Price, S.J.; Dorcas, M.E.; Gallant, A.L.; Klaver, R.W.; Willson, J.D.

    2006-01-01

    Urbanization has become the dominant form of landscape disturbance in parts of the United States. Small streams in the Piedmont region of the eastern United States support high densities of salamanders and are often the first habitats to be affected by landscape-altering factors such as urbanization. We used US Geological Survey land cover data from 1972 to 2000 and a relation between stream salamanders and land cover, established from recent research, to estimate the impact of contemporary land-cover change on the abundance of stream salamanders near Davidson, North Carolina, a Piedmont locale that has experienced rapid urbanization during this time. Our analysis indicates that southern two-lined salamander (Eurycea cirrigera) populations have decreased from 32% to 44% while northern dusky salamanders (Desmognathus fuscus) have decreased from 21% to 30% over the last three decades. Our results suggest that the widespread conversion of forest to urban land in small catchments has likely resulted in a substantial decline of populations of stream salamanders and could have serious effects on stream ecosystems. ?? 2006 Elsevier Ltd. All rights reserved.

  1. Soil acidity affects distribution, behavior, and physiology of the salamander Plethodon cinereus

    SciTech Connect

    Wyman, R.L.; Hawksley-Lescault, D.S.

    1987-12-01

    Censuses at two sites in Delaware County, New York from spring 1981 through spring 1985 indicated that the density and distribution of Plethodon cinereus were influenced by soil pH but not by soil temperature or moisture. Of 1044 1-m/sup 2/ quadrats of forest litter searched, 284 had a pH of 3.7 or less and only 25 of these (8.8%) contained salamanders. Of 760 quadrats with a pH 3.8 or more, 386 (50.8%) contained salamanders. Juvenile salamanders were never found on soils with a pH less than or equal to 3.7. Seasonal salamander density was correlated (r = -0.92) with the percentage of quadrats with a pH of 3.7 and less. Salamanders apparently were excluded from 27% of forest habitat because of low soil pH. In the laboratory, P. cinereus preferred to occupy substrates near neutral pH when given a choice among three levels of substrate acidity. The acutely lethal pH was between 2.5 and 3 and the 8-mo chronically lethal pH was between 3 and 4. Growth and respiration were reduced at low pHs. The influence of soil pH on salamander distribution might fundamentally change the forest floor decomposer food web of which P. cinereus is an upper-level consumer.

  2. Pathology, isolation, and preliminary molecular characterization of a novel iridovirus from tiger salamanders in Saskatchewan.

    PubMed

    Bollinger, T K; Mao, J; Schock, D; Brigham, R M; Chinchar, V G

    1999-07-01

    All iridovirus was confirmed to be the cause of an epizootic in larval and adult tiger salamanders (Ambystoma tigrinum diaboli) from four separate ponds in southern Saskatchewan (Canada) during the summer of 1997. This organism also is suspected, based on electron microscopic findings, to be the cause of mortality of larval tiger salamanders in a pond over 200 km to the north during the same year. Salamanders developed a generalized viremia which resulted in various lesions including: necrotizing, vesicular and ulcerative dermatitis; gastrointestinal ulceration; and necrosis of hepatic, splenic, renal, lymphoid, and hematopoietic tissues. In cells associated with these lesions, large lightly basophilic cytoplasmic inclusions and vacuolated nuclei with marginated chromatin were consistently found. Virus was isolated from tissue homogenates of infected salamanders following inoculation of epithelioma papilloma cyprini (EPC) cells. The virus, provisionally designated Regina ranavirus (RRV), was initially identified as an iridovirus by electron microscopy. Subsequent molecular characterization, including partial sequence analysis of the major capsid protein (MCP) gene, confirmed this assignment and established that RRV was a ranavirus distinct from frog virus 3 (FV3) and other members of the genus Ranavirus. Intraperitoneal inoculation of 5 x 10(6.23) TCID50 of the field isolate caused mortality in inoculated salamanders at 13 days post infection. Field, clinical, and molecular studies jointly suggest that the etiological agent of recent salamander mortalities is a highly infectious novel ranavirus. PMID:10479075

  3. Mitochondrial Myopathy

    MedlinePlus

    ... with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes. The symptoms of ... riboflavin, coenzyme Q, and carnitine (a specialized amino acid) may provide subjective improvement in fatigue and energy ...

  4. Mitochondrial DNA.

    ERIC Educational Resources Information Center

    Wright, Russell G.; Bottino, Paul J.

    1986-01-01

    Provides background information for teachers on mitochondrial DNA, pointing out that it may have once been a free-living organism. Includes a ready-to-duplicate exercise titled "Using Microchondrial DNA to Measure Evolutionary Distance." (JN)

  5. Mitochondrial Myopathies

    MedlinePlus

    ... line and are therefore called the electron transport chain, and complex V actually churns out ATP, so ... coQ10 , is a component of the electron transport chain, which uses oxygen to manufacture ATP. Some mitochondrial ...

  6. Woodland salamander responses to a shelterwood harvest-prescribed burn silvicultural treatment within Appalachian mixed-oak forests

    USGS Publications Warehouse

    Ford, W. Mark; Mahoney, Kathleen R.; Russell, Kevin R.; Rodrigue, Jane L.; Riddle, Jason D.; Schuler, Thomas M.; Adams, Mary Beth

    2015-01-01

    Forest management practices that mimic natural canopy disturbances, including prescribed fire and timber harvests, may reduce competition and facilitate establishment of favorable vegetative species within various ecosystems. Fire suppression in the central Appalachian region for almost a century has contributed to a transition from oak-dominated to more mesophytic, fire-intolerant forest communities. Prescribed fire coupled with timber removal is currently implemented to aid in oak regeneration and establishment but responses of woodland salamanders to this complex silvicultural system is poorly documented. The purpose of our research was to determine how woodland salamanders respond to shelterwood harvests following successive burns in a central Appalachian mixed-oak forest. Woodland salamanders were surveyed using coverboard arrays in May, July, and August–September 2011 and 2012. Surveys were conducted within fenced shelterwood-burn (prescribed fires, shelterwood harvest, and fencing to prevent white-tailed deer [Odocoileus virginianus] herbivory), shelterwood-burn (prescribed fires and shelterwood harvest), and control plots. Relative abundance was modeled in relation to habitat variables measured within treatments for mountain dusky salamanders (Desmognathus ochrophaeus), slimy salamanders (Plethodon glutinosus), and eastern red-backed salamanders (Plethodon cinereus). Mountain dusky salamander relative abundance was positively associated with canopy cover and there were significantly more individuals within controls than either shelterwood-burn or fenced shelterwood-burn treatments. Conversely, habitat variables associated with slimy salamanders and eastern red-backed salamanders did not differ among treatments. Salamander age-class structure within controls did not differ from shelterwood-burn or fenced shelterwood-burn treatments for any species. Overall, the woodland salamander assemblage remained relatively intact throughout the shelterwoodburn

  7. Mitochondrial genetics

    PubMed Central

    Chinnery, Patrick Francis; Hudson, Gavin

    2013-01-01

    Introduction In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. Sources of data In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. Areas of agreement The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. Areas of controversy The exact mechanisms which govern the inheritance of mtDNA are hotly debated. Growing points Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease. PMID:23704099

  8. Innovative techniques for sampling stream-inhabiting salamanders

    SciTech Connect

    T.M. Luhring; C.A. Young

    2006-01-01

    Although salamanders are excellent indicators of environmental health, the ability to catch them efficiently without substantially disrupting their habitat is not always practical or even possible with current techniques. Ripping open logs and raking leaf packs onto shore (Bruce 1972) are examples of such practices that are disruptive but widely used by herpetologists who have no other means of efficient collection. Drift fences with pitfall traps are effective in catching animals moving within or between habitats but are time consuming and require an initial financial investment and constant upkeep to maintain functionality and prevent animal fatalities (Gibbons and Semlitsch 1981). One current alternative to drift fences is the use of coverboards (Grant et al. 1992), which require less maintenance and sampling effort than drift fences. However, coverboards do not integrate captures over a long time period and often result in a lower number of captures per trap (Grant et al. 1992).

  9. Road deicing salt irreversibly disrupts osmoregulation of salamander egg clutches.

    PubMed

    Karraker, Nancy E; Gibbs, James P

    2011-03-01

    It has been postulated that road deicing salts are sufficiently diluted by spring rains to ameliorate any physiological impacts to amphibians breeding in wetlands near roads. We tested this conjecture by exposing clutches of the spotted salamander (Ambystoma maculatum) to three chloride concentrations (1 mg/L, 145 mg/L, 945 mg/L) for nine days, then transferred clutches to control water for nine days, and measured change in mass at three-day intervals. We measured mass change because water uptake by clutches reduces risks to embryos associated with freezing, predation, and disease. Clutches in controls sequestered water asymptotically. Those in the moderate concentrations lost 18% mass initially and regained 14% after transfer to control water. Clutches in high concentration lost 33% mass and then lost an additional 8% after transfer. Our results suggest that spring rains do not ameliorate the effects of deicing salts in wetlands with extremely high chloride concentrations.

  10. Ambient ultraviolet radiation causes mortality in salamander eggs

    SciTech Connect

    Blaustein, A.R.; Edmond, B.; Kiesecker, J.M.

    1995-08-01

    Previous research has shown that amphibian species have differential sensitivity to ultraviolet-B (UV-B) radiation. In some anuran species, ambient levels of UV-B cause mortality in embryonic stages and hatching success is significantly reduced. Projected increases in UV-B may affect an increasing number of species. The adverse effects of UV-B may eventually be manifested at the population level and may ultimately contribute to population declines. Using field experiments, we investigated the effects of ambient UV-B on salamander (Ambystoma gracile) embryos developing at natural oviposition sites. We show that the hatching success of eggs of A. gracile shielded from UV-B is significantly higher than those not shielded from UV-B. 27 refs., 1 fig.

  11. Immunocytochemical analysis of photoreceptors in the tiger salamander retina

    PubMed Central

    Zhang, Jian; Wu, Samuel M.

    2013-01-01

    In the tiger salamander retina, visual signals are transmitted to the inner retina via six morphologically distinct types of photoreceptors: large/small rods, large/small single cones, and double cones composed of principal and accessory members. The objective of this study was to determine the morphology of these photoreceptors and their synaptic interconnection with bipolar cells and horizontal cells in the outer plexiform layer (OPL). Here we showed that glutamate antibodies labeled all photoreceptors and recoverin antibodies strongly labeled all cones and weakly labeled all rods. Antibodies against calbindin selectively stained accessory members of double cones. Antibodies against S-cone opsin stained small rods, a subpopulation of small single cones, and the outer segments of accessory double cones and a subtype of unidentified single cones. On average, large rods and small S-cone opsin positive rods accounted for 98.6% and 1.4% of all rods, respectively. Large/small cones, principle/accessory double cones, S-cone opsin positive small single cones, and S-cone opsin positive unidentified single cones accounted for about 66.9%, 23%, 4.5%, and 5.6% of the total cones, respectively. Moreover, the differential connection between rods/cones and bipolar/horizontal cells and the wide distribution of AMPA receptor subunits GluR2/3 and GluR4 at the rod/cone synapses were observed. These results provide anatomical evidence for the physiological findings that bipolar/horizontal cells in the salamander retina are driven by rod/cone inputs of different weights, and that AMPA receptors play an important role in glutamatergic neurotransmission at the first visual synapses. The different photoreceptors selectively contacting bipolar and horizontal cells support the idea that visual signals may be conveyed to the inner retina by different functional pathways in the outer retina. PMID:18977238

  12. Mitochondrial Evolution

    PubMed Central

    Gray, Michael W.

    2012-01-01

    Viewed through the lens of the genome it contains, the mitochondrion is of unquestioned bacterial ancestry, originating from within the bacterial phylum α-Proteobacteria (Alphaproteobacteria). Accordingly, the endosymbiont hypothesis—the idea that the mitochondrion evolved from a bacterial progenitor via symbiosis within an essentially eukaryotic host cell—has assumed the status of a theory. Yet mitochondrial genome evolution has taken radically different pathways in diverse eukaryotic lineages, and the organelle itself is increasingly viewed as a genetic and functional mosaic, with the bulk of the mitochondrial proteome having an evolutionary origin outside Alphaproteobacteria. New data continue to reshape our views regarding mitochondrial evolution, particularly raising the question of whether the mitochondrion originated after the eukaryotic cell arose, as assumed in the classical endosymbiont hypothesis, or whether this organelle had its beginning at the same time as the cell containing it. PMID:22952398

  13. Individual performance in relation to cytonuclear discordance in a northern contact zone between long-toed salamander (Ambystoma macrodactylum) lineages.

    PubMed

    Lee-Yaw, Julie A; Jacobs, Chris G C; Irwin, Darren E

    2014-09-01

    Cytonuclear discordance in contact zones between related lineages is common, with mitochondrial clines often being displaced from clines in nuclear allele frequency. Proposed explanations for such a pattern include adaptive introgression of mtDNA or a neutral wake of mtDNA being left behind following hybrid zone movement. However, studies investigating these hypotheses are rare. Our previous survey of genetic variation in the long-toed salamander (Ambystoma macrodactylum) highlighted a potential case of cytonuclear discordance between two lineages in western Canada. Here, we use additional markers and samples to clarify the extent of this discordance. We simultaneously assess the feeding performance of individuals in a common environment to test for an association between mitotype and individual performance. The genetic results confirm a general pattern of cytonuclear discordance in the focal region. However, we also observed more limited introgression of a diagnostic nuclear marker. Intriguingly, although there were differences in individual performance associated with the transition between mitotypes, these differences were not fully explained by mitotype. Instead, the lowest performance was observed in individuals demonstrating the greatest mismatch between mtDNA and all nuclear markers, suggesting the potential for cytonuclear incompatibilities to be acting. These results highlight the complexity of understanding the causes and consequences of mtDNA introgression and cytonuclear discordance in contact zones.

  14. Range-wide phylogeography and conservation genetics of a narrowly endemic stream salamander, Pachyhynobius shangchengensis (Caudata, Hynobiidae): implications for conservation.

    PubMed

    Pan, T; Wang, H; Hu, C-C; Shi, W-B; Zhao, K; Huang, X; Zhang, B-W

    2014-02-13

    The Shangcheng stout salamander (Pachyhynobius shangchengensis) is an endangered amphibian endemic to the Dabie Mountains, southeast China, and is currently threatened by habitat loss and illegal poaching. Here we used the mitochondrial DNA control region sequence (768 bp) to conduct a comprehensive investigation of genetic diversity, phylogeographic pattern, and demographic history of the species across its geographic distribution to assist its conservation. We concluded that the levels of genetic variation are relatively low in all four populations. Analysis of molecular variance indicated that the most likely phylogeographic pattern is [JGT] [KHJ] [TM, BYM]. Two distinct clades were identified in the phylogenetic tree of 28 haplotypes, corresponding to the two southern populations (TM, BYM) and two northern populations (JGT, KHJ). Significant population differentiation (FST) was detected among all populations. Among the four populations, historical demographic analyses (e.g., the g parameter, the Tajima D test, and the Fu Fs test) did not reveal definite information on population expansion except for the BYM population, which had undergone a strong population expansion event. Based on the analysis of a Bayesian skyline plot, the total population underwent a significant population fluctuation around 20 kya. This may have been triggered by the end of the last glacial maximum. In conclusion, the existence of three evolutionarily significant units (BMY-TM, KHJ, and JGT) and four management units (BMY, TM, KHJ, and JGT) is supported by our study.

  15. Range-wide phylogeography and conservation genetics of a narrowly endemic stream salamander, Pachyhynobius shangchengensis (Caudata, Hynobiidae): implications for conservation.

    PubMed

    Pan, T; Wang, H; Hu, C-C; Shi, W-B; Zhao, K; Huang, X; Zhang, B-W

    2014-01-01

    The Shangcheng stout salamander (Pachyhynobius shangchengensis) is an endangered amphibian endemic to the Dabie Mountains, southeast China, and is currently threatened by habitat loss and illegal poaching. Here we used the mitochondrial DNA control region sequence (768 bp) to conduct a comprehensive investigation of genetic diversity, phylogeographic pattern, and demographic history of the species across its geographic distribution to assist its conservation. We concluded that the levels of genetic variation are relatively low in all four populations. Analysis of molecular variance indicated that the most likely phylogeographic pattern is [JGT] [KHJ] [TM, BYM]. Two distinct clades were identified in the phylogenetic tree of 28 haplotypes, corresponding to the two southern populations (TM, BYM) and two northern populations (JGT, KHJ). Significant population differentiation (FST) was detected among all populations. Among the four populations, historical demographic analyses (e.g., the g parameter, the Tajima D test, and the Fu Fs test) did not reveal definite information on population expansion except for the BYM population, which had undergone a strong population expansion event. Based on the analysis of a Bayesian skyline plot, the total population underwent a significant population fluctuation around 20 kya. This may have been triggered by the end of the last glacial maximum. In conclusion, the existence of three evolutionarily significant units (BMY-TM, KHJ, and JGT) and four management units (BMY, TM, KHJ, and JGT) is supported by our study. PMID:24615095

  16. Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander.

    PubMed

    Pereira, Ricardo J; Martínez-Solano, Iñigo; Buckley, David

    2016-04-01

    Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change. PMID:26850834

  17. Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander.

    PubMed

    Pereira, Ricardo J; Martínez-Solano, Iñigo; Buckley, David

    2016-04-01

    Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change.

  18. 76 FR 44036 - Proposed Low-Effect Habitat Conservation Plan for the California Tiger Salamander, AT&T Portable...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... Fish and Wildlife Service Proposed Low-Effect Habitat Conservation Plan for the California Tiger... potential for ``take'' of one Federally listed animal, the California tiger salamander. The applicant would... for the California tiger salamander into a new storage facility for portable generators within...

  19. IMPACT OF GUTHION ON SURVIVAL AND GROWTH OF THE FROG PSEUDACRIS REGILLA AND THE SALAMANDERS AMBYSTOMA GRACILE AND AMBYSTOMA MACULATUM

    EPA Science Inventory

    The effects of the insecticides Guthion (technical grade) and Guthion 2S(commercial formulation) on survival and growth of tadpoles of the Pacific treefrog Pseudacris regilla, and larvae of the Northwestern salamander Ambystoma gracile and the spotted salamander Ambystoma macula...

  20. Apparent survival of the salamander Salamandra salamandra is low because of high migratory activity

    PubMed Central

    Schmidt, Benedikt R; Schaub, Michael; Steinfartz, Sebastian

    2007-01-01

    Background Understanding the demographic processes underlying population dynamics is a central theme in ecology. Populations decline if losses from the population (i.e., mortality and emigration) exceed gains (i.e., recruitment and immigration). Amphibians are thought to exhibit little movement even though local populations often fluctuate dramatically and are likely to go exinct if there is no rescue effect through immigration from nearby populations. Terrestrial salamanders are generally portrayed as amphibians with low migratory activity. Our study uses demographic analysis as a key to unravel whether emigration or mortality is the main cause of "losses" from the population. In particular, we use the analysis to challenge the common belief that terrestrial salamanders show low migratory activity. Results The mark-recapture analysis of adult salamanders showed that monthly survival was high (> 90%) without a seasonal pattern. These estimates, however, translate into rather low rates of local annual survival of only ~40% and suggest that emigration was important. The estimated probability of emigration was 49%. Conclusion Our analysis shows that terrestrial salamanders exhibit more migratory activity than commonly thought. This may be due either because the spatial extent of salamander populations is underestimated or because there is a substantial exchange of individuals between populations. Our current results are in line with several other studies that suggest high migratory activity in amphibians. In particular, many amphibian populations may be characterized by high proportions of transients and/or floaters. PMID:17803829

  1. Decoding the mechanisms of gait generation in salamanders by combining neurobiology, modeling and robotics.

    PubMed

    Bicanski, Andrej; Ryczko, Dimitri; Knuesel, Jérémie; Harischandra, Nalin; Charrier, Vanessa; Ekeberg, Örjan; Cabelguen, Jean-Marie; Ijspeert, Auke Jan

    2013-10-01

    Vertebrate animals exhibit impressive locomotor skills. These locomotor skills are due to the complex interactions between the environment, the musculo-skeletal system and the central nervous system, in particular the spinal locomotor circuits. We are interested in decoding these interactions in the salamander, a key animal from an evolutionary point of view. It exhibits both swimming and stepping gaits and is faced with the problem of producing efficient propulsive forces using the same musculo-skeletal system in two environments with significant physical differences in density, viscosity and gravitational load. Yet its nervous system remains comparatively simple. Our approach is based on a combination of neurophysiological experiments, numerical modeling at different levels of abstraction, and robotic validation using an amphibious salamander-like robot. This article reviews the current state of our knowledge on salamander locomotion control, and presents how our approach has allowed us to obtain a first conceptual model of the salamander spinal locomotor networks. The model suggests that the salamander locomotor circuit can be seen as a lamprey-like circuit controlling axial movements of the trunk and tail, extended by specialized oscillatory centers controlling limb movements. The interplay between the two types of circuits determines the mode of locomotion under the influence of sensory feedback and descending drive, with stepping gaits at low drive, and swimming at high drive.

  2. Stream water temperature limits occupancy of salamanders in mid-Atlantic protected areas

    USGS Publications Warehouse

    Grant, Evan H. Campbell; Wiewel, Amber N. M.; Rice, Karen C.

    2014-01-01

    Stream ecosystems are particularly sensitive to urbanization, and tolerance of water-quality parameters is likely important to population persistence of stream salamanders. Forecasted climate and landscape changes may lead to significant changes in stream flow, chemical composition, and temperatures in coming decades. Protected areas where landscape alterations are minimized will therefore become increasingly important for salamander populations. We surveyed 29 streams at three national parks in the highly urbanized greater metropolitan area of Washington, DC. We investigated relationships among water-quality variables and occupancy of three species of stream salamanders (Desmognathus fuscus, Eurycea bislineata, and Pseudotriton ruber). With the use of a set of site-occupancy models, and accounting for imperfect detection, we found that stream-water temperature limits salamander occupancy. There was substantial uncertainty about the effects of the other water-quality variables, although both specific conductance (SC) and pH were included in competitive models. Our estimates of occupancy suggest that temperature, SC, and pH have some importance in structuring stream salamander distribution.

  3. Salamanders increase their feeding activity when infected with the pathogenic chytrid fungus Batrachochytrium dendrobatidis.

    PubMed

    Hess, Alexandra; McAllister, Caroline; DeMarchi, Joseph; Zidek, Makenzie; Murone, Julie; Venesky, Matthew D

    2015-10-27

    Immune function is a costly line of defense against parasitism. When infected with a parasite, hosts frequently lose mass due to these costs. However, some infected hosts (e.g. highly resistant individuals) can clear infections with seemingly little fitness losses, but few studies have tested how resistant hosts mitigate these costly immune defenses. We explored this topic using eastern red-backed salamanders Plethodon cinereus and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Bd is generally lethal for amphibians, and stereotypical symptoms of infection include loss in mass and deficits in feeding. However, individuals of P. cinereus can clear their Bd infections with seemingly few fitness costs. We conducted an experiment in which we repeatedly observed the feeding activity of Bd-infected and non-infected salamanders. We found that Bd-infected salamanders generally increased their feeding activity compared to non-infected salamanders. The fact that we did not observe any differences in mass change between the treatments suggests that increased feeding might help Bd-infected salamanders minimize the costs of an effective immune response.

  4. Larval long-toed salamanders incur nonconsumptive effects in the presence of nonnative trout

    USGS Publications Warehouse

    Kenison, Erin K.; Litt, Andrea R.; Pilliod, David; McMahon, Thomas E.

    2016-01-01

    Predators can influence prey directly through consumption or indirectly through nonconsumptive effects (NCEs) by altering prey behavior, morphology, and life history. We investigated whether predator-avoidance behaviors by larval long-toed salamanders (Ambystoma macrodactylum) in lakes with nonnative trout result in NCEs on morphology and development. Field studies in lakes with and without trout were corroborated by experimental enclosures, where prey were exposed only to visual and chemical cues of predators. We found that salamanders in lakes with trout were consistently smaller than in lakes without trout: 38% lower weight, 24% shorter body length, and 29% shorter tail length. Similarly, salamanders in protective enclosures grew 2.9 times slower when exposed to visual and olfactory trout cues than when no trout cues were present. Salamanders in trout-free lakes and enclosures were 22.7 times and 1.48 times, respectively, more likely to metamorphose during the summer season than those exposed to trout in lakes and/or their cues. Observed changes in larval growth rate and development likely resulted from a facultative response to predator-avoidance behavior and demonstrate NCEs occurred even when predation risk was only perceived. Reduced body size and growth, as well as delayed metamorphosis, could have ecological consequences for salamander populations existing with fish if those effects carry-over into lower recruitment, survival, and fecundity.

  5. Salamanders increase their feeding activity when infected with the pathogenic chytrid fungus Batrachochytrium dendrobatidis.

    PubMed

    Hess, Alexandra; McAllister, Caroline; DeMarchi, Joseph; Zidek, Makenzie; Murone, Julie; Venesky, Matthew D

    2015-10-27

    Immune function is a costly line of defense against parasitism. When infected with a parasite, hosts frequently lose mass due to these costs. However, some infected hosts (e.g. highly resistant individuals) can clear infections with seemingly little fitness losses, but few studies have tested how resistant hosts mitigate these costly immune defenses. We explored this topic using eastern red-backed salamanders Plethodon cinereus and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Bd is generally lethal for amphibians, and stereotypical symptoms of infection include loss in mass and deficits in feeding. However, individuals of P. cinereus can clear their Bd infections with seemingly few fitness costs. We conducted an experiment in which we repeatedly observed the feeding activity of Bd-infected and non-infected salamanders. We found that Bd-infected salamanders generally increased their feeding activity compared to non-infected salamanders. The fact that we did not observe any differences in mass change between the treatments suggests that increased feeding might help Bd-infected salamanders minimize the costs of an effective immune response. PMID:26503775

  6. Anatomy, function, and evolution of jaw and hyobranchial muscles in cryptobranchoid salamander larvae.

    PubMed

    Kleinteich, Thomas; Herzen, Julia; Beckmann, Felix; Matsui, Masafumi; Haas, Alexander

    2014-02-01

    Larval salamanders (Lissamphibia: Caudata) are known to be effective suction feeders in their aquatic environments, although they will eventually transform into terrestrial tongue feeding adults during metamorphosis. Early tetrapods may have had a similar biphasic life cycle and this makes larval salamanders a particularly interesting model to study the anatomy, function, development, and evolution of the feeding apparatus in terrestrial vertebrates. Here, we provide a description of the muscles that are involved in the feeding strike in salamander larvae of the Hynobiidae and compare them to larvae of the paedomorphic Cryptobranchidae. We provide a functional and evolutionary interpretation for the observed muscle characters. The cranial muscles in larvae from species of the Hynobiidae and Cryptobranchidae are generally very similar. Most notable are the differences in the presence of the m. hyomandibularis, a muscle that connects the hyobranchial apparatus with the lower jaw. We found this muscle only in Onychodactylus japonicus (Hynobiidae) but not in other hynobiid or cryptobranchid salamanders. Interestingly, the m. hyomandibularis in O. japonicus originates from the ceratobranchial I and not the ceratohyal, and thus exhibits what was previously assumed to be the derived condition. Finally, we applied a biomechanical model to simulate suction feeding in larval salamanders. We provide evidence that a flattened shape of the hyobranchial apparatus in its resting position is beneficial for a fast and successful suction feeding strike.

  7. Estimating superpopulation size and annual probability of breeding for pond-breeding salamanders

    USGS Publications Warehouse

    Kinkead, K.E.; Otis, D.L.

    2007-01-01

    It has long been accepted that amphibians can skip breeding in any given year, and environmental conditions act as a cue for breeding. In this paper, we quantify temporary emigration or nonbreeding probability for mole and spotted salamanders (Ambystoma talpoideum and A. maculatum). We estimated that 70% of mole salamanders may skip breeding during an average rainfall year and 90% may skip during a drought year. Spotted salamanders may be more likely to breed, with only 17% avoiding the breeding pond during an average rainfall year. We illustrate how superpopulations can be estimated using temporary emigration probability estimates. The superpopulation is the total number of salamanders associated with a given breeding pond. Although most salamanders stay within a certain distance of a breeding pond for the majority of their life spans, it is difficult to determine true overall population sizes for a given site if animals are only captured during a brief time frame each year with some animals unavailable for capture at any time during a given year. ?? 2007 by The Herpetologists' League, Inc.

  8. Hybrid vigor between native and introduced salamanders raises new challenges for conservation

    PubMed Central

    Fitzpatrick, Benjamin M.; Shaffer, H. Bradley

    2007-01-01

    Hybridization between differentiated lineages can have many different consequences depending on fitness variation among hybrid offspring. When introduced organisms hybridize with natives, the ensuing evolutionary dynamics may substantially complicate conservation decisions. Understanding the fitness consequences of hybridization is an important first step in predicting its evolutionary outcome and conservation impact. Here, we measured natural selection caused by differential viability of hybrid larvae in wild populations where native California Tiger Salamanders (Ambystoma californiense) and introduced Barred Tiger Salamanders (Ambystoma tigrinum mavortium) have been hybridizing for 50–60 years. We found strong evidence of hybrid vigor; mixed-ancestry genotypes had higher survival rates than genotypes containing mostly native or mostly introduced alleles. Hybrid vigor may be caused by heterozygote advantage (overdominance) or recombinant hybrid vigor (due to epistasis or complementation). These genetic mechanisms are not mutually exclusive, and we find statistical support for both overdominant and recombinant contributions to hybrid vigor in larval tiger salamanders. Because recombinant homozygous genotypes can breed true, a single highly fit genotype with a mosaic of native and introduced alleles may eventually replace the historically pure California Tiger Salamander (listed as Threatened under the U.S. Endangered Species Act). The management implications of this outcome are complex: Genetically pure populations may not persist into the future, but average fitness and population viability of admixed California Tiger Salamanders may be enhanced. The ecological consequences for other native species are unknown. PMID:17884982

  9. Testicular structure and germ cells morphology in salamanders

    PubMed Central

    Uribe, Mari Carmen; Mejía-Roa, Víctor

    2014-01-01

    Testes of salamanders or urodeles are paired elongated organs that are attached to the dorsal wall of the body by a mesorchium. The testes are composed of one or several lobes. Each lobe is morphologically and functionally a similar testicular unit. The lobes of the testis are joined by cords covered by a single peritoneal epithelium and subjacent connective tissue. The cords contain spermatogonia. Spermatogonia associate with Sertoli cells to form spermatocysts or cysts. The spermatogenic cells in a cyst undergo their development through spermatogenesis synchronously. The distribution of cysts displays the cephalo-caudal gradient in respect to the stage of spermatogenesis. The formation of cysts at cephalic end of the testis causes their migration along the lobules to the caudal end. Consequently, the disposition in cephalo-caudal regions of spermatogenesis can be observed in longitudinal sections of the testis. The germ cells are spermatogonia, diploid cells with mitotic activity; primary and second spermatocytes characterized by meiotic divisions that develop haploid spermatids; during spermiogenesis the spermatids differentiate to spermatozoa. During spermiation the cysts open and spermatozoa leave the testicular lobules. After spermiation occurs the development of Leydig cells into glandular tissue. This glandular tissue regressed at the end of the reproductive cycle. PMID:26413406

  10. Multiple paternity in a salamander with socially monogamous behaviour.

    PubMed

    Liebgold, Eric B; Cabe, Paul R; Jaeger, Robert G; Leberg, Paul L

    2006-11-01

    In the majority of birds and mammals, social monogamy is not congruent with genetic monogamy. No research to date has compared social and genetic monogamy in amphibians. We analysed paternity in clutches of red-backed salamanders (Plethodon cinereus), a species in which social monogamy has been demonstrated in the laboratory, and 28% of individuals in the forest are found in male-female pairs in the noncourtship season. We collected 16 clutches of eggs of P. cinereus in the southern Appalachian Mountains of Virginia and collected tail clippings from attending mothers. We genotyped embryos and adults at five microsatellite loci in order to analyse paternity of clutches. Most clutches (84.6%) had multiple sires, with two to three sires per clutch. In this study, 25% of clutches had males in addition to females attending eggs. None of the mothers of these clutches were genetically monogamous. All attending males sired some of the offspring in the clutch that they attended (between 9% and 50%) but never sired a majority in that clutch. We conclude that, at least in this population, social monogamy in P. cinereus is not concomitant with genetic monogamy.

  11. Wildlife disease. Recent introduction of a chytrid fungus endangers Western Palearctic salamanders.

    PubMed

    Martel, A; Blooi, M; Adriaensen, C; Van Rooij, P; Beukema, W; Fisher, M C; Farrer, R A; Schmidt, B R; Tobler, U; Goka, K; Lips, K R; Muletz, C; Zamudio, K R; Bosch, J; Lötters, S; Wombwell, E; Garner, T W J; Cunningham, A A; Spitzen-van der Sluijs, A; Salvidio, S; Ducatelle, R; Nishikawa, K; Nguyen, T T; Kolby, J E; Van Bocxlaer, I; Bossuyt, F; Pasmans, F

    2014-10-31

    Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.

  12. Where are we in understanding salamander locomotion: biological and robotic perspectives on kinematics.

    PubMed

    Karakasiliotis, Konstantinos; Schilling, Nadja; Cabelguen, Jean-Marie; Ijspeert, Auke Jan

    2013-10-01

    Salamanders have captured the interest of biologists and roboticists for decades because of their ability to locomote in different environments and their resemblance to early representatives of tetrapods. In this article, we review biological and robotic studies on the kinematics (i.e., angular profiles of joints) of salamander locomotion aiming at three main goals: (i) to give a clear view of the kinematics, currently available, for each body part of the salamander while moving in different environments (i.e., terrestrial stepping, aquatic stepping, and swimming), (ii) to examine what is the status of our current knowledge and what remains unclear, and (iii) to discuss how much robotics and modeling have already contributed and will potentially contribute in the future to such studies.

  13. An orphan gene is necessary for preaxial digit formation during salamander limb development

    PubMed Central

    Kumar, Anoop; Gates, Phillip B.; Czarkwiani, Anna; Brockes, Jeremy P.

    2015-01-01

    Limb development in salamanders differs from other tetrapods in that the first digits to form are the two most anterior (preaxial dominance). This has been proposed as a salamander novelty and its mechanistic basis is unknown. Salamanders are the only adult tetrapods able to regenerate the limb, and the contribution of preaxial dominance to limb regeneration is unclear. Here we show that during early outgrowth of the limb bud, a small cohort of cells express the orphan gene Prod1 together with Bmp2, a critical player in digit condensation in amniotes. Disruption of Prod1 with a gene-editing nuclease abrogates these cells, and blocks formation of the radius and ulna, and outgrowth of the anterior digits. Preaxial dominance is a notable feature of limb regeneration in the larval newt, but this changes abruptly after metamorphosis so that the formation of anterior and posterior digits occurs together within the autopodium resembling an amniote-like pattern. PMID:26498026

  14. Effects of warming conditions in eastern North American forests on red-backed salamander morphology.

    PubMed

    Gibbs, James P; Karraker, Nancy E

    2006-06-01

    Several studies have reported climate-associated changes in phenotypically plastic traits of amphibians, yet it remains unknown whether amphibians can manifest an evolutionary response to global climate change at the rate and magnitude that it is occurring. To assess this issue, we examined temporal change in the morphology of the red-backed salamander (Plethodon cinereus), a small, abundant woodland salamander distributed widely in eastern North America with two distinct morphotypes: striped individuals associated with cooler microclimates and unstriped individuals associated with warmer microclimates. We compiled morph frequencies for 50,960 individual salamanders from 558 sites as recorded in the published literature and in unpublished field notes of herpetologists between 1908 and 2004. We observed that striping probability increased with increasing latitude, longitude, and elevation and decreased (from 80% to 74% range wide) with time. The combined forces of regional climate warming and, particularly, forest disturbance have evidently been sufficient to cause morphological evolution in this amphibian over the last century.

  15. An orphan gene is necessary for preaxial digit formation during salamander limb development.

    PubMed

    Kumar, Anoop; Gates, Phillip B; Czarkwiani, Anna; Brockes, Jeremy P

    2015-10-26

    Limb development in salamanders differs from other tetrapods in that the first digits to form are the two most anterior (preaxial dominance). This has been proposed as a salamander novelty and its mechanistic basis is unknown. Salamanders are the only adult tetrapods able to regenerate the limb, and the contribution of preaxial dominance to limb regeneration is unclear. Here we show that during early outgrowth of the limb bud, a small cohort of cells express the orphan gene Prod1 together with Bmp2, a critical player in digit condensation in amniotes. Disruption of Prod1 with a gene-editing nuclease abrogates these cells, and blocks formation of the radius and ulna, and outgrowth of the anterior digits. Preaxial dominance is a notable feature of limb regeneration in the larval newt, but this changes abruptly after metamorphosis so that the formation of anterior and posterior digits occurs together within the autopodium resembling an amniote-like pattern.

  16. Heterogeneous vesicles in mucous epithelial cells of posterior esophagus of Chinese giant salamander (Andrias davidianus).

    PubMed

    Zhang, H; Guo, X; Zhong, S; Ge, T; Peng, S; Yu, P; Zhou, Z

    2015-08-25

    The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultrastructural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E). Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM). The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i) electron-lucent vesicles mucous cell (ELV-MC); ii) electron-dense vesicles mucous cell (EDV-MC); and iii) mixed vesicles mucous cell (MV-MC).

  17. Fundamental differences in dedifferentiation and stem cell recruitment during skeletal muscle regeneration in two salamander species.

    PubMed

    Sandoval-Guzmán, Tatiana; Wang, Heng; Khattak, Shahryar; Schuez, Maritta; Roensch, Kathleen; Nacu, Eugeniu; Tazaki, Akira; Joven, Alberto; Tanaka, Elly M; Simon, András

    2014-02-01

    Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals. PMID:24268695

  18. An orphan gene is necessary for preaxial digit formation during salamander limb development.

    PubMed

    Kumar, Anoop; Gates, Phillip B; Czarkwiani, Anna; Brockes, Jeremy P

    2015-01-01

    Limb development in salamanders differs from other tetrapods in that the first digits to form are the two most anterior (preaxial dominance). This has been proposed as a salamander novelty and its mechanistic basis is unknown. Salamanders are the only adult tetrapods able to regenerate the limb, and the contribution of preaxial dominance to limb regeneration is unclear. Here we show that during early outgrowth of the limb bud, a small cohort of cells express the orphan gene Prod1 together with Bmp2, a critical player in digit condensation in amniotes. Disruption of Prod1 with a gene-editing nuclease abrogates these cells, and blocks formation of the radius and ulna, and outgrowth of the anterior digits. Preaxial dominance is a notable feature of limb regeneration in the larval newt, but this changes abruptly after metamorphosis so that the formation of anterior and posterior digits occurs together within the autopodium resembling an amniote-like pattern. PMID:26498026

  19. Fundamental differences in dedifferentiation and stem cell recruitment during skeletal muscle regeneration in two salamander species.

    PubMed

    Sandoval-Guzmán, Tatiana; Wang, Heng; Khattak, Shahryar; Schuez, Maritta; Roensch, Kathleen; Nacu, Eugeniu; Tazaki, Akira; Joven, Alberto; Tanaka, Elly M; Simon, András

    2014-02-01

    Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals.

  20. Heterogeneous Vesicles in Mucous Epithelial Cells of Posterior Esophagus of Chinese Giant Salamander (Andrias Davidianus)

    PubMed Central

    Zhang, H.; Zhong, S.; Ge, T.; Peng, S.; Yu, P.; Zhou, Z.; Guo, X.

    2015-01-01

    The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultra-structural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E). Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM). The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i) electron-lucent vesicles mucous cell (ELV-MC); ii) electron-dense vesicles mucous cell (EDV-MC); and iii) mixed vesicles mucous cell (MV-MC). PMID:26428885

  1. Wildlife disease. Recent introduction of a chytrid fungus endangers Western Palearctic salamanders.

    PubMed

    Martel, A; Blooi, M; Adriaensen, C; Van Rooij, P; Beukema, W; Fisher, M C; Farrer, R A; Schmidt, B R; Tobler, U; Goka, K; Lips, K R; Muletz, C; Zamudio, K R; Bosch, J; Lötters, S; Wombwell, E; Garner, T W J; Cunningham, A A; Spitzen-van der Sluijs, A; Salvidio, S; Ducatelle, R; Nishikawa, K; Nguyen, T T; Kolby, J E; Van Bocxlaer, I; Bossuyt, F; Pasmans, F

    2014-10-31

    Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss. PMID:25359973

  2. Resource partitioning in two stream salamanders, Dicamptodon tenebrosus and Rhyacotriton cascadae, from the Oregon Cascade Mountains

    USGS Publications Warehouse

    Cudmore, Wynn W.; Bury, R. Bruce

    2014-01-01

    We investigated the potential for resource partitioning between the Coastal giant salamander (Dicamptodon tenebrosus) and the Cascade torrent salamander (Rhyacotriton cascadae) by examining their diet and microhabitats in forest streams. Larval D. tenebrosus and R. cascadae fed primarily upon aquatic insect larvae. We found similar foods in larval and adult R. cascadae and combined these results. Dicamptodon larvae consumed ephemeropteran, plecopteran, and trichopteran larvae in about equal amounts whereas R. cascadae ate more trichopteran and less ephemeropteran larvae than D. tenebrosus. Diet of all R. cascadae overlapped more with smaller than larger sized D. tenebrosus larvae. Comparisons of diets with available foods indicated R. cascadae is more selective or more gape-limited in its feeding habits than D. tenebrosus larvae. The two salamanders differed in use of microhabitats in creeks, which may contribute to their diet differences.

  3. Different season, different strategies: Feeding ecology of two syntopic forest-dwelling salamanders

    NASA Astrophysics Data System (ADS)

    Sebastiano, Salvidio; Antonio, Romano; Fabrizio, Oneto; Dario, Ottonello; Roberta, Michelon

    2012-08-01

    Trophic niche may be the most important ecological dimension for some vertebrate groups and in particular for terrestrial amphibians, that are important predators of soil invertebrates. In general, resource partitioning occurs between syntopic species with similar ecological niches, and coexistence patterns seem to be regulated by temporal resource variability. However most of the generalization on foraging strategies of terrestrial salamanders are extrapolated from studies on New World temperate species, thus we investigated the seasonal effect of resource variation in an European forest ecosystem, in which two ecologically similar but phylogenetically distinct salamander species are found. The diet of adult and juvenile cave salamanders (Speleomantes strinati), and of adult spectacled salamander (Salamandrina perspicillata) was obtained by stomach flushing, and results showed large seasonal changes both in prey availability and in salamander realised trophic niche. Values of trophic diversity were similar and niche overlaps were large among all salamander groups in spring, during high prey availability. Conversely in autumn, when a two-fold reduction in prey biomass was observed, there was a clear niche partitioning as the smaller S. perspicillata shifted from a generalist to a specialized trophic strategy. Juvenile Speleomantes strinatii, that largely overlapped in size with S. perspicillata, did not show any change in diet, suggesting that the feeding strategies were species-specific and not size-mediated. The observed patterns of variation in feeding ecology indicate that similar predators may react differently to changing prey availability to enhance niche partitioning. We also observed an increased energy intake during autumn for S perspicillata and S. strinatii juveniles, possibly related to differences in microhabitat use and activity patterns.

  4. Fictive rhythmic motor patterns produced by the tail spinal cord in salamanders.

    PubMed

    Charrier, V; Cabelguen, J-M

    2013-01-01

    Most investigations into the role of the body axis in vertebrate locomotion have focused on the trunk, although in most tetrapods, the tail also plays an active role. In salamanders, the tail contributes to propulsion during swimming and to dynamic balance and maneuverability during terrestrial locomotion. The aim of the present study was to obtain information concerning the neural mechanisms that produce tail muscle contractions during locomotion in the salamander Pleurodeles waltlii. We recorded the ventral root activities in in vitro spinal cord preparations in which locomotor-like activity was induced via bath application of N-methyl-d-aspartate (20μM) and d-serine (10μM). Recordings showed that the tail spinal cord is capable of producing propagated waves of motor activity that alternate between the left and right sides. Lesion experiments further revealed that the tail rhythmogenic network is composed of a double chain of identical hemisegmental oscillators. Finally, using spinal cord preparations bathed in a chamber partitioned into two pools, we revealed efficient short-distance coupling between the trunk and tail networks. Together, our results demonstrate the existence of a pattern generator for rhythmic tail movements in the salamander and show that the global architecture of the tail network is similar to that previously proposed for the mid-trunk locomotor network in the salamander. Our findings further support the view that salamanders can control their trunk and tail independently during stepping movements. The relevance of our results in relation to the generation of tail muscle contractions in freely moving salamanders is discussed.

  5. Salamanders ( Plethodon cinereus) go for more: rudiments of number in an amphibian.

    PubMed

    Uller, Claudia; Jaeger, Robert; Guidry, Gena; Martin, Carolyn

    2003-06-01

    Techniques traditionally used in developmental research with infants have been widely used with nonhuman primates in the investigation of comparative cognitive abilities. Recently, researchers have shown that human infants and monkeys select the larger of two numerosities in a spontaneous forced-choice discrimination task. Here we adopt the same method to assess in a series of experiments spontaneous choice of the larger of two numerosities in a species of amphibian, red-backed salamanders ( Plethodon cinereus). The findings indicate that salamanders "go for more," just like human babies and monkeys. This rudimentary capacity is a type of numerical discrimination that is spontaneously present in this amphibian.

  6. Heat shock protein induction and induced thermal tolerance are independent in adult salamanders.

    PubMed

    Easton, D P; Rutledge, P S; Spotila, J R

    1987-02-01

    Ectothermic vertebrates become thermally tolerant (heat hardened) after exposure to heat shock. Eukaryotic cells show a similar response. Cellular thermal tolerance is correlated with the induction of heat shock proteins (hsps). We have investigated the relationship between heat hardening in salamanders and the induction of hsps in the tissues of these organisms. Although the synthesis of hsps can be induced in these animals by sublethal heat shocks, conditions required for hsp induction and heat hardening often do not coincide. We conclude that induced thermal tolerance in adult salamanders is independent of hsp induction in their tissues. PMID:3559509

  7. The effect of waist twisting on walking speed of an amphibious salamander like robot

    NASA Astrophysics Data System (ADS)

    Yin, Xin-Yan; Jia, Li-Chao; Wang, Chen; Xie, Guang-Ming

    2016-06-01

    Amphibious salamanders often swing their waist to coordinate quadruped walking in order to improve their crawling speed. A robot with a swing waist joint, like an amphibious salamander, is used to mimic this locomotion. A control method is designed to allow the robot to maintain the rotational speed of its legs continuous and avoid impact between its legs and the ground. An analytical expression is established between the amplitude of the waist joint and the step length. Further, an optimization amplitude is obtained corresponding to the maximum stride. The simulation results based on automatic dynamic analysis of mechanical systems (ADAMS) and physical experiments verify the rationality and validity of this expression.

  8. Effect of arsenic on p53 mutation and occurrence of teratogenic salamanders: their potential as ecological indicators for arsenic contamination.

    PubMed

    Chang, Jin-Soo; Gu, Man Bock; Kim, Kyoung-Woong

    2009-05-01

    The p53 mutation in salamanders can be used as an indicator of arsenic contamination. The influence of arsenic exposure was studied on mutation of tumor suppressor gene in salamanders collected from several As-contaminated mine areas in Korea. Salamander eggs and larvae were exposed to arsenic in a toxicity test, and teratogenic salamanders found in heavy metal- and As-contaminated water from As-Bi mines were evaluated using PCR-SSCP to determine if they would be useful as an ecological indicator species. Changes in amino acids were shown to have occurred as a result of an arsenic-accumulating event that occurred after the DNA damage. In addition, both of the Hynobius leechii exposed groups were primarily affected by forms of skin damage, changes in the lateral tail/dorsal flexure and/or abnormality teratogenesis. Single-base sense mutation in codons 346 (AAG: Lys to ATG: Met), 224 (TTT: Phe to TTA: Leu), 211 (ATG: Met to AAG: Lys), 244 (TTT: Phe to TTTG: insertion), 245 (Glu GAG to Gln CAG) and 249 (TGT Cys to TGA stop) of the p53 gene were simultaneously found in mutated salamanders. Based on the results of our data illustrating the effect of arsenic exposure on the p53 mutation of salamanders in arsenic-contaminated mine areas, these mutated salamanders can be used as potential ecological indicators in the arsenic-contaminated ecosystems.

  9. Long bone histology of the stem salamander Kokartus honorarius (Amphibia: Caudata) from the Middle Jurassic of Kyrgyzstan.

    PubMed

    Skutschas, Pavel; Stein, Koen

    2015-04-01

    Kokartus honorarius from the Middle Jurassic (Bathonian) of Kyrgyzstan is one of the oldest salamanders in the fossil record, characterized by a mixture of plesiomorphic morphological features and characters shared with crown-group salamanders. Here we present a detailed histological analysis of its long bones. The analysis of a growth series demonstrates a significant histological maturation during ontogeny, expressed by the progressive appearance of longitudinally oriented primary vascular canals, primary osteons, growth marks, remodelling features in primary bone tissues, as well as progressive resorption of the calcified cartilage, formation of endochondral bone and development of cartilaginous to bony trabeculae in the epiphyses. Apart from the presence of secondary osteons, the long bone histology of Kokartus is very similar to that of miniaturized temnospondyls, other Jurassic stem salamanders, miniaturized seymouriamorphs and modern crown-group salamanders. We propose that the presence of secondary osteons in Kokartus honorarius is a plesiomorphic feature, and the loss of secondary osteons in the long bones of crown-group salamanders as well as in those of miniaturized temnospondyls is the result of miniaturization processes. Hitherto, all stem salamander long bong histology (Kokartus, Marmorerpeton and 'salamander A') has been generally described as having paedomorphic features (i.e. the presence of Katschenko's Line and a layer of calcified cartilage), these taxa were thus most likely neotenic forms. The absence of clear lines of arrested growth and annuli in long bones of Kokartus honorarius suggests that the animals lived in an environment with stable local conditions.

  10. What Is Mitochondrial DNA?

    MedlinePlus

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  11. Glycinergic synaptic inputs to bipolar cells in the salamander retina

    PubMed Central

    Maple, Bruce R; Wu, Samuel M

    1998-01-01

    Glycine activated strychnine-sensitive chloride conductances at both the dendrites and the axonal telodendria of most bipolar cells in the salamander retina. The chloride equilibrium potential of bipolar cells was found to be negative to -50 mV, indicating that glycinergic synapses on bipolar cells are inhibitory. Some bipolar cells exhibited discrete, strychnine-sensitive, chloride-mediated inhibitory postsynaptic currents (IPSCs). These were elicited by focal application of glutamate at the inner plexiform layer (IPL). Glycinergic synapses were localized using simultaneous focal application of calcium to retinal slices bathed in calcium-free media. Both dendritic and telodendritic glycinergic IPSCs were observed. The decay of the telodendritic IPSCs was well fitted by a single exponential with a time constant of 17.7 ± 8.7 ms. Similar kinetics were observed for dendritic IPSCs in some cells, but in one class of on-centre bipolar cell the decay of the dendritic IPSCs was better fitted by a sum of two exponentials with time constants 9.9 ± 4.3 and 51.3 ± 24.3 ms. The dendritic IPSCs were best driven by application of glutamate at the distal IPL (the off sublamina), while the telodendritic IPSCs were driven best by application near the telodendria. These results suggest that bipolar cell dendrites receive inhibitory glycinergic inputs from interplexiform cells that are excited by off-centre bipolar cells, whereas bipolar cell telodendria receive glycinergic amacrine cell inputs that are antagonistic to the photoreceptor inputs. Both inputs could be elicited in the presence of tetrodotoxin (TTX), but the dendritic IPSCs were sometimes abolished by TTX, suggesting that sodium-dependent spikes play an important role in the transmission of interplexiform cell signals to the outer plexiform layer. PMID:9503334

  12. A tadpole-induced polyphenism in the salamander Hynobius retardatus.

    PubMed

    Michimae, Hirofumi; Wakahara, Masami

    2002-10-01

    Larvae of the salamander Hynobius retardatus have two distinct morphs: normal and broad-headed, cannibal morphs. We performed three experiments to differentiate among the following hypotheses: The broad-headed morph is induced to allow: (1) feeding on nutritious conspecifics; (2) exclusion of strong competitors for food or space; or (3) feeding on large, tough prey when smaller prey items are unavailable. When newly hatched larvae were reared with a heterospecific, Rana pirica (an anuran amphibian) tadpoles, the broad-headed morph was induced more frequently compared with those reared with conspecifics. The phenotype expressed depended on the size of the tadpoles: The broad-headed morph occurred more frequently with small and the normal morph with large tadpoles. Metamorphosis occurred sooner in larvae fed conspecifics compared with those fed heterospecific tadpoles, and the mean growth rate of larvae fed conspecifics was significantly faster than that of those fed tadpoles, suggesting that the heterospecific tadpoles were less nutritive than the conspecifics. These results do not support the hypotheses that the broad-headed morph evolved for consuming conspecifics because of their better balance of nutrients or for excluding strong competitors for food or space. We tentatively conclude that the morph evolved to eat large, tough prey, including both conspecifics and heterospecific tadpoles. Because H. retardatus usually spawns very early in the spring in small ponds partially covered with ice and snow, newly hatched larvae may starve from the lack of proper food owing to extremely low water temperatures. Thus, the broad-headed morph of H. retardatus may represent a cold-habitat adaptation to overcome the severe circumstance when the only food items available are relatively large conspecifics or heterospecific tadpoles. PMID:12449490

  13. Responses of Eastern red-backed salamanders (Plethodon cinereus) to chemical cues of prey presented in soluble and volatile forms.

    PubMed

    Telfer, A C; Laberge, F

    2013-04-10

    Terrestrial salamanders are able to detect prey items using chemical cues, but the nature of the cues involved is uncertain. This study aimed to tease apart the roles of the soluble and volatile components of prey cues detected by Eastern red-backed salamanders (Plethodon cinereus), assuming the likelihood that these different components are respectively detected by the vomeronasal (accessory) and main olfactory organs. Wild-caught salamanders were exposed to control or soluble and volatile cricket cues in two different behavioural assays conducted in the laboratory. The first series of assays focused on localized presentation of soluble cues on the substrate, and the second on point sources of volatile cues delivered through plastic tubes. Room temperature was varied across experiments. Salamanders increased chemoinvestigation of the substrate via nosetapping when soluble prey cues were distributed non-uniformly on the substrate. In the warmer of two temperatures tested, salamanders additionally showed a spatial preference for location of soluble cue deposition. Attraction to a point source of volatile cues was not evident when examining the responses of salamanders grouped together; however, investigation of the volatile point source was significantly correlated with side preference only when both soluble cues and a volatile point source were present. The latter suggests that a subset of salamanders were attracted to the point source of volatile cues in the presence of soluble cues on the substrate. This study indicates that soluble prey cues alone are sufficient to trigger salamander foraging behaviour, and that temperature influences this foraging response. It supports the notion that the vomeronasal system plays an important role in prey detection, but suggests that volatile cues are also investigated by some salamanders when soluble prey cues have been detected.

  14. Elimination kinetics of acetylene and Freon 22 in resting and active lungless salamanders.

    PubMed

    Feder, M E; Full, R J; Piiper, J

    1988-05-01

    To quantify diffusion limitation in cutaneous gas exchange, the elimination of two inert gases of different diffusivity, Freon 22 (CHC1F2) and acetylene (C2H2), was measured simultaneously in exclusively skin-breathing lungless salamanders, Desmognathus quadramaculatus. In resting salamanders, elimination of both gases could be described as the sum of three exponential terms. For both the medium and the slow exponential component, the ratio of the respective rate constants (k) for acetylene and Freon averaged 1.77. This value is between the values expected for perfusion limitation (1.00) and diffusion limitation (1.94), indicating combined diffusion and perfusion limitation. In salamanders stimulated to run on a treadmill, the elimination rates and the rate constants increased more for Freon than for acetylene. During spontaneous activity, the increase in elimination of Freon was larger than that of acetylene. These findings suggest an increase in the diffusing capacity of the skin during exercise. Thus the diffusing capacity of salamander skin for gases appears to be variable and to be adjusted to meet the increased O2 requirement during exercise.

  15. Bimodal locomotion elicited by electrical stimulation of the midbrain in the salamander Notophthalmus viridescens.

    PubMed

    Cabelguen, Jean-Marie; Bourcier-Lucas, Céline; Dubuc, Réjean

    2003-03-15

    The present experiments were designed to identify the mesencephalic locomotor region (MLR) in the salamander. An in vitro semi-intact preparation from a decerebrate adult salamander (Notophthalmus viridescens) was developed in which the locomotor activities were monitored from electromyographic and video recordings. The results show that the two locomotor modes exhibited by salamanders (i.e., stepping and swimming) were evoked by electrical microstimulation (5-15 Hz; 0.1-10 microA; 2 msec pulses) of a circumscribed region in the caudal mesencephalon. At threshold current strength (0.5-3.5 microA at 15 Hz), rhythmic limb movements and intersegmental coordination, such as during stepping, were induced. As the stimulation strength was subsequently increased, the frequency of stepping became more rapid, and, at 2.0-5.5 microA, the limbs were held back against the body wall and swimming movements of the trunk were induced. An additional increase of the stimulation strength induced an increase of the frequency and amplitude of the swimming movements. Anatomical studies conducted in parallel revealed the presence of choline acetyltransferase immunoreactive cells in the functionally identified MLR region. Together, the present results indicate that the MLR is present in salamanders and that its level of activation determines the mode of locomotion. Walking is induced at low activation levels, and swimming, which constitutes a faster mode of locomotion, requires stronger stimulation of the MLR. Furthermore, as in other vertebrates, the MLR contains cholinergic cells.

  16. A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders.

    PubMed

    Anderson, Jason S; Reisz, Robert R; Scott, Diane; Fröbisch, Nadia B; Sumida, Stuart S

    2008-05-22

    The origin of extant amphibians (Lissamphibia: frogs, salamanders and caecilians) is one of the most controversial questions in vertebrate evolution, owing to large morphological and temporal gaps in the fossil record. Current discussions focus on three competing hypotheses: a monophyletic origin within either Temnospondyli or Lepospondyli, or a polyphyletic origin with frogs and salamanders arising among temnospondyls and caecilians among the lepospondyls. Recent molecular analyses are also controversial, with estimations for the batrachian (frog-salamander) divergence significantly older than the palaeontological evidence supports. Here we report the discovery of an amphibamid temnospondyl from the Early Permian of Texas that bridges the gap between other Palaeozoic amphibians and the earliest known salientians and caudatans from the Mesozoic. The presence of a mosaic of salientian and caudatan characters in this small fossil makes it a key taxon close to the batrachian (frog and salamander) divergence. Phylogenetic analysis suggests that the batrachian divergence occurred in the Middle Permian, rather than the late Carboniferous as recently estimated using molecular clocks, but the divergence with caecilians corresponds to the deep split between temnospondyls and lepospondyls, which is congruent with the molecular estimates.

  17. Vertebral development of modern salamanders provides insights into a unique event of their evolutionary history.

    PubMed

    Boisvert, Catherine Anne

    2009-01-15

    The origin of salamanders and their interrelationships to the two other modern amphibian orders (frogs and caecilians) are problematic owing to an 80-100 million year gap in the fossil record between the Carboniferous to the Lower Jurassic. This is compounded by a scarcity of adult skeletal characters linking the early representatives of the modern orders to their stem-group in the Paleozoic. The use of ontogenetic characters can be of great use in the resolution of these questions. Growth series of all ten modern salamander families (a 120 cleared and stained larvae) were examined for pattern and timing of vertebral elements chondrification and ossification. The primitive pattern is that of the neural arches developing before the centra, while the reverse represents the derived condition. Both the primitive and derived conditions are observed within the family Hynobiidae, whereas only the derived condition is observed in all other salamanders. This provides support to the claims that Hynobiidae is both the most basal of modern families and potentially polyphyletic (with Ranodon and Hybobius forming the most basal clade and Salamandrella being a part of the most derived clade). This provides insight into a unique event in salamander evolutionary history and suggests that the developmental pattern switch occurred between the Triassic and the mid-Jurassic before the last major radiation.

  18. Pathological and microbiological findings from mortality of the Chinese giant salamander (Andrias davidianus).

    PubMed

    Meng, Yan; Ma, Jie; Jiang, Nan; Zeng, Ling-Bing; Xiao, Han-Bing

    2014-06-01

    The Chinese giant salamander, Andrias davidianus, is a nationally protected and cultured species in China. Recently, a severe epizootic occurred in cultured Chinese giant salamanders in Hubei, Hunan, Sichuan, Shaanxi, and Zhejiang provinces of China, causing substantial economic losses. The typical clinical signs of diseased larval animals were jaw and abdominal swelling and subcutaneous hemorrhaging. Diseased adult animals exhibited skin hemorrhages, ulceration of the hind limbs, and multiple hemorrhagic spots in the visceral organs. Histopathological observation indicated tissue necrosis and cytoplasmic inclusions in the spleen, liver and kidney, suggestive of viral disease. A viral agent was isolated from affected tissues in cell culture. The virus was determined to be pathogenic after experimental infection. Electron microscopy revealed iridovirus-like virions with a size of 140-180 nm in diameter inside the kidney of naturally infected animals and in cell culture. The major capsid protein (MCP) of the virus exhibited 98-99 % sequence identity to ranaviruses. Additionally, phylogenetic analysis indicated that the virus belonged to the genus Ranavirus. Comparative analysis of the MCP gene sequence with those of other viruses previously isolated from Chinese giant salamanders revealed that these isolates were highly similar, although a few variations were observed. The virus was preliminarily named Chinese giant salamander iridovirus (GSIV). PMID:24385158

  19. Complete Genome Sequence of a Ranavirus Isolated from Chinese Giant Salamander (Andrias davidianus).

    PubMed

    Wang, Na; Zhang, Min; Zhang, Lifeng; Jing, Hongli; Jiang, Yulin; Wu, Shaoqiang; Lin, Xiangmei

    2014-01-09

    A ranavirus (RV) was isolated from Chinese giant salamanders (Andrias davidianus) in China in 2010 and provisionally designated Andrias davidianus ranavirus (ADRV). The complete genome sequence is 106,719 nucleotides long. Genomic sequence and phylogenetic analyses showed that ADRV has a high degree of conservation with other RVs.

  20. Stream salamander species richness and abundance in relation to environmental factors in Shenandoah National Park, Virginia

    USGS Publications Warehouse

    Grant, E.H.C.; Jung, R.E.; Rice, K.C.

    2005-01-01

    Stream salamanders are sensitive to acid mine drainage and may be sensitive to acidification and low acid neutralizing capacity (ANC) of a watershed. Streams in Shenandoah National Park, Virginia, are subject to episodic acidification from precipitation events. We surveyed 25 m by 2 m transects located on the stream bank adjacent to the water channel in Shenandoah National Park for salamanders using a stratified random sampling design based on elevation, aspect and bedrock geology. We investigated the relationships of four species (Eurycea bislineata, Desmognathus fuscus, D. monticola and Gyrinophilus porphyriticus) to habitat and water quality variables. We did not find overwhelming evidence that stream salamanders are affected by the acid-base status of streams in Shenandoah National Park. Desmognathus fuscus and D. monticola abundance was greater both in streams that had a higher potential to neutralize acidification, and in higher elevation (>700 m) streams. Neither abundance of E. bislineata nor species richness were related to any of the habitat variables. Our sampling method preferentially detected the adult age class of the study species and did not allow us to estimate population sizes. We suggest that continued monitoring of stream salamander populations in SNP will determine the effects of stream acidification on these taxa.

  1. Near infrared reflectance spectroscopy studies of Chinese giant salamanders in aquaculture production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NIR spectra were collected at three surface locations for Chinese giant salamanders to ascertain whether spectral signatures could be separated by anatomical, presumably physiologically-based, locations. The first location was the smooth area immediately above the cloaca on the animal’s abdomen, whi...

  2. Cutaneous Bacteria of the Redback Salamander Prevent Morbidity Associated with a Lethal Disease

    PubMed Central

    Becker, Matthew H.; Harris, Reid N.

    2010-01-01

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an infectious disease that causes population declines of many amphibians. Cutaneous bacteria isolated from redback salamanders, Plethodon cinereus, and mountain yellow-legged frogs, Rana muscosa, inhibit the growth of Bd in vitro. In this study, the bacterial community present on the skin of P. cinereus individuals was investigated to determine if it provides protection to salamanders from the lethal and sub-lethal effects of chytridiomycosis. When the cutaneous bacterial community was reduced prior to Bd exposure, salamanders experienced a significantly greater decrease in body mass, which is a symptom of the disease, when compared to infected individuals with a normal bacterial community. In addition, a greater proportion of infected individuals with a reduced bacterial community experienced limb-lifting, a behavior seen only in infected individuals. Overall, these results demonstrate that the cutaneous bacterial community of P. cinereus provides protection to the salamander from Bd and that alteration of this community can change disease resistance. Therefore, symbiotic microbes associated with this species appear to be an important component of its innate skin defenses. PMID:20532032

  3. Pathological and microbiological findings from mortality of the Chinese giant salamander (Andrias davidianus).

    PubMed

    Meng, Yan; Ma, Jie; Jiang, Nan; Zeng, Ling-Bing; Xiao, Han-Bing

    2014-06-01

    The Chinese giant salamander, Andrias davidianus, is a nationally protected and cultured species in China. Recently, a severe epizootic occurred in cultured Chinese giant salamanders in Hubei, Hunan, Sichuan, Shaanxi, and Zhejiang provinces of China, causing substantial economic losses. The typical clinical signs of diseased larval animals were jaw and abdominal swelling and subcutaneous hemorrhaging. Diseased adult animals exhibited skin hemorrhages, ulceration of the hind limbs, and multiple hemorrhagic spots in the visceral organs. Histopathological observation indicated tissue necrosis and cytoplasmic inclusions in the spleen, liver and kidney, suggestive of viral disease. A viral agent was isolated from affected tissues in cell culture. The virus was determined to be pathogenic after experimental infection. Electron microscopy revealed iridovirus-like virions with a size of 140-180 nm in diameter inside the kidney of naturally infected animals and in cell culture. The major capsid protein (MCP) of the virus exhibited 98-99 % sequence identity to ranaviruses. Additionally, phylogenetic analysis indicated that the virus belonged to the genus Ranavirus. Comparative analysis of the MCP gene sequence with those of other viruses previously isolated from Chinese giant salamanders revealed that these isolates were highly similar, although a few variations were observed. The virus was preliminarily named Chinese giant salamander iridovirus (GSIV).

  4. Transcriptomic analysis of the host response to an iridovirus infection in Chinese giant salamander, Andrias davidianus.

    PubMed

    Fan, Yuding; Chang, Ming Xian; Ma, Jie; LaPatra, Scott E; Hu, Yi Wei; Huang, Lili; Nie, Pin; Zeng, Lingbing

    2015-11-20

    The emergence of an infectious viral disease caused by the Chinese giant salamander iridovirus (GSIV) has led to substantial economic losses. However, no more molecular information is available for the understanding of the mechanisms associated with virus-host interaction. In this study, de novo sequencing was used to obtain abundant high-quality ESTs and investigate differentially-expressed genes in the spleen of Chinese giant salamanders that were either infected or mock infected with GSIV. Comparative expression analysis indicated that 293 genes were down-regulated and 220 genes were up-regulated. Further enrichment analysis showed that the most enriched pathway is "complement and coagulation cascades", and significantly enriched diseases include "inherited thrombophilia", "immune system diseases", "primary immunodeficiency", "complement regulatory protein defects", and "disorders of nucleotide excision repair". Additionally, 30 678 simple sequence repeats (SSRs) from all spleen samples, 26 355 single nucleotide polymorphisms (SNPs) from the spleens of uninfected animals and 36 070 SNPs from the spleens of infected animals were detected. The large amount of variation was specific for the Chinese giant salamanders that were infected with GSIV. The results reported herein provided significant and new EST information that could contribute greatly in investigations into the molecular functions of immune genes in the Chinese giant salamander.

  5. Using the Eastern Hellbender Salamander in a High School Genetics & Ecological Conservation Activity

    ERIC Educational Resources Information Center

    Chudyk, Sarah; McMillan, Amy; Lange, Catherine

    2014-01-01

    This article contains an original 5E lesson plan developed from conservation genetics research on the giant North American hellbender salamander, Cryptobranchus alleganiensis alleganiensis. The lesson plan provides background information on the hellbender, reviews basic genetics, and exposes students to the scientific process that is used during…

  6. The Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis, in Fully Aquatic Salamanders from Southeastern North America

    PubMed Central

    Chatfield, Matthew W. H.; Moler, Paul; Richards-Zawacki, Corinne L.

    2012-01-01

    Little is known about the impact that the pathogenic amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has on fully aquatic salamander species of the eastern United States. As a first step in determining the impacts of Bd on these species, we aimed to determine the prevalence of Bd in wild populations of fully aquatic salamanders in the genera Amphiuma, Necturus, Pseudobranchus, and Siren. We sampled a total of 98 salamanders, representing nine species from sites in Florida, Mississippi, and Louisiana. Overall, infection prevalence was found to be 0.34, with significant differences among genera but no clear geographic pattern. We also found evidence for seasonal variation, but additional sampling throughout the year is needed to clarify this pattern. The high rate of infection discovered in this study is consistent with studies of other amphibians from the southeastern United States. Coupled with previously published data on life histories and population densities, the results presented here suggest that fully aquatic salamanders may be serving as important vectors of Bd and the interaction between these species and Bd warrants additional research. PMID:22984569

  7. Coexistence in streams: Do source-sink dynamics allow salamanders to persist with fish predators?

    USGS Publications Warehouse

    Sepulveda, A.J.; Lowe, W.H.

    2011-01-01

    Theory suggests that source-sink dynamics can allow coexistence of intraguild predators and prey, but empirical evidence for this coexistence mechanism is limited. We used capture-mark-recapture, genetic methods, and stable isotopes to test whether source-sink dynamics promote coexistence between stream fishes, the intraguild predator, and stream salamanders (Dicamptodon aterrimus), the intraguild prey. Salamander populations from upstream reaches without fish were predicted to maintain or supplement sink populations in downstream reaches with fish. We found instead that downstream reaches with fish were not sinks even though fish consumed salamander larvae-apparent survival, recruitment, and population growth rate did not differ between upstream and downstream reaches. There was also no difference between upstream and downstream reaches in net emigration. We did find that D. aterrimus moved frequently along streams, but believe that this is a response to seasonal habitat changes rather than intraguild predation. Our study provides empirical evidence that local-scale mechanisms are more important than dispersal dynamics to coexistence of streams salamanders and fish. More broadly, it shows the value of empirical data on dispersal and gene flow for distinguishing between local and spatial mechanisms of coexistence. ?? 2011 Springer-Verlag.

  8. Molecular cloning of estrogen receptor alpha (ERalpha; ESR1) of the Japanese giant salamander, Andrias japonicus.

    PubMed

    Katsu, Yoshinao; Kohno, Satomi; Oka, Tomohiro; Mitsui, Naoko; Tooi, Osamu; Santo, Noriaki; Urushitani, Hiroshi; Fukumoto, Yukio; Kuwabara, Kazushi; Ashikaga, Kazuhide; Minami, Shinji; Kato, Shigeaki; Ohta, Yasuhiko; Guillette, Louis J; Iguchi, Taisen

    2006-09-26

    Estrogens are essential for normal reproductive activity in females and males and for ovarian differentiation during a critical developmental stage in many vertebrates. To understand the molecular mechanisms of estrogen action and to evaluate estrogen receptor ligand interactions in the Japanese giant salamander (Andrias japonicus), we isolated cDNA encoding the estrogen receptor (ER) from the liver. A full-length Japanese giant salamander ER cDNA (jgsER) was obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequence of the jgsER showed high identity to the Xenopus ERalpha (ESR1) (77.7%). We have applied both the conventional ERE-luciferase reporter assay system and the GAL4-transactivation system to characterize this receptor. In two different transient transfection assay systems using mammalian cells, the jgsER protein displayed estrogen-dependent activation of transcription. The GAL4-transactivation system showed about 10-fold greater activity of the estrogen receptor by hormone when compared to the conventional ERE-luciferase reporter assay system. Tissue distribution of ERalpha mRNA was examined and kidney, ovary and liver exhibited expression. This is the first isolation of an estrogen receptor from a salamander and also is the first functional cDNA obtained from the Japanese giant salamander, an endangered species considered a special natural monument of Japan.

  9. A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders.

    PubMed

    Anderson, Jason S; Reisz, Robert R; Scott, Diane; Fröbisch, Nadia B; Sumida, Stuart S

    2008-05-22

    The origin of extant amphibians (Lissamphibia: frogs, salamanders and caecilians) is one of the most controversial questions in vertebrate evolution, owing to large morphological and temporal gaps in the fossil record. Current discussions focus on three competing hypotheses: a monophyletic origin within either Temnospondyli or Lepospondyli, or a polyphyletic origin with frogs and salamanders arising among temnospondyls and caecilians among the lepospondyls. Recent molecular analyses are also controversial, with estimations for the batrachian (frog-salamander) divergence significantly older than the palaeontological evidence supports. Here we report the discovery of an amphibamid temnospondyl from the Early Permian of Texas that bridges the gap between other Palaeozoic amphibians and the earliest known salientians and caudatans from the Mesozoic. The presence of a mosaic of salientian and caudatan characters in this small fossil makes it a key taxon close to the batrachian (frog and salamander) divergence. Phylogenetic analysis suggests that the batrachian divergence occurred in the Middle Permian, rather than the late Carboniferous as recently estimated using molecular clocks, but the divergence with caecilians corresponds to the deep split between temnospondyls and lepospondyls, which is congruent with the molecular estimates. PMID:18497824

  10. Vertebral development of modern salamanders provides insights into a unique event of their evolutionary history.

    PubMed

    Boisvert, Catherine Anne

    2009-01-15

    The origin of salamanders and their interrelationships to the two other modern amphibian orders (frogs and caecilians) are problematic owing to an 80-100 million year gap in the fossil record between the Carboniferous to the Lower Jurassic. This is compounded by a scarcity of adult skeletal characters linking the early representatives of the modern orders to their stem-group in the Paleozoic. The use of ontogenetic characters can be of great use in the resolution of these questions. Growth series of all ten modern salamander families (a 120 cleared and stained larvae) were examined for pattern and timing of vertebral elements chondrification and ossification. The primitive pattern is that of the neural arches developing before the centra, while the reverse represents the derived condition. Both the primitive and derived conditions are observed within the family Hynobiidae, whereas only the derived condition is observed in all other salamanders. This provides support to the claims that Hynobiidae is both the most basal of modern families and potentially polyphyletic (with Ranodon and Hybobius forming the most basal clade and Salamandrella being a part of the most derived clade). This provides insight into a unique event in salamander evolutionary history and suggests that the developmental pattern switch occurred between the Triassic and the mid-Jurassic before the last major radiation. PMID:19025964

  11. Transcriptomic analysis of the host response to an iridovirus infection in Chinese giant salamander, Andrias davidianus.

    PubMed

    Fan, Yuding; Chang, Ming Xian; Ma, Jie; LaPatra, Scott E; Hu, Yi Wei; Huang, Lili; Nie, Pin; Zeng, Lingbing

    2015-01-01

    The emergence of an infectious viral disease caused by the Chinese giant salamander iridovirus (GSIV) has led to substantial economic losses. However, no more molecular information is available for the understanding of the mechanisms associated with virus-host interaction. In this study, de novo sequencing was used to obtain abundant high-quality ESTs and investigate differentially-expressed genes in the spleen of Chinese giant salamanders that were either infected or mock infected with GSIV. Comparative expression analysis indicated that 293 genes were down-regulated and 220 genes were up-regulated. Further enrichment analysis showed that the most enriched pathway is "complement and coagulation cascades", and significantly enriched diseases include "inherited thrombophilia", "immune system diseases", "primary immunodeficiency", "complement regulatory protein defects", and "disorders of nucleotide excision repair". Additionally, 30 678 simple sequence repeats (SSRs) from all spleen samples, 26 355 single nucleotide polymorphisms (SNPs) from the spleens of uninfected animals and 36 070 SNPs from the spleens of infected animals were detected. The large amount of variation was specific for the Chinese giant salamanders that were infected with GSIV. The results reported herein provided significant and new EST information that could contribute greatly in investigations into the molecular functions of immune genes in the Chinese giant salamander. PMID:26589400

  12. Cutaneous bacteria of the redback salamander prevent morbidity associated with a lethal disease.

    PubMed

    Becker, Matthew H; Harris, Reid N

    2010-06-04

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an infectious disease that causes population declines of many amphibians. Cutaneous bacteria isolated from redback salamanders, Plethodon cinereus, and mountain yellow-legged frogs, Rana muscosa, inhibit the growth of Bd in vitro. In this study, the bacterial community present on the skin of P. cinereus individuals was investigated to determine if it provides protection to salamanders from the lethal and sub-lethal effects of chytridiomycosis. When the cutaneous bacterial community was reduced prior to Bd exposure, salamanders experienced a significantly greater decrease in body mass, which is a symptom of the disease, when compared to infected individuals with a normal bacterial community. In addition, a greater proportion of infected individuals with a reduced bacterial community experienced limb-lifting, a behavior seen only in infected individuals. Overall, these results demonstrate that the cutaneous bacterial community of P. cinereus provides protection to the salamander from Bd and that alteration of this community can change disease resistance. Therefore, symbiotic microbes associated with this species appear to be an important component of its innate skin defenses.

  13. At random meetings to the creation of new species of Salamander

    NASA Astrophysics Data System (ADS)

    Brillant, Marie-Pierre

    2013-04-01

    The pupils in final year of high school (15-18 years old) study the notion "species" and the creation of new species in various ways. Having studied genetic admixtures, this activity allows the pupils to build a scenario explaining the creation of a new species of Salamander in southern California from an ancestral population existing in northern Oregon. They can observe, on Google Earth, various populations of Salamander of the genus Ensatina. Salamanders of the genus Ensatina live in California around the Joaquin and Sacramento dry valleys. In this software, the pupils get information about the salamanders' environment and photographs of individuals and environments. During a migratory movement toward new territories to be colonized, these salamanders meet an inhospitable environment that they can not occupy. This population then splits up into two migratory branches, east and west, each overcoming the obstacles in different ways. The two groups gradually colonized southern territories but they avoided the too dry and hot San Joaquin plains. The two main branches of the original population gradually move away from each other, and genetic exchanges between them decrease over time. Eventually, we can find various populations of Salamander on both sides of the valleys, since the salamanders occupied new territories and diversified along the way. Among mutations that randomly occur, only those mutations that are best adapted in the origin were conserved in the genetic heritage of every population. When the individuals stemming from different western populations met, they were interfertile and give fertile hybrids, which was verified in the laboratory. Likewise, when individuals of the different eastern subspecies met accidentally, fertile hybrids also could arise from these crossings. The pupils can observe what happens in the overlap of various populations : interfertility or not. They also have geological, geographical and climatic information about the San Joaquin

  14. Three ferritin subunit analogs in Chinese giant salamander (Andrias davidianus) and their response to microbial stimulation.

    PubMed

    You, Xiuling; Sheng, Jianghong; Liu, Liu; Nie, Dongsong; Liao, Zhiyong

    2015-10-01

    Ferritin, an evolutionarily conserved iron-binding protein, plays important roles in iron storage and detoxification and in host immune response to invading stimulus as well. In the present study, we identified three ferritin subunit analog cDNAs from Chinese giant salamander (Andrias davidianus). All the three ferritin subunit cDNAs had a putative iron responsive element in the 5'-untranslated region. Two deduced ferritin subunits (designated as cgsFerH and cgsFerM) had the highest identity of 90% to H type subunit of vertebrate ferritins, while another deduced ferritin subunit (designated as cgsFerL) had the highest identity of 84% to L type subunit of vertebrate ferritins. The Chinese giant salamander ferritin (cgsFer) was widely expressed in various tissues, with highest expression for cgsFerH and cgsFerL in liver and highest expression for cgsFerM in spleen. Infection of Chinese giant salamander with A. davidianus ranavirus showed significant induction of cgsFer expression. Both lipopolysaccharide and iron challenge drastically augmented cgsFer expression in the splenocytes and hepatocytes from Chinese giant salamander. In addition, recombinant cgsFers bound to ferrous iron in a dose-dependent manner, with significant ferroxidase activity. Furthermore, the recombinant cgsFer inhibited the growth of the pathogen Vibrio anguillarum. These results indicated that cgsFer was potential candidate of immune molecules involved in acute phase response to invading microbial pathogens in Chinese giant salamander possibly through its regulatory roles in iron homeostasis. PMID:26319314

  15. The hyal and ventral branchial muscles in caecilian and salamander larvae: homologies and evolution.

    PubMed

    Kleinteich, Thomas; Haas, Alexander

    2011-05-01

    Amphibians (Lissamphibia) are characterized by a bi-phasic life-cycle that comprises an aquatic larval stage and metamorphosis to the adult. The ancestral aquatic feeding behavior of amphibian larvae is suction feeding. The negative pressure that is needed for ingestion of prey is created by depression of the hyobranchial apparatus as a result of hyobranchial muscle action. Understanding the homologies of hyobranchial muscles in amphibian larvae is a crucial step in understanding the evolution of this important character complex. However, the literature mostly focuses on the adult musculature and terms used for hyal and ventral branchial muscles in different amphibians often do not reflect homologies across lissamphibian orders. Here we describe the hyal and ventral branchial musculature in larvae of caecilians (Gymnophiona) and salamanders (Caudata), including juveniles of two permanently aquatic salamander species. Based on previous alternative terminology schemes, we propose a terminology for the hyal and ventral branchial muscles that reflects the homologies of muscles and that is suited for studies on hyobranchial muscle evolution in amphibians. We present a discussion of the hyal and ventral branchial muscles in larvae of the most recent common ancestor of amphibians (i.e. the ground plan of Lissamphibia). Based on our terminology, the hyal and ventral branchial musculature of caecilians and salamanders comprises the following muscles: m. depressor mandibulae, m. depressor mandibulae posterior, m. hyomandibularis, m. branchiohyoideus externus, m. interhyoideus, m. interhyoideus posterior, m. subarcualis rectus I, m. subarcualis obliquus II, m. subarcualis obliquus III, m. subarcualis rectus II-IV, and m. transversus ventralis IV. Except for the m. branchiohyoideus externus, all muscles considered herein can be assigned to the ground plan of the Lissamphibia with certainty. The m. branchiohyoideus externus is either apomorphic for the Batrachia (frogs

  16. Three ferritin subunit analogs in Chinese giant salamander (Andrias davidianus) and their response to microbial stimulation.

    PubMed

    You, Xiuling; Sheng, Jianghong; Liu, Liu; Nie, Dongsong; Liao, Zhiyong

    2015-10-01

    Ferritin, an evolutionarily conserved iron-binding protein, plays important roles in iron storage and detoxification and in host immune response to invading stimulus as well. In the present study, we identified three ferritin subunit analog cDNAs from Chinese giant salamander (Andrias davidianus). All the three ferritin subunit cDNAs had a putative iron responsive element in the 5'-untranslated region. Two deduced ferritin subunits (designated as cgsFerH and cgsFerM) had the highest identity of 90% to H type subunit of vertebrate ferritins, while another deduced ferritin subunit (designated as cgsFerL) had the highest identity of 84% to L type subunit of vertebrate ferritins. The Chinese giant salamander ferritin (cgsFer) was widely expressed in various tissues, with highest expression for cgsFerH and cgsFerL in liver and highest expression for cgsFerM in spleen. Infection of Chinese giant salamander with A. davidianus ranavirus showed significant induction of cgsFer expression. Both lipopolysaccharide and iron challenge drastically augmented cgsFer expression in the splenocytes and hepatocytes from Chinese giant salamander. In addition, recombinant cgsFers bound to ferrous iron in a dose-dependent manner, with significant ferroxidase activity. Furthermore, the recombinant cgsFer inhibited the growth of the pathogen Vibrio anguillarum. These results indicated that cgsFer was potential candidate of immune molecules involved in acute phase response to invading microbial pathogens in Chinese giant salamander possibly through its regulatory roles in iron homeostasis.

  17. Mercury Speciation and Trophic Magnification Slopes in Giant Salamander Larvae from the Pacific Northwest, USA

    NASA Astrophysics Data System (ADS)

    Bank, M. S.; Crocker, J.; Wachtl, J.; Kleeman, P.; Fellers, G.; Currens, C.; Hothem, R.; Madej, M. A.

    2014-12-01

    Mercury (Hg) contamination of stream salamanders in the Pacific Northwest region of the United States has received little attention. Here we report total Hg (HgT) and methyl mercury (MeHg) concentrations in larval giant salamanders (Dicamptodon spp.) and surface water from forested and chaparral lotic ecosystems distributed along a latitudinal gradient throughout Northern California and Washington. To test hypotheses related to potential effects from mining land-use activities, salamander larvae were also sampled from a reference site at Whiskeytown National Recreation Area, California, and at a nearby, upstream site (Shasta county) on Bureau of Land Management land where Hg contamination from gold mining activities has been documented. HgT concentrations in whole body larvae ranged from 4.6 to 74.5 ng/g wet wt. and percent MeHg ranged from 67% to 86%. Both HgT and MeHg larval tissue concentrations were significantly higher at the mining site in comparison to measured background levels (P < 0.001). We conclude that salamander larvae in remote stream ecosystems, where Hg sources were dominated by atmospheric deposition, were generally low in HgT and MeHg and, in comparison, watersheds with a legacy of land-use practices (i.e., mining operations) had approximately 4.5 - 5.5 times the level of HgT bioaccumulation. Moreover, trophic magnification slopes were highest in the Shasta county region where mining was present. These findings suggest that mining activities increase HgT and MeHg exposure to salamander larvae in the region and may present a threat to other higher trophically positioned organisms, and their associated food webs.

  18. Ecological resistance surfaces predict fine-scale genetic differentiation in a terrestrial woodland salamander.

    PubMed

    Peterman, William E; Connette, Grant M; Semlitsch, Raymond D; Eggert, Lori S

    2014-05-01

    Landscape genetics has seen tremendous advances since its introduction, but parameterization and optimization of resistance surfaces still poses significant challenges. Despite increased availability and resolution of spatial data, few studies have integrated empirical data to directly represent ecological processes as genetic resistance surfaces. In our study, we determine the landscape and ecological factors affecting gene flow in the western slimy salamander (Plethodon albagula). We used field data to derive resistance surfaces representing salamander abundance and rate of water loss through combinations of canopy cover, topographic wetness, topographic position, solar exposure and distance from ravine. These ecologically explicit composite surfaces directly represent an ecological process or physiological limitation of our organism. Using generalized linear mixed-effects models, we optimized resistance surfaces using a nonlinear optimization algorithm to minimize model AIC. We found clear support for the resistance surface representing the rate of water loss experienced by adult salamanders in the summer. Resistance was lowest at intermediate levels of water loss and higher when the rate of water loss was predicted to be low or high. This pattern may arise from the compensatory movement behaviour of salamanders through suboptimal habitat, but also reflects the physiological limitations of salamanders and their sensitivity to extreme environmental conditions. Our study demonstrates that composite representations of ecologically explicit processes can provide novel insight and can better explain genetic differentiation than ecologically implicit landscape resistance surfaces. Additionally, our study underscores the fact that spatial estimates of habitat suitability or abundance may not serve as adequate proxies for describing gene flow, as predicted abundance was a poor predictor of genetic differentiation.

  19. Immunological responses and protection in Chinese giant salamander Andrias davidianus immunized with inactivated iridovirus.

    PubMed

    Liu, Wenzhi; Xu, Jin; Ma, Jie; LaPatra, Scott E; Meng, Yan; Fan, Yuding; Zhou, Yong; Yang, Xin; Zeng, Lingbing

    2014-12-01

    Chinese giant salamander hemorrhage is a newly emerged infectious disease in China and has caused huge economic losses. The causative pathogen has been identified as the giant salamander iridovirus (GSIV). In this study, the immunological responses and protection in Chinese giant salamander immunized with β-propiolactone inactivated GSIV are reported. Red and white blood cell counting and classification, phagocytic activity, neutralizing antibody titration, immune-related gene expression and determination of the relative percent survival were evaluated after vaccination. The red and white blood cell counts showed that the numbers of erythrocytes and leukocytes in the peripheral blood of immunized Chinese giant salamanders increased significantly on days 4 and 7 post-injection (P<0.01). Additionally, the differential leukocyte count of monocytes and neutrophils were significantly different compared to the control group (P<0.01); the percentage of lymphocytes was 70.45±7.52% at day 21. The phagocytic percentage and phagocytic index was 38.78±4.33% and 3.75±0.52, respectively, at day 4 post-immunization which were both significantly different compared to the control group (P<0.01). The serum neutralizing antibody titer increased at day 14 post-immunization and reached the highest titer (341±9.52) at day 21. The quantitative PCR analysis revealed that the immunization significantly up-regulated the expression of immune related genes TLR-9 and MyD88 the first two weeks after immunization. The challenge test conducted at day 30 post-injection demonstrated that the immunized group produced a relative survival of 72%. These results indicate that the inactivated GSIV could elicit significant non-specific and specific immunological responses in Chinese giant salamander that resulted in significant protection against GSIV induced disease.

  20. The hyal and ventral branchial muscles in caecilian and salamander larvae: homologies and evolution.

    PubMed

    Kleinteich, Thomas; Haas, Alexander

    2011-05-01

    Amphibians (Lissamphibia) are characterized by a bi-phasic life-cycle that comprises an aquatic larval stage and metamorphosis to the adult. The ancestral aquatic feeding behavior of amphibian larvae is suction feeding. The negative pressure that is needed for ingestion of prey is created by depression of the hyobranchial apparatus as a result of hyobranchial muscle action. Understanding the homologies of hyobranchial muscles in amphibian larvae is a crucial step in understanding the evolution of this important character complex. However, the literature mostly focuses on the adult musculature and terms used for hyal and ventral branchial muscles in different amphibians often do not reflect homologies across lissamphibian orders. Here we describe the hyal and ventral branchial musculature in larvae of caecilians (Gymnophiona) and salamanders (Caudata), including juveniles of two permanently aquatic salamander species. Based on previous alternative terminology schemes, we propose a terminology for the hyal and ventral branchial muscles that reflects the homologies of muscles and that is suited for studies on hyobranchial muscle evolution in amphibians. We present a discussion of the hyal and ventral branchial muscles in larvae of the most recent common ancestor of amphibians (i.e. the ground plan of Lissamphibia). Based on our terminology, the hyal and ventral branchial musculature of caecilians and salamanders comprises the following muscles: m. depressor mandibulae, m. depressor mandibulae posterior, m. hyomandibularis, m. branchiohyoideus externus, m. interhyoideus, m. interhyoideus posterior, m. subarcualis rectus I, m. subarcualis obliquus II, m. subarcualis obliquus III, m. subarcualis rectus II-IV, and m. transversus ventralis IV. Except for the m. branchiohyoideus externus, all muscles considered herein can be assigned to the ground plan of the Lissamphibia with certainty. The m. branchiohyoideus externus is either apomorphic for the Batrachia (frogs

  1. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods

    PubMed Central

    Kuchta, Shawn R.; Brown, Ashley D.; Converse, Paul E.; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8–19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  2. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods.

    PubMed

    Kuchta, Shawn R; Brown, Ashley D; Converse, Paul E; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8-19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  3. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods.

    PubMed

    Kuchta, Shawn R; Brown, Ashley D; Converse, Paul E; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8-19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  4. Simulation and robotics studies of salamander locomotion: applying neurobiological principles to the control of locomotion in robots.

    PubMed

    Ijspeert, Auke Jan; Crespi, Alessandro; Cabelguen, Jean-Marie

    2005-01-01

    This article presents a project that aims at understanding the neural circuitry controlling salamander locomotion, and developing an amphibious salamander-like robot capable of replicating its bimodal locomotion, namely swimming and terrestrial walking. The controllers of the robot are central pattern generator models inspired by the salamander's locomotion control network. The goal of the project is twofold: (1) to use robots as tools for gaining a better understanding of locomotion control in vertebrates and (2) to develop new robot and control technologies for developing agile and adaptive outdoor robots. The article has four parts. We first describe the motivations behind the project. We then present neuromechanical simulation studies of locomotion control in salamanders. This is followed by a description of the current stage of the robotic developments. We conclude the article with a discussion on the usefulness of robots in neuroscience research with a special focus on locomotion control.

  5. Impacts of a gape limited Brook Trout, Salvelinus fontinalis, on larval Northwestern salamander, Ambystoma gracile, growth: A field enclosure experiment

    USGS Publications Warehouse

    Currens, C.R.; Liss, W.J.; Hoffman, R.L.

    2007-01-01

    The formation of amphibian population structure is directly affected by predation. Although aquatic predators have been shown to have direct negative effects on larval salamanders in laboratory and field experiments, the potential impacts of gape-limited fish on larval salamander growth has been largely underexplored. We designed an enclosure experiment conducted in situ to quantify the effects of gape-limited Brook Trout (Salvelinus fontinalis) on larval Northwestern Salamander (Ambystoma gracile) growth. We specifically tested whether the presence of fish too small to consume larvae had a negative effect on larval growth. The results of this study indicate that the presence of a gape-limited S. fontinalis can have a negative effect on growth of larval A. gracile salamanders. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  6. From species divergence to population structure: a multimarker approach on the most basal lineage of Salamandridae, the spectacled salamanders (genus Salamandrina) from Italy.

    PubMed

    Hauswaldt, J Susanne; Angelini, Claudio; Gehara, Marcelo; Benavides, Edgar; Polok, Andy; Steinfartz, Sebastian

    2014-01-01

    The Apennine Peninsula is one of Europe's main glacial refugial areas and harbors a large number of lineages and species. Here, a pattern of higher genetic diversity in the south compared to that of the north is characteristic of most vertebrates; however, most studies that have produced these results have relied only on inferences based on mitochondrial DNA. The spectacled salamanders (genus Salamandrina) are endemic to the Apennine Peninsula and have diverged into two sibling species: S. terdigitata (in the south) and S. perspicillata (in the north), presumably in the late Miocene or early Pliocene. By sequencing one mitochondrial (cytb) and two nuclear genes (RAG1 and POMC) and genotyping 10 microsatellite loci, we traced the evolution of these sibling species from their divergence to their contemporary population structure at a fine scale. Using a multilocus coalescent-based approach, we estimated the temporal divergence of both species at approximately 2.25 mya (million years ago), which, hence, is much younger than previous estimates. The classical pattern of high genetic diversity in the south and lower diversity in the north was confirmed only for some markers, and the demographic histories of the two species differed substantially. Whereas S. perspicillata (north) expanded from a single major refugium in the center of the Apennine Peninsula, populations of S. terdigitata (south) persisted through cooler periods in multiple refugia. Further, the fine-scale population genetic structure of 16 S. perspicillata populations revealed significant genetic differentiation, even across short geographic distances. The results of our study stress that for a better understanding of phylogeographic patterns and past demographic processes, both mitochondrial and multiple nuclear loci should be analyzed to avoid gene-specific, and possibly biased results.

  7. Mitochondrial Dynamics and Mitochondrial Dysfunction in Diabetes.

    PubMed

    Wada, Jun; Nakatsuka, Atsuko

    2016-06-01

    The mitochondria are involved in active and dynamic processes, such as mitochondrial biogenesis, fission, fusion and mitophagy to maintain mitochondrial and cellular functions. In obesity and type 2 diabetes, impaired oxidation, reduced mitochondrial contents, lowered rates of oxidative phosphorylation and excessive reactive oxygen species (ROS) production have been reported. Mitochondrial biogenesis is regulated by various transcription factors such as peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), peroxisome proliferator-activated receptors (PPARs), estrogen-related receptors (ERRs), and nuclear respiratory factors (NRFs). Mitochondrial fusion is promoted by mitofusin 1 (MFN1), mitofusin 2 (MFN2) and optic atrophy 1 (OPA1), while fission is governed by the recruitment of dynamin-related protein 1 (DRP1) by adaptor proteins such as mitochondrial fission factor (MFF), mitochondrial dynamics proteins of 49 and 51 kDa (MiD49 and MiD51), and fission 1 (FIS1). Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) and PARKIN promote DRP1-dependent mitochondrial fission, and the outer mitochondrial adaptor MiD51 is required in DRP1 recruitment and PARKIN-dependent mitophagy. This review describes the molecular mechanism of mitochondrial dynamics, its abnormality in diabetes and obesity, and pharmaceuticals targeting mitochondrial biogenesis, fission, fusion and mitophagy. PMID:27339203

  8. Life history as a predictor of salamander recovery rate from timber harvest in southern appalachian forests, USA.

    PubMed

    Connette, Grant M; Semlitsch, Raymond D

    2013-12-01

    Forest management often represents a balance between social, economic, and ecological objectives. In the eastern United States, numerous studies have established that terrestrial salamander populations initially decline in abundance following timber harvest, yet the large-scale and long-term consequences are relatively unknown. We used count data from terrestrial survey points to examine the relation between salamander abundance and historic timber harvest while accounting for imperfect detection of individuals. Overall, stream- and terrestrial-breeding salamanders appeared to differ by magnitude of population decline, rate of population recovery, and extent of recolonization from surrounding forest. Specifically, estimated abundance of both species groups was positively associated with stand age and recovery rates were predicted to increase over time for red-legged salamanders (Plethodon shermani) and decrease in stream-breeding species. Abundance of stream-breeding salamanders was predicted to reach a peak by 100 years after timber harvest, and the population growth rate of red-legged salamanders was predicted to undergo a significant increase 100 years after harvest. Estimated abundance of stream-breeding salamanders in young forest stands was also negatively associated with the distance to adjacent forest, a result that suggests immigration has a role in the recovery of these species. Our results indicate that salamander abundance in young forest stands may be only modestly lower than in more mature forest but that full recovery from timber harvest may take a substantial amount of time and that species life history may affect patterns of recovery. Historia de Vida como un Vaticinador de la Tasa de Recuperación de una Salamandra a la Colecta de Madera en los Bosques del Sur de los Apalaches, E.U.A.

  9. First report of a ranavirus associated with morbidity and mortality in farmed Chinese giant salamanders (Andrias davidianus).

    PubMed

    Geng, Y; Wang, K Y; Zhou, Z Y; Li, C W; Wang, J; He, M; Yin, Z Q; Lai, W M

    2011-07-01

    From February to May 2010, an outbreak of disease occurred amongst farmed Chinese giant salamanders (Andrias davidianus) in Hanzhong County, Shanxi Province, China. Clinical signs included anorexia, lethargy, ecchymoses and swollen areas on the head and limbs, and skin ulceration. The aim of this study was to determine the cause of this disease. Necropsy examination revealed subcutaneous and intramuscular oedema, swollen and pale livers with multifocal haemorrhage, swollen kidneys with multifocal haemorrhage and distended fluid-filled intestines with areas of haemorrhage. Light microscopy revealed intracytoplasmic inclusions suggestive of a viral infection in a variety of organs, as well as degeneration and necrosis of these organs. Electron microscopy of ultrathin sections of the same tissues revealed iridovirus-like particles within the inclusions. Of the six specimens tested, all were positive for ranavirus major capsid protein (MCP) gene. Sequence alignments of the ranavirus MCP gene from these specimens showed 95-98% similarity with published ranavirus data. The virus, provisionally designated as Chinese giant salamander virus (CGSV), was isolated from tissue homogenates of diseased salamanders following inoculation of epithelioma papilloma cyprini cells. Sequence analysis of the MCP genes showed that the isolated virus was a ranavirus with marked sequence identity to other members of the genus Ranavirus. Koch's postulates were fulfilled by infecting healthy Chinese giant salamanders with the CGSV. These salamanders all died within 6-8 days. This is the first report of ranavirus infection associated with mass mortality in Chinese giant salamanders.

  10. Abundances of northwestern salamander larvae in montane lakes with and without fish, Mount Rainier National Park, Washington

    USGS Publications Warehouse

    Larson, Gary L.; Hoffman, Robert L.

    2002-01-01

    In Mount Rainier National Park, the northwestern salamander usually inhabits relatively large and deep lakes and ponds (average size = 0.3 ha; average depth > 2 m) that contain flocculent, organic bottom sediments and abundant coarse wood. Prior to 1970, salmonids were introduced into many of the park's lakes and ponds that were typical habitat of the northwestern salamander. The objective of this study was to compare, in lakes and ponds with suitable habitat characteristics for northwestern salamanders, the observed abundances of larvae in takes and ponds with and without these introduced salmonids. Day surveys of 61 lakes were conducted between 1993 and 1999. Fish were limited to takes and ponds deeper than 2 in. For the 48 lakes and ponds deeper than 2 in (i.e., 25 fishless lakes and 23 fish lakes), the mean and median observed abundances of northwestern salamander larvae in fishless lakes and ponds was significantly greater than the mean and median observed abundances of larvae in lakes and ponds with fish. Northwestern salamander larvae were not observed in 11 fish lakes. These lakes were similar in median elevation, surface area, and maximum depth to the fishless lakes. The 12 fish lakes with observed larvae were significantly lower in median elevation, larger in median surface area, and deeper in median maximum depth than the fishless lakes. Low to null observed abundances of northwestern salamander larvae in lakes and ponds with fish were attributed to a combination of fish predation of larvae and changes in larval behavior.

  11. Environmental acidification is not associated with altered plasma corticosterone levels in the stream-side salamander, Desmognathus ochrophaeus.

    PubMed

    Woodley, Sarah K; Freeman, Peter; Ricciardella, Lauren F

    2014-05-15

    As environments become increasingly altered due to anthropogenic factors, interest is growing in how endocrine systems respond to pollution and environmental degradation. Glucocorticoid hormones (GCs) are a type of stress hormones that are released upon activation of the hypothalamic-pituitary-adrenal axis and have widespread effects throughout the body. We tested the hypothesis that exposure to environmental acidification is associated with altered levels of plasma GCs in adult, stream-side Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus). We compared plasma corticosterone (CORT) in salamanders living in 9 streams that differed in pH. Although capture and handling induced a robust increase in plasma CORT in all populations of salamanders, we discerned no significant effect of environmental pH on baseline CORT or handling-induced CORT levels. In a laboratory study, low pH decreased salamander locomotory activity compared to acid-neutral controls, but there was no effect of pH on plasma CORT. Decreased locomotory activity is a common amphibian response to stress, indicating that low pH has adverse effects on Allegheny Mountain dusky salamanders. Overall, we conclude that the effects of environmental pH on salamander behavior and other potential responses are not mediated by changes in plasma CORT levels. We discuss alternative explanations for our results and describe difficulties involved in searching for relationships between plasma GCs and environmental degradation.

  12. Interactions between introduced trout and larval salamanders (Ambystoma macrodactylum) in high-elevation lakes

    USGS Publications Warehouse

    Tyler, T.; Liss, W.J.; Ganio, L.; Larson, Gary L.; Hoffman, Robert L.; Deimling, E.; Lomnicky, G.A.

    1998-01-01

    The larval stage of the long-toed salamander (Ambystoma macrodactylum) is the top vertebrate predator in high-elevation fishless lakes in the North Cascades National Park Service Complex, Washington (U.S.A.). Although most of these high-elevation lakes were naturally fishless, trout have been stocked in many of them. We sought to determine the effects of physicochemical factors and introduced trout on abundance and behavior of A. macrodactylum larvae. Larval salamander densities were estimated by snorkeling. Snorkelers carefully searched through substrate materials within 2 m of the shoreline and recorded the number of larvae observed and if larvae were hidden in benthic substrates. Physicochemical factors were measured in each lake on the same day that snorkel surveys were conducted. In fishless lakes, larval salamander densities were positively related to total Kjeldahl-N concentration and negatively related to lake elevation. Crustacean zooplankton, especially cladocerans, were important food resources for larval A. macrodactylum. Crustacean zooplankton and cladoceran densities were positively related to total Kjeldahl-N, suggesting that increased food resources contributed to increased densities of larval A. macrodactylum. Differences in larval salamander densities between fish and fishless lakes were related to total Kjeldahl-N concentrations and the reproductive status of trout. Mean larval salamander densities for fishless lakes with total Kjeldahl-N < 0.045 mg/L were not significantly different from mean larval densities in lakes with reproducing trout or in lakes with nonreproducing trout. In fishless lakes with total Kjeldahl-N a?Y 0.045 mg/L, however, mean larval densities were significantly higher than in lakes with reproducing trout where fish reached high densities. In fishless lakes with total Kjeldahl-N a?Y 0.095 mg/L, mean larval densities were significantly higher than in lakes with nonreproducing trout where trout fry were stocked at low

  13. Complete nucleotide sequence and gene rearrangement of the mitochondrial genome of the bell-ring frog, Buergeria buergeri (family Rhacophoridae).

    PubMed

    Sano, Naomi; Kurabayashi, Atsushi; Fujii, Tamotsu; Yonekawa, Hiromichi; Sumida, Masayuki

    2004-06-01

    In this study we determined the complete nucleotide sequence (19,959 bp) of the mitochondrial DNA of the rhacophorid frog Buergeria buergeri. The gene content, nucleotide composition, and codon usage of B. buergeri conformed to those of typical vertebrate patterns. However, due to an accumulation of lengthy repetitive sequences in the D-loop region, this species possesses the largest mitochondrial genome among all the vertebrates examined so far. Comparison of the gene organizations among amphibian species (Rana, Xenopus, salamanders and caecilians) revealed that the positioning of four tRNA genes and the ND5 gene in the mtDNA of B. buergeri diverged from the common vertebrate gene arrangement shared by Xenopus, salamanders and caecilians. The unique positions of the tRNA genes in B. buergeri are shared by ranid frogs, indicating that the rearrangements of the tRNA genes occurred in a common ancestral lineage of ranids and rhacophorids. On the other hand, the novel position of the ND5 gene seems to have arisen in a lineage leading to rhacophorids (and other closely related taxa) after ranid divergence. Phylogenetic analysis based on nucleotide sequence data of all mitochondrial genes also supported the gene rearrangement pathway.

  14. Complete nucleotide sequence and gene rearrangement of the mitochondrial genome of the bell-ring frog, Buergeria buergeri (family Rhacophoridae).

    PubMed

    Sano, Naomi; Kurabayashi, Atsushi; Fujii, Tamotsu; Yonekawa, Hiromichi; Sumida, Masayuki

    2004-06-01

    In this study we determined the complete nucleotide sequence (19,959 bp) of the mitochondrial DNA of the rhacophorid frog Buergeria buergeri. The gene content, nucleotide composition, and codon usage of B. buergeri conformed to those of typical vertebrate patterns. However, due to an accumulation of lengthy repetitive sequences in the D-loop region, this species possesses the largest mitochondrial genome among all the vertebrates examined so far. Comparison of the gene organizations among amphibian species (Rana, Xenopus, salamanders and caecilians) revealed that the positioning of four tRNA genes and the ND5 gene in the mtDNA of B. buergeri diverged from the common vertebrate gene arrangement shared by Xenopus, salamanders and caecilians. The unique positions of the tRNA genes in B. buergeri are shared by ranid frogs, indicating that the rearrangements of the tRNA genes occurred in a common ancestral lineage of ranids and rhacophorids. On the other hand, the novel position of the ND5 gene seems to have arisen in a lineage leading to rhacophorids (and other closely related taxa) after ranid divergence. Phylogenetic analysis based on nucleotide sequence data of all mitochondrial genes also supported the gene rearrangement pathway. PMID:15329496

  15. Acetazolamide does not disrupt limb regenerate morphogenesis in the salamander, Plethodon cinereus.

    PubMed

    Dinsmore, C E; Maren, T H

    1986-02-01

    Acetazolamide, a potent and highly specific inhibitor of carbonic anhydrase, is teratogenic in mammalian embryos and when administered during early limb development causes unique limb defects in a time- and dose-dependent manner. The regenerating urodele limb is often considered to be a good experimental analog of limb development and, if it employs the same mechanisms of tissue interactions during pattern formation, should be susceptible to teratogens which selectively disrupt developmental limb patterning. This study demonstrates that while carbonic anhydrase inhibition is toxic to the red-backed salamander, Plethodon cinereus, it does not have the same teratogenic effect on limb regeneration as seen in mammalian limb development. Several points are considered as to why the regenerating limb, at least in this salamander species, may not be suitable for studying this class of teratogen.

  16. Developmental processes underlying the evolution of a derived foot morphology in salamanders

    PubMed Central

    Jaekel, Martin; Wake, David B.

    2007-01-01

    Interdigital webbing has evolved repeatedly in tropical salamanders (bolitoglossines). This derived foot morphology is only one of many homoplastic traits in this diverse amphibian clade. Indeed, few if any morphological traits sort lineages within this clade. We investigate the processes underlying the homoplastic evolution of morphological characters in these salamanders by analyzing selective and developmental processes that generate interdigital webbing. We show that a pedomorphic developmental change generates the new foot morphology and that pedomorphosis affects a number of morphological traits, thus creating a developmental correlation among them. This correlation among traits is maintained across most species, thus facilitating the repeated evolution of traits. Although we find evidence that the changes in foot morphology are adaptive in one species, the evolution of webbing in all other species does not carry an adaptive signature. The new foot morphology therefore evolves repeatedly, even in the apparent absence of a direct selective advantage. PMID:18077320

  17. Normal table of embryonic development in the four-toed salamander, Hemidactylium scutatum.

    PubMed

    Hurney, C A; Babcock, S K; Shook, D R; Pelletier, T M; Turner, S D; Maturo, J; Cogbill, S; Snow, M C; Kinch, K

    2015-05-01

    We present a complete staging table of normal development for the lungless salamander, Hemidactylium scutatum (Caudata: Plethodontidae). Terrestrial egg clutches from naturally ovipositing females were collected and maintained at 15 °C in the laboratory. Observations, photographs, and time-lapse movies of embryos were taken throughout the 45-day embryonic period. The complete normal table of development for H. scutatum is divided into 28 stages and extends previous analyses of H. scutatum embryonic development (Bishop, 1920; Humphrey, 1928). Early embryonic stage classifications through neurulation reflect criteria described for Xenopus laevis, Ambystoma maculatum and other salamanders. Later embryonic stage assignments are based on unique features of H. scutatum embryos. Additionally, we provide morphological analysis of gastrulation and neurulation, as well as details on external aspects of eye, gill, limb, pigmentation, and tail development to support future research related to phylogeny, comparative embryology, and molecular mechanisms of development.

  18. Distribution of the Sonora Tiger Salamander (Ambystoma mavortium stebbinsi) in Mexico

    USGS Publications Warehouse

    Hossack, Blake R.; Muths, Erin L.; Rorabaugh, James C.; Lemos Espinal, Julio A.; Sigafus, Brent H.; Chambert, Thierry A; Carreon Arroyo, Gerardo; Hurtado Felix, David; Toyos Martinez, Daniel; Jones, Thomas R

    2016-01-01

    The Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi Lowe, 1954) was listed as federally endangered in the USA in 1997 (USFWS 1997). In the USA, the distribution of A. mavortium stebbinsi is limited to the San Rafael Valley (approximately 567 km2), between the Sierra San Antonio (called the Patagonia Mountains in Arizona) and Huachuca Mountains, and south of the Canelo Hills, Arizona (Fig. 1). The USA listing was triggered by loss of natural wetland habitats, threats from invasive predators, frequent die-offs from disease, introgression with the introduced Barred Tiger Salamander (A. mavortium mavortium), and small range and number of breeding sites that increases susceptibility to stochastic events (USFWS 1997). Small population sizes and limited gene flow have caused inbreeding, which may further reduce population viability and the potential for recovery (Jones et al. 1988; Storfer et al. 2014). 

  19. Tissue lesions of tiger salamanders (Ambystoma tigrinum): relationship to sewage effluents.

    PubMed

    Rose, F L

    1978-09-29

    A population of facultative neotenous tiger salamanders (A. tigrinum) inhabiting a sewage lagoon at Reese AFB, Hurlwood, Texas, was found to have an exceptionally high rate of spontaneous tissue lesions. The population is composed of an estimated 28,000 large, reproductively mature larvae that are restricted to the lagoon. Only about 17% of the population metamorphoses normally. In contrast, tiger salamanders from uncontaminated lagoons in the same general vicinity metamorphose normally; however, no neoplasms were discovered in larvae sampled from the nonsewage lagoosn. N-nitrosamine analyses of water and tissue samples of larvae were negative. Polycyclic aromatic hydrocarbon analyses revealed traces of benzo[a]pyrene in the sludge; however, perylene, a constituent of jet fuel, was found in high concentration (300 ppb). These results indicate tat preylene, which was previously found not be tumorigenic to mice and rats, should be retested as a possible agent for nonmammalian species. PMID:280184

  20. Normal table of embryonic development in the four-toed salamander, Hemidactylium scutatum.

    PubMed

    Hurney, C A; Babcock, S K; Shook, D R; Pelletier, T M; Turner, S D; Maturo, J; Cogbill, S; Snow, M C; Kinch, K

    2015-05-01

    We present a complete staging table of normal development for the lungless salamander, Hemidactylium scutatum (Caudata: Plethodontidae). Terrestrial egg clutches from naturally ovipositing females were collected and maintained at 15 °C in the laboratory. Observations, photographs, and time-lapse movies of embryos were taken throughout the 45-day embryonic period. The complete normal table of development for H. scutatum is divided into 28 stages and extends previous analyses of H. scutatum embryonic development (Bishop, 1920; Humphrey, 1928). Early embryonic stage classifications through neurulation reflect criteria described for Xenopus laevis, Ambystoma maculatum and other salamanders. Later embryonic stage assignments are based on unique features of H. scutatum embryos. Additionally, we provide morphological analysis of gastrulation and neurulation, as well as details on external aspects of eye, gill, limb, pigmentation, and tail development to support future research related to phylogeny, comparative embryology, and molecular mechanisms of development. PMID:25617760

  1. Embryo development inside female salamander (Ambystoma jeffersonianum-laterale) prior to egg laying.

    PubMed

    Charney, Noah D; Castorino, John J; Dobro, Megan J; Steely, Sarah L

    2014-01-01

    The length of embryo retention prior to oviposition is a critical evolutionary trait. In all oviparous salamanders, which include the vast majority of species in the order, fertilization is thought to occur at the time of egg laying. Embryos then enter the first cleavage stage several hours after being deposited. This pattern holds for previously studied individuals in the Ambystoma jeffersonianum-laterale complex. Here, we document an instance in which a female Ambystoma jeffersonianum-laterale was carrying embryos internally that had already reached stage 10 of development. Development likely began several days prior to the start of migration to the breeding pond. This is the first such record for any egg-laying salamander, and suggests a degree of plasticity in the timing of fertilization and development not previously recognized. Further work is needed to ascertain the prevalence, mechanics, and evolutionary significance of this phenomenon. PMID:24651275

  2. Microbial community dynamics and effect of environmental microbial reservoirs on red-backed salamanders (Plethodon cinereus).

    PubMed

    Loudon, Andrew H; Woodhams, Douglas C; Parfrey, Laura Wegener; Archer, Holly; Knight, Rob; McKenzie, Valerie; Harris, Reid N

    2014-04-01

    Beneficial cutaneous bacteria on amphibians can protect against the lethal disease chytridiomycosis, which has devastated many amphibian species and is caused by the fungus Batrachochytrium dendrobatidis. We describe the diversity of bacteria on red-backed salamanders (Plethodon cinereus) in the wild and the stability of these communities through time in captivity using culture-independent Illumina 16S rRNA gene sequencing. After field sampling, salamanders were housed with soil from the field or sterile media. The captive conditions led to different trajectories of bacterial communities. Eight OTUs present on >90% of salamanders in the field, through time, and in both treatments were defined as the core community, suggesting that some bacteria are closely associated with the host and are independent of an environmental reservoir. One of these taxa, a Pseudomonas sp., was previously cultured from amphibians and found to be antifungal. As all host-associated bacteria were found in the soil reservoir, environmental microbes strongly influence host-microbial diversity and likely regulate the core community. Using PICRUSt, an exploratory bioinformatics tool to predict gene functions, we found that core skin bacteria provided similar gene functions to the entire community. We suggest that future experiments focus on testing whether core bacteria on salamander skin contribute to the observed resistance to chytridiomycosis in this species even under hygenic captive conditions. For disease-susceptible hosts, providing an environmental reservoir with defensive bacteria in captive-rearing programs may improve outcomes by increasing bacterial diversity on threatened amphibians or increasing the likelihood that defensive bacteria are available for colonization.

  3. Comparing Population Patterns to Processes: Abundance and Survival of a Forest Salamander following Habitat Degradation

    PubMed Central

    Otto, Clint R. V.; Roloff, Gary J.; Thames, Rachael E.

    2014-01-01

    Habitat degradation resulting from anthropogenic activities poses immediate and prolonged threats to biodiversity, particularly among declining amphibians. Many studies infer amphibian response to habitat degradation by correlating patterns in species occupancy or abundance with environmental effects, often without regard to the demographic processes underlying these patterns. We evaluated how retention of vertical green trees (CANOPY) and coarse woody debris (CWD) influenced terrestrial salamander abundance and apparent survival in recently clearcut forests. Estimated abundance of unmarked salamanders was positively related to CANOPY (Canopy  = 0.21 (0.02–1.19; 95% CI), but not CWD (CWD  = 0.11 (−0.13–0.35) within 3,600 m2 sites, whereas estimated abundance of unmarked salamanders was not related to CANOPY (Canopy  = −0.01 (−0.21–0.18) or CWD (CWD  = −0.02 (−0.23–0.19) for 9 m2 enclosures. In contrast, apparent survival of marked salamanders within our enclosures over 1 month was positively influenced by both CANOPY and CWD retention (Canopy  = 0.73 (0.27–1.19; 95% CI) and CWD  = 1.01 (0.53–1.50). Our results indicate that environmental correlates to abundance are scale dependent reflecting habitat selection processes and organism movements after a habitat disturbance event. Our study also provides a cautionary example of how scientific inference is conditional on the response variable(s), and scale(s) of measure chosen by the investigator, which can have important implications for species conservation and management. Our research highlights the need for joint evaluation of population state variables, such as abundance, and population-level process, such as survival, when assessing anthropogenic impacts on forest biodiversity. PMID:24718498

  4. Microbial community dynamics and effect of environmental microbial reservoirs on red-backed salamanders (Plethodon cinereus).

    PubMed

    Loudon, Andrew H; Woodhams, Douglas C; Parfrey, Laura Wegener; Archer, Holly; Knight, Rob; McKenzie, Valerie; Harris, Reid N

    2014-04-01

    Beneficial cutaneous bacteria on amphibians can protect against the lethal disease chytridiomycosis, which has devastated many amphibian species and is caused by the fungus Batrachochytrium dendrobatidis. We describe the diversity of bacteria on red-backed salamanders (Plethodon cinereus) in the wild and the stability of these communities through time in captivity using culture-independent Illumina 16S rRNA gene sequencing. After field sampling, salamanders were housed with soil from the field or sterile media. The captive conditions led to different trajectories of bacterial communities. Eight OTUs present on >90% of salamanders in the field, through time, and in both treatments were defined as the core community, suggesting that some bacteria are closely associated with the host and are independent of an environmental reservoir. One of these taxa, a Pseudomonas sp., was previously cultured from amphibians and found to be antifungal. As all host-associated bacteria were found in the soil reservoir, environmental microbes strongly influence host-microbial diversity and likely regulate the core community. Using PICRUSt, an exploratory bioinformatics tool to predict gene functions, we found that core skin bacteria provided similar gene functions to the entire community. We suggest that future experiments focus on testing whether core bacteria on salamander skin contribute to the observed resistance to chytridiomycosis in this species even under hygenic captive conditions. For disease-susceptible hosts, providing an environmental reservoir with defensive bacteria in captive-rearing programs may improve outcomes by increasing bacterial diversity on threatened amphibians or increasing the likelihood that defensive bacteria are available for colonization. PMID:24335825

  5. SURGICAL IMPLANTATION OF COELOMIC RADIOTRANSMITTERS AND POSTOPERATIVE SURVIVAL OF CHINESE GIANT SALAMANDERS (ANDRIAS DAVIDIANUS) FOLLOWING REINTRODUCTION.

    PubMed

    Marcec, Ruth; Kouba, Andrew; Zhang, Lu; Zhang, Hongxing; Wang, Qijun; Zhao, Hu; Jiang, Wei; Willard, Scott

    2016-03-01

    Worldwide, there are only a handful of reintroduction programs for threatened salamander species, and very few have conducted postrelease studies to examine survival, habitat selection, and dispersal. Limitations in postrelease monitoring are primarily due to size constraints of amphibians and to dimensions of the radiotransmitters available for implantation. However, due to the large size of the critically endangered Chinese giant salamander (Andrias davidianus), these animals make optimal candidates for surgical implantation of radiotransmitters prior to reintroduction or translocation. The objective of this study was to develop an anesthetic protocol using tricane methanesulfonate (MS-222) and test a surgical procedure for coelomic implantation of radiotransmitters for this species. A total of 32 Chinese giant salamanders from two age groups (Group A: 4.7 yr old, n = 16; Group B: 2.7 yr old, n = 16) were implanted with 4-g radiotransmitters designed for underwater monitoring of fish. Group A was held 16 wk before release while Group B was held 6 wk before release, and the salamanders' survival and postoperative complications recorded for the first month postrelease. Group A animals took longer to reach a surgical plane of anesthesia than did Group B animals, and this was directly correlated to mass of the animals. Postsurgery, one animal from Group B died of dehiscence before release while 83.9% animals survived after the first month in the wild. All of the animals that died postrelease were from Group B; three animals experienced dehiscence of the suture site and died while another two animals expired from trauma and fungal infection, respectively. Improvements for future studies include use of alternative suture material for closure after implantation and additional healing time of the incision. PMID:27010279

  6. Microbial community dynamics and effect of environmental microbial reservoirs on red-backed salamanders (Plethodon cinereus)

    PubMed Central

    Loudon, Andrew H; Woodhams, Douglas C; Parfrey, Laura Wegener; Archer, Holly; Knight, Rob; McKenzie, Valerie; Harris, Reid N

    2014-01-01

    Beneficial cutaneous bacteria on amphibians can protect against the lethal disease chytridiomycosis, which has devastated many amphibian species and is caused by the fungus Batrachochytrium dendrobatidis. We describe the diversity of bacteria on red-backed salamanders (Plethodon cinereus) in the wild and the stability of these communities through time in captivity using culture-independent Illumina 16S rRNA gene sequencing. After field sampling, salamanders were housed with soil from the field or sterile media. The captive conditions led to different trajectories of bacterial communities. Eight OTUs present on >90% of salamanders in the field, through time, and in both treatments were defined as the core community, suggesting that some bacteria are closely associated with the host and are independent of an environmental reservoir. One of these taxa, a Pseudomonas sp., was previously cultured from amphibians and found to be antifungal. As all host-associated bacteria were found in the soil reservoir, environmental microbes strongly influence host–microbial diversity and likely regulate the core community. Using PICRUSt, an exploratory bioinformatics tool to predict gene functions, we found that core skin bacteria provided similar gene functions to the entire community. We suggest that future experiments focus on testing whether core bacteria on salamander skin contribute to the observed resistance to chytridiomycosis in this species even under hygenic captive conditions. For disease-susceptible hosts, providing an environmental reservoir with defensive bacteria in captive-rearing programs may improve outcomes by increasing bacterial diversity on threatened amphibians or increasing the likelihood that defensive bacteria are available for colonization. PMID:24335825

  7. Amphibian chemical defense: antifungal metabolites of the microsymbiont Janthinobacterium lividum on the salamander Plethodon cinereus.

    PubMed

    Brucker, Robert M; Harris, Reid N; Schwantes, Christian R; Gallaher, Thomas N; Flaherty, Devon C; Lam, Brianna A; Minbiole, Kevin P C

    2008-11-01

    Disease has spurred declines in global amphibian populations. In particular, the fungal pathogen Batrachochytrium dendrobatidis has decimated amphibian diversity in some areas unaffected by habitat loss. However, there is little evidence to explain how some amphibian species persist despite infection or even clear the pathogen beyond detection. One hypothesis is that certain bacterial symbionts on the skin of amphibians inhibit the growth of the pathogen. An antifungal strain of Janthinobacterium lividum, isolated from the skin of the red-backed salamander Plethodon cinereus, produces antifungal metabolites at concentrations lethal to B. dendrobatidis. Antifungal metabolites were identified by using reversed phase high performance liquid chromatography, high resolution mass spectrometry, nuclear magnetic resonance, and UV-Vis spectroscopy and tested for efficacy of inhibiting the pathogen. Two metabolites, indole-3-carboxaldehyde and violacein, inhibited the pathogen's growth at relatively low concentrations (68.9 and 1.82 microM, respectively). Analysis of fresh salamander skin confirmed the presence of J. lividum and its metabolites on the skin of host salamanders in concentrations high enough to hinder or kill the pathogen (51 and 207 microM, respectively). These results support the hypothesis that cutaneous, mutualistic bacteria play a role in amphibian resistance to fungal disease. Exploitation of this biological process may provide long-term resistance to B. dendrobatidis for vulnerable amphibians and serve as a model for managing future emerging diseases in wildlife populations. PMID:18949519

  8. Seasonal cell proliferation in the chemosensory epithelium and brain of red-backed salamanders, Plethodon cinereus.

    PubMed

    Dawley, E M; Fingerlin, A; Hwang, D; John, S S; Stankiewicz, C A

    2000-06-01

    The chemosensory epithelium of vertebrates retains the ability to produce new receptor neurons throughout life, presumably as a mechanism to replace aging or damaged receptors. We examined cell division in the main olfactory and vomeronasal epithelia of red-backed salamanders (Plethodon cinereus) because previous studies had shown that the volume of sensory epithelia changes seasonally. Cell division was compared throughout the year by injecting salamanders once with 5-bromo-2'-deoxyuridine (BrdU), which is incorporated into the DNA of cells during DNA synthesis, and sacrificing them one hour after injection. We used immunocytochemistry to locate cells that had arisen from cell division since BrdU injection and compared the number of labeled cells per area among animals. Animals collected in May had significantly more labeled nuclei than animals collected in any other month. However, proliferation rates among the other months were not significantly different and were quite low. Labeled nuclei also were found around the cerebral ventricles of salamanders collected in May, but rarely in any other month, although other tissues in the head often were heavily labeled. Cell proliferation appears to be up-regulated in the chemosensory epithelia and in the telencephalon during May, and we hypothesize that new receptors, and perhaps their interneurons in the telencephalon, are being generated in anticipation of seasonal events that are mediated by chemoreception.

  9. Amphibian chemical defense: antifungal metabolites of the microsymbiont Janthinobacterium lividum on the salamander Plethodon cinereus.

    PubMed

    Brucker, Robert M; Harris, Reid N; Schwantes, Christian R; Gallaher, Thomas N; Flaherty, Devon C; Lam, Brianna A; Minbiole, Kevin P C

    2008-11-01

    Disease has spurred declines in global amphibian populations. In particular, the fungal pathogen Batrachochytrium dendrobatidis has decimated amphibian diversity in some areas unaffected by habitat loss. However, there is little evidence to explain how some amphibian species persist despite infection or even clear the pathogen beyond detection. One hypothesis is that certain bacterial symbionts on the skin of amphibians inhibit the growth of the pathogen. An antifungal strain of Janthinobacterium lividum, isolated from the skin of the red-backed salamander Plethodon cinereus, produces antifungal metabolites at concentrations lethal to B. dendrobatidis. Antifungal metabolites were identified by using reversed phase high performance liquid chromatography, high resolution mass spectrometry, nuclear magnetic resonance, and UV-Vis spectroscopy and tested for efficacy of inhibiting the pathogen. Two metabolites, indole-3-carboxaldehyde and violacein, inhibited the pathogen's growth at relatively low concentrations (68.9 and 1.82 microM, respectively). Analysis of fresh salamander skin confirmed the presence of J. lividum and its metabolites on the skin of host salamanders in concentrations high enough to hinder or kill the pathogen (51 and 207 microM, respectively). These results support the hypothesis that cutaneous, mutualistic bacteria play a role in amphibian resistance to fungal disease. Exploitation of this biological process may provide long-term resistance to B. dendrobatidis for vulnerable amphibians and serve as a model for managing future emerging diseases in wildlife populations.

  10. Seasonal variation in microhabitat of salamanders: environmental variation or shift of habitat selection?

    PubMed Central

    Manenti, Raoul; Ficetola, Gentile Francesco

    2015-01-01

    Relationships between species and their habitats are not always constant. Different processes may determine changes in species-habitat association: individuals may prefer different habitat typologies in different periods, or they may be forced to occupy a different habitat in order to follow the changing environment. The aim of our study was to assess whether cave salamanders change their habitat association pattern through the year, and to test whether such changes are determined by environmental changes or by changes in preferences. We monitored multiple caves in Central Italy through one year, and monthly measured biotic and abiotic features of microhabitat and recorded Italian cave salamanders distribution. We used mixed models and niche similarity tests to assess whether species-habitat relationships remain constant through the year. Microhabitat showed strong seasonal variation, with the highest variability in the superficial sectors. Salamanders were associated to relatively cold and humid sectors in summer, but not during winter. Such apparent shift in habitat preferences mostly occurred because the environmental gradient changed through the year, while individuals generally selected similar conditions. Nevertheless, juveniles were more tolerant to dry sectors during late winter, when food demand was highest. This suggests that tolerance for suboptimal abiotic conditions may change through time, depending on the required resources. Differences in habitat use are jointly determined by environmental variation through time, and by changes in the preferred habitat. The trade-offs between tolerance and resources requirement are major determinant of such variation. PMID:26290788

  11. Eradication of the chytrid fungus Batrachochytrium dendrobatidis in the Japanese giant salamander Andrias japonicus.

    PubMed

    Une, Yumi; Matsui, Kumi; Tamukai, Kenichi; Goka, Koichi

    2012-04-26

    The purpose of this study was to establish a method for eradicating a chytrid fungus (Batrachochytrium dendrobatidis; Bd) from the Japanese giant salamander Andrias japonicus. The emerging agent (Bd) has a high rate of detection in this endangered amphibian species, which is designated as a special natural monument in Japan. Four Japanese giant salamanders with Bd confirmed by PCR assay were bathed in 0.01% itraconazole for 5 min d-1 over 10 successive days. PCR assays were conducted prior to treatment, on Days 5 and 10 of treatment, and on Days 7 and 14 post-treatment. By treatment Day 5, all individuals tested negative for Bd and remained negative until the end of the experiment. No side effects associated with itraconazole were observed. The present method appears to be a safe and effective approach for Bd eradication and may contribute to reducing the threat and spread of Bd among endangered amphibians. Notably, this study represents the first reported Bd eradication experiment involving Japanese giant salamanders. PMID:22535874

  12. Evidence for the local evolution of mechanisms underlying limb regeneration in salamanders.

    PubMed

    Garza-Garcia, A Acely; Driscoll, Paul C; Brockes, Jeremy P

    2010-10-01

    The most extensive regenerative ability in adult vertebrates is found in the salamanders. Although it is often suggested that regeneration is an ancestral property for vertebrates, our studies on the cell-surface three-finger-protein Prod 1 provide clear evidence for the importance of local evolution of limb regeneration in salamanders. Prod 1 is implicated in both patterning and growth in the regeneration of limbs. It interacts with well-conserved proteins such as the epidermal growth-factor receptor and the anterior gradient protein that are widely expressed in phylogeny. A detailed analysis of the structure and sequence of Prod 1 in relation to other vertebrate three-finger proteins in mammals and zebra fish supports the view that it is a salamander-specific protein. This is the first example of a taxon-specific protein that is clearly implicated in the mechanisms of regeneration. We propose the hypothesis that regeneration depends on the activity of taxon-specific components in orchestrating a cellular machinery that is extensively conserved between regenerating and non-regenerating taxa. This hypothesis has significant implications for our outlook on regeneration in vertebrates, as well as for the strategies employed in extending regenerative ability in mammals.

  13. Morphological characterization of the glandular system in the salamander Plethodon shermani (Caudata, Plethodontidae).

    PubMed

    von Byern, Janek; Dicke, Ursula; Heiss, Egon; Grunwald, Ingo; Gorb, Stanislav; Staedler, Yannick; Cyran, Norbert

    2015-10-01

    Amphibians have evolved a wide variety of mechanisms that provide a certain degree of protection against predators, including camouflage, tail autonomy, encounter behavior and noxious or toxic skin secretions. In addition to these strategies, some amphibians release a glue-like secretion onto the surface of their skin when threatened. While some information regarding the origin and production of these adhesive secretions is available for frogs such as Notaden bennetti, these aspects are only partially understood in salamanders. We contribute to an earlier study and provide additional information regarding the origin, production, and characterization of the adhesive secretion in the red-legged salamander (Plethodon shermani) at a microanatomical level. When stressed, this salamander secretes a milky, viscous liquid from its dorsal and ventral skin. This secretion is extremely adhesive and hardens within seconds upon exposure to air. This study describes two cutaneous gland types (mucous and granular) in the dorsal and ventral epithelial tissue that differ considerably in their secretory content. While the smaller mucous glands contains flocculent to granular material, mostly acidic glycoproteins, the granular glands synthesize various granules of differing size and density that consist of basic proteinaceous material. The results strongly indicate that the secretions of both gland types from the dorsal as well as the ventral side form the adhesive mucus in Plethodon shermani, consisting of basic and acidic glycoproteins, glycoconjugates with mannose and α-L-fucose residues as well as lipid components.

  14. Biogeography and body size shuffling of aquatic salamander communities on a shifting refuge.

    PubMed

    Bonett, Ronald M; Trujano-Alvarez, Ana Lilia; Williams, Michael J; Timpe, Elizabeth K

    2013-05-01

    Freshwater habitats of coastal plains are refugia for many divergent vertebrate lineages, yet these environments are highly vulnerable to sea-level fluctuations, which suggest that resident communities have endured dynamic histories. Using the fossil record and a multi-locus nuclear phylogeny, we examine divergence times, biogeography, body size evolution and patterns of community assembly of aquatic salamanders from North American coastal plains since the Late Cretaceous. At least five salamander families occurred on the extensive Western Interior Coastal Plain (WICP), which existed from the Late Cretaceous through the Eocene. Four of these families subsequently colonized the emergent Southeastern Coastal Plain (SECP) by the Early Oligocene to Late Miocene. Three families ultimately survived and underwent extensive body size evolution in situ on the SECP. This included at least two major size reversals in recent taxa that are convergent with confamilial WICP ancestors. Dynamics of the coastal plain, major lineage extinctions and frequent extreme changes in body size have resulted in significant shuffling of the size structure of aquatic salamander communities on this shifting refuge since the Cretaceous.

  15. Spatial data for Eurycea salamander habitats associated With three aquifers in south-central Texas

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Reece, Brian D.

    2006-01-01

    Eurycea salamander taxa comprise 12 known species that inhabit springs and caves in south-central Texas. Many of these are threatened or endangered species, and some are found only at one location. A number of the neotenic salamanders might be at risk from habitat loss associated with declines in ground-water levels. Eurycea salamander habitats are associated with three aquifers in south-central Texas: (1) the Edwards-Trinity (Plateau) aquifer, (2) the Edwards (Balcones Fault Zone) aquifer, and (3) the Trinity aquifer. The Edwards (Balcones fault zone) aquifer is commonly separated into three segments: from southwest to northeast, the San Antonio segment, the Barton Springs segment, and the northern segment. The Trinity aquifer south of the Colorado River can be divided into three permeable zones, the upper, middle, and lower zone. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, developed this report (geodatabase) to aggregate the spatial data necessary to assess the potential effects of ground-water declines on known Eurycea habitat locations in south-central Texas. The geodatabase provides information about spring habitats, spring flow, cave habitats, aquifers, and projected water levels.

  16. Data set for transcriptome analysis of the Chinese giant salamander (Andrias davidianus )

    PubMed Central

    Jiang, Xuemei; Wang, Yuan; Zhang, Xiaoying

    2015-01-01

    The Chinese giant salamander (Andrias davidianus) occupies a seat at the phylogenetic and species evolution process, which makes it an invaluable model for genetics; however, the genetic information and gene sequences about the Chinese giant salamander in public databases are scanty. Hence, we aimed to perform transcriptome analysis with the help of high-throughput sequencing. In this data, 61,317,940 raw reads were acquired from Chinese giant salamander mRNA using Illumina paired-end sequencing platform. After de novo assembly, a total of 72,072 unigenes were gained, in which 33,834 (46.95%) and 29,479 (40.91%) transcripts exhibited homology to sequences in the Nr database and Swiss-Prot database, (E-value <10−5), respectively. In the obtained unigenes, 18,019 (25%) transcripts were assigned with at least one Gene Ontology term, of which 1218 (6.8%) transcripts were assigned to immune system processes. In addition, a total of 17,572 assembled sequences were assigned into 241 predicted KEGG metabolic pathways. Among these, 2552 (14.5%) transcripts were assigned to the immune system relevant pathway and 5 transcripts were identified as potential antimicrobial peptides (AMPs). PMID:26759822

  17. The effects of atrazine on spotted salamander embryos and their symbiotic alga.

    PubMed

    Olivier, Heather M; Moon, Brad R

    2010-04-01

    Worldwide amphibian declines have been a concern for biologists for the past several decades. The causes of such declines may include habitat loss, invasive species, pathogens, and man-made chemicals. Agricultural herbicides, in particular, are known to interfere with reproduction in amphibians and are likely contributing to population declines. We tested the effects of the herbicide atrazine on developing spotted salamanders (Ambystoma maculatum) and their symbiotic green alga Oophila amblystomatis. We exposed spotted salamander egg masses to atrazine at concentrations of 0 microg/L (control), 50, 100, 200, and 400 microg/L. Algae were eliminated in all atrazine treatments. Hatching success was significantly lower for atrazine-treated egg masses than for the controls, and was inversely related to atrazine concentration. The highest developmental stage reached by the embryos was significantly lower in the atrazine treatments than in the controls, and was inversely related to atrazine concentration. These results indicate that atrazine exposure affected spotted salamanders both directly by causing pathologies and mortality in embryos and indirectly by eliminating their symbiotic alga. PMID:19924530

  18. Data set for transcriptome analysis of the Chinese giant salamander (Andrias davidianus ).

    PubMed

    Jiang, Xuemei; Wang, Yuan; Zhang, Xiaoying

    2016-03-01

    The Chinese giant salamander (Andrias davidianus) occupies a seat at the phylogenetic and species evolution process, which makes it an invaluable model for genetics; however, the genetic information and gene sequences about the Chinese giant salamander in public databases are scanty. Hence, we aimed to perform transcriptome analysis with the help of high-throughput sequencing. In this data, 61,317,940 raw reads were acquired from Chinese giant salamander mRNA using Illumina paired-end sequencing platform. After de novo assembly, a total of 72,072 unigenes were gained, in which 33,834 (46.95%) and 29,479 (40.91%) transcripts exhibited homology to sequences in the Nr database and Swiss-Prot database, (E-value <10(-5)), respectively. In the obtained unigenes, 18,019 (25%) transcripts were assigned with at least one Gene Ontology term, of which 1218 (6.8%) transcripts were assigned to immune system processes. In addition, a total of 17,572 assembled sequences were assigned into 241 predicted KEGG metabolic pathways. Among these, 2552 (14.5%) transcripts were assigned to the immune system relevant pathway and 5 transcripts were identified as potential antimicrobial peptides (AMPs). PMID:26759822

  19. Eradication of the chytrid fungus Batrachochytrium dendrobatidis in the Japanese giant salamander Andrias japonicus.

    PubMed

    Une, Yumi; Matsui, Kumi; Tamukai, Kenichi; Goka, Koichi

    2012-04-26

    The purpose of this study was to establish a method for eradicating a chytrid fungus (Batrachochytrium dendrobatidis; Bd) from the Japanese giant salamander Andrias japonicus. The emerging agent (Bd) has a high rate of detection in this endangered amphibian species, which is designated as a special natural monument in Japan. Four Japanese giant salamanders with Bd confirmed by PCR assay were bathed in 0.01% itraconazole for 5 min d-1 over 10 successive days. PCR assays were conducted prior to treatment, on Days 5 and 10 of treatment, and on Days 7 and 14 post-treatment. By treatment Day 5, all individuals tested negative for Bd and remained negative until the end of the experiment. No side effects associated with itraconazole were observed. The present method appears to be a safe and effective approach for Bd eradication and may contribute to reducing the threat and spread of Bd among endangered amphibians. Notably, this study represents the first reported Bd eradication experiment involving Japanese giant salamanders.

  20. Toxicological responses of red-backed salamanders (Plethodon cinereus) to subchronic soil exposures of 2,4,6-trinitrotoluene.

    PubMed

    Bazar, Mathew A; Quinn, Michael J; Mozzachio, Kristie; Johnson, Mark S

    2008-06-01

    Since World War I, trinitrotoluene (TNT) has been the most commonly used explosive. Environmental contamination associated with synthesis, manufacture of weapons, and use during training exercises has been extensive, with soil concentrations reaching 145,000 mg/kg. Some of these areas include habitats for amphibian species. Earlier studies have shown that salamanders dermally absorb TNT from soil. To ascertain what soil concentrations of TNT are toxic to amphibians, red-backed salamanders (Plethodon cinereus) were exposed to one of five concentrations of TNT in soil for 28 d and evaluated for indicators of toxicity. A total of 100 salamanders were randomly sorted by weight and assigned to target TNT concentrations in soil of either 3,000, 1,500, 750, 325, or 0 mg/kg dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Survival was reduced in salamanders exposed to 1,500 and 3,000 mg/kg by 10 and 55%, respectively. Most mortality/morbidity occurred within the first week of exposure. Salamanders had a reduction in hemoglobin at 750 mg/kg or greater and a reduction in red blood cell concentration at 1,500 mg/kg or greater. Food consumption was affected in salamanders at 750 mg/kg or greater; a reduction in body mass and liver glycogen content also occurred at and above this concentration. Splenic congestion also was observed in salamanders from these groups. These data suggest that soil TNT concentrations of 373 +/- 41.0 mg/kg or greater result in reduced body mass, reduced feed intake, and hematological effects.

  1. Vertebrate Hosts as Islands: Dynamics of Selection, Immigration, Loss, Persistence, and Potential Function of Bacteria on Salamander Skin

    PubMed Central

    Loudon, Andrew H.; Venkataraman, Arvind; Van Treuren, William; Woodhams, Douglas C.; Parfrey, Laura Wegener; McKenzie, Valerie J.; Knight, Rob; Schmidt, Thomas M.; Harris, Reid N.

    2016-01-01

    Skin bacterial communities can protect amphibians from a fungal pathogen; however, little is known about how these communities are maintained. We used a neutral model of community ecology to identify bacteria that are maintained on salamanders by selection or by dispersal from a bacterial reservoir (soil) and ecological drift. We found that 75% (9/12) of bacteria that were consistent with positive selection, <1% of bacteria that were consistent with random dispersal and none of the bacteria that were consistent under negative selection had a 97% or greater match to antifungal isolates. Additionally we performed an experiment where salamanders were either provided or denied a bacterial reservoir and estimated immigration and loss (emigration and local extinction) rates of bacteria on salamanders in both treatments. Loss was strongly related to bacterial richness, suggesting competition is important for structuring the community. Bacteria closely related to antifungal isolates were more likely to persist on salamanders with or without a bacterial reservoir, suggesting they had a competitive advantage. Furthermore, over-represented and under-represented operational taxonomic units (OTUs) had similar persistence on salamanders when a bacterial reservoir was present. However, under-represented OTUs were less likely to persist in the absence of a bacterial reservoir, suggesting that the over-represented and under-represented bacteria were selected against or for on salamanders through time. Our findings from the neutral model, migration and persistence analyses show that bacteria that exhibit a high similarity to antifungal isolates persist on salamanders, which likely protect hosts against pathogens and improve fitness. This research is one of the first to apply ecological theory to investigate assembly of host associated-bacterial communities, which can provide insights for probiotic bioaugmentation as a conservation strategy against disease. PMID:27014249

  2. Vertebrate Hosts as Islands: Dynamics of Selection, Immigration, Loss, Persistence, and Potential Function of Bacteria on Salamander Skin.

    PubMed

    Loudon, Andrew H; Venkataraman, Arvind; Van Treuren, William; Woodhams, Douglas C; Parfrey, Laura Wegener; McKenzie, Valerie J; Knight, Rob; Schmidt, Thomas M; Harris, Reid N

    2016-01-01

    Skin bacterial communities can protect amphibians from a fungal pathogen; however, little is known about how these communities are maintained. We used a neutral model of community ecology to identify bacteria that are maintained on salamanders by selection or by dispersal from a bacterial reservoir (soil) and ecological drift. We found that 75% (9/12) of bacteria that were consistent with positive selection, <1% of bacteria that were consistent with random dispersal and none of the bacteria that were consistent under negative selection had a 97% or greater match to antifungal isolates. Additionally we performed an experiment where salamanders were either provided or denied a bacterial reservoir and estimated immigration and loss (emigration and local extinction) rates of bacteria on salamanders in both treatments. Loss was strongly related to bacterial richness, suggesting competition is important for structuring the community. Bacteria closely related to antifungal isolates were more likely to persist on salamanders with or without a bacterial reservoir, suggesting they had a competitive advantage. Furthermore, over-represented and under-represented operational taxonomic units (OTUs) had similar persistence on salamanders when a bacterial reservoir was present. However, under-represented OTUs were less likely to persist in the absence of a bacterial reservoir, suggesting that the over-represented and under-represented bacteria were selected against or for on salamanders through time. Our findings from the neutral model, migration and persistence analyses show that bacteria that exhibit a high similarity to antifungal isolates persist on salamanders, which likely protect hosts against pathogens and improve fitness. This research is one of the first to apply ecological theory to investigate assembly of host associated-bacterial communities, which can provide insights for probiotic bioaugmentation as a conservation strategy against disease. PMID:27014249

  3. Multimodal communication, mismatched messages and the effects of turbidity on the antipredator behavior of the Barton Springs salamander, Eurycea sosorum.

    PubMed

    Zabierek, Kristina C; Gabor, Caitlin R

    2016-09-01

    Prey may use multiple sensory channels to detect predators, whose cues may differ in altered sensory environments, such as turbid conditions. Depending on the environment, prey may use cues in an additive/complementary manner or in a compensatory manner. First, to determine whether the purely aquatic Barton Springs salamander, Eurycea sosorum, show an antipredator response to visual cues, we examined their activity when exposed to either visual cues of a predatory fish (Lepomis cyanellus) or a non-predatory fish (Etheostoma lepidum). Salamanders decreased activity in response to predator visual cues only. Then, we examined the antipredator response of these salamanders to all matched and mismatched combinations of chemical and visual cues of the same predatory and non-predatory fish in clear and low turbidity conditions. Salamanders decreased activity in response to predator chemical cues matched with predator visual cues or mismatched with non-predator visual cues. Salamanders also increased latency to first move to predator chemical cues mismatched with non-predator visual cues. Salamanders decreased activity and increased latency to first move more in clear as opposed to turbid conditions in all treatment combinations. Our results indicate that salamanders under all conditions and treatments preferentially rely on chemical cues to determine antipredator behavior, although visual cues are potentially utilized in conjunction for latency to first move. Our results also have potential conservation implications, as decreased antipredator behavior was seen in turbid conditions. These results reveal complexity of antipredator behavior in response to multiple cues under different environmental conditions, which is especially important when considering endangered species. PMID:27370360

  4. Multimodal communication, mismatched messages and the effects of turbidity on the antipredator behavior of the Barton Springs salamander, Eurycea sosorum.

    PubMed

    Zabierek, Kristina C; Gabor, Caitlin R

    2016-09-01

    Prey may use multiple sensory channels to detect predators, whose cues may differ in altered sensory environments, such as turbid conditions. Depending on the environment, prey may use cues in an additive/complementary manner or in a compensatory manner. First, to determine whether the purely aquatic Barton Springs salamander, Eurycea sosorum, show an antipredator response to visual cues, we examined their activity when exposed to either visual cues of a predatory fish (Lepomis cyanellus) or a non-predatory fish (Etheostoma lepidum). Salamanders decreased activity in response to predator visual cues only. Then, we examined the antipredator response of these salamanders to all matched and mismatched combinations of chemical and visual cues of the same predatory and non-predatory fish in clear and low turbidity conditions. Salamanders decreased activity in response to predator chemical cues matched with predator visual cues or mismatched with non-predator visual cues. Salamanders also increased latency to first move to predator chemical cues mismatched with non-predator visual cues. Salamanders decreased activity and increased latency to first move more in clear as opposed to turbid conditions in all treatment combinations. Our results indicate that salamanders under all conditions and treatments preferentially rely on chemical cues to determine antipredator behavior, although visual cues are potentially utilized in conjunction for latency to first move. Our results also have potential conservation implications, as decreased antipredator behavior was seen in turbid conditions. These results reveal complexity of antipredator behavior in response to multiple cues under different environmental conditions, which is especially important when considering endangered species.

  5. Molecular Phylogeography and Population Genetic Structure of an Endangered Species Pachyhynobius shangchengensis (hynobiid Salamander) in a Fragmented Habitat of Southeastern China

    PubMed Central

    Zhao, Yanyu; Zhang, Yanhua; Li, Xiaochen

    2013-01-01

    The salamander Pachyhynobius shangchengensis (Hynobiidae) is a vulnerable species restricted to a patchy distribution associated with small mountain streams surrounded by forested slopes in the Mount Dabieshan region in southeastern China. However, molecular phylogeography and population genetic structure of P. shangchengensis remain poorly investigated. In this study, we explored the genetic structure and phylogeography of P. shangchengensis based on partial sequences of the mitochondrial DNA (mtDNA) cytochrome b and cytochrome c oxidase subunit I genes. Fifty-one haplotypes and four clades were found among 93 samples. Phylogenetic analyses revealed four deeply divergent and reciprocally monophyletic mtDNA lineages that approximately correspond to four geographic regions separated by complicated topography and long distances. The distinct geographic distributions of all lineages and the estimated divergence time suggest spatial and temporal separation coinciding with climatic changes during the Pleistocene. Analysis of molecular variance indicated that most of the observed genetic variation occurred among the four groups, implying long-term interruption of gene flow, and the possible separation of P. shangchengensis into four management units for conservation. PMID:24205092

  6. Mitochondrial RNA granules: Compartmentalizing mitochondrial gene expression

    PubMed Central

    Jourdain, Alexis A.; Boehm, Erik; Maundrell, Kinsey

    2016-01-01

    In mitochondria, DNA replication, gene expression, and RNA degradation machineries coexist within a common nondelimited space, raising the question of how functional compartmentalization of gene expression is achieved. Here, we discuss the recently characterized “mitochondrial RNA granules,” mitochondrial subdomains with an emerging role in the regulation of gene expression. PMID:26953349

  7. Salamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies

    USGS Publications Warehouse

    Grant, Evan H. Campbell; Muths, Erin L.; Katz, Rachel A.; Canessa, Stefano; Adams, Michael J.; Ballard, Jennifer R.; Berger, Lee; Briggs, Cheryl J.; Coleman, Jeremy; Gray, Matthew J.; Harris, M. Camille; Harris, Reid N.; Hossack, Blake R.; Huyvaert, Kathryn P.; Kolby, Jonathan E.; Lips, Karen R.; Lovich, Robert E.; McCallum, Hamish I.; Mendelson, Joseph R.; Nanjappa, Priya; Olson, Deanna H.; Powers, Jenny G.; Richgels, Katherine L.D.; Russell, Robin E.; Schmidt, Benedikt R.; Spitzen-van der Sluijs, Annemarieka; Watry, Mary Kay; Woodhams, Douglas C.; White, C. LeAnn

    2016-01-20

    The recently (2013) identified pathogenic chytrid fungus, Batrachochytrium salamandrivorans (Bsal), poses a severe threat to the distribution and abundance of salamanders within the United States and Europe. Development of a response strategy for the potential, and likely, invasion of Bsal into the United States is crucial to protect global salamander biodiversity. A formal working group, led by Amphibian Research and Monitoring Initiative (ARMI) scientists from the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center, Fort Collins Science Center, and Forest and Rangeland Ecosystem Science Center, was held at the USGS Powell Center for Analysis and Synthesis in Fort Collins, Colorado, United States from June 23 to June 25, 2015, to identify crucial Bsal research and monitoring needs that could inform conservation and management strategies for salamanders in the United States. Key findings of the workshop included the following: (1) the introduction of Bsal into the United States is highly probable, if not inevitable, thus requiring development of immediate short-term and long-term intervention strategies to prevent Bsal establishment and biodiversity decline; (2) management actions targeted towards pathogen containment may be ineffective in reducing the long-term spread of Bsal throughout the United States; and (3) early detection of Bsal through surveillance at key amphibian import locations, among high-risk wild populations, and through analysis of archived samples is necessary for developing management responses. Top research priorities during the preinvasion stage included the following: (1) deployment of qualified diagnostic methods for Bsal and establishment of standardized laboratory practices, (2) assessment of susceptibility for amphibian hosts (including anurans), and (3) development and evaluation of short- and long-term pathogen intervention and management strategies. Several outcomes were achieved during the workshop, including development

  8. Salamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies

    USGS Publications Warehouse

    Grant, Evan H. Campbell; Muths, Erin L.; Katz, Rachel A.; Canessa, Stefano; Adams, Michael J.; Ballard, Jennifer R.; Berger, Lee; Briggs, Cheryl J.; Coleman, Jeremy; Gray, Matthew J.; Harris, M. Camille; Harris, Reid N.; Hossack, Blake R.; Huyvaert, Kathryn P.; Kolby, Jonathan E.; Lips, Karen R.; Lovich, Robert E.; McCallum, Hamish I.; Mendelson, Joseph R., III; Nanjappa, Priya; Olson, Deanna H.; Powers, Jenny G.; Richgels, Katherine L.D.; Russell, Robin E.; Schmidt, Benedikt R.; Spitzen-van der Sluijs, Annemarieka; Watry, Mary Kay; Woodhams, Douglas C.; White, C. LeAnn

    2016-01-01

    The recently (2013) identified pathogenic chytrid fungus, Batrachochytrium salamandrivorans (Bsal), poses a severe threat to the distribution and abundance of salamanders within the United States and Europe. Development of a response strategy for the potential, and likely, invasion of Bsal into the United States is crucial to protect global salamander biodiversity. A formal working group, led by Amphibian Research and Monitoring Initiative (ARMI) scientists from the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center, Fort Collins Science Center, and Forest and Rangeland Ecosystem Science Center, was held at the USGS Powell Center for Analysis and Synthesis in Fort Collins, Colorado, United States from June 23 to June 25, 2015, to identify crucial Bsal research and monitoring needs that could inform conservation and management strategies for salamanders in the United States. Key findings of the workshop included the following: (1) the introduction of Bsal into the United States is highly probable, if not inevitable, thus requiring development of immediate short-term and long-term intervention strategies to prevent Bsal establishment and biodiversity decline; (2) management actions targeted towards pathogen containment may be ineffective in reducing the long-term spread of Bsal throughout the United States; and (3) early detection of Bsal through surveillance at key amphibian import locations, among high-risk wild populations, and through analysis of archived samples is necessary for developing management responses. Top research priorities during the preinvasion stage included the following: (1) deployment of qualified diagnostic methods for Bsal and establishment of standardized laboratory practices, (2) assessment of susceptibility for amphibian hosts (including anurans), and (3) development and evaluation of short- and long-term pathogen intervention and management strategies. Several outcomes were achieved during the workshop, including development

  9. Intraerythrocytic rickettsial inclusions in Ocoee salamanders (Desmognathus ocoee): prevalence, morphology, and comparisons with inclusions of Plethodon cinereus.

    PubMed

    Davis, Andrew K; Cecala, Kristen

    2010-07-01

    Reports of an unusual intraerythrocytic pathogen in amphibian blood have been made for decades; these pathogens appear as membrane-bound vacuoles within erythrocytes. It is now understood that the pathogen is a Rickettsia bacteria, which are obligate intracellular parasites, and most are transmitted by arthropod vectors. In an effort to further understand the host range and characteristics of this pathogen, we examined 20 Ocoee salamanders (Desmognathus ocoee) from a site in southwest North Carolina for the presence of rickettsial inclusions and report the general characteristics of infections. Seven individuals (35%) were infected, and this level of prevalence was consistent with all other members of this genus examined to date. In contrast, infections within the genus Plethodon tend to occur in less than 10% of individuals, based on review of the literature. The difference could be related to the semi-aquatic nature of Desmognathus salamanders versus the completely terrestrial Plethodon. It is also possible that both groups are hosts to different types of rickettsial bacteria, since the inclusions found here only vaguely resembled those found recently in red-backed salamanders (Plethodon cinereus). Inclusions in Ocoee salamanders measured 4 microm in diameter on average, and most cells (88%) only had one inclusion. Of all infected individuals, inclusions occurred in approximately 3% of erythrocytes. Similar to that found in red-backed salamanders, infected hosts were significantly larger than non-infected. Future investigations into the nature of this unusual parasite of amphibians would help to further our understanding of its life cycle and transmission.

  10. Toxicological responses of red-backed salamanders (Plethodon cinereus) to subchronic soil exposures of 2,4-dinitrotoluene.

    PubMed

    Johnson, Mark S; Suski, Jamie; Bazar, Matthew A

    2007-06-01

    Dinitrotoluenes are used as propellants and in explosives by the military and as such have been found at relatively high concentrations in the soil. To determine whether concentrations of 2,4-dinitrotoluene (2,4-DNT) in soil are toxic to amphibians, 100 red-backed salamanders (Plethodon cinereus) were exposed to either 1500, 800, 200, 75 or 0mg 2,4-DNT/kg soil for 28 days and evaluated for indicators of toxicity. Concentrations of 2,4-DNT were less than targets and varied with time. Most salamanders exposed to concentrations exceeding 1050 mg/kg died or were moribund within the first week. Salamanders exposed to soil concentrations exceeding 345 mg/kg lost >6% of their body mass though no mortality occurred. Overt effects included a reduction in feed consumption and an increase in bucco-pharyngeal oscillations in salamanders. These results suggest that only high soil concentrations of 2,4-DNT have the potential to cause overtly toxic effects in terrestrial salamanders.

  11. A comparative study of potassium-induced relaxation in vascular smooth muscle of tiger salamanders and rats.

    PubMed

    Malvin, G M; Webb, R C

    1984-07-01

    This study compares potassium-induced relaxation in vascular tissue of an amphibian (Ambystoma tigrinum) and a mammal (rat). Aortas (salamanders) and tail arteries (rats) were cut into helical strips for isometric force recording. After norepinephrine-induced contraction in potassium-free solution, arteries relaxed in response to added potassium (1-20 mmol/l). Potassium-induced relaxation was greater in rat tail arteries than in salamander aortas. Half-maximal relaxation occurred at a potassium concentration of approximately 3 mmol/l in both species. Ouabain inhibited potassium-induced relaxation; salamanders were more sensitive to the glycoside than rats. Potassium-induced relaxation decreased as the temperature of the bathing medium was lowered; half-maximal inhibition occurred at 19 and 29 degrees C for salamander aortas and rat tail arteries, respectively. Potassium-induced relaxation also varied with the interval in potassium-free solution, the hydrogen ion concentration (rats only), and the magnitude of norepinephrine-induced contraction. It appears that the cellular mechanism causing potassium-induced relaxation is similar in blood vessels of salamanders and rats. The observations are consistent with the hypothesis that stimulated electrogenic sodium transport produced membrane hyperpolarization and relaxation in vascular smooth muscle.

  12. Influence of observers and stream flow on northern two-lined salamander (Eurycea bislineata bislineata) relative abundance estimates in Acadia and Shenandoah National Parks, USA

    USGS Publications Warehouse

    Crocker, J.B.; Bank, M.S.; Loftin, C.S.; Jung Brown, R.E.

    2007-01-01

    We investigated effects of observers and stream flow on Northern Two-Lined Salamander (Eurycea bislineata bislineata) counts in streams in Acadia (ANP) and Shenandoah National Parks (SNP). We counted salamanders in 22 ANP streams during high flow (May to June 2002) and during low flow (July 2002). We also counted salamanders in SNP in nine streams during high flow (summer 2003) and 11 streams during low flow (summers 2001?02, 2004). In 2002, we used a modified cover-controlled active search method with a first and second observer. In succession, observers turned over 100 rocks along five 1-m belt transects across the streambed. The difference between observers in total salamander counts was not significant. We counted fewer E. b. bislineata during high flow conditions, confirming that detection of this species is reduced during high flow periods and that assessment of stream salamander relative abundance is likely more reliable during low or base flow conditions.

  13. Human Mitochondrial Protein Database

    National Institute of Standards and Technology Data Gateway

    SRD 131 Human Mitochondrial Protein Database (Web, free access)   The Human Mitochondrial Protein Database (HMPDb) provides comprehensive data on mitochondrial and human nuclear encoded proteins involved in mitochondrial biogenesis and function. This database consolidates information from SwissProt, LocusLink, Protein Data Bank (PDB), GenBank, Genome Database (GDB), Online Mendelian Inheritance in Man (OMIM), Human Mitochondrial Genome Database (mtDB), MITOMAP, Neuromuscular Disease Center and Human 2-D PAGE Databases. This database is intended as a tool not only to aid in studying the mitochondrion but in studying the associated diseases.

  14. The identification of 2,4-diacetylphloroglucinol as an antifungal metabolite produced by cutaneous bacteria of the salamander Plethodon cinereus.

    PubMed

    Brucker, Robert M; Baylor, Cambria M; Walters, Robert L; Lauer, Antje; Harris, Reid N; Minbiole, Kevin P C

    2008-01-01

    Beneficial bacteria that live on salamander skins have the ability to inhibit pathogenic fungi. Our study aimed to identify the specific chemical agent(s) of this process and asked if any of the antifungal compounds known to operate in analogous plant-bacteria-fungi systems were present. Crude extracts of bacteria isolated from salamander skin were exposed to HPLC, UV-Vis, GC-MS, and HR-MS analyses. These investigations show that 2,4-diacetylphloroglucinol is produced by the bacteria isolate Lysobacter gummosus (AB161361), which was found on the red-backed salamander, Plethodon cinereus. Furthermore, exposure of the amphibian fungal pathogen, Batrachochytrium dendrobatidis (isolate JEL 215), to different concentrations of 2,4-diacetylphloroglucinol resulted in an IC50 value of 8.73 microM, comparable to crude extract concentrations. This study is the first to show that an epibiotic bacterium on an amphibian species produces a chemical that inhibits pathogenic fungi.

  15. Experimental exposure of adult San Marcos salamanders and larval leopard frogs to the cercariae of Centrocestus formosanus.

    PubMed

    Huston, D C; Cantu, V; Huffman, D G

    2014-04-01

    The gill parasite Centrocestus formosanus (Trematoda: Heterophyidae) is an exotic parasite of concern in Texas because it has been shown to infect multiple threatened and endangered fish species. The purpose of this study was to determine if C. formosanus could present a threat to larval anurans, as well as threatened neotenic salamanders endemic to the spring-fed systems of Texas. We exposed adults of the San Marcos salamander Eurycea nana (Caudata: Plethodontidae) and tadpoles of the Rio Grande leopard frog Lithobates berlandieri (Anura: Ranidae) to the cercariae of C. formosanus . The San Marcos salamander showed no signs of metacercarial infection, suggesting that E. nana may be refractory to C. formosanus cercariae. Centrocestus formosanus readily infects the gills of leopard frog tadpoles, but the metacercariae apparently died prior to reaching maturity in our tadpoles.

  16. Metals, Parasites, and Environmental Conditions Affecting Breeding Populations of Spotted Salamanders (Ambystoma maculatum) in Northern Arkansas, USA.

    PubMed

    DeMali, Heather M; Trauth, Stanley E; Bouldin, Jennifer L

    2016-06-01

    The spotted salamander (Ambystoma maculatum) is indigenous to northern Arkansas, and several breeding sites are known to exist in the region. Spotted salamanders (n = 17) were collected and examined for parasites and only three females harbored nematodes (Physaloptera spp.). Chronic aquatic bioassays were conducted using water collected from eight breeding ponds during different hydroperiod events. No lethal or sublethal effects were measured in Ceriodaphnia dubia; however, decreased growth and survival were seen in Pimephales promelas. Aqueous, sediment, and salamander hepatic samples were analyzed for As, Cd, Cu, Pb, and Ni. Metal analysis revealed possible increased metal exposure following precipitation, with greatest metal concentrations measured in sediment samples. Hepatic metal concentrations were similar in parasitized and non-parasitized individuals, and greatest Pb concentrations were measured following normal precipitation events. Determining environmental stressors of amphibians, especially during their breeding and subsequent larval life stage, is imperative to improve species conservation. PMID:26886425

  17. Propulsive forces of mudskipper fins and salamander limbs during terrestrial locomotion: implications for the invasion of land.

    PubMed

    Kawano, Sandy M; Blob, Richard W

    2013-08-01

    The invasion of land was a pivotal event in vertebrate evolution that was associated with major appendicular modifications. Although fossils indicate that the evolution of fundamentally limb-like appendages likely occurred in aquatic environments, the functional consequences of using early digited limbs, rather than fins, for terrestrial propulsion have had little empirical investigation. Paleontological and experimental analyses both have led to the proposal of an early origin of "hind limb-driven" locomotion among tetrapods or their ancestors. However, the retention of a pectoral appendage that had already developed terrestrial adaptations has been proposed for some taxa, and few data are available from extant functional models that can provide a foundation for evaluating the relative contributions of pectoral and pelvic appendages to terrestrial support among early stem tetrapods. To examine these aspects of vertebrate locomotor evolution during the invasion of land, we measured three-dimensional ground reaction forces (GRFs) produced by isolated pectoral fins of mudskipper fishes (Periophthalmus barbarus) during terrestrial crutching, and compared these to isolated walking footfalls by the forelimbs and hind limbs of tiger salamanders (Ambystoma tigrinum), a species with subequally-sized limbs that facilitate comparisons to early tetrapods. Pectoral appendages of salamanders and mudskippers exhibited numerous differences in GRFs. Compared with salamander forelimbs, isolated fins of mudskippers bear lower vertical magnitudes of GRFs (as a proportion of body weight), and had GRFs that were oriented more medially. Comparing the salamanders' forelimbs and hind limbs, although the peak net GRF occurs later in stance for the forelimb, both limbs experience nearly identical mediolateral and vertical components of GRF, suggesting comparable contributions to support. Thus, forelimbs could also have played a significant locomotor role among basal tetrapods that had limbs

  18. In search of critically endangered species: the current situation of two tiny salamander species in the Neotropical mountains of Mexico.

    PubMed

    Sandoval-Comte, Adriana; Pineda, Eduardo; Aguilar-López, José L

    2012-01-01

    Worldwide, one in every three species of amphibian is endangered, 39 species have gone extinct in the last 500 years and another 130 species are suspected to have gone extinct in recent decades. Of the amphibians, salamanders have the highest portion of their species in one of the risk categories, even higher than the frogs. To date there have been few studies that have used recent field data to examine the status of populations of endangered salamanders. In this study we evaluate the current situation of two tiny salamanders, Parvimolge townsendi and Thorius pennatulus, both of which are distributed at intermediate elevations in the mountains of the northern Neotropics and are considered to be critically endangered; the first has been proposed as possibly extinct. By carrying out exhaustive surveys in both historical and potentially suitable sites for these two species, we evaluated their abundance and the characteristics of their habitats, and we estimated their potential geographic distribution. We visited 22 sites, investing 672 person-hours of sampling effort in the surveys, and found 201 P. townsendi salamanders in 11 sites and only 13 T. pennatulus salamanders in 5 sites. Both species were preferentially found in cloud forest fragments that were well conserved or only moderately transformed, and some of the salamanders were found in shade coffee plantations. The potential distribution area of both species is markedly fragmented and we estimate that it has decreased by more than 48%. The results of this study highlight the importance of carrying out exhaustive, systematic field surveys to obtain accurate information about the current situation of critically endangered species, and help us better understand the crisis that amphibians are facing worldwide.

  19. Establishment of three cell lines from Chinese giant salamander and their sensitivities to the wild-type and recombinant ranavirus.

    PubMed

    Yuan, Jiang-Di; Chen, Zhong-Yuan; Huang, Xing; Gao, Xiao-Chan; Zhang, Qi-Ya

    2015-06-12

    Known as lethal pathogens, Ranaviruses have been identified in diseased fish, amphibians (including Chinese giant salamander Andrias davidianus, the world's largest amphibian) and reptiles, causing organ necrosis and systemic hemorrhage. Here, three Chinese giant salamander cell lines, thymus cell line (GSTC), spleen cell line (GSSC) and kidney cell line (GSKC) were initially established. Their sensitivities to ranaviruses, wild-type Andrias davidianus ranavirus (ADRV) and recombinant Rana grylio virus carrying EGFP gene (rRGV-EGFP) were tested. Temporal transcription pattern of ranavirus major capsid protein (MCP), fluorescence and electron microscopy observations showed that both the wild-type and recombinant ranavirus could replicate in the cell lines.

  20. Dose rate estimation of the Tohoku hynobiid salamander, Hynobius lichenatus, in Fukushima.

    PubMed

    Fuma, Shoichi; Ihara, Sadao; Kawaguchi, Isao; Ishikawa, Takahiro; Watanabe, Yoshito; Kubota, Yoshihisa; Sato, Youji; Takahashi, Hiroyuki; Aono, Tatsuo; Ishii, Nobuyoshi; Soeda, Haruhi; Matsui, Kumi; Une, Yumi; Minamiya, Yukio; Yoshida, Satoshi

    2015-05-01

    The radiological risks to the Tohoku hynobiid salamanders (class Amphibia), Hynobius lichenatus due to the Fukushima Dai-ichi Nuclear Power Plant accident were assessed in Fukushima Prefecture, including evacuation areas. Aquatic egg clutches (n = 1 for each sampling date and site; n = 4 in total), overwintering larvae (n = 1-5 for each sampling date and site; n = 17 in total), and terrestrial juveniles or adults (n = 1 or 3 for each sampling date and site; n = 12 in total) of H. lichenatus were collected from the end of April 2011 to April 2013. Environmental media such as litter (n = 1-5 for each sampling date and site; n = 30 in total), soil (n = 1-8 for each sampling date and site; n = 31 in total), water (n = 1 for each sampling date and site; n = 17 in total), and sediment (n = 1 for each sampling date and site; n = 17 in total) were also collected. Activity concentrations of (134)Cs + (137)Cs were 1.9-2800, 0.13-320, and 0.51-220 kBq (dry kg) (-1) in the litter, soil, and sediment samples, respectively, and were 0.31-220 and <0.29-40 kBq (wet kg)(-1) in the adult and larval salamanders, respectively. External and internal absorbed dose rates to H. lichenatus were calculated from these activity concentration data, using the ERICA Assessment Tool methodology. External dose rates were also measured in situ with glass dosimeters. There was agreement within a factor of 2 between the calculated and measured external dose rates. In the most severely contaminated habitat of this salamander, a northern part of Abukuma Mountains, the highest total dose rates were estimated to be 50 and 15 μGy h(-1) for the adults and overwintering larvae, respectively. Growth and survival of H. lichenatus was not affected at a dose rate of up to 490 μGy h(-1) in the previous laboratory chronic gamma-irradiation experiment, and thus growth and survival of this salamander would not be affected, even in the most severely contaminated habitat in Fukushima Prefecture. However, further

  1. Loading mechanics of the femur in tiger salamanders (Ambystoma tigrinum) during terrestrial locomotion.

    PubMed

    Sheffield, K Megan; Blob, Richard W

    2011-08-01

    Salamanders are often used as representatives of the basal tetrapod body plan in functional studies, but little is known about the loads experienced by their limb bones during locomotion. Although salamanders' slow walking speeds might lead to low locomotor forces and limb bone stresses similar to those of non-avian reptiles, their highly sprawled posture combined with relatively small limb bones could produce elevated limb bone stresses closer to those of avian and mammalian species. This study evaluates the loads on the femur of the tiger salamander (Ambystoma tigrinum) during terrestrial locomotion using three-dimensional measurements of the ground reaction force (GRF) and hindlimb kinematics, as well as anatomical measurements of the femur and hindlimb muscles. At peak stress (29.8 ± 2.0% stance), the net GRF magnitude averaged 0.42 body weights and was directed nearly vertically for the middle 20-40% of the contact interval, essentially perpendicular to the femur. Although torsional shear stresses were significant (4.1 ± 0.3 MPa), bending stresses experienced by the femur were low compared with other vertebrate lineages (tensile: 14.9 ± 0.8 MPa; compressive: -18.9 ± 1.0 MPa), and mechanical property tests indicated yield strengths that were fairly standard for tetrapods (157.1 ± 3.7 MPa). Femoral bending safety factors (10.5) were considerably higher than values typical for birds and mammals, and closer to the elevated values calculated for reptilian species. These results suggest that high limb bone safety factors may have an ancient evolutionary history, though the underlying cause of high safety factors (e.g. low limb bone loads, high bone strength or a combination of the two) may vary among lineages.

  2. A salamander's flexible spinal network for locomotion, modeled at two levels of abstraction.

    PubMed

    Knüsel, Jeremie; Bicanski, Andrej; Ryczko, Dimitri; Cabelguen, Jean-Marie; Ijspeert, Auke Jan

    2013-08-01

    Animals have to coordinate a large number of muscles in different ways to efficiently move at various speeds and in different and complex environments. This coordination is in large part based on central pattern generators (CPGs). These neural networks are capable of producing complex rhythmic patterns when activated and modulated by relatively simple control signals. Although the generation of particular gaits by CPGs has been successfully modeled at many levels of abstraction, the principles underlying the generation and selection of a diversity of patterns of coordination in a single neural network are still not well understood. The present work specifically addresses the flexibility of the spinal locomotor networks in salamanders. We compare an abstract oscillator model and a CPG network composed of integrate-and-fire neurons, according to their ability to account for different axial patterns of coordination, and in particular the transition in gait between swimming and stepping modes. The topology of the network is inspired by models of the lamprey CPG, complemented by additions based on experimental data from isolated spinal cords of salamanders. Oscillatory centers of the limbs are included in a way that preserves the flexibility of the axial network. Similarly to the selection of forward and backward swimming in lamprey models via different excitation to the first axial segment, we can account for the modification of the axial coordination pattern between swimming and forward stepping on land in the salamander model, via different uncoupled frequencies in limb versus axial oscillators (for the same level of excitation). These results transfer partially to a more realistic model based on formal spiking neurons, and we discuss the difference between the abstract oscillator model and the model built with formal spiking neurons.

  3. Behavioral and physiological antipredator responses of the San Marcos salamander, Eurycea nana.

    PubMed

    Davis, Drew R; Gabor, Caitlin R

    2015-02-01

    Exposure to predatory stimuli typically results in the elevation of circulating glucocorticoid levels and a behavioral response of freezing or escape behavior in many prey species. Corticosterone (CORT) is the main glucocorticoid in amphibians and is known to be important in modulating many behaviors and developmental functions. The federally threatened San Marcos salamander, Eurycea nana, decreases activity in response to both native and introduced predatory fish, however, experience may further influence these interactions. To better understand the indirect effects of fish predators on this salamander, we examined both the antipredator behavior and water-borne CORT release rates in response to chemical cues (kairomones) from two fish species that varied in temporal risk of predation: (1) a low encounter frequency predator (largemouth bass, Micropterus salmoides), (2) a high encounter frequency predator (redbreast sunfish, Lepomis auritus), and (3) a blank water control. Salamanders reduced activity (antipredator response) after exposure to both predator treatments, but not to the blank water control, and the response to M. salmoides was significantly stronger than that to L. auritus. The CORT response (post-stimulus/pre-stimulus release rates) did not differ between the blank water control and L. auritus treatments, and both were significantly less than the CORT response to M. salmoides. Overall, E. nana showed a decreased antipredator response and no CORT response towards the high encounter frequency L. auritus as compared to the low encounter frequency M. salmoides. Eurycea nana may mute antipredator and CORT responses to high temporal frequency predators. There was, however, no correlation between CORT release rates and antipredator behavior, which suggests that the presence of predators may be affecting CORT response and behavior independently. PMID:25446225

  4. Using counts to simultaneously estimate abundance and detection probabilities in a salamander community

    USGS Publications Warehouse

    Dodd, C.K.; Dorazio, R.M.

    2004-01-01

    A critical variable in both ecological and conservation field studies is determining how many individuals of a species are present within a defined sampling area. Labor intensive techniques such as capture-mark-recapture and removal sampling may provide estimates of abundance, but there are many logistical constraints to their widespread application. Many studies on terrestrial and aquatic salamanders use counts as an index of abundance, assuming that detection remains constant while sampling. If this constancy is violated, determination of detection probabilities is critical to the accurate estimation of abundance. Recently, a model was developed that provides a statistical approach that allows abundance and detection to be estimated simultaneously from spatially and temporally replicated counts. We adapted this model to estimate these parameters for salamanders sampled over a six vear period in area-constrained plots in Great Smoky Mountains National Park. Estimates of salamander abundance varied among years, but annual changes in abundance did not vary uniformly among species. Except for one species, abundance estimates were not correlated with site covariates (elevation/soil and water pH, conductivity, air and water temperature). The uncertainty in the estimates was so large as to make correlations ineffectual in predicting which covariates might influence abundance. Detection probabilities also varied among species and sometimes among years for the six species examined. We found such a high degree of variation in our counts and in estimates of detection among species, sites, and years as to cast doubt upon the appropriateness of using count data to monitor population trends using a small number of area-constrained survey plots. Still, the model provided reasonable estimates of abundance that could make it useful in estimating population size from count surveys.

  5. Effects of temperature on muscle pHi and phosphate metabolites in newts and lungless salamanders.

    PubMed

    Johnson, D C; Burt, C T; Perng, W C; Hitzig, B M

    1993-11-01

    The effect of acute alterations in body temperature (BT) on intracellular pH (pHi) and phosphate metabolites was assessed in white skeletal muscle of intact newts and lungless red-backed salamanders using 31P-nuclear magnetic resonance spectroscopy. pHi decreased with increasing BT in the tail muscle of both newts and lungless red-backed salamanders. The change in pH with change in temperature from 10 to 30 degrees C was -0.018 U/degrees C in newts and -0.041 U/degrees C in red backs. The calculated alpha-imidazole for skeletal muscle cytosol did not change (0.56) in newts from 10 to 30 degrees C but fell from 0.69 to 0.43 in red-backed salamanders. Phosphocreatine (PCr)/Pi fell and Pi/beta-ATP rose with increasing temperature in both newts and red backs; however, the change was much greater in red backs. Providing the red backs with O2 at 30 degrees C led to higher pH and alpha-imidazole, comparable to that of newts, along with increased PCr/Pi and lower Pi/beta-ATP. Thus newts maintain white skeletal muscle cell cytosol alpha-imidazole constant with changes in BT, whereas red backs apparently do not. However, at the BT of preference, red backs and newts maintain similar muscle pHi and alpha-imidazole. The method of gas exchange appears to strongly influence the ability of an animal to maintain its acid-base status over a range of temperatures, and our results suggest that behavioral regulation of BT may involve alpha-imidazole regulation as well.

  6. The role of climate in the dynamics of a hybrid zone in Appalachian salamanders

    USGS Publications Warehouse

    Walls, S.C.

    2009-01-01

    I examined the potential influence of climate change on the dynamics of a previously studied hybrid zone between a pair of terrestrial salamanders at the Coweeta Hydrologic Laboratory, U.S. Forest Service, in the Nantahala Mountains of North Carolina, USA. A 16-year study led by Nelson G. Hairston, Sr. revealed that Plethodon teyahalee and Plethodon shermani hybridized at intermediate elevations, forming a cline between 'pure' parental P. teyahalee at lower elevations and 'pure' parental P. shermani at higher elevations. From 1974 to 1990 the proportion of salamanders at the higher elevation scored as 'pure' P. shermani declined significantly, indicating that the hybrid zone was spreading upward. To date there have been no rigorous tests of hypotheses for the movement of this hybrid zone. Using temperature and precipitation data from Coweeta, I re-analyzed Hairston's data to examine whether the observed elevational shift was correlated with variation in either air temperature or precipitation from the same time period. For temperature, my analysis tracked the results of the original study: the proportion of 'pure' P. shermani at the higher elevation declined significantly with increasing mean annual temperature, whereas the proportion of 'pure' P. teyahalee at lower elevations did not. There was no discernable relationship between proportions of 'pure' individuals of either species with variation in precipitation. From 1974 to 1990, low-elevation air temperatures at the Coweeta Laboratory ranged from annual means of 11.8 to 14.2??C, compared with a 55-year average (1936-1990) of 12.6??C. My re-analyses indicate that the upward spread of the hybrid zone is correlated with increasing air temperatures, but not precipitation, and provide an empirical test of a hypothesis for one factor that may have influenced this movement. My results aid in understanding the potential impact that climate change may have on the ecology and evolution of terrestrial salamanders in

  7. The role of climate in the dynamics of a hybrid zone in Appalachian salamanders

    USGS Publications Warehouse

    Walls, Susan

    2009-01-01

    I examined the potential influence of climate change on the dynamics of a previously studied hybrid zone between a pair of terrestrial salamanders at the Coweeta Hydrologic Laboratory, U.S. Forest Service, in the Nantahala Mountains of North Carolina, USA. A 16-year study led by Nelson G. Hairston, Sr. revealed that Plethodon teyahalee and Plethodon shermani hybridized at intermediate elevations, forming a cline between 'pure' parental P. teyahalee at lower elevations and 'pure' parental P. shermani at higher elevations. From 1974 to 1990 the proportion of salamanders at the higher elevation scored as 'pure' P. shermani declined significantly, indicating that the hybrid zone was spreading upward. To date there have been no rigorous tests of hypotheses for the movement of this hybrid zone. Using temperature and precipitation data from Coweeta, I re-analyzed Hairston's data to examine whether the observed elevational shift was correlated with variation in either air temperature or precipitation from the same time period. For temperature, my analysis tracked the results of the original study: the proportion of 'pure' P. shermani at the higher elevation declined significantly with increasing mean annual temperature, whereas the proportion of 'pure' P. teyahalee at lower elevations did not. There was no discernable relationship between proportions of 'pure' individuals of either species with variation in precipitation. From 1974 to 1990, low-elevation air temperatures at the Coweeta Laboratory ranged from annual means of 11.8 to 14.2 °C, compared with a 55-year average (1936-1990) of 12.6 °C. My re-analyses indicate that the upward spread of the hybrid zone is correlated with increasing air temperatures, but not precipitation, and provide an empirical test of a hypothesis for one factor that may have influenced this movement. My results aid in understanding the potential impact that climate change may have on the ecology and evolution of terrestrial salamanders in

  8. Elevational differences in trait response to UV-B radiation by long-toed salamander populations.

    PubMed

    Thurman, Lindsey L; Garcia, Tiffany S; Hoffman, Peter D

    2014-07-01

    Amphibian species capable of optimizing trait response to environmental stressors may develop complex strategies for defending against rapid environmental change. Trait responses may differ between populations, particularly if stressor strength varies across spatial or temporal gradients. Ultraviolet-B (UV-B) radiation is one such stressor that poses a significant threat to amphibian species. We examined the ability of long-toed salamanders (Ambystoma macrodactylum) at high- and low-elevation breeding sites to cooperatively employ behavioral and physiological trait responses to mediate UV-B damage. We performed a microhabitat survey to examine differences in oviposition behavior and UV-B conditions among breeding populations at high- (n = 3; >1,500 m) and low-elevation (n = 3; <100 m) sites. We found significant differences in oviposition behavior across populations, with females at high-elevation sites selecting oviposition substrates in UV-B protected microhabitats. We also collected eggs (n = 633) from each of the breeding sites for analysis of photolyase activity, a photoreactivating enzyme that repairs UV-B damage to the DNA, using a photoproduct immunoassay. Our results revealed no significant differences in photolyase activity between long-toed salamander populations at high and low elevations. For high-elevation salamander populations, relatively low physiological repair capabilities in embryos appear to be buffered by extensive behavioral modifications to reduce UV-B exposure and standardize developmental temperatures. This study provides valuable insight into environmental stress responses via the assessment of multiple traits in allowing sensitive species to persist in rapidly changing landscapes.

  9. Behavioral and physiological antipredator responses of the San Marcos salamander, Eurycea nana.

    PubMed

    Davis, Drew R; Gabor, Caitlin R

    2015-02-01

    Exposure to predatory stimuli typically results in the elevation of circulating glucocorticoid levels and a behavioral response of freezing or escape behavior in many prey species. Corticosterone (CORT) is the main glucocorticoid in amphibians and is known to be important in modulating many behaviors and developmental functions. The federally threatened San Marcos salamander, Eurycea nana, decreases activity in response to both native and introduced predatory fish, however, experience may further influence these interactions. To better understand the indirect effects of fish predators on this salamander, we examined both the antipredator behavior and water-borne CORT release rates in response to chemical cues (kairomones) from two fish species that varied in temporal risk of predation: (1) a low encounter frequency predator (largemouth bass, Micropterus salmoides), (2) a high encounter frequency predator (redbreast sunfish, Lepomis auritus), and (3) a blank water control. Salamanders reduced activity (antipredator response) after exposure to both predator treatments, but not to the blank water control, and the response to M. salmoides was significantly stronger than that to L. auritus. The CORT response (post-stimulus/pre-stimulus release rates) did not differ between the blank water control and L. auritus treatments, and both were significantly less than the CORT response to M. salmoides. Overall, E. nana showed a decreased antipredator response and no CORT response towards the high encounter frequency L. auritus as compared to the low encounter frequency M. salmoides. Eurycea nana may mute antipredator and CORT responses to high temporal frequency predators. There was, however, no correlation between CORT release rates and antipredator behavior, which suggests that the presence of predators may be affecting CORT response and behavior independently.

  10. Catastrophic reproductive failure, terrestrial survival, and persistence of the marbled salamander.

    PubMed

    Taylor, Barbara E; Scott, David E; Gibbons, J Whitfield

    2006-06-01

    Wide variation in reproductive success is common among amphibians that breed in seasonal ponds, but persistence of adults can buffer against these fluctuations, particularly for long-lived species. We hypothesized that the frequent episodes of catastrophic failure of the marbled salamander (Ambystoma opacum) enhance the importance of high terrestrial survival. At Rainbow Bay in South Carolina reproductive success was poor (< 1 metamorph/breeding female) in nearly half of the 22 years that the species bred. Complete failure occurred in 6 of 22 years. To study catastrophic failure, we adapted an age-structured, individual-based model with density-dependent growth and survival of larvae. The model was based on extensive data from local field studies and experiments. With consistently good survival in the pond stages, the simulated population required survival probabilities in the upland stages (juveniles and adults) near 0.5/year to persist and near 0.8/year to achieve the increases observed. Catastrophic failure, occurring randomly with probability 0.5/year created additional fluctuations in the population, raised the thresholds of survival required for persistence, and caused extinction under conditions that were otherwise favorable. The marbled salamander at Rainbow Bay is not at great risk of extinction because of catastrophic failure, but the risk increases dramatically if life span is decreased or frequency of failure is increased. Any reduction in terrestrial survival will have deleterious consequences by reducing the breeding populations at equilibrium, even if it does not jeopardize persistence. Our model provides assessments of risk that can be applied to poorly studied species with similar life histories, such as the endangered flatwoods salamander (A. cingulatum). PMID:16909572

  11. Elevational differences in trait response to UV-B radiation by long-toed salamander populations.

    PubMed

    Thurman, Lindsey L; Garcia, Tiffany S; Hoffman, Peter D

    2014-07-01

    Amphibian species capable of optimizing trait response to environmental stressors may develop complex strategies for defending against rapid environmental change. Trait responses may differ between populations, particularly if stressor strength varies across spatial or temporal gradients. Ultraviolet-B (UV-B) radiation is one such stressor that poses a significant threat to amphibian species. We examined the ability of long-toed salamanders (Ambystoma macrodactylum) at high- and low-elevation breeding sites to cooperatively employ behavioral and physiological trait responses to mediate UV-B damage. We performed a microhabitat survey to examine differences in oviposition behavior and UV-B conditions among breeding populations at high- (n = 3; >1,500 m) and low-elevation (n = 3; <100 m) sites. We found significant differences in oviposition behavior across populations, with females at high-elevation sites selecting oviposition substrates in UV-B protected microhabitats. We also collected eggs (n = 633) from each of the breeding sites for analysis of photolyase activity, a photoreactivating enzyme that repairs UV-B damage to the DNA, using a photoproduct immunoassay. Our results revealed no significant differences in photolyase activity between long-toed salamander populations at high and low elevations. For high-elevation salamander populations, relatively low physiological repair capabilities in embryos appear to be buffered by extensive behavioral modifications to reduce UV-B exposure and standardize developmental temperatures. This study provides valuable insight into environmental stress responses via the assessment of multiple traits in allowing sensitive species to persist in rapidly changing landscapes. PMID:24833287

  12. Twisting and bending: the functional role of salamander lateral hypaxial musculature during locomotion.

    PubMed

    Bennett, W O; Simons, R S; Brainerd, E L

    2001-06-01

    The function of the lateral hypaxial muscles during locomotion in tetrapods is controversial. Currently, there are two hypotheses of lateral hypaxial muscle function. The first, supported by electromyographic (EMG) data from a lizard (Iguana iguana) and a salamander (Dicamptodon ensatus), suggests that hypaxial muscles function to bend the body during swimming and to resist long-axis torsion during walking. The second, supported by EMG data from lizards during relatively high-speed locomotion, suggests that these muscles function primarily to bend the body during locomotion, not to resist torsional forces. To determine whether the results from D. ensatus hold for another salamander, we recorded lateral hypaxial muscle EMGs synchronized with body and limb kinematics in the tiger salamander Ambystoma tigrinum. In agreement with results from aquatic locomotion in D. ensatus, all four layers of lateral hypaxial musculature were found to show synchronous EMG activity during swimming in A. tigrinum. Our findings for terrestrial locomotion also agree with previous results from D. ensatus and support the torsion resistance hypothesis for terrestrial locomotion. We observed asynchronous EMG bursts of relatively high intensity in the lateral and medial pairs of hypaxial muscles during walking in tiger salamanders (we call these 'alpha-bursts'). We infer from this pattern that the more lateral two layers of oblique hypaxial musculature, Mm. obliquus externus superficialis (OES) and obliquus externus profundus (OEP), are active on the side towards which the trunk is bending, while the more medial two layers, Mm. obliquus internus (OI) and transversus abdominis (TA), are active on the opposite side. This result is consistent with the hypothesis proposed for D. ensatus that the OES and OEP generate torsional moments to counteract ground reaction forces generated by forelimb support, while the OI and TA generate torsional moments to counteract ground reaction forces from hindlimb

  13. A new species of lentic breeding Korean salamander of the genus Hynobius (Amphibia, Urodela).

    PubMed

    Kim, Jong-Bum; Min, Mi-Sook; Matsui, Masafumi

    2003-09-01

    A new species of salamander, Hynobius yangi, is described from Kori (=Hyoam-ri), Busan-shi, southeastern Korea. It is a lentic breeder belonging to the H. nebulosus species group, and has long been confused with another Korean species H. leechii. The new species, however, is genetically substantially differentiated from Korean and Japanese relatives. Hynobius yangi is morphologically very similar to H. leechii, but could be differentiated from it by the tail shape, degree of limb separation, shape of vomerine teeth series, shape of egg sac, and dorsal coloration. PMID:14578577

  14. Role of habitat complexity in predator-prey dynamics between an introduced fish and larval Long-toed Salamanders (Ambystoma macrodactylum)

    USGS Publications Warehouse

    Kenison, Erin K; Litt, Andrea R.; Pilliod, David; McMahon, Tom E

    2016-01-01

    Predation by nonnative fishes has reduced abundance and increased extinction risk for amphibian populations worldwide. Although rare, fish and palatable amphibians have been observed to coexist where aquatic vegetation and structural complexity provide suitable refugia. We examined whether larval long-toed salamanders (Ambystoma macrodactylum Baird, 1849) increased use of vegetation cover in lakes with trout and whether adding vegetation structure could reduce predation risk and nonconsumptive effects (NCEs), such as reductions in body size and delayed metamorphosis. We compared use of vegetation cover by larval salamanders in lakes with and without trout and conducted a field experiment to investigate the influence of added vegetation structure on salamander body morphology and life history. The probability of catching salamanders in traps in lakes with trout was positively correlated with the proportion of submerged vegetation and surface cover. Growth rates of salamanders in enclosures with trout cues decreased as much as 85% and the probability of metamorphosis decreased by 56%. We did not find evidence that adding vegetation reduced NCEs in experimental enclosures, but salamanders in lakes with trout utilized more highly-vegetated areas which suggests that adding vegetation structure at the scale of the whole lake may facilitate coexistence between salamanders and introduced trout.

  15. Mitochondrial Dysfunction Meets Senescence.

    PubMed

    Gallage, Suchira; Gil, Jesús

    2016-03-01

    Cellular senescence and mitochondrial dysfunction are hallmarks of ageing, but until now their relationship has not been clear. Recent work by Wiley et al. shows that mitochondrial defects can cause a distinct senescence phenotype termed MiDAS (mitochondrial dysfunction-associated senescence). MiDAS has a specific secretome that is able to drive some of the aging phenotypes. These findings suggest novel therapeutic opportunities for treating age-related pathologies. PMID:26874922

  16. MYC and Mitochondrial Biogenesis

    PubMed Central

    Morrish, Fionnuala; Hockenbery, David

    2014-01-01

    Mitochondria, the powerhouses of the cell, face two imperatives concerning biogenesis. The first is the requirement for dividing cells to replicate their mitochondrial content by growth of existing mitochondria. The second is the dynamic regulation of mitochondrial content in response to organismal and cellular cues (e.g., exercise, caloric restriction, energy status, temperature). MYC provides the clearest example of a programmed expansion of mitochondrial content linked to the cell cycle. As an oncogene, MYC also presents intriguing questions about the role of its mitochondrial targets in cancer-related phenotypes, such as the Warburg effect and MYC-dependent apoptosis. PMID:24789872

  17. Linking the evolution of habitat choice to ecosystem functioning: direct and indirect effects of pond-reproducing fire salamanders on aquatic-terrestrial subsidies.

    PubMed

    Reinhardt, Timm; Steinfartz, Sebastian; Paetzold, Achim; Weitere, Markus

    2013-09-01

    Shifts in life history traits and in the behaviour of species can potentially alter ecosystem functioning. The reproduction of the central European fire salamander (Salamandra salamandra), which usually deposits its larvae in first-order streams, in small pool and pond-like habitats, is an example of a recent local adaptation in this species. Here we aimed to quantify the direct and indirect effects of the predatory larvae on the aquatic food webs in the ponds and on the flux of matter between the ponds and adjacent terrestrial habitats. Our estimates are based on biomass data of the present pond fauna as well as on the analysis of stomach content data, growth rates and population dynamics of the salamander larvae in pond habitats. By their deposition of larvae in early spring, female fire salamanders import between 0.07 and 2.86 g dry mass m(-2) larval biomass into the ponds. Due to high mortality rates in the larval phase and the relatively small size at metamorphosis of the pond-adapted salamanders compared to stream-adapted ones, the biomass export of the metamorphosed salamanders clearly falls below the initial biomass import. Catastrophic events such as high water temperatures and low oxygen levels may even occasionally result in mass mortalities of salamander larvae and thus in a net 100 % import of the salamander biomass into the pond food webs. Indirect effects further accelerate this net import of matter into the aquatic habitat, e.g. the feeding of salamanders on aquatic insect larvae with the emergence of terrestrial adults-thus preventing export-and on terrestrial organisms that fall on the water surface (supporting import). This study demonstrates that the adaptation of salamanders to pond reproduction can alter food web linkages across ecosystem boundaries by enhancing the flux of materials and energy from terrestrial (i.e. forest) to the aquatic (i.e. pond) habitat.

  18. Persistence and extirpation in invaded landscapes: patch characteristics and connectivity determine effects of non-native predatory fish on native salamanders

    USGS Publications Warehouse

    Pilliod, David S.; Arkle, Robert S.; Maxell, Bryce A.

    2012-01-01

    Studies have demonstrated negative effects of non-native, predatory fishes on native amphibians, yet it is still unclear why some amphibian populations persist, while others are extirpated, following fish invasion. We examined this question by developing habitat-based occupancy models for the long-toed salamander (Ambystoma macrodactylum) and nonnative fish using survey data from 1,749 water bodies across 470 catchments in the Northern Rocky Mountains, USA. We first modeled the habitat associations of salamanders at 468 fishless water bodies in 154 catchments where non-native fish were historically, and are currently, absent from the entire catchment. Wethen applied this habitat model to the complete data set to predict the probability of salamander occupancy in each water body, removing any effect of fish presence. Finally, we compared field-observed occurrences of salamanders and fish to modeled probability of salamander occupancy. Suitability models indicated that fish and salamanders had similar habitat preferences, possibly resulting in extirpations of salamander populations from entire catchments where suitable habitats were limiting. Salamanders coexisted with non-native fish in some catchments by using marginal quality, isolated (no inlet or outlet) habitats that remained fishless. They rarely coexisted with fish within individual water bodies and only where habitat quality was highest. Connectivity of water bodies via streams resulted in increased probability of fish invasion and consequently reduced probability of salamander occupancy.These results could be used to identify and prioritize catchments and water bodies where control measures would be most effective at restoring amphibian populations. Our approach could be useful as a framework for improved investigations into questions of persistence and extirpation of native species when non-native species have already become established.

  19. An additional discovery of salamanders, Salamandrella keyserlingii Dybowski, with no blood vessels in the brain parenchyma except in the olfactory bulb.

    PubMed

    Takahashi, K; Ninomiya, T

    1992-03-01

    The brain parenchyma of Salamandrella keyserlingii Dybowski (SKD) is not vascularized except in the olfactory bulb. In the brains of SKD, neuronal and glial perikarya are seen densely aggregated at the periventricular regions and no blood vessels enter the brain parenchyma from the meningeal vessels. Former investigators have discovered no blood vessels in the brains of nine species of salamanders in the Hynobiidae, all of which inhabit Japan. This report adds one more avascular species of salamander which is found in Hokkaido, Japan. The reasons why the brain of Hynobiid salamanders is not vascularized and why only the olfactory bulbs are vascularized cannot be speculated on at the present time.

  20. Feeding Preferences of the Larval Southern Two-Lined Salamander, Eurycea Cirrigera, in an Impacted Agricultural Area, Southwest Georgia.

    NASA Astrophysics Data System (ADS)

    Muenz, T. K.; Golladay, S. W.; Smith, L. L.; Vellidis, G.

    2005-05-01

    Feeding preference of the stream-dwelling Southern Two-lined Salamander, Eurycea cirrigera, was examined in streams affected by agricultural practices in southwest Georgia. Larvae were collected within bimonthly benthic macroinvertebrate samples from February 2002 to February 2003. Five stream reaches were sampled, two of which were fenced from cattle and three allowed cattle access. Forty larvae were recovered from the invertebrate collections, with significantly higher captures at fenced sites than unfenced sites. The entire digestive tract was removed from larvae and stomach contents were examined to better understand prey selection in streams with differing intensities of adjacent agricultural land-use. Invertebrates were enumerated in 34 salamander stomachs, with Chironomidae comprising the largest percentage of individuals found, both in stomach contents and habitat collections. Electivity values showed a wide range of variability among individual salamanders, however, overall indices suggest slight positive selection for a subfamily of the Chironomidae, the Tanypodinae. It appears that E.cirrigera larvae select for Tanypodinae, however, this invertebrate group was found at all stream sites, suggesting factors other than prey abundance, such as stream habitat quality, may also influence larval salamander abundance.

  1. Transcriptome analysis of the endangered Chinese giant salamander (Andrias davidianus): Immune modulation in response to Aeromonas hydrophila infection.

    PubMed

    Qi, Zhitao; Zhang, Qihuan; Wang, Zisheng; Ma, Tianyi; Zhou, Jie; Holland, Jason W; Gao, Qian

    2016-01-01

    The endangered Chinese giant salamander (Andrias davidianus) is the largest extant amphibian species. Disease outbreaks represent one of the major factors threatening A. davidianus populations in the wild and the viability of artificial breeding programmes. Development of future immune therapies to eliminate infectious disease in A. davidianus is dependent on a thorough understanding of the immune mechanisms elicited by pathogen encounters. To this end we have undertaken, for the first time in amphibians, differential transcriptome analysis of the giant salamander response to Aeromonas hydrophila, one of the most devastating pathogens affecting amphibian populations. Out of 87,204 non-redundant consensus unigenes 19,216 were annotated, 6834 of which were upregulated and 906 down-regulated following bacterial infection. 2058 unigenes were involved with immune system processes, including 287 differentially expressed unigenes indicative of the impact of bacterial infection on several innate and adaptive immune pathways in the giant salamander. Other pathways not directly associated with immune-related activity were differentially expressed, including developmental, structural, molecular and growth processes. Overall, this work provides valuable insights into the underlying immune mechanisms elicited during bacterial infection in amphibians that may aid in the future development of disease control measures in protecting the Chinese giant salamander. With the unique position of amphibians in the transition of tetrapods from aquatic to terrestrial habitats, our study will also be invaluable towards the further understanding of the evolution of tetrapod immunity.

  2. 76 FR 55413 - Proposed Safe Harbor Agreement for California Red-legged Frog, California Tiger Salamander, Smith...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Register on June 17, 1999 (64 FR 32717), the Service would issue a permit to the Applicant authorizing take... Tiger Salamander, Smith's Blue Butterfly, and Yadon's Piperia at Palo Corona Regional Park, Monterey... californiense) and federally endangered Smith's blue butterfly (Euphilotes enoptes smithi) under the...

  3. Successful treatment of Batrachochytrium salamandrivorans infections in salamanders requires synergy between voriconazole, polymyxin E and temperature.

    PubMed

    Blooi, M; Pasmans, F; Rouffaer, L; Haesebrouck, F; Vercammen, F; Martel, A

    2015-06-30

    Chytridiomycosis caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) poses a serious threat to urodelan diversity worldwide. Antimycotic treatment of this disease using protocols developed for the related fungus Batrachochytrium dendrobatidis (Bd), results in therapeutic failure. Here, we reveal that this therapeutic failure is partly due to different minimum inhibitory concentrations (MICs) of antimycotics against Bsal and Bd. In vitro growth inhibition of Bsal occurs after exposure to voriconazole, polymyxin E, itraconazole and terbinafine but not to florfenicol. Synergistic effects between polymyxin E and voriconazole or itraconazole significantly decreased the combined MICs necessary to inhibit Bsal growth. Topical treatment of infected fire salamanders (Salamandra salamandra), with voriconazole or itraconazole alone (12.5 μg/ml and 0.6 μg/ml respectively) or in combination with polymyxin E (2000 IU/ml) at an ambient temperature of 15 °C during 10 days decreased fungal loads but did not clear Bsal infections. However, topical treatment of Bsal infected animals with a combination of polymyxin E (2000 IU/ml) and voriconazole (12.5 μg/ml) at an ambient temperature of 20 °C resulted in clearance of Bsal infections. This treatment protocol was validated in 12 fire salamanders infected with Bsal during a field outbreak and resulted in clearance of infection in all animals.

  4. Successful treatment of Batrachochytrium salamandrivorans infections in salamanders requires synergy between voriconazole, polymyxin E and temperature

    PubMed Central

    Blooi, M.; Pasmans, F.; Rouffaer, L.; Haesebrouck, F.; Vercammen, F.; Martel, A.

    2015-01-01

    Chytridiomycosis caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) poses a serious threat to urodelan diversity worldwide. Antimycotic treatment of this disease using protocols developed for the related fungus Batrachochytrium dendrobatidis (Bd), results in therapeutic failure. Here, we reveal that this therapeutic failure is partly due to different minimum inhibitory concentrations (MICs) of antimycotics against Bsal and Bd. In vitro growth inhibition of Bsal occurs after exposure to voriconazole, polymyxin E, itraconazole and terbinafine but not to florfenicol. Synergistic effects between polymyxin E and voriconazole or itraconazole significantly decreased the combined MICs necessary to inhibit Bsal growth. Topical treatment of infected fire salamanders (Salamandra salamandra), with voriconazole or itraconazole alone (12.5 μg/ml and 0.6 μg/ml respectively) or in combination with polymyxin E (2000 IU/ml) at an ambient temperature of 15 °C during 10 days decreased fungal loads but did not clear Bsal infections. However, topical treatment of Bsal infected animals with a combination of polymyxin E (2000 IU/ml) and voriconazole (12.5 μg/ml) at an ambient temperature of 20 °C resulted in clearance of Bsal infections. This treatment protocol was validated in 12 fire salamanders infected with Bsal during a field outbreak and resulted in clearance of infection in all animals. PMID:26123899

  5. Computer-assisted photo identification outperforms visible implant elastomers in an endangered salamander, Eurycea tonkawae.

    PubMed

    Bendik, Nathan F; Morrison, Thomas A; Gluesenkamp, Andrew G; Sanders, Mark S; O'Donnell, Lisa J

    2013-01-01

    Despite recognition that nearly one-third of the 6300 amphibian species are threatened with extinction, our understanding of the general ecology and population status of many amphibians is relatively poor. A widely-used method for monitoring amphibians involves injecting captured individuals with unique combinations of colored visible implant elastomer (VIE). We compared VIE identification to a less-invasive method - computer-assisted photographic identification (photoID) - in endangered Jollyville Plateau salamanders (Eurycea tonkawae), a species with a known range limited to eight stream drainages in central Texas. We based photoID on the unique pigmentation patterns on the dorsal head region of 1215 individual salamanders using identification software Wild-ID. We compared the performance of photoID methods to VIEs using both 'high-quality' and 'low-quality' images, which were taken using two different camera types and technologies. For high-quality images, the photoID method had a false rejection rate of 0.76% compared to 1.90% for VIEs. Using a comparable dataset of lower-quality images, the false rejection rate was much higher (15.9%). Photo matching scores were negatively correlated with time between captures, suggesting that evolving natural marks could increase misidentification rates in longer term capture-recapture studies. Our study demonstrates the utility of large-scale capture-recapture using photo identification methods for Eurycea and other species with stable natural marks that can be reliably photographed. PMID:23555669

  6. Purification and characterization of cholecystokinin from the skin of salamander Tylototriton verrucosus.

    PubMed

    Jiang, Wen-Bin; Hakim, Ma; Luo, Lei; Li, Bo-Wen; Yang, Shi-Long; Song, Yu-Zhu; Lai, Ren; Lu, Qiu-Min

    2015-05-18

    As a group of intestinal hormones and neurotransmitters, cholecystokinins (CCKs) regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A cDNA encoding the CCK precursor containing 129 amino acid residues was cloned from the cDNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0 x 10⁻¹¹ mol/L and inducing maximal contraction at a concentration of 2.0 x 10⁻⁶ mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian. PMID:26018861

  7. Kinetics of inert gas equilibration in an exclusively skin-breathing salamander, Desmognathus fuscus.

    PubMed

    Gatz, R N; Crawford, E C; Piiper, J

    1975-06-01

    Characteristics of cutaneous gas exchange in amphibians were studied by analysis of the equilibration kinetics of an inert test gas in salamanders which have neither lungs nor gills. Specimens of the common dusky salamander (Desmognathus fuscus, Plethodontidae, Urodela), average body mass 6.1 g were equilibrated with 20% chlorodifluoromethane (Freon 22) in oxygen. The time course of subsequent elimination of Freon 22 into atmospheric air was more rapid in living than in dead animals. This difference was attributed to convective transport by blood flow. Several alternative models were proposed, providing a basis for quantitative analysis of the data. All models yielded similar values for convective conductance due to blood flow. In order to calculate blood flow therefrom, a simplified circulation model based on anatomical evidence was used: the cardiac output is in part directed to the skin, subserving gas exchange with the environment, and in part to the internal organs; the blood returning from both skin and internal organs is mixed before reaching the heart. Depending on assumptions regarding the model and the partitioning of blood flow to the skin and to internal organs, the following range of values was calculated from the experimental data: cardiac output, 85-195 mul/(min-g body mass); cutaneous blood flow, 27-63 mul/(min-g body mass). Due to inherent assumptions these values must be considered minimum estimates.

  8. Tuataras and salamanders show that walking and running mechanics are ancient features of tetrapod locomotion.

    PubMed

    Reilly, Stephen M; McElroy, Eric J; Andrew Odum, R; Hornyak, Valerie A

    2006-06-22

    The lumbering locomotor behaviours of tuataras and salamanders are the best examples of quadrupedal locomotion of early terrestrial vertebrates. We show they use the same walking (out-of-phase) and running (in-phase) patterns of external mechanical energy fluctuations of the centre-of-mass known in fast moving (cursorial) animals. Thus, walking and running centre-of-mass mechanics have been a feature of tetrapods since quadrupedal locomotion emerged over 400 million years ago. When walking, these sprawling animals save external mechanical energy with the same pendular effectiveness observed in cursorial animals. However, unlike cursorial animals (that change footfall patterns and mechanics with speed), tuataras and salamanders use only diagonal couplet gaits and indifferently change from walking to running mechanics with no significant change in total mechanical energy. Thus, the change from walking to running is not related to speed and the advantage of walking versus running is unclear. Furthermore, lumbering mechanics in primitive tetrapods is reflected in having total mechanical energy driven by potential energy (rather than kinetic energy as in cursorial animals) and relative centre-of-mass displacements an order of magnitude greater than cursorial animals. Thus, large vertical displacements associated with lumbering locomotion in primitive tetrapods may preclude their ability to increase speed.

  9. Coalescence patterns of endemic Tibetan species of stream salamanders (Hynobiidae: Batrachuperus).

    PubMed

    Lu, Bin; Zheng, Yuchi; Murphy, Robert W; Zeng, Xiaomao

    2012-07-01

    Orogenesis of topographically diverse montane regions often drives complex evolutionary histories of species. The extensive biodiversity of the eastern edge of the Tibetan Plateau, which gradually decreases eastwardly, facilitates a comparison of historical patterns. We use coalescence methods to compare species of stream salamanders (Batrachuperus) that occur at high and low elevations. Coalescent simulations reveal that closely related species are likely to have been influenced by different drivers of diversification. Species living in the western high-elevation region with its northsouth extending mountains appear to have experienced colonization via dispersal followed by isolation and divergence. In contrast, species on the eastern low-elevation region, which has many discontinuous mountain ranges, appear to have experienced fragmentation, sometimes staged, of wide-ranging ancestral populations. The two groups of species appear to have been affected differently by glaciation. High-elevation species, which are more resistant to cooler temperatures, appear to have experienced population declines as recently as the last glaciation (0.016-0.032Ma). In contrast, salamanders dwelling in the warmer and wetter habitats at low-elevation environs appear to have been affected less by the relatively recent, milder glaciation, and more so by harsher, extensive glaciations (0.5-0.175 Ma). Thus, elevation, topography and cold tolerance appear to drive evolutionary patterns of diversification and demography even among closely related taxa. The comparison of multiple species in genealogical analyses can lead to an understanding of the evolutionary drivers. PMID:22571598

  10. Cutaneous mastocytomas in the neotenic caudate amphibians Ambystoma mexicanum (axolotl) and Ambystoma tigrinum (tiger salamander).

    PubMed

    Harshbarger, J C; Chang, S C; DeLanney, L E; Rose, F L; Green, D E

    1999-01-01

    Spontaneous mastocytomas studied in 18 axolotls (Ambystoma mexicanum) and six tiger salamanders (Ambystoma tigrinum) were gray-white, uni- to multilobular cutaneous protrusions from 2 mm to 2 cm in diameter. Tumors were moderately cellular unencapsulated masses that usually infiltrated the dermis and hypodermis with the destruction of intervening tissues. Some tumors were invading superficial bundles of the underlying skeletal muscle. Tumors consisted of mitotically active cells derived from a single lineage but showing a range of differentiation. Immature cells had nearly smooth to lightly cleft or folded basophilic nuclei bordered by a band of cytoplasm with few cytoplasmic processes and containing a few small uniform eccentric granules. Mature cells had basophilic nuclei with deep clefts or folds and abundant eosinophilic cytoplasm with multiple long intertwining cytoplasmic extensions packed with metachromatic granules. The axolotls were old individuals from an inbred laboratory colony. The tiger salamanders were wild animals from a single polluted pond. They could have been old and inbred. Both groups were neotenic. These are the first mastocytomas discovered in cold-blooded animals.

  11. Amino acid sequences of lower vertebrate parvalbumins and their evolution: parvalbumins of boa, turtle, and salamander.

    PubMed

    Maeda, N; Zhu, D X; Fitch, W M

    1984-11-01

    One major parvalbumin each was isolated from the skeletal muscle of two reptiles, a boa snake, Boa constrictor, and a map turtle, Graptemys geographica, while two parvalbumins were isolated from an amphibian, the salamander Amphiuma means. The amino acid sequences of all four parvalbumins were determined from the sequences of their tryptic peptides, which were ordered partially by homology to other parvalbumins. Phylogenetic study of these and 16 other parvalbumin sequences revealed that the turtle parvalbumin belongs to beta lineage, while the salamander sequences belong, one each, to the alpha and beta lineages defined by Goodman and Pechère (1977). Boa parvalbumin, however, while belonging to the beta lineage, clusters within the fish in all reasonably parsimonious trees. The most parsimonious trees show many parallel or back mutations in the evolution of many parvalbumin residues, although the residues responsible for Ca2+ binding are very well conserved. These most parsimonious trees show an actinopterygian rather than a crossoptyrigian origin of the tetrapods in both the alpha and beta groups. One of two electric eel parvalbumins is evolving more than 10 times faster than its paralogous partner, suggesting it may be on its way to becoming a pseudogene. It is concluded that varying rates of amino acid replacement, much homoplasy, considerable gene duplication, plus complicated lineages make the set of parvalbumin sequences unsuitable for systematic study of the origin of the tetrapods and other higher-taxa divergence, although it may be suitable within a genus or family.

  12. Toxicological responses of red-backed salamanders (Plethodon cinereus) to soil exposures of copper.

    PubMed

    Bazar, Matthew A; Quinn, Michael J; Mozzachio, Kristie; Bleiler, John A; Archer, Christine R; Phillips, Carlton T; Johnson, Mark S

    2009-07-01

    Copper (Cu) has widespread military use in munitions and small arms, particularly as a protective jacket for lead projectiles. The distribution of Cu at many US military sites is substantial and sites of contamination include habitats in and around military storage facilities, manufacturing, load and packing plants, open burning/open detonation areas, and firing ranges. Some of these areas include habitat for amphibian species, which generally lack toxicity data for risk assessment purposes. In an effort to ascertain Cu concentrations in soil that are toxic to terrestrial amphibians, 100 red-backed salamanders (Plethodon cinereus) were randomly sorted by weight, assigned to either a control soil or one of four treatments amended with copper acetate in soil, and exposed for 28 days. Analytical mean soil concentrations were 18, 283, 803, 1333, and 2700 mg Cu/kg soil dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Survival was reduced in salamanders exposed to 1333 and 2700 mg/kg by 55% and 100%, respectively. Mortality/morbidity occurred within the first 4 days of exposure. These data suggest that a Cu soil concentration of and exceeding 1333.3 +/- 120.2 mg/kg results in reduced survival, whereas hematology analyses suggest that a concentration of and exceeding 803.3 +/- 98.4 mg/kg might result in reduced total white blood cell count. No effects were observed at 283.3 +/- 36.7 mg/kg.

  13. Avian, salamander, and forest floor mercury concentrations increase with elevation in a terrestrial ecosystem.

    PubMed

    Townsend, Jason M; Driscoll, Charles T; Rimmer, Christopher C; McFarland, Kent P

    2014-01-01

    High-elevation ecosystems of the northeastern United States are vulnerable to deposition and environmental accumulation of atmospheric pollutants, yet little work has been done to assess mercury (Hg) concentrations in organisms occupying montane ecosystems. The authors present data on Hg concentrations in ground-foraging insectivorous songbirds, a terrestrial salamander, and forest floor horizons sampled along a forested elevational gradient from 185 m to 1273 m in the Catskill Mountains, New York, USA. Mean Hg concentrations in Catharus thrushes and the salamander Plethodon cinereus increased with elevation, as did Hg concentrations in all forest floor horizons. Mean Hg concentrations in organic soils at approximately 1200 m elevation (503.5 ± 17.7 ng/g, dry wt) were 4.4-fold greater than those at approximately 200 m. Montane ecosystems of the northeastern United States, and probably elsewhere, are exposed to higher levels of atmospheric Hg deposition as reflected in accumulation patterns in the forest floor and associated high-elevation fauna. This information can be used to parameterize and test Hg transport and bioaccumulation models of landscape-specific patterns and may serve as a monitoring tool for decision makers considering future controls on Hg emissions. Further investigation is needed into the potential effects of increased Hg concentrations on high-elevation fauna.

  14. Toxicological responses of red-backed salamanders (Plethodon cinereus) to soil exposures of copper.

    PubMed

    Bazar, Matthew A; Quinn, Michael J; Mozzachio, Kristie; Bleiler, John A; Archer, Christine R; Phillips, Carlton T; Johnson, Mark S

    2009-07-01

    Copper (Cu) has widespread military use in munitions and small arms, particularly as a protective jacket for lead projectiles. The distribution of Cu at many US military sites is substantial and sites of contamination include habitats in and around military storage facilities, manufacturing, load and packing plants, open burning/open detonation areas, and firing ranges. Some of these areas include habitat for amphibian species, which generally lack toxicity data for risk assessment purposes. In an effort to ascertain Cu concentrations in soil that are toxic to terrestrial amphibians, 100 red-backed salamanders (Plethodon cinereus) were randomly sorted by weight, assigned to either a control soil or one of four treatments amended with copper acetate in soil, and exposed for 28 days. Analytical mean soil concentrations were 18, 283, 803, 1333, and 2700 mg Cu/kg soil dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Survival was reduced in salamanders exposed to 1333 and 2700 mg/kg by 55% and 100%, respectively. Mortality/morbidity occurred within the first 4 days of exposure. These data suggest that a Cu soil concentration of and exceeding 1333.3 +/- 120.2 mg/kg results in reduced survival, whereas hematology analyses suggest that a concentration of and exceeding 803.3 +/- 98.4 mg/kg might result in reduced total white blood cell count. No effects were observed at 283.3 +/- 36.7 mg/kg. PMID:18825446

  15. Phenotypic variation in metamorphosis and paedomorphosis in the salamander Ambystoma talpoideum

    SciTech Connect

    Semlitsch, R.D.; Gibbons, J.W.

    1985-08-01

    Phenotypic variation in metamorphosis and paedomorphosis in the salamander Ambystoma talpoideum was examined to determine its environmental or genetic basis. Eight artificial ponds were maintained, four at each of two environmental treatments: constant water level, to simulate fish-free permanent breeding ponds, and gradual drying out, to simulate temporary breeding ponds. Two populations of salamanders were used, derived from two breeding ponds having different frequencies of paedomorphosis. The water level in the drying treatment was lowered during the last 10 wk of the experimental period with no apparent differences in water chemistry parameters between treatments and only a slight change in water temperature during the last 2 wk. The effects of water level were potentially confounded by those of water temperature, density of larvae, and amount food. Population differences in the frequency of metamorphosis and paedomorphosis could potentially represent genetic differences resulting from the different selective regimes that individuals encounter in breeding ponds varying in drying frequency. 35 references, 3 figures, 4 tables.

  16. Retrotransposon long interspersed nucleotide element-1 (LINE-1) is activated during salamander limb regeneration.

    PubMed

    Zhu, Wei; Kuo, Dwight; Nathanson, Jason; Satoh, Akira; Pao, Gerald M; Yeo, Gene W; Bryant, Susan V; Voss, S Randal; Gardiner, David M; Hunter, Tony

    2012-09-01

    Salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. In our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. In this work, we focus on one of these genes, the long interspersed nucleotide element-1 (LINE-1) retrotransposon, which is usually active in germ cells and silent in most of the somatic tissues in other organisms. LINE-1 was found to be dramatically upregulated during regeneration. In addition, higher genomic LINE-1 content was also detected in the limb regenerate when compared to that before amputation indicating that LINE-1 retrotransposition is indeed active during regeneration. Active LINE-1 retrotransposition has been suggested to have a potentially deleterious impact on genomic integrity. Silencing of activated LINE-1 by small RNAs has been reported to be part of the machinery aiming to maintain genomic integrity. Indeed, we were able to identify putative LINE-1-related piRNAs in the limb blastema. Transposable element-related piRNAs have been identified frequently in the germline in other organisms. Thus, we present here a scenario in which a unique germline-like state is established during axolotl limb regeneration, and the re-activation of LINE-1 may serve as a marker for cellular dedifferentiation in the early-stage of limb regeneration.

  17. Transcriptome analysis of predator- and prey-induced phenotypic plasticity in the Hokkaido salamander (Hynobius retardatus).

    PubMed

    Matsunami, Masatoshi; Kitano, Jun; Kishida, Osamu; Michimae, Hirofumi; Miura, Toru; Nishimura, Kinya

    2015-06-01

    Predator- and prey-induced phenotypic plasticity is widely observed among amphibian species. Although ecological factors inducing diverse phenotypic responses have been extensively characterized, we know little about the molecular bases of variation in phenotypic plasticity. Larvae of the Hokkaido salamander, Hynobius retardatus, exhibit two distinct morphs: the presence of their prey, Rana pirica tadpoles, induces a broad-headed attack morph, and the presence of predatory dragonfly nymphs (Aeshna nigroflava) induces a defence morph with enlarged external gills and a high tail. To compare the genes involved in predator- and prey-induced phenotypic plasticity, we carried out a de novo transcriptome analysis of Hokkaido salamander larvae exposed to either prey or predator individuals. First, we found that the number of genes involved in the expression of the defence morph was approximately five times the number involved in the expression of the attack morph. This result is consistent with the fact that the predator-induced plasticity involves more drastic morphological changes than the prey-induced plasticity. Second, we found that particular sets of genes were upregulated during the induction of both the attack and defence morphs, but others were specific to the expression of one or the other morph. Because both shared and unique molecular mechanisms were used in the expression of each morph, the evolution of a new plastic phenotype might involve both the co-option of pre-existing molecular mechanisms and the acquisition of novel regulatory mechanisms. PMID:25943778

  18. Successful treatment of Batrachochytrium salamandrivorans infections in salamanders requires synergy between voriconazole, polymyxin E and temperature.

    PubMed

    Blooi, M; Pasmans, F; Rouffaer, L; Haesebrouck, F; Vercammen, F; Martel, A

    2015-01-01

    Chytridiomycosis caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) poses a serious threat to urodelan diversity worldwide. Antimycotic treatment of this disease using protocols developed for the related fungus Batrachochytrium dendrobatidis (Bd), results in therapeutic failure. Here, we reveal that this therapeutic failure is partly due to different minimum inhibitory concentrations (MICs) of antimycotics against Bsal and Bd. In vitro growth inhibition of Bsal occurs after exposure to voriconazole, polymyxin E, itraconazole and terbinafine but not to florfenicol. Synergistic effects between polymyxin E and voriconazole or itraconazole significantly decreased the combined MICs necessary to inhibit Bsal growth. Topical treatment of infected fire salamanders (Salamandra salamandra), with voriconazole or itraconazole alone (12.5 μg/ml and 0.6 μg/ml respectively) or in combination with polymyxin E (2000 IU/ml) at an ambient temperature of 15 °C during 10 days decreased fungal loads but did not clear Bsal infections. However, topical treatment of Bsal infected animals with a combination of polymyxin E (2000 IU/ml) and voriconazole (12.5 μg/ml) at an ambient temperature of 20 °C resulted in clearance of Bsal infections. This treatment protocol was validated in 12 fire salamanders infected with Bsal during a field outbreak and resulted in clearance of infection in all animals. PMID:26123899

  19. Non-additive response of larval ringed salamanders to intraspecific density.

    PubMed

    Ousterhout, Brittany H; Semlitsch, Raymond D

    2016-04-01

    Conditions experienced in early developmental stages can have long-term consequences for individual fitness. High intraspecific density during the natal period can affect juvenile and eventually adult growth rates, metabolism, immune function, survival, and fecundity. Despite the important ecological and evolutionary effects of early developmental density, the form of the relationship between natal density and resulting juvenile phenotype is poorly understood. To test competing hypotheses explaining responses to intraspecific density, we experimentally manipulated the initial larval density of ringed salamanders (Ambystoma annulatum), a pond-breeding amphibian, over 11 densities. We modeled the functional form of the relationship between natal density and juvenile traits, and compared the relative support for the various hypotheses based on their goodness of fit. These functional form models were then used to parameterize a simple simulation model of population growth. Our data support non-additive density dependence and presents an alternate hypothesis to additive density dependence, self-thinning and Allee effects in larval amphibians. We posit that ringed salamander larvae may be under selective pressure for tolerance to high density and increased efficiency in resource utilization. Additionally, we demonstrate that models of population dynamics are sensitive to assumptions of the functional form of density dependence. PMID:26683834

  20. Transcriptome analysis of predator- and prey-induced phenotypic plasticity in the Hokkaido salamander (Hynobius retardatus).

    PubMed

    Matsunami, Masatoshi; Kitano, Jun; Kishida, Osamu; Michimae, Hirofumi; Miura, Toru; Nishimura, Kinya

    2015-06-01

    Predator- and prey-induced phenotypic plasticity is widely observed among amphibian species. Although ecological factors inducing diverse phenotypic responses have been extensively characterized, we know little about the molecular bases of variation in phenotypic plasticity. Larvae of the Hokkaido salamander, Hynobius retardatus, exhibit two distinct morphs: the presence of their prey, Rana pirica tadpoles, induces a broad-headed attack morph, and the presence of predatory dragonfly nymphs (Aeshna nigroflava) induces a defence morph with enlarged external gills and a high tail. To compare the genes involved in predator- and prey-induced phenotypic plasticity, we carried out a de novo transcriptome analysis of Hokkaido salamander larvae exposed to either prey or predator individuals. First, we found that the number of genes involved in the expression of the defence morph was approximately five times the number involved in the expression of the attack morph. This result is consistent with the fact that the predator-induced plasticity involves more drastic morphological changes than the prey-induced plasticity. Second, we found that particular sets of genes were upregulated during the induction of both the attack and defence morphs, but others were specific to the expression of one or the other morph. Because both shared and unique molecular mechanisms were used in the expression of each morph, the evolution of a new plastic phenotype might involve both the co-option of pre-existing molecular mechanisms and the acquisition of novel regulatory mechanisms.

  1. Embryonic yolk removal affects a suite of larval salamander life history traits.

    PubMed

    Landberg, Tobias

    2014-01-01

    Egg size is a key life history trait affecting fitness, and it varies abundantly. The value of egg size to a mother and her offspring is often determined by a trade-off between investing more yolk in a few large eggs or less yolk into many more, smaller eggs. Smaller eggs are generally expected to be phenotypically inferior or females could increase their fitness by making more smaller eggs. However, many females produce a mix of egg sizes and natural yolk variation induces normal developmental responses which may persist into subsequent stages of a complex life history. Since sources of phenotypic variation are easily confounded, I surgically removed yolk from embryonic spotted salamanders (Ambystoma maculatum) using a sham surgery as a control and a split-clutch design to isolate the effects of yolk reserve variation from genetic sources of variation. Yolk removal induced early hatching, reduced developmental stage and hatchling body size. Small hatchlings stayed relatively small through the early larval period, but 17 weeks later the correlation with early larval body size was lost. When the experiment ended, larger individuals were further along in metamorphic development but mortality was independent of early larval body size. Variation in spotted salamander yolk reserves affects a suite of hatchling life history traits that persists into the larval period. Outside the laboratory, egg size effects may cascade throughout complex amphibian life histories. Applied experimentally and comparatively, this simple yolk removal technique may help identify how traits increase or decrease their response to maternal yolk investment.

  2. Purification and characterization of cholecystokinin from the skin of salamander Tylototriton verrucosus.

    PubMed

    Jiang, Wen-Bin; Hakim, Ma; Luo, Lei; Li, Bo-Wen; Yang, Shi-Long; Song, Yu-Zhu; Lai, Ren; Lu, Qiu-Min

    2015-05-18

    As a group of intestinal hormones and neurotransmitters, cholecystokinins (CCKs) regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A cDNA encoding the CCK precursor containing 129 amino acid residues was cloned from the cDNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0 x 10⁻¹¹ mol/L and inducing maximal contraction at a concentration of 2.0 x 10⁻⁶ mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian.

  3. Ultrastructural morphogenesis of an amphibian iridovirus isolated from Chinese giant salamander (Andrias davidianus).

    PubMed

    Ma, J; Zeng, L; Zhou, Y; Jiang, N; Zhang, H; Fan, Y; Meng, Y; Xu, J

    2014-01-01

    Haemorrhagic disease of Chinese giant salamanders (Andrias davidianus) (CGSs) is an emerging condition caused by an iridovirus of the genus Ranavirus within the family Iridoviridae. Several studies have described different biological properties of the virus, but some aspects of its replication cycle, including ultrastructural alterations, remain unknown. The aim of the present study was to describe the morphogenesis of Chinese giant salamander iridovirus (GSIV) in an epithelioma papulosum cyprinid (EPC) cell line at the ultrastructural level. Cells were infected with GSIV at a multiplicity of infection (MOI) of 10 and examined at 1, 2, 4, 6, 12, 24, 48, 72, 84 and 96 h post infection. GSIV entered EPC cells by endocytosis or fusion after adsorption to the cell membrane. Following uncoating, the viral cores translocated to the nucleus and the virus began to replicate. Different stages of virus self-assembly were observed in the slightly electron-lucent viromatrix near the cell nucleus. In the late phase of virus infection, most nucleocapsids were mature and formed a typical icosahedral shape and aggregated in pseudocrystalline array at the viromatrix or were budding at the plasma membrane. Virus infection was readily detected by electron microscopy before cytopathic effect appeared in cell culture. The EPC cell line represents a suitable in-vitro model for study of GSIV morphogenesis and characterization of the GSIV replication cycle.

  4. Characterization of Chinese giant salamander iridovirus tissue tropism and inflammatory response after infection.

    PubMed

    Jiang, Nan; Fan, Yuding; Zhou, Yong; Liu, Wenzhi; Ma, Jie; Meng, Yan; Xie, Congxin; Zeng, Lingbing

    2015-06-01

    The Chinese giant salamander iridovirus (GSIV), belonging to the genus Ranavirus in the family Iridoviridae, causes severe hemorrhagic lesions and nearly 100% mortality in naturally infected Chinese giant salamanders Andrias davidiamus. However, the replication and distribution of the virus has not been well characterized in vivo. Using in situ hybridization, the expression of the GSIV major capsid protein (MCP) was detected in the cytoplasm of cells of the spleen, kidney, liver and gut tissues. MCP expression in the spleen and kidney appeared to fluctuate significantly during the acute phase of infection. Using an immunofluorescence assay, GSIV antigens were abundant in the spleen and kidney tissues but appeared to be at relatively low levels in the liver and gut. Additionally, there were significant changes in the expression of the pro-inflammatory cytokines macrophage migration inhibitory factor (MIF), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in different tissues in response to infection with GSIV. The expression of MIF, TNF-α and IL-1β had significantly increased in the spleen at 3 d post-infection; this correlated with a decrease in virus replication in the spleen. These results suggest that the spleen and kidney are the major target tissues of GSIV, and the increased expression of MIF, TNF‑α and IL-1β may contribute to a reduction of virus replication in the spleen.

  5. Computer-Assisted Photo Identification Outperforms Visible Implant Elastomers in an Endangered Salamander, Eurycea tonkawae

    PubMed Central

    Bendik, Nathan F.; Morrison, Thomas A.; Gluesenkamp, Andrew G.; Sanders, Mark S.; O’Donnell, Lisa J.

    2013-01-01

    Despite recognition that nearly one-third of the 6300 amphibian species are threatened with extinction, our understanding of the general ecology and population status of many amphibians is relatively poor. A widely-used method for monitoring amphibians involves injecting captured individuals with unique combinations of colored visible implant elastomer (VIE). We compared VIE identification to a less-invasive method – computer-assisted photographic identification (photoID) – in endangered Jollyville Plateau salamanders (Eurycea tonkawae), a species with a known range limited to eight stream drainages in central Texas. We based photoID on the unique pigmentation patterns on the dorsal head region of 1215 individual salamanders using identification software Wild-ID. We compared the performance of photoID methods to VIEs using both ‘high-quality’ and ‘low-quality’ images, which were taken using two different camera types and technologies. For high-quality images, the photoID method had a false rejection rate of 0.76% compared to 1.90% for VIEs. Using a comparable dataset of lower-quality images, the false rejection rate was much higher (15.9%). Photo matching scores were negatively correlated with time between captures, suggesting that evolving natural marks could increase misidentification rates in longer term capture-recapture studies. Our study demonstrates the utility of large-scale capture-recapture using photo identification methods for Eurycea and other species with stable natural marks that can be reliably photographed. PMID:23555669

  6. Aquatic herbicide exposure increases salamander desiccation risk eight months later in a terrestrial environment.

    PubMed

    Rohr, Jason R; Palmer, Brent D

    2005-05-01

    Contaminants and climate change may be factors in amphibian declines. However, few studies have explored their joint impacts on postmetamorphic amphibians, a life stage of great importance to amphibian population dynamics. Here, we examine the effects of premetamorphic exposure (mean exposure of 64 d) to ecologically relevant concentrations of the globally common herbicide atrazine (0, 4, 40, 400 microg/L) on the behavior and water retention of lone and grouped postmetamorphic, streamside salamanders, Ambystoma barbouri. Salamanders exposed to > or = 40 microg/L of atrazine exhibited greater activity, fewer water-conserving behaviors, and accelerated water loss four and eight months after exposure compared to controls. No recovery from atrazine exposure was detected and its effects were independent of the presence of conspecifics. These results are consistent with the hypothesis that adverse climatic conditions and contaminants can interact to harm post-metamorphic amphibians; however, they suggest that these two stressors need not be experienced simultaneously to do so. These results emphasize the importance of considering both latent and cumulative effects of temporally linked stressors in ecotoxicology.

  7. Aquatic herbicide exposure increases salamander desiccation risk eight months later in a terrestrial environment.

    PubMed

    Rohr, Jason R; Palmer, Brent D

    2005-05-01

    Contaminants and climate change may be factors in amphibian declines. However, few studies have explored their joint impacts on postmetamorphic amphibians, a life stage of great importance to amphibian population dynamics. Here, we examine the effects of premetamorphic exposure (mean exposure of 64 d) to ecologically relevant concentrations of the globally common herbicide atrazine (0, 4, 40, 400 microg/L) on the behavior and water retention of lone and grouped postmetamorphic, streamside salamanders, Ambystoma barbouri. Salamanders exposed to > or = 40 microg/L of atrazine exhibited greater activity, fewer water-conserving behaviors, and accelerated water loss four and eight months after exposure compared to controls. No recovery from atrazine exposure was detected and its effects were independent of the presence of conspecifics. These results are consistent with the hypothesis that adverse climatic conditions and contaminants can interact to harm post-metamorphic amphibians; however, they suggest that these two stressors need not be experienced simultaneously to do so. These results emphasize the importance of considering both latent and cumulative effects of temporally linked stressors in ecotoxicology. PMID:16111008

  8. Environment-dependent admixture dynamics in a tiger salamander hybrid zone.

    PubMed

    Fitzpatrick, Benjamin M; Shaffer, H Bradley

    2004-06-01

    After an estimated five million years of independent evolution, the barred tiger salamander (Ambystoma tigrinum mavortium) was introduced by bait dealers into the native range of the California tiger salamander (A. californiense). Hybridization and backcrossing have been occurring in central California for 50-60 years, or an estimated 15-30 generations. We studied genetic and ecological factors influencing admixture of these two divergent gene pools by analyzing frequencies of hybrid genotypes in three kinds of breeding habitats: natural vernal pools, ephemeral man-made cattle ponds, and perennial man-made ponds. Perennial ponds tended to have higher frequencies of nonnative alleles than either type of seasonal pond, even in cases where perennial and seasonal ponds are within a few hundred meters. Thus, the hybrid zone has a mosaic structure that depends on pond hydrology or ecology. The presence of some broadly acting constraints on admixture is suggested by linkage disequilibria between physically unlinked molecular markers within ponds. In addition, we found several marker-specific deviations from Hardy-Weinberg equilibrium. One marker showed a consistent deficit of heterozygotes across pond types. Another showed heterozygote deficits only in vernal pools. A third was more likely to have heterozygote excess in ephemeral cattle ponds. These patterns indicate that admixture is influenced by complex genotype-by-environment interactions. PMID:15266977

  9. Cutaneous mastocytomas in the neotenic caudate amphibians Ambystoma mexicanum (axolotl) and Ambystoma tigrinun (tiger salamander)

    USGS Publications Warehouse

    Harshbarger, J.C.; Chang, S.C.; DeLanney, L.E.; Rose, F.L.; Green, D.E.

    1999-01-01

    Spontaneous mastocytomas studied in 18 axolotls (Ambystoma mexicanum) and six tiger salamanders (Ambystoma tigrinum) were gray-white, uni- to multilobular cutaneous protrusions from 2mm to 2cm in diameter. Tumors were moderately cellular unencapsulated masses that usually infiltrated the dermis and hypodermis with the destruction of intervening tissues. Some tumors were invading superficial bundles of the underlying skeletal muscle. Tumors consisted of mitotically active cells derived from a single lineage but showing a range of differentiation. Immature cells had nearly smooth to lightly cleft or folded basophilic nuclei bordered by a band of cytoplasm with few cytoplasmic processes and containing a few small uniform eccentric granules. Mature cells had basophilic nuclei with deep clefts or folds and abundant eosinophilic cytoplasm with multiple long intertwining cytoplasmic extensions packed with metachromatic granules. The axolotls were old individuals from an inbred laboratory colony. The tiger salamanders were wild animals from a single polluted pond. They could have been old and inbred. Both groups were neotenic. These are the first mastocytomas discovered in cold-blooded animals.

  10. Phylogeography and spatial genetic structure of the Southern torrent salamander: Implications for conservation and management

    USGS Publications Warehouse

    Miller, M.P.; Haig, S.M.; Wagner, R.S.

    2006-01-01

    The Southern torrent salamander (Rhyacotriton variegatus) was recently found not warranted for listing under the US Endangered Species Act due to lack of information regarding population fragmentation and gene flow. Found in small-order streams associated with late-successional coniferous forests of the US Pacific Northwest, threats to their persistence include disturbance related to timber harvest activities. We conducted a study of genetic diversity throughout this species' range to 1) identify major phylogenetic lineages and phylogeographic barriers and 2) elucidate regional patterns of population genetic and spatial phylogeographic structure. Cytochrome b sequence variation was examined for 189 individuals from 72 localities. We identified 3 major lineages corresponding to nonoverlapping geographic regions: a northern California clade, a central Oregon clade, and a northern Oregon clade. The Yaquina River may be a phylogeographic barrier between the northern Oregon and central Oregon clades, whereas the Smith River in northern California appears to correspond to the discontinuity between the central Oregon and northern California clades. Spatial analyses of genetic variation within regions encompassing major clades indicated that the extent of genetic structure is comparable among regions. We discuss our results in the context of conservation efforts for Southern torrent salamanders. ?? The American Genetic Association. 2006. All rights reserved.

  11. Spatial genetic structure and regional demography in the southern torrent salamander: Implications for conservation and management

    USGS Publications Warehouse

    Miller, Mark P.; Haig, Susan M.; Wagner, R.S.

    2006-01-01

    The Southern torrent salamander (Rhyacotriton variegatus) was recently found not warranted for listing under the US Endangered Species Act due to lack of information regarding population fragmentation and gene flow. Found in small-order streams associated with late-successional coniferous forests of the US Pacific Northwest, threats to their persistence include disturbance related to timber harvest activities. We conducted a study of genetic diversity throughout this species' range to 1) identify major phylogenetic lineages and phylogeographic barriers and 2) elucidate regional patterns of population genetic and spatial phylogeographic structure. Cytochrome b sequence variation was examined for 189 individuals from 72 localities. We identified 3 major lineages corresponding to nonoverlapping geographic regions: a northern California clade, a central Oregon clade, and a northern Oregon clade. The Yaquina River may be a phylogeographic barrier between the northern Oregon and central Oregon clades, whereas the Smith River in northern California appears to correspond to the discontinuity between the central Oregon and northern California clades. Spatial analyses of genetic variation within regions encompassing major clades indicated that the extent of genetic structure is comparable among regions. We discuss our results in the context of conservation efforts for Southern torrent salamanders.

  12. Twin Mitochondrial Sequence Analysis.

    PubMed

    Bouhlal, Yosr; Martinez, Selena; Gong, Henry; Dumas, Kevin; Shieh, Joseph T C

    2013-09-01

    When applying genome-wide sequencing technologies to disease investigation, it is increasingly important to resolve sequence variation in regions of the genome that may have homologous sequences. The human mitochondrial genome challenges interpretation given the potential for heteroplasmy, somatic variation, and homologous nuclear mitochondrial sequences (numts). Identical twins share the same mitochondrial DNA (mtDNA) from early life, but whether the mitochondrial sequence remains similar is unclear. We compared an adult monozygotic twin pair using high throughput-sequencing and evaluated variants with primer extension and mitochondrial pre-enrichment. Thirty-seven variants were shared between the twin individuals, and the variants were verified on the original genomic DNA. These studies support highly identical genetic sequence in this case. Certain low-level variant calls were of high quality and homology to the mitochondrial DNA, and they were further evaluated. When we assessed calls in pre-enriched mitochondrial DNA templates, we found that these may represent numts, which can be differentiated from mtDNA variation. We conclude that twin identity extends to mitochondrial DNA, and it is critical to differentiate between numts and mtDNA in genome sequencing, particularly since significant heteroplasmy could influence genome interpretation. Further studies on mtDNA and numts will aid in understanding how variation occurs and persists. PMID:24040623

  13. Clinical mitochondrial genetics

    PubMed Central

    Chinnery, P.; Howell, N.; Andrews, R.; Turnbull, D.

    1999-01-01

    The last decade has been an age of enlightenment as far as mitochondrial pathology is concerned. Well established nuclear genetic diseases, such as Friedreich's ataxia,12 Wilson disease,3 and autosomal recessive hereditary spastic paraplegia,4 have been shown to have a mitochondrial basis, and we are just starting to unravel the complex nuclear genetic disorders which directly cause mitochondrial dysfunction (table 1). However, in addition to the 3 billion base pair nuclear genome, each human cell typically contains thousands of copies of a small, 16.5 kb circular molecule of double stranded DNA (fig 1). Mitochondrial DNA (mtDNA) accounts for only 1% of the total cellular nucleic acid content. It encodes for 13 polypeptides which are essential for aerobic metabolism and defects of the mitochondrial genome are an important cause of human disease.9293 Since the characterisation of the first pathogenic mtDNA defects in 1988,513 over 50 point mutations and well over 100 rearrangements of the mitochondrial genome have been associated with human disease9495 (http://www.gen.emory.edu/mitomap.html). These disorders form the focus of this article.


Keywords: mitochondrial DNA; mitochondrial disease; heteroplasmy; genetic counselling PMID:10874629

  14. Mitochondrial regulation of apoptosis.

    PubMed

    Mayer, Bernd; Oberbauer, Rainer

    2003-06-01

    Mitochondria play a central part in cellular survival and apoptotic death. These processes are highly regulated by pro- and antiapoptotic Bcl-2 superfamily members. A key feature within apoptosis cascades is disruption of mitochondrial transmembrane potential and apoptogenic protein release, caused by opening of the permeability transition pore (PT). New data, however, indicate that mitochondrial apoptosis may occur without PT involvement.

  15. Mitochondrial Therapeutics for Cardioprotection

    PubMed Central

    Carreira, Raquel S.; Lee, Pamela; Gottlieb, Roberta A.

    2013-01-01

    Mitochondria represent approximately one-third of the mass of the heart and play a critical role in maintaining cellular function—however, they are also a potent source of free radicals and pro-apoptotic factors. As such, maintaining mitochondrial homeostasis is essential to cell survival. As the dominant source of ATP, continuous quality control is mandatory to ensure their ongoing optimal function. Mitochondrial quality control is accomplished by the dynamic interplay of fusion, fission, autophagy, and mitochondrial biogenesis. This review examines these processes in the heart and considers their role in the context of ischemia-reperfusion injury. Interventions that modulate mitochondrial turnover, including pharmacologic agents, exercise, and caloric restriction are discussed as a means to improve mitochondrial quality control, ameliorate cardiovascular dysfunction, and enhance longevity. PMID:21718247

  16. Cloning, sequence analysis and expression profiles of Toll-like receptor 7 from Chinese giant salamander Andrias davidianus.

    PubMed

    Huang, Lili; Fan, Yuding; Zhou, Yong; Jiang, Nan; Liu, Wenzhi; Meng, Yan; Zeng, Lingbing

    2015-06-01

    The Chinese giant salamander, Andrias davidianus, is the largest extant amphibian species in the world, which is of significance due to its specific position in the evolutionary history of vertebrates. Currently, limited information about the innate immune system of this animal is known. In this study, the toll-like receptor 7 (TLR7), designated CgsTLR7, was cloned from Chinese giant salamander, A. davidianus. The full-length cDNA of CgsTLR7 is 3747 bp, with an open reading frame of 3150 bp, encoding 1049 amino acids. The TLR family motifs, including the leucine-rich repeat (LRR) and Toll/interleukin (IL)-1 receptor (TIR) domain are conserved in CgsTLR7, which includes 19 LRRs and a TIR domain. The predicted amino acid sequence of CgsTLR7 has 71%, 65%, 63% and 55% identity with turtle, chicken, human and fugu TLR7 homologues, respectively. Phylogenetic analysis showed that CgsTLR7 is closest to that of frog TLR7 among the examined species. Quantitative real-time PCR analysis revealed broad expression of CgsTLR7 in tissues from apparently healthy Chinese giant salamanders with the highest expression in the liver and the lowest expression in the intestine. The mRNA expression was up-regulated and reached a peak level in the kidney, liver and spleen at 12 h, 24 h and 48 h after infecting the animals with the giant salamander iridovirus (GSIV), respectively. These results suggest that CgsTLR7 has a conserved gene structure and might play an important role in immune regulation against viral infections in the Chinese giant salamander.

  17. The effects of used motor oil, silt, and the water mold Saprolegnia parasitica on the growth and survival of mole salamanders (genus Ambystoma).

    PubMed

    Lefcort, H; Hancock, K A; Maur, K M; Rostal, D C

    1997-05-01

    Amphibians appear to be declining worldwide. One cause of their decline may be used crankcase oil which leaks from motor vehicles and washes into ponds. Once in ponds, the oil may either be directly toxic to amphibians, or may indirectly affect them by disrupting food chains. The effects of oil may also be compounded by naturally occurring materials in the water column such as silt. Silt may interfere with respiration across gill surfaces. This study examined the effects of oil and silt on the growth and metamorphosis of larval mole salamanders, Ambystoma opacum and A. tigrinum tigrinum. In Experiment One it examined ponds with and without silty water and oil pollution to determine their suitability as habitats for salamander larvae. In Experiment Two it studied the effects of low levels of oil combined with silt on animals raised in the laboratory and fed prey items not raised in oil. In Experiment Three, it explored the effects of oil at an ecosystem level by raising the salamanders in the field in plastic micromesocosms that mimicked small ponds. Finally, in Experiment Four, in the laboratory, it examined the short-term survival of salamanders in high concentrations of oil. This study found that ponds containing oil and silt produce salamanders of reduced size and weight. Furthermore, while salamanders are relatively robust to the short term effects of large concentrations of used motor oil, oil has deleterious effects on the community and therefore exerts an indirect negative effect on salamanders. In the mi- cro-mesocosms containing oil, salamanders were smaller and weighed less than animals not raised in oil. Furthermore, silt results in reduced growth, earlier metamorphosis, and increased susceptibility to the water mold Saprolegnia parasitica.

  18. Can the eastern red-backed salamander (Plethodon cinereus) persist in an acidified landscape?

    USGS Publications Warehouse

    Bondi, Cheryl A; Beier, Colin M.; Ducey, Peter K; Lawrence, Gregory B.; Bailey, Scott W.

    2016-01-01

    Hardwood forests of eastern North America have experienced decades of acidic deposition, leading to soil acidification where base cation supply was insufficient to neutralize acid inputs. Negative impacts of soil acidity on amphibians include disrupted embryonic development, lower growth rates, and habitat loss. However, some amphibians exhibit intraspecific variation in acid tolerance, suggesting the potential for local adaptation in areas where soils are naturally acidic. The eastern red-backed salamander (Plethodon cinereus) is a highly abundant top predator of the northern hardwood forest floor. Early research found that P. cinereus was sensitive to acidic soils, avoiding substrates with pH < 3.8 and experiencing decreased growth rates in acidic habitats. However, recent studies have documented P. cinereus populations in lower pH conditions than previously observed, suggesting some populations may persist in acidic conditions. Here, we evaluated relationships between organic horizon soil pH and P. cinereus abundance, adult health (body size and condition), and microhabitat selection, based on surveys of 34 hardwood forests in northeastern United States that encompass a regional soil pH gradient. We found no associations between soil pH and P. cinereus abundance or health, and observed that this salamander used substrates with pH similar to that available, suggesting that pH does not mediate their fine-scale distributions. The strongest negative predictor of P. cinereus abundance was the presence of dusky salamanders (Desmognathus spp.), which were most abundant in the western Adirondacks. Our results indicate that P. cinereus occupies a wider range of soil pH than has been previously thought, which has implications for their functional role in forest food webs and nutrient cycles in acid-impaired ecosystems. Tolerance of P. cinereus for more acidic habitats, including anthropogenically acidified forests, may be due to local adaptation in

  19. Distribution and Abundance of California Giant Salamander (Dicamptodon ensatus) and Signal Crayfish (Pacifastacus leniusculus) in the Upper Redwood Creek Watershed, Marin County, California

    USGS Publications Warehouse

    Fong, Darren; Howell, Judd A.

    2006-01-01

    A survey was conducted in 1997-1998 to identify the distribution of non-native signal crayfish (Pacifastacus leniusculus) and larval California giant salamanders (Dicamptodon ensatus) within the upper Redwood Creek watershed (Marin County, California). The crayfish is widely distributed along the mainstem Redwood Creek. It was found in lower Fern Creek but not in any first order tributaries or above fish barriers. While present throughout the study area, larval California giant salamanders were found mainly in small headwater tributaries. Larval salamanders appear to use habitats in accordance to their availability, while signal crayfish were rarely found in shallow water habitats and appeared to prefer scour pools. Evidence of predation by signal crayfish on larval giant salamanders was found under confined conditions. Controlled laboratory and field experiments would be needed to determine whether competitive exclusion is occurring. Because of its widespread occurrence in the headwater streams surveyed in this project, California giant salamanders would be an appropriate indicator species for those interested in monitoring the health of small headwater streams. Future long-term monitoring using California giant salamanders should be based on permanent monitoring reaches with periodic basinwide habitat and animal surveys to determine if reaches are representative of basinwide conditions.

  20. Mitochondrial biogenesis: pharmacological approaches.

    PubMed

    Valero, Teresa

    2014-01-01

    Organelle biogenesis is concomitant to organelle inheritance during cell division. It is necessary that organelles double their size and divide to give rise to two identical daughter cells. Mitochondrial biogenesis occurs by growth and division of pre-existing organelles and is temporally coordinated with cell cycle events [1]. However, mitochondrial biogenesis is not only produced in association with cell division. It can be produced in response to an oxidative stimulus, to an increase in the energy requirements of the cells, to exercise training, to electrical stimulation, to hormones, during development, in certain mitochondrial diseases, etc. [2]. Mitochondrial biogenesis is therefore defined as the process via which cells increase their individual mitochondrial mass [3]. Recent discoveries have raised attention to mitochondrial biogenesis as a potential target to treat diseases which up to date do not have an efficient cure. Mitochondria, as the major ROS producer and the major antioxidant producer exert a crucial role within the cell mediating processes such as apoptosis, detoxification, Ca2+ buffering, etc. This pivotal role makes mitochondria a potential target to treat a great variety of diseases. Mitochondrial biogenesis can be pharmacologically manipulated. This issue tries to cover a number of approaches to treat several diseases through triggering mitochondrial biogenesis. It contains recent discoveries in this novel field, focusing on advanced mitochondrial therapies to chronic and degenerative diseases, mitochondrial diseases, lifespan extension, mitohormesis, intracellular signaling, new pharmacological targets and natural therapies. It contributes to the field by covering and gathering the scarcely reported pharmacological approaches in the novel and promising field of mitochondrial biogenesis. There are several diseases that have a mitochondrial origin such as chronic progressive external ophthalmoplegia (CPEO) and the Kearns- Sayre syndrome (KSS

  1. Mitochondrial biogenesis: pharmacological approaches.

    PubMed

    Valero, Teresa

    2014-01-01

    Organelle biogenesis is concomitant to organelle inheritance during cell division. It is necessary that organelles double their size and divide to give rise to two identical daughter cells. Mitochondrial biogenesis occurs by growth and division of pre-existing organelles and is temporally coordinated with cell cycle events [1]. However, mitochondrial biogenesis is not only produced in association with cell division. It can be produced in response to an oxidative stimulus, to an increase in the energy requirements of the cells, to exercise training, to electrical stimulation, to hormones, during development, in certain mitochondrial diseases, etc. [2]. Mitochondrial biogenesis is therefore defined as the process via which cells increase their individual mitochondrial mass [3]. Recent discoveries have raised attention to mitochondrial biogenesis as a potential target to treat diseases which up to date do not have an efficient cure. Mitochondria, as the major ROS producer and the major antioxidant producer exert a crucial role within the cell mediating processes such as apoptosis, detoxification, Ca2+ buffering, etc. This pivotal role makes mitochondria a potential target to treat a great variety of diseases. Mitochondrial biogenesis can be pharmacologically manipulated. This issue tries to cover a number of approaches to treat several diseases through triggering mitochondrial biogenesis. It contains recent discoveries in this novel field, focusing on advanced mitochondrial therapies to chronic and degenerative diseases, mitochondrial diseases, lifespan extension, mitohormesis, intracellular signaling, new pharmacological targets and natural therapies. It contributes to the field by covering and gathering the scarcely reported pharmacological approaches in the novel and promising field of mitochondrial biogenesis. There are several diseases that have a mitochondrial origin such as chronic progressive external ophthalmoplegia (CPEO) and the Kearns- Sayre syndrome (KSS

  2. Protective immunity of a Pichia pastoris expressed recombinant iridovirus major capsid protein in the Chinese giant salamander, Andrias davidianus.

    PubMed

    Zhou, Yong; Fan, Yuding; LaPatra, Scott E; Ma, Jie; Xu, Jin; Meng, Yan; Jiang, Nan; Zeng, Lingbing

    2015-10-13

    The major capsid protein (MCP) is the main immunogenic protein of iridoviruses, that has been widely used as an immunogen in vaccination trials. In this study, the codon-optimized giant salamander iridovirus (GSIV) MCP gene (O-MCP) was synthesized and cloned into a pPICZα B vector for secretory expression in the methylotrophic yeast Pichia pastoris after methanol induction. The expression of the O-MCP protein was detected by the Bradford protein assay, SDS-PAGE, Western blotting and electron microscopy. The Bradford protein assay indicated that the concentration of the O-MCP expressed was about 40 μg/ml in culture supernatants. SDS-PAGE analysis revealed that the O-MCP had a molecular weight of about 66 kDa and reacted with a His-specific MAb that was confirmed by Western blotting. Electron microscopy observations revealed that the purified O-MCP could self-assemble into virus-like particles. Healthy giant salamanders were vaccinated by intramuscular injection with the O-MCP antigen at a dose of 20 μg/individual. The numbers of erythrocytes and leukocytes in the peripheral blood of immunized Chinese giant salamanders increased significantly at day 3 and reached a peak at day 5 post-immunization. Meanwhile, the differential leukocyte counts of monocytes and neutrophils increased significantly at day 5 post-immunization compared to that of the control group. The percentage of lymphocytes was 71.33 ± 3.57% at day 21 post-immunization. The neutralization assay showed that the serum neutralizing antibody titer reached 321 at day 21 post-immunization. The GSIV challenge test revealed that the relative percent survival of Chinese giant salamanders vaccinated with O-MCP was 78%. These results indicated that the O-MCP antigen expressed by the Pichia pastoris system elicited significant immune response in the Chinese giant salamander against GSIV and might represent a potential yeast-derived vaccine candidate that could be used for the control of disease caused by the

  3. Effects of structural complexity enhancement on eastern red-backed salamander (Plethodon cinereus) populations in northern hardwood forests

    USGS Publications Warehouse

    McKenny, H.C.; Keeton, W.S.; Donovan, T.M.

    2006-01-01

    Managing for stand structural complexity in northern hardwood forests has been proposed as a method for promoting microhabitat characteristics important to eastern red-backed salamanders (Plethodon cinereus). We evaluated the effects of alternate, structure-based silvicultural systems on red-backed salamander populations at two research sites in northwestern Vermont. Treatments included two uneven-aged approaches (single-tree selection and group-selection) and one unconventional approach, termed "structural complexity enhancement" (SCE), that promotes development of late-successional structure, including elevated levels of coarse woody debris (CWD). Treatments were applied to 2 ha units and were replicated two to four times depending on treatment. We surveyed red-backed salamanders with a natural cover search method of transects nested within vegetation plots 1 year after logging. Abundance estimates corrected for detection probability were calculated from survey data with a binomial mixture model. Abundance estimates differed between study areas and were influenced by forest structural characteristics. Model selection was conducted using Akaike Information Criteria, corrected for over-dispersed data and small sample size (QAICc). We found no difference in abundance as a response to treatment as a whole, suggesting that all of the uneven-aged silvicultural systems evaluated can maintain salamander populations after harvest. However, abundance was tied to specific structural habitat attributes associated with study plots within treatments. The most parsimonious model of habitat covariates included site, relative density of overstory trees, and density of more-decayed and less-decayed downed CWD. Abundance responded positively to the density of downed, well-decayed CWD and negatively to the density of poorly decayed CWD and to overstory relative density. CWD volume was not a strong predictor of salamander abundance. We conclude that structural complexity enhancement

  4. Population Structure and Evolution after Speciation of the Hokkaido Salamander (Hynobius retardatus)

    PubMed Central

    Matsunami, Masatoshi; Igawa, Takeshi; Michimae, Hirofumi; Miura, Toru; Nishimura, Kinya

    2016-01-01

    The Hokkaido salamander (Hynobius retardatus) is endemic to Hokkaido Island, Japan, and shows intriguing flexible phenotypic plasticity and regional morphological diversity. However, to date, allozymes and partial mitochondria DNA sequences have provided only an outline of its demographic histories and the pattern of its genetic diversification. To understand the finer details of the population structure of this species and its evolution since speciation, we genotyped five regional populations by using 12 recently developed microsatellite polymorphic markers. We found a clear population structure with low gene flow among the five populations, but a close genetic relationship between the Teshio and Kitami populations. Our demographic analysis suggested that Teshio and Erimo had the largest effective population sizes among the five populations. These findings regarding the population structure and demography of H. retardatus improve our understanding of the faunal phylogeography on Hokkaido Island and also provide fundamental genetic information that will be useful for future studies. PMID:27257807

  5. Low pH effects on swimming activity of Ambystoma salamander larvae

    SciTech Connect

    Kutka, F.J. . Dept. of Animal Ecology)

    1994-11-01

    Swimming activity of larval Ambystoma laterale increased linearly with pH between pH 4.0 and 6.5; near inactivity occurred at pH 4.0. Ambystoma maculatum exhibited a weaker relationship between activity and pH, and overall was less active than A. laterale. However, survival of larval A. maculatum declined linearly with pH in the presence of adult diving beetles (Dytiscus verticalis), with significantly lower survival below pH 4.8. These results suggest that, as with embryos, salamander larvae may suffer from pH levels below 5.0, even though these levels are not directly lethal. Because of their sensitivity, ease, and short duration, activity tests are recommended with amphibian larvae for use in other risk assessments.

  6. Phyllodistomum kanae sp. nov. (Trematoda: Gorgoderidae), a bladder fluke from the Ezo salamander Hynobius retardatus.

    PubMed

    Nakao, Minoru

    2015-10-01

    The Ezo salamander, Hynobius retardatus, is endemic only to Hokkaido, the northernmost island of Japan. Gravid flukes of the family Gorgoderidae were discovered from the urinary bladder of H. retardatus. The parasites were identified as a new species named Phyllodistomum kanae sp. nov. In the neighboring Honshu island another bladder fluke, Phyllodistomum patellare, has already been found from the Japanese newt. The new species clearly differs from P. patellare in having a spherical ovary and very weakly lobed testes. The discovery of species of Phyllodistomum from urodelan amphibians is very uncommon in Eurasia. A molecular phylogeny based on 28S ribosomal DNA suggests that sphaeriid bivalves may serve as the first intermediate host for the new species.

  7. Ontogenetic changes of trunk muscle structure in the Japanese black salamander (Hynobius nigrescens).

    PubMed

    Omura, Ayano; Anzai, Wataru; Koyabu, Daisuke; Endo, Hideki

    2015-08-01

    We investigated ontogenetic changes in the trunk muscles of the Japanese black salamander (Hynobius nigrescens) before, during and after metamorphosis. Given that amphibians change their locomotive patterns with metamorphosis, we hypothesized that they may also change the structure of their trunk muscles. The trunk muscles were macroscopically observed, and the weight ratios of each trunk muscle group were quantified at six different developmental stages. Immediately after hatching, we found that the lateral hypaxial muscle was composed of one thick M. ventralis, from ventral edge of which M. transversus abdominis arose later, followed by M. obliquus externus and M. rectus abdominis. The weight ratios of the dorsal and abdominal muscles to the trunk muscles increased with growth. We suggest that a single thick and large lateral hypaxial muscle facilitates swimming during early developmental stages. The increase in the weight ratios of the dorsal and abdominal muscles with growth possibly assists with gravity resistance necessary for terrestrial life.

  8. Analysis of climatic factors influencing migrations of the salamander Ambystoma talpoideum

    SciTech Connect

    Semlitsch, R.D.

    1985-01-01

    Migrations of breeding adult and metamorphosing juvenile mole salamanders, Ambystoma talpoideum, were studied in five populations in South Carolina from September 1978 through July 1982. Onset of breeding immigrations occurred as early as September but migrations ''en masse'' did not occur until November, December, or January. Time of peak migration varied annually depending upon meteorological conditions. Total number of breeding adults or breeding population size, was significantly correlated with cumulative rainfall during the time of immigration. Sex ratio of immigrating adults was significantly biased towards males at the beginning of the breeding season whereas by the end of the season it was biased towards females. During the very dry year of 1980 - 1981 water levels in two relatively permanent breeding sites were substantially metamorphosis and emigration of sexually mature gilled morphs. Statistical models which predict the magnitude of migrations indicated that rainfall, water level, and minimum air temperature were consistently important environmental variables.

  9. Ontogenetic changes of trunk muscle structure in the Japanese black salamander (Hynobius nigrescens)

    PubMed Central

    OMURA, Ayano; ANZAI, Wataru; KOYABU, Daisuke; ENDO, Hideki

    2015-01-01

    We investigated ontogenetic changes in the trunk muscles of the Japanese black salamander (Hynobius nigrescens) before, during and after metamorphosis. Given that amphibians change their locomotive patterns with metamorphosis, we hypothesized that they may also change the structure of their trunk muscles. The trunk muscles were macroscopically observed, and the weight ratios of each trunk muscle group were quantified at six different developmental stages. Immediately after hatching, we found that the lateral hypaxial muscle was composed of one thick M. ventralis, from ventral edge of which M. transversus abdominis arose later, followed by M. obliquus externus and M. rectus abdominis. The weight ratios of the dorsal and abdominal muscles to the trunk muscles increased with growth. We suggest that a single thick and large lateral hypaxial muscle facilitates swimming during early developmental stages. The increase in the weight ratios of the dorsal and abdominal muscles with growth possibly assists with gravity resistance necessary for terrestrial life. PMID:25816856

  10. Phyllodistomum kanae sp. nov. (Trematoda: Gorgoderidae), a bladder fluke from the Ezo salamander Hynobius retardatus.

    PubMed

    Nakao, Minoru

    2015-10-01

    The Ezo salamander, Hynobius retardatus, is endemic only to Hokkaido, the northernmost island of Japan. Gravid flukes of the family Gorgoderidae were discovered from the urinary bladder of H. retardatus. The parasites were identified as a new species named Phyllodistomum kanae sp. nov. In the neighboring Honshu island another bladder fluke, Phyllodistomum patellare, has already been found from the Japanese newt. The new species clearly differs from P. patellare in having a spherical ovary and very weakly lobed testes. The discovery of species of Phyllodistomum from urodelan amphibians is very uncommon in Eurasia. A molecular phylogeny based on 28S ribosomal DNA suggests that sphaeriid bivalves may serve as the first intermediate host for the new species. PMID:25892565

  11. Population Structure and Evolution after Speciation of the Hokkaido Salamander (Hynobius retardatus).

    PubMed

    Matsunami, Masatoshi; Igawa, Takeshi; Michimae, Hirofumi; Miura, Toru; Nishimura, Kinya

    2016-01-01

    The Hokkaido salamander (Hynobius retardatus) is endemic to Hokkaido Island, Japan, and shows intriguing flexible phenotypic plasticity and regional morphological diversity. However, to date, allozymes and partial mitochondria DNA sequences have provided only an outline of its demographic histories and the pattern of its genetic diversification. To understand the finer details of the population structure of this species and its evolution since speciation, we genotyped five regional populations by using 12 recently developed microsatellite polymorphic markers. We found a clear population structure with low gene flow among the five populations, but a close genetic relationship between the Teshio and Kitami populations. Our demographic analysis suggested that Teshio and Erimo had the largest effective population sizes among the five populations. These findings regarding the population structure and demography of H. retardatus improve our understanding of the faunal phylogeography on Hokkaido Island and also provide fundamental genetic information that will be useful for future studies. PMID:27257807

  12. Population genetic structure of critically endangered salamander (Hynobius amjiensis) in China: recommendations for conservation.

    PubMed

    Yang, J; Chen, C S; Chen, S H; Ding, P; Fan, Z Y; Lu, Y W; Yu, L P; Lin, H D

    2016-01-01

    Amji's salamander (Hynobius amjiensis) is a critically endangered species (IUCN Red List), which is endemic to mainland China. In the present study, five haplotypes were genotyped for the mtDNA cyt b gene in 45 specimens from three populations. Relatively low levels of haplotype diversity (h = 0.524) and nucleotide diversity (π = 0.00532) were detected. Analyses of the phylogenic structure of H. amjiensis showed no evidence of major geographic partitions or substantial barriers to historical gene flow throughout the species' range. Two major phylogenetic haplotype groups were revealed, and were estimated to have diverged about 1.262 million years ago. Mismatch distribution analysis, neutrality tests, and Bayesian skyline plots revealed no evidence of dramatic changes in the effective population size. According to the SAMOVA and STRUCTURE analyses, H. amjiensis should be regarded as two different management units. PMID:27323156

  13. United Mitochondrial Disease Foundation

    MedlinePlus

    ... to Mitochondrial Disease FAQ's MitoFirst Handbook More Information Mito 101 Symposium Archives Get Connected Find an Event Adult Advisory Council Team Ask The Mito Doc Grand Rounds Kids & Teens Medical Child Abuse ...

  14. Metabolism, gas exchange, and acid-base balance of giant salamanders.

    PubMed

    Ultsch, Gordon R

    2012-08-01

    The giant salamanders are aquatic and paedomorphic urodeles including the genera Andrias and Cryptobranchus (Cryptobranchidae), Amphiuma (Amphiumidae), Siren (Sirenidae), and Necturus (Proteidae, of which only N. maculosus is considered 'a giant'). Species in the genera Cryptobranchus and Necturus are considered aquatic salamanders well adapted for breathing water, poorly adapted for breathing air, and with limited abilities to compensate acid-base disturbances. As such, they are water-breathing animals with a somewhat fish-like respiratory and acid-base physiology, whose habitat selection is limited to waters that do not typically become hypoxic or hypercarbic (although this assertion has been questioned for N. maculosus). Siren and Amphiuma species, by contrast, are dependent upon air-breathing, have excellent lungs, inefficient (Siren) or no (Amphiuma) gills, and are obligate air-breathers with an acid-base status more similar to that of terrestrial tetrapods. As such, they can be considered to be air-breathing animals that live in water. Their response to the aquatic hypercarbia that they often encounter is to maintain intracellular pH (pH(i) ) and abandon extracellular pH regulation, a process that has been referred to as preferential pH(i) regulation. The acid-base status of some present-day tropical air-breathing fishes, and of Siren and Amphiuma, suggests that the acid-base transition from a low PCO(2) -low [] system typical of water-breathing fishes to the high PCO(2) -high [] systems of terrestrial tetrapods may have been completed before emergence onto land, and likely occurred in habitats that were typically both hypoxic and hypercarbic.

  15. Sexual and seasonal differences in the vomeronasal epithelium of the red-backed salamander (Plethodon cinereus).

    PubMed

    Dawley, E M; Crowder, J

    1995-08-28

    Sexually dimorphic behaviors often are associated with sexually dimorphic neural structures. Perinatal hormonal levels influence structural sexual dimorphism, and seasonal structural changes also can be the result of seasonal hormonal fluctuations. We compared the volume of vomeronasal organs of male and female red-backed salamanders (Plethodon cinereus) throughout the year. Odorants are delivered to vomeronasal receptors through nasolabial grooves when salamanders touch the bases of these grooves to objects (nose tapping). Males may locate and identify potential mates through nose tapping during the prolonged breeding season that lasts from October through May. We compared vomeronasal organ data through multiple regression by using total body size, sex, and season as variables that may influence vomeronasal organ volume. Gonads also were examined as an indicator of reproductive status. Total body size and sex significantly affect vomeronasal organ volume; as body size increases, so does vomeronasal organ volume, and males have significantly larger vomeronasal organs than females at all times of the year. During the summer, both males and females have larger vomeronasal organs than at any other time of the year. Summer also is a period of intense foraging and the initiation of a new cycle of gametogenesis. Previous studies of circulating hormone levels in amphibians have shown that the initial stages of gametogenesis correspond to a period of low estradiol and testosterone levels but high gonadotropin-releasing hormone levels. The functional significance of sexual and seasonal differences in the vomeronasal organs of P. cinereus may relate to the neurogenesis of specialized receptors for courtship and mating.

  16. Using multilevel spatial models to understand salamander site occupancy patterns after wildfire.

    PubMed

    Chelgren, Nathan D; Adams, Michael J; Bailey, Larissa L; Bury, R Bruce

    2011-02-01

    Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of variation in the response that may occur when there are dependence structures such as smaller sampling units that are nested within larger sampling units. We used multilevel Bayesian occupancy modeling to handle dependence structures and to partition sources of variation in occupancy of sites by terrestrial salamanders (family Plethodontidae) within and surrounding an earlier wildfire in western Oregon, USA. Comparison of model fit favored a spatial N-mixture model that accounted for variation in salamander abundance over models that were based on binary detection/non-detection data. Though catch per unit effort was higher in burned areas than unburned, there was strong support that this pattern was due to a higher probability of capture for individuals in burned plots. Within the burn, the odds of capturing an individual given it was present were 2.06 times the odds outside the burn, reflecting reduced complexity of ground cover in the burn. Ther was weak support that true occupancy was lower within the burned area. While the odds of occupancy in the burn were 0.49 times the odds outside the burn among the five species, the magnitude of variation attributed to the burn was small in comparison to variation attributed to other landscape variables and to unexplained, spatially autocorrelated random variation. While ordinary occupancy models may separate the biological pattern of interest from variation in detection probability when all sources of variation are known, the addition of random effects structures for unexplained sources of variation in occupancy and detection

  17. Morphological variation in salamanders and their potential response to climate change

    PubMed Central

    Ficetola, Gentile Francesco; Colleoni, Emiliano; Renaud, Julien; Scali, Stefano; Padoa-Schioppa, Emilio; Thuiller, Wilfried

    2016-01-01

    Despite the recognition that some species might quickly adapt to new conditions under climate change, demonstrating and predicting such a fundamental response is challenging. Morphological variations in response to climate may be caused by evolutionary changes or phenotypic plasticity, or both, but teasing apart these processes is difficult. Here we built on the number of thoracic vertebrae (NTV) in ectothermic vertebrates, a known genetically-based feature, to establish a link with body size and evaluate how climate change might affect the future morphological response of this group of species. First we show that in old-world salamanders, NTV variation is strongly related to changes in body size. Secondly, using 22 salamander species as a case study, we found support for relationships between the spatial variation in selected bioclimatic variables and NTV for most of species. For 44% of species, precipitation and aridity were the predominant drivers of geographical variation of the NTV. Temperature features were dominant for 31% of species, while for 19% temperature and precipitation played a comparable role. This two-step analysis demonstrates that ectothermic vertebrates may evolve in response to climate change by modifying the number of thoracic vertebrae. These findings allow to develop scenarios for potential morphological evolution under future climate change, and to identify areas and species in which the most marked evolutionary responses are expected. Resistance to climate change estimated from species distribution models was positively related to present-day species morphological response, suggesting that the ability of morphological evolution may play a role for species’ persistence under climate change. The possibility that present-day capacity for local adaptation might help the resistance response to climate change can be integrated into analyses of the impact of global changes, and should also be considered when planning management actions

  18. Characterization and expression of cyp19a gene in the Chinese giant salamander Andrias davidianus.

    PubMed

    Hu, Qiaomu; Xiao, Hanbing; Tian, HaiFeng; Meng, Yan

    2016-02-01

    We cloned the full length cyp19a of Chinese giant salamander Andrias davidianus, determined its distribution in tissues and developing gonads, and analyzed the CpG methylation pattern of the cyp19a promoter. The results revealed isoforms of 1706 bp (G arom) and 1698 bp (B arom) in length, differing in the 5' flanking region, both encoding 502 amino acids. The G arom gene was observed mainly in the ovary and kidney, with little in other investigated tissues, while B arom expression was high in the brain, ovary, testis, and pituitary, with low or undetected expression in other examined tissues. Total aromatase expression was high in the ovary; moderate in the kidney, brain, testis, and pituitary; and low in the remaining tissues. G arom expression was significantly higher in the ovary than in the testis and gradually decreased with maturation of the salamander. A single injection of methyltestosterone or letrozole resulted in ovarian G arom expression decreasing over a 12-96 h period. A 1366 bp sequence of the cyp19a promoter was cloned and shown to be conserved in selected species. CpG methylation level was negatively correlated with cyp19a expression in the examined tissues and developing ovaries. Five and three CpG methylation sites positively correlated with DNA methylation levels in tissues and developing ovary, suggesting that they play an important role in regulating cyp19a expression. The aromatase gene showed two isoforms with distinct expression patterns, and the promoter methylation level at specific CpG sites was associated with variation in expression profiles of tissues and developing ovaries.

  19. Variation in salamander tail regeneration is associated with genetic factors that determine tail morphology.

    PubMed

    Voss, Gareth J; Kump, D Kevin; Walker, John A; Voss, S Randal

    2013-01-01

    Very little is known about the factors that cause variation in regenerative potential within and between species. Here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. A hybrid ambystomatid salamander (Ambystoma mexicanum x A. andersoni) was crossed to an A. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. Following metamorphosis, each salamander's tail tip was amputated and allowed to regenerate, and then amputated a second time and allowed to regenerate. Also, DNA was isolated from all individuals and genotypes were determined for 187 molecular markers distributed throughout the genome. The area of tissue that regenerated after the first and second amputations was highly positively correlated across males and females. Males presented wider tails and regenerated more tail tissue during both episodes of regeneration. Approximately 66-68% of the variation in regenerative outgrowth was explained by tail width, while tail length and genetic sex did not explain a significant amount of variation. A small effect QTL was identified as having a sex-independent effect on tail regeneration, but this QTL was only identified for the first episode of regeneration. Several molecular markers significantly affected regenerative outgrowth during both episodes of regeneration, but the effect sizes were small (<4%) and correlated with tail width. The results show that ambysex and minor effect QTL explain variation in adult tail morphology and importantly, tail width. In turn, tail width at the amputation plane largely determines the rate of regenerative outgrowth. Because amputations in this study were made at approximately the same position of the tail, our results resolve an outstanding question in regenerative biology: regenerative outgrowth positively co-varies as a function of tail width at the amputation site.

  20. Using multilevel spatial models to understand salamander site occupancy patterns after wildfire

    USGS Publications Warehouse

    Chelgren, N.D.; Adams, M.J.; Bailey, L.L.; Bury, R.B.

    2011-01-01

    Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of variation in the response that may occur when there are dependence structures such as smaller sampling units that are nested within larger sampling units. We used multilevel Bayesian occupancy modeling to handle dependence structures and to partition sources of variation in occupancy of sites by terrestrial salamanders (family Plethodontidae) within and surrounding an earlier wildfire in western Oregon, USA. Comparison of model fit favored a spatial N-mixture model that accounted for variation in salamander abundance over models that were based on binary detection/non-detection data. Though catch per unit effort was higher in burned areas than unburned, there was strong support that this pattern was due to a higher probability of capture for individuals in burned plots. Within the burn, the odds of capturing an individual given it was present were 2.06 times the odds outside the burn, reflecting reduced complexity of ground cover in the burn. There was weak support that true occupancy was lower within the burned area. While the odds of occupancy in the burn were 0.49 times the odds outside the burn among the five species, the magnitude of variation attributed to the burn was small in comparison to variation attributed to other landscape variables and to unexplained, spatially autocorrelated random variation. While ordinary occupancy models may separate the biological pattern of interest from variation in detection probability when all sources of variation are known, the addition of random effects structures for unexplained sources of variation in occupancy and detection

  1. Terrestrial distribution of pond-breeding salamanders around an isolated wetland.

    PubMed

    Scott, David E; Komoroski, Mark J; Croshaw, Dean A; Dixon, Philip M

    2013-11-01

    Terrestrial habitats surrounding isolated wetlands are a critical resource for many pond-breeding amphibian species, yet few studies have examined the terrestrial distribution of post-metamorphic juveniles and adults. We used an encircling drift fence at a breeding pond in conjunction with partial fences at 90, 172, and 332 m from the wetland to estimate the terrestrial distribution of adult marbled salamanders (Ambystoma opacum; four breeding seasons) and mole salamanders (A. talpoideum; two seasons), as well as the dispersion of newly metamorphosed A. opacum (one summer). For newly metamorphosed A. opacum, 79% emigrated < 90 m from the wetland, and 8% moved beyond 172 m; movement distance was unrelated to body size. Distribution of adult A. opacum varied among years, with an average of 28% (range 23-31%) occurring beyond 172 m in all years. Averaged across two years, 51% of adult A. talpoideum occurred beyond 172 m. Lognormal models provided a good fit to both the juvenile and adult ambystomatid distributions, and parameters differed between age classes, sexes, species, and years within species. For adult A. opacum a buffer radius of 300 m or 340 m, depending on the year, is estimated to include 95% of adults; for A. talpoideum the estimate is 464 m or 501 m. A reanalysis of distribution data for seven ambystomatid species shows that a previous estimate of a 164-m radius to protect 95% of a population underestimates the needed buffer radius by 185 m. Because our study wetland requires a nearly 500 m wide radius to protect 95% of its ambystomatid adults, preservation of similar communities may require much more surrounding terrestrial habitat than previously thought. PMID:24400505

  2. Morphological variation in salamanders and their potential response to climate change.

    PubMed

    Ficetola, Gentile Francesco; Colleoni, Emiliano; Renaud, Julien; Scali, Stefano; Padoa-Schioppa, Emilio; Thuiller, Wilfried

    2016-06-01

    Despite the recognition that some species might quickly adapt to new conditions under climate change, demonstrating and predicting such a fundamental response is challenging. Morphological variations in response to climate may be caused by evolutionary changes or phenotypic plasticity, or both, but teasing apart these processes is difficult. Here, we built on the number of thoracic vertebrae (NTV) in ectothermic vertebrates, a known genetically based feature, to establish a link with body size and evaluate how climate change might affect the future morphological response of this group of species. First, we show that in old-world salamanders, NTV variation is strongly related to changes in body size. Secondly, using 22 salamander species as a case study, we found support for relationships between the spatial variation in selected bioclimatic variables and NTV for most of species. For 44% of species, precipitation and aridity were the predominant drivers of geographical variation of the NTV. Temperature features were dominant for 31% of species, while for 19% temperature and precipitation played a comparable role. This two-step analysis demonstrates that ectothermic vertebrates may evolve in response to climate change by modifying the number of thoracic vertebrae. These findings allow to develop scenarios for potential morphological evolution under future climate change and to identify areas and species in which the most marked evolutionary responses are expected. Resistance to climate change estimated from species distribution models was positively related to present-day species morphological response, suggesting that the ability of morphological evolution may play a role for species' persistence under climate change. The possibility that present-day capacity for local adaptation might help the resistance response to climate change can be integrated into analyses of the impact of global changes and should also be considered when planning management actions favouring

  3. Morphological variation in salamanders and their potential response to climate change.

    PubMed

    Ficetola, Gentile Francesco; Colleoni, Emiliano; Renaud, Julien; Scali, Stefano; Padoa-Schioppa, Emilio; Thuiller, Wilfried

    2016-06-01

    Despite the recognition that some species might quickly adapt to new conditions under climate change, demonstrating and predicting such a fundamental response is challenging. Morphological variations in response to climate may be caused by evolutionary changes or phenotypic plasticity, or both, but teasing apart these processes is difficult. Here, we built on the number of thoracic vertebrae (NTV) in ectothermic vertebrates, a known genetically based feature, to establish a link with body size and evaluate how climate change might affect the future morphological response of this group of species. First, we show that in old-world salamanders, NTV variation is strongly related to changes in body size. Secondly, using 22 salamander species as a case study, we found support for relationships between the spatial variation in selected bioclimatic variables and NTV for most of species. For 44% of species, precipitation and aridity were the predominant drivers of geographical variation of the NTV. Temperature features were dominant for 31% of species, while for 19% temperature and precipitation played a comparable role. This two-step analysis demonstrates that ectothermic vertebrates may evolve in response to climate change by modifying the number of thoracic vertebrae. These findings allow to develop scenarios for potential morphological evolution under future climate change and to identify areas and species in which the most marked evolutionary responses are expected. Resistance to climate change estimated from species distribution models was positively related to present-day species morphological response, suggesting that the ability of morphological evolution may play a role for species' persistence under climate change. The possibility that present-day capacity for local adaptation might help the resistance response to climate change can be integrated into analyses of the impact of global changes and should also be considered when planning management actions favouring

  4. Salamander locomotion-induced head movement and retinal motion sensitivity in a correlation-based motion detector model.

    PubMed

    Begley, Jeffrey R; Arbib, Michael A

    2007-06-01

    We report on a computational model of retinal motion sensitivity based on correlation-based motion detectors. We simulate object motion detection in the presence of retinal slip caused by the salamander's head movements during locomotion. Our study offers new insights into object motion sensitive ganglion cells in the salamander retina. A sigmoidal transformation of the spatially and temporally filtered retinal image substantially improves the sensitivity of the system in detecting a small target moving in place against a static natural background in the presence of comparatively large, fast simulated eye movements, but is detrimental to the direction-selectivity of the motion detector. The sigmoid has insignificant effects on detector performance in simulations of slow, high contrast laboratory stimuli. These results suggest that the sigmoid reduces the system's noise sensitivity.

  5. Coprophagy in a cave-adapted salamander; the importance of bat guano examined through nutritional and stable isotope analyses

    PubMed Central

    Fenolio, Danté B; Graening, G.O; Collier, Bret A; Stout, Jim F

    2005-01-01

    During a two year population ecology study in a cave environment, 15 Eurycea (=Typhlotriton) spelaea were observed ingesting bat guano. Furthermore, E. spelaea capture numbers increased significantly during the time that grey bats (Myotis grisescens) deposited fresh guano. We investigated the hypothesis that this behaviour was not incidental to the capture of invertebrate prey, but a diet switch to an energy-rich detritus in an oligotrophic environment. Stable isotope assays determined that guano may be assimilated into salamander muscle tissue, and nutritional analyses revealed that guano is a comparable food source to potential invertebrate prey items. This is the first report of coprophagy in a salamander and in any amphibian for reasons other than intestinal inoculation. Because many temperate subterranean environments are often energy poor and this limitation is thought to select for increased diet breadth, we predict that coprophagy may be common in subterranean vertebrates where it is not currently recognized. PMID:16615210

  6. Comparison of direct, indirect, and ecosystem engineering effects of an earthworm on the red-backed salamander.

    PubMed

    Ransom, Tami S

    2012-10-01

    In addition to creating or modifying habitat, ecosystem engineers interact with other species as predators, prey, or competitors. The earthworm, Lumbricus terrestris, interacts with the common woodland salamander, Plethodon cinereus, via: (1) ecosystem engineering, by providing burrows that are used as a refuge, (2) direct effects as a prey item, and (3) indirectly, by competing with microinvertebrates, another prey item for P. cinereus. Using enclosures in the forest, I examined the relative strengths of these component pathways between seasons and salamander age classes. I found that the relative strength (partial eta2) of the positive direct (trophic) effect of L. terrestris on the change in mass of P. cineresus was greater than that of the negative indirect effect, but only in summer. Positive effects of ecosystem engineering were only evident over the winter as increased adult survival. This research has implications for how habitat provisioning complements more well-studied species interactions, such as competition and predation, within communities. PMID:23185881

  7. Coprophagy in a cave-adapted salamander; the importance of bat guano examined through nutritional and stable isotope analyses.

    PubMed

    Fenolio, Danté B; Graening, G O; Collier, Bret A; Stout, Jim F

    2006-02-22

    During a two year population ecology study in a cave environment, 15 Eurycea (= Typhlotriton) spelaea were observed ingesting bat guano. Furthermore, E. spelaea capture numbers increased significantly during the time that grey bats (Myotis grisescens) deposited fresh guano. We investigated the hypothesis that this behaviour was not incidental to the capture of invertebrate prey, but a diet switch to an energy-rich detritus in an oligotrophic environment. Stable isotope assays determined that guano may be assimilated into salamander muscle tissue, and nutritional analyses revealed that guano is a comparable food source to potential invertebrate prey items. This is the first report of coprophagy in a salamander and in any amphibian for reasons other than intestinal inoculation. Because many temperate subterranean environments are often energy poor and this limitation is thought to select for increased diet breadth, we predict that coprophagy may be common in subterranean vertebrates where it is not currently recognized.

  8. Comparison of direct, indirect, and ecosystem engineering effects of an earthworm on the red-backed salamander.

    PubMed

    Ransom, Tami S

    2012-10-01

    In addition to creating or modifying habitat, ecosystem engineers interact with other species as predators, prey, or competitors. The earthworm, Lumbricus terrestris, interacts with the common woodland salamander, Plethodon cinereus, via: (1) ecosystem engineering, by providing burrows that are used as a refuge, (2) direct effects as a prey item, and (3) indirectly, by competing with microinvertebrates, another prey item for P. cinereus. Using enclosures in the forest, I examined the relative strengths of these component pathways between seasons and salamander age classes. I found that the relative strength (partial eta2) of the positive direct (trophic) effect of L. terrestris on the change in mass of P. cineresus was greater than that of the negative indirect effect, but only in summer. Positive effects of ecosystem engineering were only evident over the winter as increased adult survival. This research has implications for how habitat provisioning complements more well-studied species interactions, such as competition and predation, within communities.

  9. New findings from an old pathogen: intraerythrocytic bacteria (family Anaplasmatacea) in red-backed salamanders Plethodon cinereus.

    PubMed

    Davis, Andrew K; DeVore, Jayna L; Milanovich, Joseph R; Cecala, Kristen; Maerz, John C; Yabsley, Michael J

    2009-06-01

    During a recent study of red-backed salamanders (Plethodon cinereus), we discovered an intraerythrocytic organism typified by violet-staining, intracellular inclusions, consistent with descriptions of Cytamoeba or Aegyptianella (bacteria). Here we characterize its taxonomic status using molecular techniques and ask basic questions about its nature. Blood smears from 102 salamanders were examined from Pennsylvania, New York, and Virginia to determine prevalence, and whole blood from several infected animals was tested using a PCR which targets the 16S rRNA gene of bacteria. Phylogenetic analysis of partial 16S rRNA gene sequence (1201 bp) indicated this organism was in the order Rickettsiales and is likely a member of the family Anaplasmatacea. The organism differed from currently described taxa and was clearly differentiated from Aegyptianella pullorum of birds and "Candidatus Hemobacterium ranarum" (formally A. ranarum) of frogs. Of all salamanders, 17 (16.7%) were infected and these were significantly larger (snout-vent length) and had higher body condition scores than uninfected ones, and males were more likely to be infected than females. Erythrocytes affected by the pathogen were 5% larger than unaffected ones, but otherwise similar in morphology. Infected animals tended to have a greater number of circulating white blood cells, based on estimates from smears, indicating a nonspecific response to the pathogen by the innate immune system. Given its phylogenetic position, this pathogen is likely transmitted by an arthropod vector, and the male-biased prevalence strongly implicates trombiculid mites, which also live in leaf litter and affect male salamanders more so than females.

  10. Geographic Variation in Genetic Dominance of the Color Morphs of the Red-Backed Salamander, PLETHODON CINEREUS.

    PubMed

    Highton, R

    1975-06-01

    Female parent-offspring phenotypic data on color morph frequencies in the red-backed salamander, Plethodon cinereus, were obtained from two Virginia localities (164 broods from Greene County and 97 broods from Giles County). The color morph data indicate that the striped morph is genetically dominant in Giles County and recessive in Greene County. It is suggested that epistatic interaction of two or more loci is responsible for the difference between the localities.

  11. Landscape influences on dispersal behaviour: a theoretical model and empirical test using the fire salamander, Salamandra infraimmaculata.

    PubMed

    Kershenbaum, Arik; Blank, Lior; Sinai, Iftach; Merilä, Juha; Blaustein, Leon; Templeton, Alan R

    2014-06-01

    When populations reside within a heterogeneous landscape, isolation by distance may not be a good predictor of genetic divergence if dispersal behaviour and therefore gene flow depend on landscape features. Commonly used approaches linking landscape features to gene flow include the least cost path (LCP), random walk (RW), and isolation by resistance (IBR) models. However, none of these models is likely to be the most appropriate for all species and in all environments. We compared the performance of LCP, RW and IBR models of dispersal with the aid of simulations conducted on artificially generated landscapes. We also applied each model to empirical data on the landscape genetics of the endangered fire salamander, Salamandra infraimmaculata, in northern Israel, where conservation planning requires an understanding of the dispersal corridors. Our simulations demonstrate that wide dispersal corridors of the low-cost environment facilitate dispersal in the IBR model, but inhibit dispersal in the RW model. In our empirical study, IBR explained the genetic divergence better than the LCP and RW models (partial Mantel correlation 0.413 for IBR, compared to 0.212 for LCP, and 0.340 for RW). Overall dispersal cost in salamanders was also well predicted by landscape feature slope steepness (76%), and elevation (24%). We conclude that fire salamander dispersal is well characterised by IBR predictions. Together with our simulation findings, these results indicate that wide dispersal corridors facilitate, rather than hinder, salamander dispersal. Comparison of genetic data to dispersal model outputs can be a useful technique in inferring dispersal behaviour from population genetic data.

  12. Transcriptomic Analysis of Endangered Chinese Salamander: Identification of Immune, Sex and Reproduction-Related Genes and Genetic Markers

    PubMed Central

    Che, Rongbo; Sun, Yuena; Wang, Rixin; Xu, Tianjun

    2014-01-01

    Background The Chinese salamander (Hynobius chinensis), an endangered amphibian species of salamander endemic to China, has attracted much attention because of its value of studying paleontology evolutionary history and decreasing population size. Despite increasing interest in the Hynobius chinensis genome, genomic resources for the species are still very limited. A comprehensive transcriptome of Hynobius chinensis, which will provide a resource for genome annotation, candidate genes identification and molecular marker development should be generated to supplement it. Principal Findings We performed a de novo assembly of Hynobius chinensis transcriptome by Illumina sequencing. A total of 148,510 nonredundant unigenes with an average length of approximately 580 bp were obtained. In all, 60,388 (40.66%) unigenes showed homologous matches in at least one database and 33,537 (22.58%) unigenes were annotated by all four databases. In total, 41,553 unigenes were categorized into 62 sub-categories by BLAST2GO search, and 19,468 transcripts were assigned to 140 KEGG pathways. A large number of unigenes involved in immune system, local adaptation, reproduction and sex determination were identified, as well as 31,982 simple sequence repeats (SSRs) and 460,923 putative single nucleotide polymorphisms (SNPs). Conclusion This dataset represents the first transcriptome analysis of the Chinese salamander (Hynobius chinensis), an endangered species, to be also the first time of hynobiidae. The transcriptome will provide valuable resource for further research in discovery of new genes, protection of population, adaptive evolution and survey of various pathways, as well as development of molecule markers in Chinese salamander; and reference information for closely related species. PMID:24498226

  13. Spiroxys hanzaki n. sp. (Nematoda: Gnathostomatidae) collected from the giant salamander, Andrias japonicus (Caudata: Cryptobranchidae), in Japan.

    PubMed

    Hasegawa, H; Miyata, A; Doi, T

    1998-08-01

    Spiroxys hanzaki n. sp. (Nematoda: Gnathostomatidae) taken from the giant salamander, Andrias japonicus (Temminck, 1836) (Caudata: Cryptobranchidae) from Hyogo Prefecture, Japan, is described. It closely resembles Spiroxys allegheniensis Walton, 1930, from the hellbender, Cryptobranchus alleganiensis (Daudin, 1803) (Cryptobranchidae), of North America, in that it has minute dorsal and ventral lobes of the pseudolabium and a reduced gubernaculum but is readily distinguished by a pseudolabium with 2 apical, 1 dorsal, and 1 ventral tooth on the median lobe. PMID:9714220

  14. Using stable isotopes to test for trophic niche partitioning: a case study with stream salamanders and fish

    USGS Publications Warehouse

    Sepulveda, Adam; Lowe, Winsor H.; Marra, Peter P.

    2012-01-01

    5. Although we did not identify mechanisms that facilitate salamander and fish coexistence, our empirical data and use of novel approaches to describe the trophic niche did yield important insights on the role of predator–prey interactions and cannibalism as alternative coexistence mechanisms. In addition, we found that 95% kernel estimators are a simple and robust method to describe population-level measure of trophic structure.

  15. Interactive effects of temperature and glyphosate on the behavior of blue ridge two-lined salamanders (Eurycea wilderae).

    PubMed

    Gandhi, Jaina S; Cecala, Kristen K

    2016-09-01

    The objective of the present study was to evaluate the potential interactive effects of stream temperatures and environmentally relevant glyphosate-based herbicide concentrations on movement and antipredator behaviors of larval Eurycea wilderae (Blue Ridge two-lined salamander). Larval salamanders were exposed to 1 of 4 environmentally relevant glyphosate concentrations (0.00 µg acid equivalent [a.e.]/L, 0.73 µg a.e./L, 1.46 µg a.e./L, and 2.92 µg a.e./L) at either ambient (12 °C) or elevated (23 °C) water temperature. Behaviors observed included the exploration of a novel habitat, use of refuge, habitat selection relative to a potential predator, and burst movement distance. In the absence of glyphosate, temperature consistently affected movement and refuge-use behavior, with individuals moving longer distances more frequently and using refuge less at warm temperatures; however, when glyphosate was added, the authors observed inconsistent effects of temperature that may have resulted from differential toxicity at various temperatures. Larval salamanders made shorter, more frequent movements and demonstrated reduced burst distance at higher glyphosate concentrations. The authors also found that lower glyphosate concentrations sometimes had stronger effects than higher concentrations (i.e., nonmonotonic dose responses), suggesting that standard safety tests conducted only at higher glyphosate concentrations might overlook important sublethal effects on salamander behavior. These data demonstrate that sublethal effects of glyphosate-based herbicides on natural behaviors of amphibians can occur with short-term exposure to environmentally relevant concentrations. Environ Toxicol Chem 2016;35:2297-2303. © 2016 SETAC.

  16. Insights into the mating habits of the tiger salamander (Ambystoma tigrinum tigrinum) as revealed by genetic parentage analyses.

    PubMed

    Gopurenko, David; Williams, Rod N; McCormick, Cory R; DeWoody, J Andrew

    2006-06-01

    Among urodeles, ambystomatid salamanders are particularly amenable to genetic parentage analyses because they are explosive aggregate breeders that typically have large progeny arrays. Such analyses can lead to direct inferences about otherwise cryptic aspects of salamander natural history, including the rate of multiple mating, individual reproductive success, and the spatial distribution of clutches. In 2002, we collected eastern tiger salamander (Ambystoma tigrinum tigrinum) egg masses (> 1000 embryos) from a approximately 80 m linear transect in Indiana, USA. Embryos were genotyped at four variable microsatellite loci and the resulting progeny array data were used to reconstruct multilocus genotypes of the parental dams and sires for each egg mass. UPGMA analysis of genetic distances among embryos resolved four instances of egg mass admixture, where two or more females had oviposited at exactly the same site resulting in the mixing of independent cohorts. In total, 41 discrete egg masses were available for parentage analyses. Twenty-three egg masses (56%) consisted exclusively of full-siblings (i.e. were singly sired) and 18 (44%) were multiply sired (mean 2.6 males/clutch). Parentage could be genetically assigned to one of 17 distinct parent pairs involving at least 15 females and 14 different males. Reproductive skew was evident among males who sired multiply sired clutches. Additional evidence of the effects of sexual selection on male reproductive success was apparent via significant positive correlations between male mating and reproductive success. Females frequently partitioned their clutches into multiple discrete egg masses that were separated from one another by as many as 43 m. Collectively, these data provide the first direct evidence for polygynandry in a wild population of tiger salamanders. PMID:16689907

  17. Interactive effects of temperature and glyphosate on the behavior of blue ridge two-lined salamanders (Eurycea wilderae).

    PubMed

    Gandhi, Jaina S; Cecala, Kristen K

    2016-09-01

    The objective of the present study was to evaluate the potential interactive effects of stream temperatures and environmentally relevant glyphosate-based herbicide concentrations on movement and antipredator behaviors of larval Eurycea wilderae (Blue Ridge two-lined salamander). Larval salamanders were exposed to 1 of 4 environmentally relevant glyphosate concentrations (0.00 µg acid equivalent [a.e.]/L, 0.73 µg a.e./L, 1.46 µg a.e./L, and 2.92 µg a.e./L) at either ambient (12 °C) or elevated (23 °C) water temperature. Behaviors observed included the exploration of a novel habitat, use of refuge, habitat selection relative to a potential predator, and burst movement distance. In the absence of glyphosate, temperature consistently affected movement and refuge-use behavior, with individuals moving longer distances more frequently and using refuge less at warm temperatures; however, when glyphosate was added, the authors observed inconsistent effects of temperature that may have resulted from differential toxicity at various temperatures. Larval salamanders made shorter, more frequent movements and demonstrated reduced burst distance at higher glyphosate concentrations. The authors also found that lower glyphosate concentrations sometimes had stronger effects than higher concentrations (i.e., nonmonotonic dose responses), suggesting that standard safety tests conducted only at higher glyphosate concentrations might overlook important sublethal effects on salamander behavior. These data demonstrate that sublethal effects of glyphosate-based herbicides on natural behaviors of amphibians can occur with short-term exposure to environmentally relevant concentrations. Environ Toxicol Chem 2016;35:2297-2303. © 2016 SETAC. PMID:26872413

  18. How mitochondrial dynamism orchestrates mitophagy

    PubMed Central

    Shirihai, Orian; Song, Moshi; Dorn, Gerald W

    2015-01-01

    Mitochondria are highly dynamic, except in adult cardiomyocytes. Yet, the fission and fusion-promoting proteins that mediate mitochondrial dynamism are highly expressed in, and essential to the normal functioning of, hearts. Here, we review accumulating evidence supporting important roles for mitochondrial fission and fusion in cardiac mitochondrial quality control, focusing on the PINK1-Parkin mitophagy pathway.Based in part on recent findings from in vivo mouse models in which mitofusin-mediated mitochondrial fusion or Drp1-mediated mitochondrial fission were conditionally interrupted in cardiac myocytes, we propose several new concepts that may provide insight into the cardiac mitochondrial dynamism-mitophagy interactome. PMID:25999423

  19. Development of a loop-mediated isothermal amplification assay for rapid detection of iridovirus in the Chinese giant salamander.

    PubMed

    Meng, Yan; Zhang, Hui; Liang, Hongwei; Zeng, Lingbing; Xiao, Hanbing; Xie, Congxin

    2013-12-01

    The Chinese giant salamander (Andrias davidianus) iridovirus (GSIV) is an emerging infectious pathogen responsible for severe hemorrhagic disease and high mortality in cultured Chinese giant salamanders. A loop-mediated isothermal amplification (LAMP) assay based on the major caspid protein (MCP) gene has been developed to detect this virus. Primer pairs for the LAMP assay were designed based on the GSIV MCP gene sequence. Amplification results indicate that under optimized conditions the LAMP assay has the ability to specifically detect the virus in both diseased animals and infected epithelioma papilloma cyprinid (EPC) cells. The assay was shown to be 10-fold more sensitive than nested PCR and was able to detect concentrations of 10(-9) (approximately 0.01 pg/μL). The LAMP assay is relatively easy to perform in situ and the amplification products can be observed directly under UV light or via staining with SYBR Green I. The LAMP assay is also rapid and cost-effective. This study establishes the use of a LAMP assay for rapid detection of GSIV, which is a novel and important tool for the diagnosis of GSIV infection in laboratory or farmed Chinese giant salamanders. PMID:24025343

  20. Response of the green alga Oophila sp., a salamander endosymbiont, to a PSII-inhibitor under laboratory conditions.

    PubMed

    Baxter, Leilan; Brain, Richard; Rodriguez-Gil, Jose Luis; Hosmer, Alan; Solomon, Keith; Hanson, Mark

    2014-08-01

    In a rare example of autotroph-vertebrate endosymbiosis, eggs of the yellow-spotted salamander (Ambystoma maculatum) are colonized by a green alga (Oophila sp.) that significantly enhances salamander development. Previous studies have demonstrated the potential for impacts to the salamander embryo when growth of the algae is impaired by exposure to herbicides. To further investigate this relationship, the authors characterized the response of the symbiotic algae (Oophila sp.) alone to the photosystem II (PSII) inhibitor atrazine under controlled laboratory conditions. After extraction of the alga from A. maculatum eggs and optimization of culturing conditions, 4 toxicity assays (96 h each) were conducted. Recovery of the algal population was also assessed after a further 96 h in untreated media. Average median effective concentration (EC50) values of 123 µg L(-1) (PSII yield), 169 µg L(-1) (optical density), and 299 µg L(-1) (growth rate) were obtained after the 96-h exposure. Full recovery of exposed algal populations after 96 h in untreated media was observed for all endpoints, except for optical density at the greatest concentration tested (300 µg L(-1) ). Our results show that, under laboratory conditions, Oophila sp. is generally less sensitive to atrazine than standard test species. Although conditions of growth in standard toxicity tests are not identical to those in the natural environment, these results provide an understanding of the tolerance of this alga to PSII inhibitors as compared with other species.

  1. Sustained ERK activation underlies reprogramming in regeneration-competent salamander cells and distinguishes them from their mammalian counterparts.

    PubMed

    Yun, Maximina H; Gates, Phillip B; Brockes, Jeremy P

    2014-07-01

    In regeneration-competent vertebrates, such as salamanders, regeneration depends on the ability of various differentiated adult cell types to undergo natural reprogramming. This ability is rarely observed in regeneration-incompetent species such as mammals, providing an explanation for their poor regenerative potential. To date, little is known about the molecular mechanisms mediating natural reprogramming during regeneration. Here, we have identified the extent of extracellular signal-regulated kinase (ERK) activation as a key component of such mechanisms. We show that sustained ERK activation following serum induction is required for re-entry into the cell cycle of postmitotic salamander muscle cells, partially by promoting the downregulation of p53 activity. Moreover, ERK activation induces epigenetic modifications and downregulation of muscle-specific genes such as Sox6. Remarkably, while long-term ERK activation is found in salamander myotubes, only transient activation is seen in their mammalian counterparts, suggesting that the extent of ERK activation could underlie differences in regenerative competence between species.

  2. Development of a loop-mediated isothermal amplification assay for rapid detection of iridovirus in the Chinese giant salamander.

    PubMed

    Meng, Yan; Zhang, Hui; Liang, Hongwei; Zeng, Lingbing; Xiao, Hanbing; Xie, Congxin

    2013-12-01

    The Chinese giant salamander (Andrias davidianus) iridovirus (GSIV) is an emerging infectious pathogen responsible for severe hemorrhagic disease and high mortality in cultured Chinese giant salamanders. A loop-mediated isothermal amplification (LAMP) assay based on the major caspid protein (MCP) gene has been developed to detect this virus. Primer pairs for the LAMP assay were designed based on the GSIV MCP gene sequence. Amplification results indicate that under optimized conditions the LAMP assay has the ability to specifically detect the virus in both diseased animals and infected epithelioma papilloma cyprinid (EPC) cells. The assay was shown to be 10-fold more sensitive than nested PCR and was able to detect concentrations of 10(-9) (approximately 0.01 pg/μL). The LAMP assay is relatively easy to perform in situ and the amplification products can be observed directly under UV light or via staining with SYBR Green I. The LAMP assay is also rapid and cost-effective. This study establishes the use of a LAMP assay for rapid detection of GSIV, which is a novel and important tool for the diagnosis of GSIV infection in laboratory or farmed Chinese giant salamanders.

  3. Response of the green alga Oophila sp., a salamander endosymbiont, to a PSII-inhibitor under laboratory conditions.

    PubMed

    Baxter, Leilan; Brain, Richard; Rodriguez-Gil, Jose Luis; Hosmer, Alan; Solomon, Keith; Hanson, Mark

    2014-08-01

    In a rare example of autotroph-vertebrate endosymbiosis, eggs of the yellow-spotted salamander (Ambystoma maculatum) are colonized by a green alga (Oophila sp.) that significantly enhances salamander development. Previous studies have demonstrated the potential for impacts to the salamander embryo when growth of the algae is impaired by exposure to herbicides. To further investigate this relationship, the authors characterized the response of the symbiotic algae (Oophila sp.) alone to the photosystem II (PSII) inhibitor atrazine under controlled laboratory conditions. After extraction of the alga from A. maculatum eggs and optimization of culturing conditions, 4 toxicity assays (96 h each) were conducted. Recovery of the algal population was also assessed after a further 96 h in untreated media. Average median effective concentration (EC50) values of 123 µg L(-1) (PSII yield), 169 µg L(-1) (optical density), and 299 µg L(-1) (growth rate) were obtained after the 96-h exposure. Full recovery of exposed algal populations after 96 h in untreated media was observed for all endpoints, except for optical density at the greatest concentration tested (300 µg L(-1) ). Our results show that, under laboratory conditions, Oophila sp. is generally less sensitive to atrazine than standard test species. Although conditions of growth in standard toxicity tests are not identical to those in the natural environment, these results provide an understanding of the tolerance of this alga to PSII inhibitors as compared with other species. PMID:24782078

  4. Light and scanning microscopy of the taste organs and vascularization of the tongue of the spotted salamander, Salamandra salamandra (L.).

    PubMed

    Jasiński, A; Miodoński, A

    1979-01-01

    The mucosa of the spotted salamander tongue and its taste organs were investigated by means of light and scanning electron microscopy. The most striking feature of the salamander tongue is an almost complete lack of papillae which are replaced by long, radially disposed folds with linear arrays of taste organs along their ridges. In respect of morphology, the taste organs of the salamander occupy an intermediate position between the taste buds of Urodela and taste discs of Salientia. Scanning electron microscopic examination of microcorrosion casts of the blood vessels of the tongue has revealed that the structure of subepidermal capillary network reflects the topography of the tongue surface and the distribution of its taste organs. In the core regions of the folds the capillary loops accompanying gustatory receptors empty via their shorter, descending arms into the draining vessels, the initial segments of which retain a course parallel to that of the folds. In the few fungiform papillae the capillary vessels form single loops whose distal ends come to lie in the vicinity of taste discs.

  5. The Spectrum of Mitochondrial Ultrastructural Defects in Mitochondrial Myopathy.

    PubMed

    Vincent, Amy E; Ng, Yi Shiau; White, Kathryn; Davey, Tracey; Mannella, Carmen; Falkous, Gavin; Feeney, Catherine; Schaefer, Andrew M; McFarland, Robert; Gorman, Grainne S; Taylor, Robert W; Turnbull, Doug M; Picard, Martin

    2016-01-01

    Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus provide insight into the underlying pathogenesis of inherited and acquired mitochondrial diseases. Following a systematic literature review on ultrastructural defects in mitochondrial myopathy, we investigated skeletal muscle biopsies from seven subjects with genetically defined mtDNA mutations. Mitochondrial ultrastructure and morphology were characterized using two complimentary approaches: transmission electron microscopy (TEM) and serial block face scanning EM (SBF-SEM) with 3D reconstruction. Six ultrastructural abnormalities were identified including i) paracrystalline inclusions, ii) linearization of cristae and abnormal angular features, iii) concentric layering of cristae membranes, iv) matrix compartmentalization, v) nanotunelling, and vi) donut-shaped mitochondria. In light of recent molecular advances in mitochondrial biology, these findings reveal novel aspects of mitochondrial ultrastructure and morphology in human tissues with implications for understanding the mechanisms linking mitochondrial dysfunction to disease. PMID:27506553

  6. The Spectrum of Mitochondrial Ultrastructural Defects in Mitochondrial Myopathy

    PubMed Central

    Vincent, Amy E.; Ng, Yi Shiau; White, Kathryn; Davey, Tracey; Mannella, Carmen; Falkous, Gavin; Feeney, Catherine; Schaefer, Andrew M.; McFarland, Robert; Gorman, Grainne S.; Taylor, Robert W.; Turnbull, Doug M.; Picard, Martin

    2016-01-01

    Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus provide insight into the underlying pathogenesis of inherited and acquired mitochondrial diseases. Following a systematic literature review on ultrastructural defects in mitochondrial myopathy, we investigated skeletal muscle biopsies from seven subjects with genetically defined mtDNA mutations. Mitochondrial ultrastructure and morphology were characterized using two complimentary approaches: transmission electron microscopy (TEM) and serial block face scanning EM (SBF-SEM) with 3D reconstruction. Six ultrastructural abnormalities were identified including i) paracrystalline inclusions, ii) linearization of cristae and abnormal angular features, iii) concentric layering of cristae membranes, iv) matrix compartmentalization, v) nanotunelling, and vi) donut-shaped mitochondria. In light of recent molecular advances in mitochondrial biology, these findings reveal novel aspects of mitochondrial ultrastructure and morphology in human tissues with implications for understanding the mechanisms linking mitochondrial dysfunction to disease. PMID:27506553

  7. Mitochondrial Dysfunction in Cancer

    PubMed Central

    Boland, Michelle L.; Chourasia, Aparajita H.; Macleod, Kay F.

    2013-01-01

    A mechanistic understanding of how mitochondrial dysfunction contributes to cell growth and tumorigenesis is emerging beyond Warburg as an area of research that is under-explored in terms of its significance for clinical management of cancer. Work discussed in this review focuses less on the Warburg effect and more on mitochondria and how dysfunctional mitochondria modulate cell cycle, gene expression, metabolism, cell viability, and other established aspects of cell growth and stress responses. There is increasing evidence that key oncogenes and tumor suppressors modulate mitochondrial dynamics through important signaling pathways and that mitochondrial mass and function vary between tumors and individuals but the significance of these events for cancer are not fully appreciated. We explore the interplay between key molecules involved in mitochondrial fission and fusion and in apoptosis, as well as in mitophagy, biogenesis, and spatial dynamics of mitochondria and consider how these distinct mechanisms are coordinated in response to physiological stresses such as hypoxia and nutrient deprivation. Importantly, we examine how deregulation of these processes in cancer has knock on effects for cell proliferation and growth. We define major forms of mitochondrial dysfunction and address the extent to which the functional consequences of such dysfunction can be determined and exploited for cancer diagnosis and treatment. PMID:24350057

  8. Mitochondrial fusion and inheritance of the mitochondrial genome.

    PubMed

    Takano, Hiroyoshi; Onoue, Kenta; Kawano, Shigeyuki

    2010-03-01

    Although maternal or uniparental inheritance of mitochondrial genomes is a general rule, biparental inheritance is sometimes observed in protists and fungi,including yeasts. In yeast, recombination occurs between the mitochondrial genomes inherited from both parents.Mitochondrial fusion observed in yeast zygotes is thought to set up a space for DNA recombination. In the last decade,a universal mitochondrial fusion mechanism has been uncovered, using yeast as a model. On the other hand, an alternative mitochondrial fusion mechanism has been identified in the true slime mold Physarum polycephalum.A specific mitochondrial plasmid, mF, has been detected as the genetic material that causes mitochondrial fusion in P. polycephalum. Without mF, fusion of the mitochondria is not observed throughout the life cycle, suggesting that Physarum has no constitutive mitochondrial fusion mechanism.Conversely, mitochondria fuse in zygotes and during sporulation with mF. The complete mF sequence suggests that one gene, ORF640, encodes a fusogen for Physarum mitochondria. Although in general, mitochondria are inherited uniparentally, biparental inheritance occurs with specific sexual crossing in P. polycephalum.An analysis of the transmission of mitochondrial genomes has shown that recombinations between two parental mitochondrial genomes require mitochondrial fusion,mediated by mF. Physarum is a unique organism for studying mitochondrial fusion. PMID:20196232

  9. Mitochondrial fusion and inheritance of the mitochondrial genome.

    PubMed

    Takano, Hiroyoshi; Onoue, Kenta; Kawano, Shigeyuki

    2010-03-01

    Although maternal or uniparental inheritance of mitochondrial genomes is a general rule, biparental inheritance is sometimes observed in protists and fungi,including yeasts. In yeast, recombination occurs between the mitochondrial genomes inherited from both parents.Mitochondrial fusion observed in yeast zygotes is thought to set up a space for DNA recombination. In the last decade,a universal mitochondrial fusion mechanism has been uncovered, using yeast as a model. On the other hand, an alternative mitochondrial fusion mechanism has been identified in the true slime mold Physarum polycephalum.A specific mitochondrial plasmid, mF, has been detected as the genetic material that causes mitochondrial fusion in P. polycephalum. Without mF, fusion of the mitochondria is not observed throughout the life cycle, suggesting that Physarum has no constitutive mitochondrial fusion mechanism.Conversely, mitochondria fuse in zygotes and during sporulation with mF. The complete mF sequence suggests that one gene, ORF640, encodes a fusogen for Physarum mitochondria. Although in general, mitochondria are inherited uniparentally, biparental inheritance occurs with specific sexual crossing in P. polycephalum.An analysis of the transmission of mitochondrial genomes has shown that recombinations between two parental mitochondrial genomes require mitochondrial fusion,mediated by mF. Physarum is a unique organism for studying mitochondrial fusion.

  10. Adult-onset mitochondrial myopathy.

    PubMed Central

    Fernandez-Sola, J.; Casademont, J.; Grau, J. M.; Graus, F.; Cardellach, F.; Pedrol, E.; Urbano-Marquez, A.

    1992-01-01

    Mitochondrial diseases are polymorphic entities which may affect many organs and systems. Skeletal muscle involvement is frequent in the context of systemic mitochondrial disease, but adult-onset pure mitochondrial myopathy appears to be rare. We report 3 patients with progressive skeletal mitochondrial myopathy starting in adult age. In all cases, the proximal myopathy was the only clinical feature. Mitochondrial pathology was confirmed by evidence of ragged-red fibres in muscle histochemistry, an abnormal mitochondrial morphology in electron microscopy and by exclusion of other underlying diseases. No deletions of mitochondrial DNA were found. We emphasize the need to look for a mitochondrial disorder in some non-specific myopathies starting in adult life. Images Figure 1 Figure 2 PMID:1589382

  11. Renal Mitochondrial Cytopathies

    PubMed Central

    Emma, Francesco; Montini, Giovanni; Salviati, Leonardo; Dionisi-Vici, Carlo

    2011-01-01

    Renal diseases in mitochondrial cytopathies are a group of rare diseases that are characterized by frequent multisystemic involvement and extreme variability of phenotype. Most frequently patients present a tubular defect that is consistent with complete De Toni-Debré-Fanconi syndrome in most severe forms. More rarely, patients present with chronic tubulointerstitial nephritis, cystic renal diseases, or primary glomerular involvement. In recent years, two clearly defined entities, namely 3243 A > G tRNALEU mutations and coenzyme Q10 biosynthesis defects, have been described. The latter group is particularly important because it represents the only treatable renal mitochondrial defect. In this paper, the physiopathologic bases of mitochondrial cytopathies, the diagnostic approaches, and main characteristics of related renal diseases are summarized. PMID:21811680

  12. Cancer: Mitochondrial Origins.

    PubMed

    Stefano, George B; Kream, Richard M

    2015-12-01

    The primacy of glucose derived from photosynthesis as an existential source of chemical energy across plant and animal phyla is universally accepted as a core principle in the biological sciences. In mammalian cells, initial processing of glucose to triose phosphate intermediates takes place within the cytosolic glycolytic pathway and terminates with temporal transport of reducing equivalents derived from pyruvate metabolism by membrane-associated respiratory complexes in the mitochondrial matrix. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionary fashioned chemiosmotic production of ATP as a high-efficiency biological process. The mechanistic bases of carcinogenesis have demonstrated profound alteration of normative mitochondrial function, notably dysregulated respiratory processes. Accordingly, the classic Warburg effect functionally links aerobic glycolysis, aberrant production and release of lactate, and metabolic down-regulation of mitochondrial oxidative processes with the carcinogenetic phenotype. We surmise, however, that aerobic fermentation by cancer cells may also represent a developmental re-emergence of an evolutionarily conserved early phenotype, which was "sidelined" with the emergence of mitochondrial oxidative phosphorylation as a primary mechanism for ATP production in normal cells. Regardless of state-dependent physiological status in mixed populations of cancer cells, it has been established that mitochondria are functionally linked to the initiation of cancer and its progression. Biochemical, molecular, and physiological differences in cancer cell mitochondria, notably mtDNA heteroplasmy and allele-specific expression of selected nuclear genes, may represent major focal points for novel targeting and elimination of cancer cells in metastatic disease afflicting human populations. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial

  13. Cancer: Mitochondrial Origins

    PubMed Central

    Stefano, George B.; Kream, Richard M.

    2015-01-