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Decapod Crustaceans of the Chesapeake Bay.  

National Technical Information Service (NTIS)

In this supplement 'Biota of Chesapeake Bay' a separate section is devoted to 'Taxa and Special Effects Summaries'. The author presents an assessment of the present status of knowledge of decapod crustaceans of Chesapeake Bay; their distribution and abund...

A. B. Williams



Decapod crustacean chelipeds: an overview.  


The structure, growth, differentiation and function of crustacean chelipeds are reviewed. In many decapod crustaceans growth of chelae is isometric with allometry level reaching unity till the puberty moult. Afterwards the same trend continues in females, while in males there is a marked spurt in the level of allometry accompanied by a sudden increase in the relative size of chelae. Subsequently they are differentiated morphologically into crusher and cutter making them heterochelous and sexually dimorphic. Of the two, the major chela is used during agonistic encounters while the minor is used for prey capture and grooming. Various biotic and abiotic factors exert a negative effect on cheliped growth. The dimorphic growth pattern of chelae can be adversely affected by factors such as parasitic infection and substrate conditions. Display patterns of chelipeds have an important role in agonistic and aggressive interactions. Of the five pairs of pereiopods, the chelae are versatile organs of offence and defence which also make them the most vulnerable for autotomy. Regeneration of the autotomized chelipeds imposes an additional energy demand called "regeneration load" on the incumbent, altering energy allocation for somatic and/or reproductive processes. Partial withdrawal of chelae leading to incomplete exuviation is reported for the first time in the laboratory and field in Macrobrachium species. PMID:11022233

Mariappan, P; Balasundaram, C; Schmitz, B



Behavioural indicators of pain in crustacean decapods.  


Whether invertebrates are able or not to experience pain is a highly controversial issue. An operative way to solve such a controversy might be to investigate their responses to potentially noxious stimuli and to collect evidence of their behavioural complexities as proxies of cognitive capacities. The principle of argument-by-analogy can be then applied to these data: the behaviour displayed by invertebrates is compared with that of "higher" animals, its similarity denoting the former's capacity to have analogous experiences. Here, the author discusses some examples, extracted from the literature on crustacean decapods, that pinpoint their nature of "sentient" animals. This review, however, also shows that research is still scanty in the field. The studies that examine the potential links between stress responses and pain experience are few, and the several papers that help elucidate cognitive abilities in decapods have been limited to a few taxa and are not specifically directed to the question of "sentience". On the contrary, also in the light of the expected revision of the current EU legislation in the matter, more scientific efforts should be expended on exploring the issue of pain experience in invertebrates. PMID:20061665

Gherardi, Francesca




EPA Science Inventory

Vitellogenesis, the production of vitellin (major yolk protein), is controlled in decapod crustaceans by several hormones. With increasing efforts world-wide to successfully culture economically important crustaceans, such as shrimp, there is growing interest in attaining a bette...


Aspartic proteinases in the digestive tract of marine decapod crustaceans  

Microsoft Academic Search

Decapod crustaceans synthesize highly active proteolytic enzymes in the midgut gland and release at least a part of them into the stomach where they facilitate the first step in peptide hydrolysis. The most common proteinases in the gastric fluid characterized so far are serine proteinases, that is, trypsin and chymotrypsin. These enzymes show highest activities at neutral or slightly alkaline

Fernando García-carreÑo; Manuel Díaz López; Laura Celis-guerrero; Reinhard Saborowski



Predictive modelling and spatial mapping of freshwater fish and decapod assemblages using GIS and neural networks  

Microsoft Academic Search

SUMMARY 1. We used stream fish and decapod spatial occurrence data extracted from a national database and recent surveys with geospatial landuse data, geomorphologic, climatic, and spatial data in a geographical information system (GIS) to model fish and decapod occurrence in the Wellington Region, New Zealand. 2. To predict the occurrence of each species at a site from a common

Michael K. Joy; Russell G. Death



Topographical and typological comparison of the rodlike setae of ambulatory dactylopodites in decapod crustaceans  

Microsoft Academic Search

The arrangement and external morphology of the rodlike setae and associated structures located on the dactylopodites of the walking legs of six species of decapod crustaceans are compared. The dactyls of littoral species, represented by the rock crab, Cancer antennarius, and the spiny lobster, Panulirus interruptus, have dense tufts and bands of rodlike setae, as is typical of many decapods,

K. A. Hamilton



Warm-water decapods and the trophic amplification of climate in the North Sea  

PubMed Central

A long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime.

Lindley, J. A.; Beaugrand, G.; Luczak, C.; Dewarumez, J.-M.; Kirby, R. R.



Warm-water decapods and the trophic amplification of climate in the North Sea.  


A long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime. PMID:20554562

Lindley, J A; Beaugrand, G; Luczak, C; Dewarumez, J-M; Kirby, R R



Aspartic proteinases in the digestive tract of marine decapod crustaceans.  


Decapod crustaceans synthesize highly active proteolytic enzymes in the midgut gland and release at least a part of them into the stomach where they facilitate the first step in peptide hydrolysis. The most common proteinases in the gastric fluid characterized so far are serine proteinases, that is, trypsin and chymotrypsin. These enzymes show highest activities at neutral or slightly alkaline conditions. The presence of acid proteinases, as they prevail in vertebrates, has been discussed contradictorily yet in invertebrates. In this study, we show that acid aspartic proteinases appear in the gastric fluid of several decapods. Lobsters Homarus gammarus showed the highest activity with a maximum at pH 3. These activities were almost entirely inhibited by pepstatin A, which indicates a high share of aspartic proteinases. In other species (Panulirus interruptus, Cancer pagurus, Callinectes arcuatus and Callinectes bellicosus), proteolytic activities were present at acid conditions but were distinctly lower than in H. gammarus. Zymograms at pH 3 showed in each of the studied species at least one, but mostly two-four bands of activity. The apparent molecular weight of the enzymes ranged from 17.8 to 38.6 kDa. Two distinct bands were identified which were inhibited by pepstatin A. Acid aspartic proteinases may play an important role in the process of extracellular digestion in decapod crustaceans. Activities were significantly higher in clawed lobster than in spiny lobster and three species of brachyurans. Therefore, it may be suggested that the expression of acid proteinases is favored in certain groups and reduced in others. PMID:16788916

Navarrete del Toro, María de Los Angeles; García-Carreño, Fernando; López, Manuel Díaz; Celis-Guerrero, Laura; Saborowski, Reinhard



Decapod crustaceans in fresh waters of southeastern Bahia, Brazil.  


A total of 117 species of freshwater decapod crustaceans are known from Brazil. Knowledge regarding the fauna of Decapoda from inland waters in the state of Bahia, northeast Brazil, is incipient. In spite of its wide territory and rich hydrographic net, only 13 species of limnetic decapods have been reported from that state. The objective of this contribution was to survey decapod crustaceans of some hydrographic basins in southeastern Bahia. The material described herein was obtained in samplings conducted between 1997 and 2005. Voucher specimens were deposited in the carcinological collections of the Museu de Zoologia, Universidade Estadual de Santa Cruz, Ilhéus, Brazil, and Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, Brazil. A total of 13 species was collected. The carideans were represented by the atyids Atya scabra (Leach, 1815) and Potimirim potimirim (Müller, 1881) and the palaemonids Macrobrachium acanthurus (Wiegmann, 1836), M. amazonicum (Heller, 1862), M. carcinus (Linnaeus, 1758), M. heterochirus (Wiegmann, 1836), M. jelskii (Miers, 1877), M. olfersi (Wiegmann, 1836), and Palaemon (Palaemon) pandaliformis (Stimpson, 1871). The brachyurans were represented by the portunids Callinectes bocourti A. Milne-Edwards, 1879 and C. sapidus Rathbun, 1895, the trichodactylid Trichodactylus fluviatilis Latreille, 1828 and the panopeid Panopeus rugosus A. Milne-Edwards, 1881. Macrobrachium heterochirus represents a new record from Bahia, and M. amazonicum is reported for the first time in southeast Bahia. The occurrence of two extreme different forms of T. fluviatilis was observed. Form A is characterized by the frontal margin of carapace bordered by conspicuous granules, the anterolateral margin provided with developed teeth plus granules, and the posterolateral margin provided with granulation similar to that found on the front. In form B the frontal margin is smooth or has an inconspicuous granulation; the anterolateral margin is usually provided with 1-3 notches, and teeth (1-2), if present, are small; and the posterolateral margin is smooth or slightly granulated. PMID:19419041

de Almeida, Alexandre Oliveira; Coelho, Petrônio Alves; Luz, Joaldo Rocha; dos Santos, José Tiago Almeida; Ferraz, Neyva Ribeiro



Chronobiology of deep-water decapod crustaceans on continental margins.  


Species have evolved biological rhythms in behaviour and physiology with a 24-h periodicity in order to increase their fitness, anticipating the onset of unfavourable habitat conditions. In marine organisms inhabiting deep-water continental margins (i.e. the submerged outer edges of continents), day-night activity rhythms are often referred to in three ways: vertical water column migrations (i.e. pelagic), horizontal displacements within benthic boundary layer of the continental margin, along bathymetric gradients (i.e. nektobenthic), and endobenthic movements (i.e. rhythmic emergence from the substrate). Many studies have been conducted on crustacean decapods that migrate vertically in the water column, but much less information is available for other endobenthic and nektobenthic species. Also, the types of displacement and major life habits of most marine species are still largely unknown, especially in deep-water continental margins, where steep clines in habitat factors (i.e. light intensity and its spectral quality, sediment characteristics, and hydrography) take place. This is the result of technical difficulties in performing temporally scheduled sampling and laboratory testing on living specimens. According to this scenario, there are several major issues that still need extensive research in deep-water crustacean decapods. First, the regulation of their behaviour and physiology by a biological clock is almost unknown compared to data for coastal species that are easily accessible to direct observation and sampling. Second, biological rhythms may change at different life stages (i.e. size-related variations) or at different moments of the reproductive cycle (e.g. at egg-bearing) based on different intra- and interspecific interactions. Third, there is still a major lack of knowledge on the links that exist among the observed bathymetric distributions of species and selected autoecological traits that are controlled by their biological clock, such as the diel rhythm of behaviour. Species evolved in a photically variable environment where intra- and inter-specific interactions change along with the community structure over 24 h. Accordingly, the regulation of their biology through a biological clock may be the major evolutionary constraint that is responsible for their reported bathymetric distributions. In this review, our aim is to propose a series of innovative guidelines for a discussion of the modulation of behavioural rhythms of adult decapod crustaceans, focusing on the deep waters of the continental margin areas of the Mediterranean as a paradigm for other marine zones of the world. PMID:20959158

Aguzzi, Jacopo; Company, Joan B



Primary structures of decapod crustacean metallothioneins with special emphasis on freshwater and semi-terrestrial species.  


Cadmium injections induced only a single form of metallothionein (MT) in the midgut gland of Potamon potamios, whereas the same treatment induced two isoforms in Astacus astacus. The only difference between the two latter isoforms was that one had an extra N-terminal methionine residue. MT from P. potamios showed structural differences from other decapod crustacean MTs. It contained a Gly-Thr motif at positions 8 and 8a, which had previously been found only in certain vertebrate and molluscan MTs. Furthermore P. potamios MT contained two to three times as many glutamic acid residues as normally found in decapod crustacean MT. The primary structure of MT from the freshwater crayfish A. astacus showed a high degree of sequence identity with MT from other decapod crustaceans, especially the marine astacidean Homarus americanus, although two valine residues were unexpectedly found at positions 8 and 21, where lysine residues are normally found. PMID:8921011

Pedersen, S N; Pedersen, K L; Højrup, P; Depledge, M H; Knudsen, J



Adult neurogenesis in the decapod crustacean brain: A hematopoietic connection?  

PubMed Central

New neurons are produced and integrated into circuits in the adult brains of many organisms, including crustaceans. In some crustacean species, the 1st- generation neuronal precursors reside in a niche exhibiting characteristics analogous to mammalian neurogenic niches. However, unlike mammalian niches where several generations of neuronal precursors coexist, the lineage of precursor cells in crayfish is spatially separated allowing the influence of environmental and endogenous regulators on specific generations in the neuronal precursor lineage to be defined. Experiments also demonstrate that the 1st-generation neuronal precursors in the crayfish Procambarus clarkii are not self-renewing. A source external to the neurogenic niche must therefore provide cells that replenish the 1st-generation precursor pool, because although these cells divide and produce a continuous efflux of 2nd-generation cells from the niche, the population of 1st-generation niche precursors is not diminished with growth and aging. In vitro studies show that cells extracted from the hemolymph, but not other tissues, are attracted to and incorporated into the neurogenic niche, a phenomenon that appears to involve serotonergic mechanisms. We propose that in crayfish, the hematopoietic system may be a source of cells that replenish the niche cell pool. These and other studies reviewed here establish decapod crustaceans as model systems in which the processes underlying adult neurogenesis, such as stem cell origins and transformation, can be readily explored. Studies in diverse species where adult neurogenesis occurs will result in a broader understanding of fundamental mechanisms and how evolutionary processes may have shaped the vertebrate/mammalian condition.

Beltz, Barbara S.; Zhang, Yi; Benton, Jeanne L.; Sandeman, David C.



Freshwater decapod crustaceans (Palaemonidae, Cambaridae) of the Savannah River Plant, South Carolina  

Microsoft Academic Search

Decapod crustaceans (specifically crayfishes and freshwater shrimps) are quite numerous in the drainages of the southeastern United States and occupy an extremely important niche in aquatic systems. As predators they act as disturbance components on benthic freshwater communities and may serve an integral position in the early stages of detrital decomposition. They constitute an important prey item in the diets

H. H. Hobbs; J. H. Thorp; G. E. Anderson



A morphological approach for relating decapod crustacean cephalothorax shape with distribution in the water column  

Microsoft Academic Search

Cephalothorax profiles for individuals of 18 decapod crustacean species were obtained from pictures of specimens captured using various experimental bottom trawls in the Mediterranean basin, at depths ranging from 200 to 4000 m in 2000 and 2002. Profiles were compared using the shape (outline) of the entire cephalothorax (including and excluding the rostrum). Principal component analysis (PCA) of the profiles, rostrum

F. Sardà; J. B. Company



Paleozoic-Mesozoic crayfish from Antarctica: Earliest evidence of freshwater decapod crustaceans  

Microsoft Academic Search

Discovery of an Early Permian claw from Antarctica extends the fossil record of crayfish by ˜65 m.y. and demonstrates that decapod crustaceans had radiated into freshwater habitats by the late Paleozoic. Burrows in Lower Triassic rocks of Antarctica are among the oldest apparently constructed by crayfish. Their morphology is similar to modern crayfish burrows, and this demonstrates that burrowing behavior

Loren E. Babcock; Molly F. Miller; John L. Isbell; James W. Collinson; Stephen T. Hasiotis



Experimental taphonomy of a decapod crustacean: Long-term data and their implications  

Microsoft Academic Search

Despite being a common element in many modern marine habitats, decapod crustaceans have a patchy yet long-ranging fossil record. While a strong susceptibility to decay early in the post-mortem history is generally acknowledged, specific controls on the preservation potential of this group are poorly understood. To aid in the full understanding of the details of the taphonomic process for this

Richard A. Krause; Karla Parsons-Hubbard; Sally E. Walker


Temporal and Spatial Patterns of Microhabitat Use by Fishes and Decapod Crustaceans in a Louisiana Estuary  

Microsoft Academic Search

We used a 1-m beam trawl to characterize microhabitat use by fishes and decapod crustaceans in monthly samples collected in Vermilion and West Cote Blanche bays in central coastal Louisiana. Randomized sampling within strata characterized the distributions of species, size-classes, and environmental conditions throughout the coastal bays. Microhabitats were characterized by salinity, temperature, dissolved oxygen, depth, distance from shore, substrate

Donald M. Baltz; Robert F. Jones



Biogeography of subterranean decapods in North and Central America and the Caribbean region (Caridea, Astacidea, Brachyura)  

Microsoft Academic Search

A significant number of decapod crustaceans (81 troglobites and 58 other cavernicoles) has been described from various subterranean waters in North and Central America (United States south to Costa Rica) and from the islands in the western north Atlantic and the Caribbean Sea, posing puzzling questions concerning their evolution and biogeography. Of these troglobitic species, 36 are shrimps (1 procarid,

Horton H. Hobbs



Experimental infection of white spot baculovirus in some cultured and wild decapods in Taiwan  

Microsoft Academic Search

Techniques for the detection of white spot baculovirus virus (WSBV) by polymerase chain reaction are well established. In this study, two primer sets designed from an isolate of WSBV from Penaeus monodon, PmNOB III, were used to detect WSBV infection in cultured and wild decapods in Taiwan. WSBV positive cases were found in all of four major marine cultured shrimp,

Yu-Chi Wang; Chu-Fang Lo; Poh-Shing Chang; Guang-Hsiung Kou



Abundance and diversity of decapod crustaceans in the deep-Catalan Sea (Western Mediterranean)  

Microsoft Academic Search

The deep-slope decapod fauna of the Catalan Sea was extensively sampled with an OTSB-14 bottom trawl. A total of 67 bottom tows were taken from 1985 to 1989 at bottom depths ranging from 552 to 2261 m. Species in which abundance decreased with depth were Plesionika acanthonotus, Polycheles typhlops, Calocaris macandreae and Geryon longipes. Highest densities of Acanthephyra eximia, Stereomastis

J. E. Cartes; F. Sardà



Zonation of deep-sea decapod fauna in the Catalan Sea (Western Mediterranean)  

Microsoft Academic Search

Zonation of deep-sea decapod crustacean fauna was established in the Catalan Sea (Western Mediterranean) based on a total of 66 bottom trawls carried out between 552 and 2261 m depth. An OTSB-14 bottom trawl was used as sampling gear. The main boundaries were located at 1200 to 1300 m and around 1900 to 2000 m. The 1200 to 1300 m

J. E. Cartes; F. Sarda



When did decapods invade hydrothermal vents? Clues from the Western Pacific and Indian Oceans.  


Hydrothermal vents are typically located in midocean ridges and back-arc basins and are usually generated by the movement of tectonic plates. Life thrives in these environments despite the extreme conditions. In addition to chemoautotrophic bacteria, decapod crustaceans are dominant in many of the hydrothermal vents discovered to date. Contrary to the hypothesis that these species are remnants of relic fauna, increasing evidence supports the notion that hydrothermal vent decapods have diversified in more recent times with previous research attributing the origin of alvinocarid shrimps to the Miocene. This study investigated seven representative decapod species from four hydrothermal vents throughout the Western Pacific and Indian Oceans. A partitioned mix-model phylogenomic analysis of mitochondrial DNA produced a consistent phylogenetic topology of these vent-endemic species. Additionally, molecular dating analysis calibrated using multiple fossils suggested that both bythograeid crabs and alvinocarid shrimps originated in the late Mesozoic and early Cenozoic. Although of limited sampling, our estimates support the extinction/repopulation hypothesis, which postulates recent diversification times for most hydrothermal vent species due to their mass extinction by global deep-water anoxic/dysoxic events during the Late Cretaceous and Early Tertiary. The continental-derived property of the West Pacific province is compatible with the possibility that vent decapods diversified from ancestors from shallow-water regions such as cold seeps. Our results move us a step closer toward understanding the evolutionary origin of hydrothermal vent species and their distribution in the Western Pacific-Indian Ocean Region. PMID:23002089

Yang, Jin-Shu; Lu, Bo; Chen, Dian-Fu; Yu, Yan-Qin; Yang, Fan; Nagasawa, Hiromichi; Tsuchida, Shinji; Fujiwara, Yoshihiro; Yang, Wei-Jun



Community Characteristics of Dominant Forage Fishes and Decapods in the Whitewater Bay: Shark River Estuary, Everglades National Park.  

National Technical Information Service (NTIS)

The report presents the results of studies on the community characteristics (relative abundance, seasonal occurrence, size, reproductive activity, and food habitats) on the following dominant epibenthic forage fish and decapod crustacean species: pink shr...

T. W. Schmidt



Mitogenomic analysis of decapod crustacean phylogeny corroborates traditional views on their relationships.  


Phylogenetic relationships within decapod crustaceans are highly controversial. Even recent analyses based on molecular datasets have shown largely contradictory results. Previous studies using mitochondrial genomes are promising but suffer from a poor and unbalanced taxon sampling. To fill these gaps we sequenced the (nearly) complete mitochondrial genomes of 13 decapod species: Stenopus hispidus, Polycheles typhlops, Panulirus versicolor, Scyllarides latus, Enoplometopus occidentalis, Homarus gammarus, Procambarus fallax f. virginalis, Upogebia major, Neaxius acanthus, Calocaris macandreae, Corallianassa coutierei, Cryptolithodes sitchensis, Neopetrolisthes maculatus, and add that of Dromia personata. Our new data allow for comprehensive analyses of decapod phylogeny using the mitochondrial genomes of 50 species covering all major taxa of the Decapoda. Five species of Stomatopoda and one species of Euphausiacea serve as outgroups. Most of our analyses using Maximum Likelihood (ML) and Bayesian inference (BI) of nucleotide and amino acid datasets revealed congruent topologies for higher level decapod relationships: (((((((Anomala, Brachyura), Thalassinida: Gebiidea), Thalassinida: Axiidea), (Astacidea, Polychelida), Achelata), Stenopodidea), Caridea), Dendrobranchiata). This result corroborates several traditional morphological views and adds new perspectives. In particular, the position of Polychelida is surprising. Nevertheless, some problems can be identified. In a minority of analyses the basal branching of Reptantia is not fully resolved, Thalassinida are monophyletic; Polychelida are the sister group to Achelata, and Stenopodidea are resolved as sister group to Caridea. Despite this and although some nodal supports are low in our phylogenetic trees, we think that the largely stable topology of the trees regardless of different types of analyses suggests that mitochondrial genomes show good potential to resolve the relationship within Decapoda. PMID:23202543

Shen, Hong; Braband, Anke; Scholtz, Gerhard



Megabenthic decapod crustacean assemblages on the Galician continental shelf and upper slope (north-west Spain)  

Microsoft Academic Search

The structure of megabenthic decapod crustacean assemblages on the Galician (north-west Spain) continental shelf (100 to\\u000a 200 depth) and upper slope (200 to 500 m) was analyzed based on surveys carried out in autumn and spring, from 1980 to 1987.\\u000a Forty species belonging to 19 families were caught. The portunid crab Polybius henslowii, a species with pelagic phases, was the

A. C. Fariña; J. Freire; E. González-Gurriarán




Microsoft Academic Search

Five species of decapod crustaceans new to science are described. These are caridean shrimps of the family Bresiliidae-Alvinocaris markf!nsis from a Mid-Atlantic Rift Valley hydrothermal field, A. muricola from a cold brine seep at the foot ofthe West Florida Escarpment in the GulfofMexico, and A. stactophila from a hydrocarbon seep on the continental slope of the northern Gulfof Mexico, with



Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina  

Microsoft Academic Search

Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid\\u000a crab species,Cyrtograpsus angulatus andChasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November–December 1992), the physical\\u000a properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon\\u000a is characterized by

K. Anger; E. Spivak; C. Bas; D. Ismael; T. Luppi



Adult neurogenesis: Examples from the decapod crustaceans and comparisons with mammals  

PubMed Central

Defining evolutionary origins is a means of understanding an organism’s position within the integrated web of living beings, and to not only to trace characteristics back in time, but also to project forward in an attempt to reveal relationships with more recently evolved forms. Both the vertebrates and arthropods possess condensed nervous systems, but this is dorsal in the vertbrates and ventral in the arthropods. Also, whereas the nervous system in the vertebrates develops from a neural tube in the embryo, that of the arthropods comes from an ectodermal plate. Despite these apparently fundamental differences, it is now generally accepted that life-long neurogenesis, the generation of functionally integrated neurons from progenitor cells, is a common feature of the adult brains of a variety of organisms, ranging from insects and crustaceans to birds and mammals. Among decapod crustaceans, there is evidence for adult neurogenesis in basal species of the Dendrobranchiata, as well as in more recent terrestrial, marine and fresh-water species. The widespread nature of this phenomenon in decapod species may relate to the importance of the adult-born neurons, although their functional contribution is not yet known. The many similarities between the systems generating neurons in the adult brains of decapod crustaceans and mammals, reviewed in this paper, suggest that adult neurogenesis is governed by common ancestral mechanisms that have been retained in a phylogenetically broad group of species.

Sandeman, David C.; Bazin, Francois; Beltz, Barbara S.



Seasonal distribution and abundance of fishes and decapod crustaceans in a Cape Cod estuary  

USGS Publications Warehouse

Sampling in several habitat types (sand/mud, eelgrass, sand, gravel, macroalgae/mud) during all seasons with a variety of gears in Nauset Marsh, Massachusetts during 1985-1987 found a fauna consisting of 35 fish and 10 decapod crustacean species. Although most of the abundant species were found in several habitat types, species richness and habitat use appeared to be highest for vegetated habitats (eelgrass, macroalgae). The fishes and decapods were numerically dominated by cold-water taxa; however, numerous fish species, represented by rare individuals of predominantly southern forms, enriched the fauna. Species composition of Nauset Marsh could be distinguished from estuaries south of Cape Cod and even from the south shore of the cape. Both fishes and decapods were most abundant during the summer, apparently due to the contributions from spring and summer spawning in the estuary and the adjacent Atlantic Ocean. The location of Nauset Marsh and other estuaries on Cape Cod provide a unique opportunity to evaluate the importance of this region as a faunal boundary to estuarine species.

Able, K.W.; Fahay, M.P.; Heck, K.L.; Roman, C.T.; Lazzari, M.A.; Kaiser, S.C.




PubMed Central

Extranuclear basic proteins have been detected in the capsule of the spermatozoa of three species of decapod crustaceans (Nephrops norvegicus L., Macrura; Eupagurus bernhardus L., Anomura; Carcinus maenas Penn., Brachyura). Their properties have been studied by cytochemical methods. Their position inside the capsule of the spermatozoon has been specified with the aid of the electron microscope. Present in a constant fashion in the three species cited, their relative importance is very variable. In contrast to the refringent cone of the spermatozoon of Ascaris, which contains an acid protein, ascaradine, the capsule of the spermatozoon of the three decapod crustaceans studied contains basic proteins which we propose to designate by the general term "decapodine".

Chevaillier, Philippe



Hematodinium sp. (Alveolata, Syndinea) detected in marine decapod crustaceans from waters of Denmark and Greenland.  


Five decapod crustacean species were examined for presence of the parasitic dinoflagellate Hematodinium spp. (Alveolata, Syndinea) by morphological methods (colour and pleopod methods) as well as by PCR and nested PCR with Hematodinium-specific primers. Nephrops norvegicus, Pagurus bernhardus and Liocarcinus depurator were sampled by trawling in Danish waters and Chionoecetes opilio and Hyas araneus were sampled by trapping off the west coast of Greenland. The existence of Hematodinium has not previoiusly been documented in Danish waters, but it was detected in all 3 decapod species examined in the present study. Hematodinium sp. was also detected for the first time in H. araneus and the existence of Hematodinium sp. in Greenlandic C. opilio was documented by PCR. Analyses of 26 Hematodinium sp. ITS1 sequences, including sequences from all 5 host species sampled, revealed more than 95% sequence similarity between 24 of the sequences. Two Hematodinium sp. ITS1 sequences from C. opilio were only 81% similar to the 24 other ITS1 sequences. The nested PCR approach resulted in the highest reported percentages of positive samples for Hematodinium the hosts investigated (between 45 and 87.5%). However, no decapods were found to be infected with Hematodinium sp. based on morphological methods. Consequently, Hematodinium sp. may be more common than previously believed, and, assuming that the DNA found originated from viable and infectious parasite cells, infections may not always be fatal. We suggest that the hosts investigated may have been subject to latent infections that could develop into a fatal disease only if the hosts were physiologically stressed due to other factors. PMID:21166315

Eigemann, F; Burmeister, A; Skovgaard, A



Model-based multi-locus estimation of decapod phylogeny and divergence times.  


Phylogenetic relationships among all of the major decapod infraorders have never been estimated using molecular data, while morphological studies produce conflicting results. In the present study, the phylogenetic relationships among the decapod basal suborder Dendrobranchiata and all of the currently recognized decapod infraorders within the suborder Pleocyemata (Caridea, Stenopodidea, Achelata, Astacidea, Thalassinidea, Anomala, and Brachyura) were inferred using 16S mtDNA, 18S and 28S rRNA, and the histone H3 gene. Phylogenies were reconstructed using the model-based methods of maximum likelihood and Bayesian methods coupled with Markov Chain Monte Carlo inference. The phylogenies revealed that the seven infraorders are monophyletic, with high clade support values (bp>70; pP>0.95) under both methods. The two suborders also were recovered as monophyletic, but with weaker support (bp=70; pP=0.74). Although the nodal support values for infraordinal relationships were low (bp<50; pP<0.77) the Anomala and Brachyura were basal to the rest of the 'Reptantia' in both reconstructions and using Bayesian tree topology tests alternate morphology-based hypotheses were rejected (P<0.01). Newly developed multi-locus Bayesian and likelihood heuristic rate-smoothing methods to estimate divergence times were compared using eight fossil and geological calibrations. Estimated times revealed that the Decapoda originated earlier than 437MYA and that the radiation within the group occurred rapidly, with all of the major lineages present by 325MYA. Node time estimation under both approaches is severely affected by the number and phylogenetic distribution of the fossil calibrations chosen. For analyses incorporating fossils as fixed ages, more consistent results were obtained by using both shallow and deep or clade-related calibration points. Divergence time estimation using fossils as lower and upper limits performed well with as few as one upper limit and a single deep fossil lower limit calibration. PMID:16112880

Porter, Megan L; Pérez-Losada, Marcos; Crandall, Keith A



Aspects of Benthic Decapod Diversity and Distribution from Rocky Nearshore Habitat at Geographically Widely Dispersed Sites  

PubMed Central

Relationships of diversity, distribution and abundance of benthic decapods in intertidal and shallow subtidal waters to 10 m depth are explored based on data obtained using a standardized protocol of globally-distributed samples. Results indicate that decapod species richness overall is low within the nearshore, typically ranging from one to six taxa per site (mean?=?4.5). Regionally the Gulf of Alaska decapod crustacean community structure was distinguishable by depth, multivariate analysis indicating increasing change with depth, where assemblages of the high and mid tide, low tide and 1 m, and 5 and 10 m strata formed three distinct groups. Univariate analysis showed species richness increasing from the high intertidal zone to 1 m subtidally, with distinct depth preferences among the 23 species. A similar depth trend but with peak richness at 5 m was observed when all global data were combined. Analysis of latitudinal trends, confined by data limitations, was equivocal on a global scale. While significant latitudinal differences existed in community structure among ecoregions, a semi-linear trend in changing community structure from the Arctic to lower latitudes did not hold when including tropical results. Among boreal regions the Canadian Atlantic was relatively species poor compared to the Gulf of Alaska, whereas the Caribbean and Sea of Japan appeared to be species hot spots. While species poor, samples from the Canadian Atlantic were the most diverse at the higher infraordinal level. Linking 11 environmental variables available for all sites to the best fit family-based biotic pattern showed a significant relationship, with the single best explanatory variable being the level of organic pollution and the best combination overall being organic pollution and primary productivity. While data limitations restrict conclusions in a global context, results are seen as a first-cut contribution useful in generating discussion and more in-depth work in the still poorly understood field of biodiversity distribution.

Pohle, Gerhard; Iken, Katrin; Clarke, K. Robert; Trott, Thomas; Konar, Brenda; Cruz-Motta, Juan Jose; Wong, Melisa; Benedetti-Cecchi, Lisandro; Mead, Angela; Miloslavich, Patricia; Mieszkowska, Nova; Milne, Rebecca; Tamburello, Laura; Knowlton, Ann; Kimani, Edward; Shirayama, Yoshihisa



Marine snake epibiosis: a review and first report of decapods associated with Pelamis platurus.  


Under circumstances in which area for settlement is limited, the colonization of living substrata may become a highly valuable strategy for survival of marine invertebrates. This phenomenon, termed epibiosis, results in spatially close associations between two or more living organisms. Pelamis platurus, the yellow-bellied sea snake, is the only exclusively pelagic marine snake and its propensity for foraging along ocean slicks facilitates its colonization by pelagic epibionts. Herein, we report epibionts associated with P. platurus inhabiting the waters off the northwestern Pacific coast of Costa Rica. These associations include the first records of decapod epibionts from any marine snake. Decapod epibionts were found on 18.9% of P. platurus, and size of snake (total length) had a significant positive effect on the frequency and intensity of epibiosis. We discuss the spatial and ecological mechanisms that facilitate these interactions, as well as the suite of factors that either promote or deter epibiosis and ultimately dictate the frequency and intensity of these interactions. Finally, we provide a review of marine snake epibiosis. The intention of this review is to (1) provide contemporary researchers with a single, accessible reference to all known reports of epibionts associated with marine snakes and (2) discuss what is currently known with respect to diversity of epibionts from marine snakes. PMID:22505588

Pfaller, Joseph B; Frick, Michael G; Brischoux, François; Sheehy, Coleman M; Lillywhite, Harvey B



Decapod burrows in mangrove?channel and back?reef environments at the Atlantic barrier reef, Belize  

Microsoft Academic Search

Burrows of decapod crustaceans were investigated by in situ resin casting in various mangrove and back?reef environments. Alpheid shrimps (A. floridanus and A. heterochaelis) were the most numerous burrowing shrimps in soft muddy sediments of mangrove channels. Their burrows consist either of a single U or a series of U's inhabited by a pair of shrimp or are Y?shaped and

Peter C. Dworschak; Jörg A. Ott



Acanthaster planci Outbreak: Decline in Coral Health, Coral Size Structure Modification and Consequences for Obligate Decapod Assemblages  

PubMed Central

Although benthic motile invertebrate communities encompass the vast majority of coral reef diversity, their response to habitat modification has been poorly studied. A variety of benthic species, particularly decapods, provide benefits to their coral host enabling them to cope with environmental stressors, and as a result benefit the overall diversity of coral-associated species. However, little is known about how invertebrate assemblages associated with corals will be affected by global perturbations, (either directly or indirectly via their coral host) or their consequences for ecosystem resilience. Analysis of a ten year dataset reveals that the greatest perturbation at Moorea over this time was an outbreak of the corallivorous sea star Acanthaster planci from 2006 to 2009 impacting habitat health, availability and size structure of Pocillopora spp. populations and highlights a positive relationship between coral head size and survival. We then present the results of a mensurative study in 2009 conducted at the end of the perturbation (A. planci outbreak) describing how coral-decapod communities change with percent coral mortality for a selected coral species, Pocillopora eydouxi. The loss of coral tissue as a consequence of A. planci consumption led to an increase in rarefied total species diversity, but caused drastic modifications in community composition driven by a shift from coral obligate to non-obligate decapod species. Our study highlights that larger corals left with live tissue in 2009, formed a restricted habitat where coral obligate decapods, including mutualists, could subsist. We conclude that the size structure of Pocillopora populations at the time of an A. planci outbreak may greatly condition the magnitude of coral mortality as well as the persistence of local populations of obligate decapods.

Leray, Matthieu; Beraud, Maxime; Anker, Arthur; Chancerelle, Yannick; Mills, Suzanne C.



Selfing in a malacostracan crustacean: why a tanaidacean but not decapods.  


The crustacean class Malacostraca, with over 22,000 species, includes commercially important members, such as crabs, shrimps, and lobsters. A few simultaneous hermaphrodites are known in this group, but self-fertilization was unknown. Here we show, through microscopy and breeding experiments, that the simultaneously hermaphroditic malacostracan Apseudes sp. (order Tanaidacea) can self-fertilize; individuals reared in isolation become hermaphroditic via a male-like phase and produce eggs that develop into fertile adults. Although selfing occurs in crustaceans like the Branchiopoda, in which simultaneous hermaphrodites have the sex ducts united, in decapods the separation of gonadal ducts and gonopores, specialized mating organs, and complex mating behavior appear to have constrained the evolution of selfing. In contrast, in most tanaidaceans, sperm is released externally by a male and reaches the eggs in the female brood pouch, where fertilization occurs. This mode of fertilization permitted Apseudes sp. to achieve selfing without large modifications in morphology or behavior. PMID:23846305

Kakui, Keiichi; Hiruta, Chizue



Paleozoic-Mesozoic crayfish from Antarctica: Earliest evidence of freshwater decapod crustaceans  

NASA Astrophysics Data System (ADS)

Discovery of an Early Permian claw from Antarctica extends the fossil record of crayfish by ˜65 m.y. and demonstrates that decapod crustaceans had radiated into freshwater habitats by the late Paleozoic. Burrows in Lower Triassic rocks of Antarctica are among the oldest apparently constructed by crayfish. Their morphology is similar to modern crayfish burrows, and this demonstrates that burrowing behavior was established early in the evolution of this group. The new discoveries show that the earliest Permian crayfish were distributed in high paleolatitudes of southernmost Pangea, where they lived in freshwater lakes fed by glacial meltwater. Modern crayfish habitat, used as a guide to crayfish temperature tolerance, indicates that summer temperatures of streams and lakes near the South Pole that supported the crayfish probably reached 10 20 °C during Permian-Triassic interglacial intervals.

Babcock, Loren E.; Miller, Molly F.; Isbell, John L.; Collinson, James W.; Hasiotis, Stephen T.



Haemolymph Mg(2+) regulation in decapod crustaceans: physiological correlates and ecological consequences in polar areas.  


Reptant decapod crustaceans are almost absent from the Southern Ocean south of the Antarctic Convergence. We tested the hypothesis that this may be due to the reduced ability of this group to regulate Mg(2+) levels in the haemolymph ([Mg(2+)](HL)). Mg(2+) acts as an anaesthetic in marine invertebrates and its level is higher in Reptantia (crabs such as Cancer spp., Chionoecetes spp., Maja spp., 30-50 mmol l(-)(1)) than in Natantia (prawns such as Pandalus spp., Palaemon spp., Crangon spp., 5-12 mmol l(-)(1)). We varied [Mg(2+)](HL) in three species of reptant decapod crustaceans, Carcinus maenas, Hyas araneus and Eurypodius latreillei, and investigated heart rate, the rate of oxygen consumption and levels of spontaneous and forced activity at different temperatures. The rate of oxygen consumption and heart rate increased significantly with reduction in [Mg(2+)](HL) over the entire temperature range investigated in E. latreillei. In H. araneus, an increase in metabolic and heart rates compared with control values was found only at temperatures below 2 degrees C. Forced and spontaneous activity levels increased significantly in the group of [Mg(2+)](HL)-reduced animals below 0 degrees C, at which control animals were mostly inactive. At a reduced [Mg(2+)](HL) of 5-12 mmol l(-)(1), which is the [Mg(2+)](HL) of caridean shrimps in the Southern Ocean, Q(10) and activation energy were reduced for all these variables and extended the temperature range over which physiological functions were maintained. We suggest that the high [Mg(2+)](HL) in Reptantia causes relaxation of the animals and reduces their scope for activity, especially at temperatures below 0 degrees C. The hypothesis that the synergistic effects of high [Mg(2+)](HL) and low temperature probably prevented the Reptantia from recolonizing the permanently cold water of polar areas is discussed. PMID:10729286

Frederich, M; Sartoris, F J; Arntz, W E; Pörtner, H



Comparative seasonal and spatial distribution of decapod larvae assemblages in three coastal zones off the south-western Iberian Peninsula  

NASA Astrophysics Data System (ADS)

Plankton studies over the long southern coast of Iberian Peninsula are very scarce and restricted to a few specific taxonomic groups. In order to know the dynamic of decapod larvae coastal assemblages from south-western of Iberian Peninsula, three zones were studied: Guadalquivir Estuary, Cádiz Bay and Algeciras Bay. The three zones differ by their freshwater inflow and turbidity (highest in Guadalquivir Estuary), primary production (highest in Cádiz Bay) and nutrient concentrations (lowest in Algeciras Bay). The material is based upon plankton samples (250 ?m mesh) collected monthly at eight stations distributed between these zones, during 1 year. Maximum values of abundance and diversity were found in Cádiz Bay, while the lowest were recorded in Algeciras Bay. Brachyura was the main abundant taxonomic group in larval decapod assemblages, while Dendrobranchiata, Palinura, Stenopodidea, and Astacidea were scarcely represented or absent. From the 69 taxa identified, 11 were considered rare and 12 taxa constituted 87% of the total larvae collected. Liocarcinus spp. was the most representative taxon, being present in all stations and showing high abundance and dominance values. The annual distribution was specifically studied for Liocarcinus spp., Carcinus maenas, Xantho spp., Ilia nucleus, Uca tangeri, Brachynotus spp., Hippolyte spp., Philocheras spp., Pisidia longicornis, Diogenes pugilator, Pilumnus spp. and Upogebia sp. Attending to the temporal distribution of dominant taxa, three abundance patterns are shown for decapod larvae at study zones: (i) species present in non-warm months; (ii) species present in warm months; (iii) species present through all year.

González-Gordillo, J. I.; Rodríguez, A.


Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina  

NASA Astrophysics Data System (ADS)

Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid crab species, Cyrtograpsus angulatus and Chasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November December 1992), the physical properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon is characterized by highly variable physical conditions, with oligohaline waters frequently predominating over extended periods. The adjacent coastal waters show a complex pattern of semidiurnal tides that often do not influence the lagoon, due to the existence of a sandbar across its entrance. Besides frequently occurring larvae (exclusively freshly hatched zoeae and a few megalopae) of the two dominating crab species, those of three other brachyurans ( Plathyxanthus crenulatus, Uca uruguayensis, Pinnixa patagonica) and of one anomuran (the porcellanid Pachycheles haigae) were also found occasionally. Caridean shrimp ( Palaemonetes argentinus) larvae occurred in a moderate number of samples, with a maximum density of 800·m-3. The highest larval abundance was recorded in C. angulatus, with almost 8000°m-3. Significantly more C. angulatus and C. granulata zoeae occurred at night than during daylight conditions, and more larvae (statistically significant only in the former species) during ebb (outflowing) than during flood (inflowing) tides. In consequence, most crab zoeae were observed during nocturnal ebb, the least with diurnal flood tides. Our data suggest that crab larvae do not develop in the lagoon, where the adult populations live, but exhibit an export strategy, probably based upon exogenously coordinated egg hatching rhythms. Zoeal development must take place in coastal marine waters, from where the megalopa eventually returns for settlement and metamorphosis in the lagoon. Significantly higher larval frequency of C. granulata in low salinities (?12‰) and at a particular sampling site may be related to local distribution patterns of the reproducing adult population. Unlike crab larvae, those of shrimp ( P. argentinus) are retained inside the lagoon, where they develop from hatching through metamorphosis. They significantly prefer low salinity and occur at the lagoon surface more often at night. These patterns cannot be explained by larval release rhythms like those in brachyuran crabs, but may reflect diel vertical migrations to the bottom. It is concluded that osmotic stress as well as predation pressure exerted by visually directed predators (small species or life-cycle stages of estuarine fishes) may be the principal selection factors for the evolution of hatching and migration rhythms in decapod larvae, and that these are characteristics of export or retention mechanisms, respectively.

Anger, K.; Spivak, E.; Bas, C.; Ismael, D.; Luppi, T.



Preliminary study of sperm chromatin characteristics of the brachyuran crab Maja brachydactyla. Histones and nucleosome-like structures in decapod crustacean sperm nuclei previously described without SNBPs.  


An interesting characteristic of decapod crustacean sperm nuclei is that they do not contain highly packaged chromatin. In the present study we re-examine the presence of DNA-interacting proteins in sperm nuclei of the brachyuran Maja brachydactyla. Although previous reports have indicated that, unlike the majority of sperm cells, DNA of decapod sperm is not organized by basic proteins, in this work we show that: (1) histones are present in sperm of M. brachydactyla; (2) histones are associated with sperm DNA; (3) histone H3 appears in lower proportions than the other core histones, while histone H2B appears in higher proportions; and (4) histone H3 in sperm nuclei is acetylated. This work complements a previous study of sperm histones of Cancer pagurus and supports the suggestion that decapod crustacean sperm chromatin deserves further attention. PMID:19324386

Kurtz, K; Ausió, J; Chiva, M



Setal morphology of the grooming appendages of Macrobrachium rosenbergii (Crustacea: Decapoda: Caridea: Palaemonidae) and review of decapod setal classification.  


Setae are vital in grooming activities and aiding in the removal of epibionts and sedimentary fouling from the body surfaces of decapod crustaceans. Thus, the setal structures and their arrangement on the grooming appendages and sensory structures of the commercially important shrimp, Macrobrachium rosenbergii, were examined using scanning electron microscopy. Macrobrachium rosenbergii is extensively grown in aquaculture and exhibits unique male morphological forms, termed morphotypes. The three male morphotypes are termed blue-clawed males, orange-clawed males, and small-clawed or undifferentiated males and all three differ in their dominance, behavior, body morphology, and reproductive success. Seven setal types, two of which have never been described in the literature, are identified on the grooming appendages (third maxillipeds, first, second, and fifth pereopods) and antennae: simple, serrate, serrulate, spiniform, pappose, crinoid, and spinulate. The latter two setae are newly identified. Certain setal types, such as serrate and serrulate setae were located and associated with specific grooming appendages such as the first pereopods. The types of setae on the grooming appendages varied among females and male morphotypes and the novel setal types (crinoid and spinulate) were found only on two of the male morphotypes. A literature review of terminology related to the structure of setae and setal types in decapod crustaceans is offered as the usage of various terms is ambiguous and conflicting in the literature. The intention of this review is to provide future authors with a comprehensive collection of terms and images that can be used to describe various aspects of setal morphology in decapods. PMID:24500885

Wortham, Jennifer L; Vanmaurik, Lauren N; Wayne Price, W





Aquatic and terrestrial crustaceans are dependent on both aerobic and anaerobic metabolism for energy production during exercise. Anaerobic energy production is marked by an accumulation of lactate in both muscle tissue and haemolymph, but the metabolic fate of lactate is not clear. Lactate recycling via gluconeogenesis and the potential role of carbonic anhydrase (CA) in supplying bicarbonate for the carboxylation of pyruvate were investigated in three species of decapod crustaceans: Callinectes sapidus (aquatic), Cardisoma guanhumi (semi-terrestrial) and Gecarcinus lateralis (terrestrial). CA activity was found in mitochondria and cytoplasmic fractions of gill, hepatopancreas and muscle of all three species. Significant activities of key enzymes of gluconeogenesis (e.g. pyruvate carboxylase, phosphoenolpyruvate carboxykinase and fructose bisphosphatase), however, could not be detected. Exercise to exhaustion produced a species-specific pattern of accumulation and clearance of lactate in tissue and haemolymph, indicating a differential degree of reliance on anaerobic energy production. Treatment with acetazolamide, a CA inhibitor, did not significantly alter the pattern of lactate dynamics in animals given repeated bouts of exhaustive exercise interspersed with periods of recovery. Injection of [U-14C]lactate resulted in the appearance of label in both muscle glycogen and excreted carbon dioxide, suggesting multiple metabolic fates for lactate. Lactate turnover rates for G. lateralis were similar to those reported for fish. In these animals, gluconeogenesis possibly proceeds via the reversal of pyruvate kinase, or via the typical Cori cycle but so slowly that the uncatalysed supply of bicarbonate is sufficient to keep pace with the low activities of pyruvate carboxylase and the subsequent low rates of pyruvate carboxylation. PMID:9317667




Bioaccumulation and retention kinetics of cadmium in the freshwater decapod Macrobrachium australiense.  


The potential sources and mechanisms of cadmium bioaccumulation by the native freshwater decapods Macrobrachium species in the waters of the highly turbid Strickland River in Papua New Guinea were examined using (109)Cd-labelled water and food sources and the Australian species Macrobrachium australiense as a surrogate. Synthetic river water was spiked with environmentally relevant concentrations of cadmium and animals were exposed for 7 days with daily renewal of test solutions. Dietary assimilation of cadmium was assessed through pulse-chase experiments where prawns were fed separately (109)Cd-labelled fine sediment, filamentous algae and carrion (represented by cephalothorax tissue of water-exposed prawns). M. australiense readily accumulated cadmium from the dissolved phase and the uptake rate increased linearly with increasing exposure concentration. A cadmium uptake rate constant of 0.10 ± 0.05 L/g/d was determined in synthetic river water. During depuration following exposure to dissolved cadmium, efflux rates were low (0.9 ± 5%/d) and were not dependent on exposure concentration. Assimilation efficiencies of dietary sources were comparable for sediment and algae (48-51%), but lower for carrion (28 ± 5%) and efflux rates were low (0.2-2.6%/d) demonstrating that cadmium was well retained by M. australiense. A biokinetic model of cadmium accumulation by M. australiense predicted that for exposures to environmentally relevant cadmium concentrations in the Strickland River, uptake from ingestion of fine sediment and carrion would be the predominant sources of cadmium to the organism. The model predicted the total dietary route would represent 70-80% of bioaccumulated cadmium. PMID:24508761

Cresswell, Tom; Simpson, Stuart L; Smith, Ross E W; Nugegoda, Dayanthi; Mazumder, Debashish; Twining, John



Trophic transfer of trace metals: Subcellular compartmentalization in a polychaete and assimilation by a decapod crustacean  

USGS Publications Warehouse

The chemical form of accumulated trace metal in prey is important in controlling the bioavailataility of dietary metal to a predator. This study investigated the trophic transfer of radiolabelled Ag, Cd and Zn from the polychaete worm Nereis diversicolor to the decapod crustacean Palaemonetes varians. We used 2 populations of worms with different proportions of accumulated metals in different subcellular fractions as prey, and loaded the worms with radiolabelled metals either from sediment or from solution. Accumulated radiolabelled metals were fractionated into 5 components : metal-rich granules (MRG), cellular debris, organelles, metallothionein-like proteins (MTLP), and other (heat-sensitive) proteins (HSP). Assimilation efficiencies (AE) of the metals by P. varians were measured from the 4 categories of prey (i.e. 2 populations, radiolabelled from sediment or solution). There were significant differences for each metal between the AEs from the different prey categories, confirming that origin of prey and route of uptake of accumulated trace metal will cause intraspecific differences in subsequent metal assimilation. Correlations were sought between AEs and selected fractions or combinations of fractions of metals in the prey-MRG, Trophically Available Metal (TAM = MTLP + HSP + organelles) and total protein (MTLP + HSP). TAM explained 28% of the variance in AEs for Ag, but no consistent relationships emerged between AEs and TAM or total protein when the metals were considered separately. AEs did, however, show significant positive regressions with both TAM and total protein when the 3 metals were considered together, explaining only about 21 % of the variance in each case. A significant negative relationship was observed between MRG and AE for all metals combined. The predator (P. varians) can assimilate dietary metal from a range of the fractions binding metals in the prey (N. diversicolor), with different assimilation efficiencies summated across these fractions. TAM and/or total protein may represent an approximate minimum for trophic availability but neither of these alone is a fully accurate predictor. ?? Inter-Research 2006.

Rainbow, P. S.; Poirier, L.; Smith, B. D.; Brix, K. V.; Luoma, S. N.



Putative neurohemal release zones in the stomatogastric nervous system of decapod crustaceans.  


The stomatogastric nervous system (STNS) of decapod crustaceans has long been used to study the modulation of small neural circuits. Profiles in the sheath of the nerves and ganglia of the STNS, which contain only dense-core vesicles, have been described in electron microscopical studies (Friend [1976] Cell Tissue Res. 175:369-380; Kilman and Marder [1997] Soc Neurosci Abstr. 23:477; Skiebe and Ganeshina [2000] J Comp Neurol 420:373-397). These profiles resemble those found in neurohemal organs and suggest the presence of neurohemal release zones in the STNS. To map these putative neurohemal release zones, a combination of two antibodies was used in the present study. A synapsin antibody recognizing vesicle proteins of clear vesicles was combined with a synaptotagmin antibody recognizing vesicle proteins of clear and dense-core vesicles. Exclusive synaptotagmin-like staining, therefore, indicated the regions with only dense-core vesicles. Such a staining was found in a mesh in the perineural sheath of nerves in the STNS of all three species investigated. In the crayfish Cherax destructor and the lobster Homarus americanus, the stained mesh was located in the sheath of nerves connecting all four ganglia of the STNS, whereas in the crab Cancer pagurus it was found on different nerves, which are more directly exposed to the hemolymph in this species. Exclusive synaptotagmin-like staining was also found in a putative neurohemal release zone in the sheath of the circumoesophageal connectives and the postoesophageal commissure in C. destructor. These data suggest that an important source of modulation of the networks and the muscles of the stomach is a compartmentalized release of neurohormones from zones in the STNS. PMID:12378588

Skiebe, Petra; Wollenschläger, Tina



Comparing trace metal bioaccumulation characteristics of three freshwater decapods of the genus Macrobrachium.  


Potential sources and kinetics of metal bioaccumulation by the three Macrobrachium prawn species M. australiense, M. rosenbergii and M. latidactylus were assessed in laboratory experiments. The prawns were exposed to two scenarios: cadmium in water only; and exposure to metal-rich mine tailings in the same water. The cadmium accumulation from the dissolved exposure during 7 days, followed by depuration in cadmium-free water for 7 days, was compared with predictions from a biokinetic model that had previously been developed for M. australiense. M. australiense and M. latidactylus accumulated significant tissue cadmium during the exposure phase, albeit with different uptake rates. All three species retained >95% of the bioaccumulated cadmium during the depuration phase, indicating very slow efflux rates. Following exposure to tailings, there were significant (p<0.05) differences in tissue arsenic, cadmium, lead and zinc concentrations among species. Cadmium and zinc concentrations were increased relative to controls for all three species but were not different between treatments (direct/indirect contact with tailings), suggesting these metals were primarily accumulated via the dissolved phase. All species bioaccumulated significantly greater arsenic and lead when in direct contact with mine tailings, demonstrating the importance of an ingestion pathway for these metals. Copper was not bioaccumulated above control concentrations for any species. The differences between the metal accumulation of the three prawns indicated that a biokinetic model of cadmium bioaccumulation for M. australiense could potentially be used to describe the metal bioaccumulation of the other two prawn species, albeit with an over-prediction of 3-9 times. Despite these being the same genus of decapod crustacean, the study highlights the issues with using surrogate species, even under controlled laboratory conditions. It is recommended that future studies using surrogate species quantify the metal bioaccumulation characteristics of each species in order to account for any differences between species. PMID:24800868

Cresswell, Tom; Smith, Ross E W; Nugegoda, Dayanthi; Simpson, Stuart L




Microsoft Academic Search

The decapod crustacean community in Estero El Verde, Camacho, Sinaloa included 31 species, 17 genera and 12 families. The genus Uca (Ocypodidae) was the most common. The swimming crabs Callinectes arcuatus and C. toxotes and the shrimp Litopenaeus vannamei, L. stylirostris and Farfantepenaeus californiensis were particularly notable among the commercial species. Macrobrachium tenellum and Gecarcinus planatus might represent alternatives for

JF Arzola-González; LM Flores-Campaña


Descending into the abyss: Bathymetric patterns of diversity in decapod crustaceans shift with taxonomic level and life strategies  

NASA Astrophysics Data System (ADS)

The aim of this study was to examine the depth-related changes in the diversity of decapod crustaceans from the intertidal to abyssal zones off Madeira Archipelago, a chain of islands in the subtropical North East Atlantic Ocean. The bathymetric gradient in species richness was evaluated using the reported ranges of 175 out of approximately 186 decapod species known in this archipelago. The depth-related changes at different taxonomic (order, sub-orders and families) and life strategy (pelagic, benthopelagic and benthic) levels were investigated and different ecological hypotheses (species-energy, mid-domain and Rapoport's effects) were tested to explain the observed patterns. No unimodal trend of Decapoda diversity was revealed and, instead, a monotonic decrease towards the abyss was observed, mainly as a consequence of the depth-related changes in the benthic diversity of the suborder Pleocyemata. Nonetheless, all bathymetric gradients of pelagic diversity (at order and suborder levels) displayed parabolic trends. There was also a general increase in bathymetric range towards greater depth, and the major faunal break was identified within the continental shelf area. All species richness-depth patterns were significantly nested, but there was a clear increasing trend in randomness from the benthic to the pelagic realm. The present study shows for the first time that even within the same taxonomic group and geographic region different bathymetric patterns of diversity can be observed, depending on the taxonomic level and, more importantly, on the group's life strategies. Moreover, our analysis supports the species-energy hypothesis, implicating a combination of temperature and food availability as the main causal predictors explaining diversity variation.

Rosa, Rui; Boavida-Portugal, Joana; Trübenbach, Katja; Baptista, Miguel; Araújo, Ricardo; Calado, Ricardo



Estimating densities of small fishes and decapod crustaceans in shallow estuarine habitats: A review of sampling design with focus on gear selection  

Microsoft Academic Search

Shallow estuarine habitats often support large populations of small nekton (fishes and decapod crustaceans), but unique characteristics\\u000a of these habitats make sampling these nekton populations difficult. We discuss development of sampling designs and evaluate\\u000a some commonly used devices for quantitatively sampling nekton populations. Important considerations of the sampling design\\u000a include the size and number of samples, their distribution in time

Lawrence P. Rozas; Thomas J. Minello



Community structure and dynamics of deep-water decapod assemblages from Le Danois Bank (Cantabrian Sea, NE Atlantic): Influence of environmental variables and food availability  

NASA Astrophysics Data System (ADS)

The community structure of the decapod crustaceans inhabiting Le Danois Bank (Cantabrian Sea, NE Atlantic Ocean) was studied on two cruises performed in October 2003 and April 2004. Otter and beam-trawls were used to collect this fauna. At depths ranging between 455 and 1048 m, we found distinct decapod assemblages on the bank summit and deeper in the inner basin (between the bank and the continental shelf). The faunal discontinuity between these groups appeared at around 600 m (e.g. between 612 and 642 m in the basis of species replacement). The summit assemblage was characterized by low diversity (in terms of number and relative abundances of species) and by the dominance of hermit crabs ( Pagurus alatus, Anapagurus laevis, Pagurus excavatus), the crangonid Pontophilus spinosus and the squat lobster Munida sarsi. Species characterizing the deeper assemblage, which was richer in terms of diversity, were Munida tenuimana, Parapagurus pilosimanus, Pontophilus norvegicus, the crab Geryon trispinosus and a number of bathypelagic shrimps ( Sergia robusta, Acanthephyra pelagica and Pasiphaea tarda). Changes in decapod composition characterized by multidimensional scaling analyses were correlated with different variables, e.g. %mud and %organic matter (OM), temperature and salinity close to the bottom. Among those the %OM and %mud in sediments affected decapod distributions the most. The summit of the bank was covered by fine sediments with low proportion of mud (13.9-29.3%) and OM (2.55-3.50%). By contrast, sediment of the inner basin had a higher proportion of OM and mud (64.1-84.2%; 6.26-7.00%, respectively). The low proportion of mud at the summit of Le Danois Bank may explain the absence or scarcity of burrowing species (e.g. the lobster Nephrops norvegicus, the shrimps Calocaris macandreae and Alpheus glaber and the crab Goneplax rhomboides), that are dominant at similar depths (400-500 m) in the upper muddy assemblage on the mainland-continental slope in the Bay of Biscay (44-46°N). The dominance of certain species on the summit of submarine mounts can probably be related to their biology and feeding ecology. For example, pagurids are deposit feeders, even consuming marine snow (e.g. Chl- a identified in guts of Pagurus alatus), and they have low gut fullness (probably indicating a capacity to withstand long periods under starvation), that would favour their adaptability to a rather unpredictable habitat such as Le Danois Bank summit. Regarding prey availability, zooplankton/micronekton and infauna distributed around Le Danois Bank showed different depth-related patterns. Among zooplankton, mesopelagic decapods, mysids, and fishes were absent at the bank summit, while euphausiids exhibited high abundances over the summit. No significant trends with depth were found for infauna abundance, and for instance polychaete densities were similar both at the summit and the inner basin. Therefore, prey availability was lower for summit assemblages regarding zooplankton/micronekton. Patterns in mean size vs. depth were species specific for decapods, and the possible role of the bank summit as a recruitment area was not general for the whole decapod assemblage.

Cartes, Joan E.; Serrano, Alberto; Velasco, Francisco; Parra, Santiago; Sánchez, Francisco



A new look at embryonic development of the visual system in decapod crustaceans: neuropil formation, neurogenesis, and apoptotic cell death.  


In recent years, comparing the structure and development of the central nervous system in crustaceans has provided new insights into the phylogenetic relationships of arthropods. Furthermore, the structural evolution of the compound eyes and optic ganglia of adult arthropods has been discussed, but it was not possible to compare the ontogeny of arthropod visual systems, owing to the lack of data on species other than insects. In the present report, we studied the development of the crustacean visual system by examining neurogenesis, neuropil formation, and apoptotic cell death in embryos of the American lobster, Homarus americanus, the spider crab, Hyas araneus, and the caridean shrimp, Palaemonetes argentinus, and compare these processes with those found in insects. Our results on the patterns of stem cell proliferation provide evidence that in decapod crustaceans and hemimetabolous insects, there exist considerable similarities in the mechanisms by which accretion of the compound eyes and growth of the optic lobes is achieved, suggesting an evolutionary conservation of these mechanisms. PMID:10235683

Harzsch, S; Benton, J; Dawirs, R R; Beltz, B



Trophic transfer of trace metals from the polychaete worm Nereis diversicolor to the polychaete N. virens and the decapod crustacean Palaemonetes varians  

USGS Publications Warehouse

Diet is an important exposure route for the uptake of trace metals by aquatic invertebrates, with trace metal trophic transfer depending on 2 stages - assimilation and subsequent accumulation by the predator. This study investigated the trophic transfer of trace metals from the sediment-dwelling polychaete worm Nereis diversicolor from metal-rich estuarine sediments in southwestern UK to 2 predators - another polychaete N. virens (Cu, Zn, Pb, Cd, Fe) and the decapod crustacean Palaemonetes varians (Cu, Zn, Pb, Cd, Fe, Ag, As, Mn). N. virens showed net accumulation of Cu, Zn, Pb and Cd from the prey; accumulation increased with increasing prey concentration, but a coefficient of trophic transfer decreased with increasing prey concentration, probably because a higher proportion of accumulated metal in the prey is bound in less trophically available (insoluble) detoxified forms. The trace metal accumulation patterns of P. varians apparently restricted significant net accumulation of metals from the diet of N. diversicolor to just Cd. There was significant mortality of the decapods fed on the diets of metal-rich worms. Metal-rich invertebrates that have accumulated metals from the rich historical store in the sediments of particular SW England estuaries can potentially pass these metals along food chains, with accumulation and total food chain transfer depending on the metal assimilation efficiencies and accumulation patterns of the animal at each trophic level. This trophic transfer may be significant enough to have ecotoxicological effects. ?? Inter-Research 2006.

Rainbow, P. S.; Poirier, L.; Smith, B. D.; Brix, K. V.; Luoma, S. N.



Deep-Sea decapod crustaceans (Caridea, Polychelida, Anomura and Brachyura) collected from the Nikko Seamounts, Mariana Arc, using a remotely operated vehicle "Hyper-Dolphin".  


Samples and images of deep-water benthic decapod crustaceans were collected from the Nikko Seamounts, Mariana Arc, at depths of 520-680 m, by using the remotely operate vehicle "Hyper-Dolphin", equipped with a high definition camera, digital camera, manipulators and slurp gun (suction sampler). The following seven species were collected, of which three are new to science: Plesionika unicolor n. sp. (Caridea: Pandalidae), Homeryon armarium Galil, 2000 (Polychelida: Polychelidae), Eumunida nikko n. sp. (Anomura: Eumunididae), Michelopagurus limatulus (Henderson, 1888) (Anomura: Paguridae), Galilia petricola n. sp. (Brachyura: Leucosiidae), Cyrtomaia micronesica Richer de Forges & Ng, 2007 (Brachyura: Inachidae), and Progeryon mus Ng & Guinot, 1999 (Brachyura: Progeryonidae). Affinities of these three new species are discussed. All but H. armarium are recorded from the Japanese Exclusive Economic Zone for the first time. Brief notes on ecology and/or behavior are given for each species. PMID:24870636

Komai, Tomoyuki; Tsuchida, Shinji



cDNA cloning and transcript distribution of two novel members of the neuroparsin peptide family in a hemipteran insect (Nezara viridula) and a decapod crustacean (Jasus lalandii).  


Two novel neuroparsin (NP) precursor cDNAs were cloned: one from the corpora cardiaca of an insect, the green stink bug Nezara viridula, and the other from the X-organ of a decapod crustacean, the spiny lobster Jasus lalandii. The translated NP precursor consists of 106 amino acid residues in N. viridula and 103 amino acid residues in J. lalandii, with 14 and 12 cysteine residues, respectively, in conserved positions when aligned with known NPs. Reverse transcriptase PCR shows that in both arthropods, NP is expressed in some neural tissues: corpora cardiaca, sub-esophageal ganglion and brain of N. viridula; X-organ, brain, sub-esophageal and thoracic ganglion in J. lalandii. Additionally, NP is also expressed in non-neural tissues, such as fat body, leg muscle, flight muscle, reproductive organs and antennae in N. viridula, and heart and ovary in J. lalandii. There are no major differences in the NP transcript expression in mature and immature stink bugs, and also no difference between male and female stink bugs. PMID:24512948

Marco, Heather G; Anders, Lance; Gäde, Gerd



Molecular and mass spectral identification of the broadly conserved decapod crustacean neuropeptide pQIRYHQCYFNPISCF: the first PISCF-allatostatin (Manduca sexta- or C-type allatostatin) from a non-insect  

PubMed Central

The PISCF-allatostatins (Manduca sexta- or C-type allatostatins) are a family of pentadecapeptides characterized by a pyroglutamine blocked N-terminus, an unamidated –PISCF C-terminus, and a disulfide bridge between two internal Cys residues. Several isoforms of PISCF-AST are known, all from holometabolous insects. Using a combination of transcriptomics and mass spectrometry, we have identified the first PISCF-type peptides from a non-insect species. In silico analysis of crustacean ESTs identified several Litopenaeus vannamei (infraorder Penaeidea) transcripts encoding putative PISCF-AST precursors. Translation of these ESTs, with subsequent prediction of their putative post-translational processing, revealed the existence of as many as three PISCF-type peptides, including pQIRYHQCYFNPISCF (disulfide bridging between Cys7 and Cys14). Although none of the predicted isoforms was detected by mass spectrometry in L. vannamei, MALDI-FTMS mass profiling identified an m/z signal corresponding to pQIRYHQCYFNPISCF (disulfide bridge present) in neural tissue from 28 other decapods, which included members of six infraorders (Stenopodidea, Astacidea, Thalassinidea, Achelata, Anomura and Brachyura). Further characterization of the peptide using SORI-CID and chemical derivatization/enzymatic digestion supported the theorized structure. In both the crab Cancer borealis and the lobster Homarus americanus, MALDI-based tissue surveys suggest that pQIRYHQCYFNPISCF is broadly distributed in the nervous system; it was also detected in the posterior midgut caecum. Collectively, our data show that members of the PISCF-AST family are not restricted to the holometabolous insects, but instead may be broadly conserved within the Pancrustacea. Moreover, our data suggest that one highly conserved PISCF-type peptide, pQIRYHQCYFNPISCF, is present in decapod crustaceans, functioning as a brain-gut paracrine/hormone.

Stemmler, Elizabeth A.; Bruns, Emily A.; Cashman, Christopher R.; Dickinson, Patsy S.; Christie, Andrew E.



Molecular and mass spectral identification of the broadly conserved decapod crustacean neuropeptide pQIRYHQCYFNPISCF: the first PISCF-allatostatin (Manduca sexta- or C-type allatostatin) from a non-insect.  


The PISCF-allatostatins (Manduca sexta- or C-type allatostatins) are a family of pentadecapeptides characterized by a pyroglutamine blocked N-terminus, an unamidated-PISCF C-terminus, and a disulfide bridge between two internal Cys residues. Several isoforms of PISCF-AST are known, all from holometabolous insects. Using a combination of transcriptomics and mass spectrometry, we have identified the first PISCF-type peptides from a non-insect species. In silico analysis of crustacean ESTs identified several Litopenaeus vannamei (infraorder Penaeidea) transcripts encoding putative PISCF-AST precursors. Translation of these ESTs, with subsequent prediction of their putative post-translational processing, revealed the existence of as many as three PISCF-type peptides, including pQIRYHQCYFNPISCF (disulfide bridging between Cys(7) and Cys(14)). Although none of the predicted isoforms was detected by mass spectrometry in L. vannamei, MALDI-FTMS mass profiling identified an m/z signal corresponding to pQIRYHQCYFNPISCF (disulfide bridge present) in neural tissue from 28 other decapods, which included members of six infraorders (Stenopodidea, Astacidea, Thalassinidea, Achelata, Anomura and Brachyura). Further characterization of the peptide using SORI-CID and chemical derivatization/enzymatic digestion supported the theorized structure. In both the crab Cancer borealis and the lobster Homarus americanus, MALDI-based tissue surveys suggest that pQIRYHQCYFNPISCF is broadly distributed in the nervous system; it was also detected in the posterior midgut caecum. Collectively, our data show that members of the PISCF-AST family are not restricted to the holometabolous insects, but instead may be broadly conserved within the Pancrustacea. Moreover, our data suggest that one highly conserved PISCF-type peptide, pQIRYHQCYFN-PISCF, is present in decapod crustaceans, functioning as a brain-gut paracrine/hormone. PMID:19467234

Stemmler, Elizabeth A; Bruns, Emily A; Cashman, Christopher R; Dickinson, Patsy S; Christie, Andrew E



Neurosecretory systems in decapod Crustacea  

Microsoft Academic Search

The sinus glands of the Brachyura are composed of swollen nerve fiber endings, which store and release secretory material synthesized within cells of the eyestalks, the brain and probably the thoracic ganglionic mass. Removal of the sinus glands from the land crab, Gecarcinus lateralis, does not induce molt, because sinus glands are reservoirs, not sources, of molt-inhibiting hormone. Increase in

Dorothy E. Bliss; James B. Durand; John H. Welsh



Digestive enzymes in a decapod crustacean Caridina weberi de man  

Microsoft Academic Search

1. A detailed account of the enzymes in the hepatopancreas inCaridina weberi is given.\\u000a \\u000a 2. The carbohydrases present include amylase, glycogenase, maltase, lactase and sucrase while raffinase and cellulase are\\u000a absent. The optimum pH is 6·8 for the enzyme amylase. The enzyme gets destroyed completely between 65 and 70° C. The optimum\\u000a pH for digestion of glycogen is 7·0 and

B. Chinnayya



Digital electromagnetic telemetry system for studying behaviour of decapod crustaceans.  


1 year and the receiving system batteries are replaced by divers at intervals of up to 4 weeks. In field tests, crab (Cancer pagurus L.) and lobster (Homarus gammarus (L.)) activity was monitored at an artificial reef for 14 months. Examples of the type of information acquired are presented to illustrate the capabilities of the system and potential applications are discussed. Limitations of digital electromagnetic telemetry stem mainly from the short range of detection, the need for cables on the seabed and the size and shape of the transmitting tag. PMID:10742505

Smith; Collins; Jensen



The impact of pathogens on exploited populations of decapod crustaceans.  


Several crustacean fisheries have experienced significant outbreaks of disease that have damaged their industries. Not only do fisheries suffer from direct losses to pathogens, such as disease-induced mortalities or reduced product value, but they can also incur indirect losses such as stunting, castration, and increased risk of predation. In some cases, the indirect losses can be substantial, yet they are often overlooked by the fishing industry as their primary focus is on recruits to the fishery, and not on the affected juvenile pre-recruits. Low levels of pathogens are to be expected in natural populations of commercial species, but baseline data on the prevalence and intensity of even the most common agents is often lacking. It is important to establish baselines for two reasons. First, it is important to know what pathogens exist in heavily exploited populations so as to gauge their potential to damage the industry; and second, during outbreaks, it is important to know whether an outbreak is a newly emergent event or whether it is a component of a cyclical phenomenon. Pathogens frequently act in concert with environmental stressors, and a variety of stressors have contributed to outbreaks of emerging agents in crustacean fisheries. Pollution, poor water quality, hypoxia, temperature extremes, and overexploitation have all been implicated as stressors in various outbreaks. This review focuses on epidemic diseases of commercially fished crustaceans. Outbreaks in cultured stocks are not covered. Disease epizootics have occurred in fished populations of crayfish and shrimp but they are less well known than the issues arising from extensive aquaculture of these species. PMID:22434001

Shields, Jeffrey D




EPA Science Inventory

A variety of physiological functions was examined in an estuarine mysid (Mysidopsis bahia) during life-cycle exposures to four classes of pesticides. Pesticide exposure initially elevated respiration rates of juveniles. These increased metabolic requirements reduced the amount of...



Microsoft Academic Search

Summary Aquatic and terrestrial crustaceans are dependent on both aerobic and anaerobic metabolism for energy production during exercise. Anaerobic energy production is marked by an accumulation of lactate in both muscle tissue and haemolymph, but the metabolic fate of lactate is not clear. Lactate recycling via gluconeogenesis and the potential role of carbonic anhydrase (CA) in supplying bicarbonate for the



Functional morphology of the cuticular terraces in burrowing terrestrial brachyuran decapods  

Microsoft Academic Search

Observations on Gecarcinus lateralis and Ocypode quadrata from Bermuda show that their cuticular terraces are not functional as burrowing sculptures, as previously assumed. Instead, they increase the friction against the walls of the burrow when the animal wedges itself to avoid being extracted by predators. No significant increase in the number of terraces takes place during growth in the size




Histochemical and biochemical characterization of two slow fiber types in decapod crustacean muscles.  


Myofibrillar proteins in muscles of the claws and abdomen of lobster, Homarus americanus, and the claws of fiddler crab, Uca pugnax, and land crab, Gecarcinus lateralis, have been analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fibers contained numerous isoforms of structural and regulatory proteins in assemblages correlated with fiber type. One fast (F) and two slow (S1 and S2) fibers were identified. All F fibers possessed two isoforms of paramyosin (P1 and P2), while all slow fibers, with the exception of Uca major claw, contained only the P2 variant. S1 and S2 fibers were distinguished by the distribution of a large isoform of troponin-T (T1; Mr = 55,000); S2 fibers in all three species contained T1 in addition to one or two smaller-molecular-weight variants usually associated with S1 fibers. In order to determine whether the slow fibers differed in histochemical properties, land crab claw closer muscle was cryosectioned and stained for myofibrillar ATPase and NADH diaphorase activities. Most S2 fibers had lower ATPase and higher NADH diaphorase activities than S1 fibers, which indicated that S2 fibers had a lower rate of contraction and were more fatigue-resistant than S1 fibers. It is proposed that the S1 and S2 fibers defined by biochemical and histochemical criteria are identical to the slow-twitch and tonic fibers, respectively characterized physiologically. PMID:2968438

Mykles, D L



Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France)  

Microsoft Academic Search

The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp?-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed.

N. Bodin; A. Abarnou; A.-M. Le Guellec; V. Loizeau; X. Philippon



Skeletal adaptations for forwards and sideways walking in three species of decapod crustaceans.  


Crustaceans have been successfully employed to study legged locomotion for decades. Most studies have focused on either forwards-walking macrurans, or sideways-walking brachyurans. Libinia emarginata is a Majoid crab (Brachyura) and as such belongs to the earliest group to have evolved the crab form from homoloid ancestors. Unlike most brachyurans, Libinia walks forwards 80% of the time. We employed standard anatomical techniques and motion analysis to compare the skeleton, stance, and the range of motion of the legs of Libinia to the sideways-walking green shore crab (Carcinus maenas), and to the forwards-walking crayfish (Procambarus clarkii). We found animals tended to have greater ranges of motion for joints articulating in the preferred direction of locomotion. Leg segments proximal to such joints were comparatively longer. Thorax elongation, leg length and placement at rest also reflected walking preference. Comparative studies of walking in Libinia and other brachyurans may shed light on the neuroethology of legged locomotion, and on the anatomical and physiological changes necessary for sideways-walking in crustaceans. PMID:18089130

Vidal-Gadea, A G; Rinehart, M D; Belanger, J H



Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France).  


The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp'-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed. The spider crab was the only species found in the five sampling sites, thus enabling comparison between areas. Specimens from Antifer were much more contaminated (summation operator 16 PCBs in hepatopancreas=2000-4000 ng g(-1) dry weight) than those from other sites (50-1000 ng g(-1) d.w.). Among all the three species, the spider crab appeared more contaminated by PCBs than the edible crab, by a factor 2-3, probably in relation with specific differences in their life cycle. There was no difference due to the gender of the species. Within the different analysed tissues, contamination levels increased from muscle to gonads and hepatopancreas in relation with the fat content. A very similar PCB composition was observed in all samples, PCB fingerprints being characterised by the relative importance of the more persistent PCB congeners: CB153, 138, 180, 187, and 118. Finally, these results were compared to recent food regulations first of maximum marker PCB intake and secondly of maximum dioxin-like PCB intake. By considering the muscle, all samples were far below the regulatory limits; for hepatopancreas and gonads, however, some samples were unfit for human consumption. PMID:17223177

Bodin, N; Abarnou, A; Le Guellec, A-M; Loizeau, V; Philippon, X



Molecular evidence for sequential colonization and taxon cycling in freshwater decapod shrimps on a Caribbean island.  


Taxon cycling, i.e. sequential phases of expansions and contractions in species' distributions associated with ecological or morphological shifts, are postulated to characterize dynamic biogeographic histories in various island faunas. The Caribbean freshwater shrimp assemblage is mostly widespread and sympatric throughout the region, although one species (Atyidae: Atya lanipes) is geographically restricted and ecologically and morphologically differentiated from other Atya species. Using patterns of nucleotide variation at the COI mtDNA gene in five species of freshwater shrimp (A. lanipes, A. scabra, A. innocuous; Xiphocarididae: Xiphocaris elongata; Palaemonidae: Macrobrachium faustinum) from Puerto Rico, we expected to detect a signature of sequential colonization in these shrimp, consistent with the concept of taxon cycling, and expected that A. lanipes would be at a different taxon stage (i.e. an early stage species) to all other species. We also examined patterns of genetic population structure in each species expected with poor, intermediate and well-developed abilities for among-river dispersal. Population expansions were detected in all species, although the relative timing of the expansions varied among them. Assuming that population expansions followed colonization of Puerto Rico by freshwater shrimp, results bear the hallmarks of sequential colonization and taxon cycling in this fauna. A. lanipes had a star phylogeny, low mean pairwise nucleotide differences and recent (Holocene) estimates for an in situ population expansion in Puerto Rico, and it was inferred as an early stage species in the taxon cycle undergoing a secondary phase of expansion. All other species were inferred as late stage species undergoing regional population expansions, as their mean pairwise nucleotide differences were relatively high and phylogenetic patterns were more complex than A. lanipes. High rates of gene flow without isolation by distance among rivers were detected in all species, although results should be treated cautiously as some populations are unlikely to be in mutation-drift equilibrium. Nested clade analysis produced inconsistent results among species that all have high rates of gene flow and expanding populations. PMID:18261048

Cook, Benjamin D; Pringle, Catherine M; Hughes, Jane M




Microsoft Academic Search

Temperature is one of the environmental factors to which the organism must adjust if it is to exist successfully in its habitat. In temperate-zone forms the severe temperature extremes of mid-winter and late summer may result in a shift of metabolic processes, tending to compensate for these extremes. However, tropical forms living in a relatively constant thermal environment do not



Genomic Sequence and Experimental Tractability of a New Decapod Shrimp Model, Neocaridina denticulata  

PubMed Central

The speciose Crustacea is the largest subphylum of arthropods on the planet after the Insecta. To date, however, the only publically available sequenced crustacean genome is that of the water flea, Daphnia pulex, a member of the Branchiopoda. While Daphnia is a well-established ecotoxicological model, previous study showed that one-third of genes contained in its genome are lineage-specific and could not be identified in any other metazoan genomes. To better understand the genomic evolution of crustaceans and arthropods, we have sequenced the genome of a novel shrimp model, Neocaridina denticulata, and tested its experimental malleability. A library of 170-bp nominal fragment size was constructed from DNA of a starved single adult and sequenced using the Illumina HiSeq2000 platform. Core eukaryotic genes, the mitochondrial genome, developmental patterning genes (such as Hox) and microRNA processing pathway genes are all present in this animal, suggesting it has not undergone massive genomic loss. Comparison with the published genome of Daphnia pulex has allowed us to reveal 3750 genes that are indeed specific to the lineage containing malacostracans and branchiopods, rather than Daphnia-specific (E-value: 10?6). We also show the experimental tractability of N. denticulata, which, together with the genomic resources presented here, make it an ideal model for a wide range of further aquacultural, developmental, ecotoxicological, food safety, genetic, hormonal, physiological and reproductive research, allowing better understanding of the evolution of crustaceans and other arthropods.

Kenny, Nathan J.; Sin, Yung Wa; Shen, Xin; Zhe, Qu; Wang, Wei; Chan, Ting Fung; Tobe, Stephen S.; Shimeld, Sebastian M.; Chu, Ka Hou; Hui, Jerome H. L.



Methodical aspects of rearing decapod larvae, Pagurus bernhardus (Paguridae) and Carcinus maenas (Portunidae)  

NASA Astrophysics Data System (ADS)

Improved methods for experimental rearing of Pagurus bernhardus and Carcinus maenas larvae are presented. Isolated maintenance was found essential for reliable statistical evaluation of results obtained from stages older than zoea-1. Only by isolated rearing is it possible to calculate mean values ±95% confidence intervals of stage duration. Mean values (without confidence intervals) can only be given for group-reared larvae if mortality is zero. Compared to group rearing, isolated rearing led to better survival, shorter periods of development and stimulated growth. Due to different swimming behavior P. bernhardus zoeae needed larger water volumes than Carcinus maenas larvae. P. bernhardus zoeae were reared with best results when isolated in Petri dishes (ca. 50 ml). They fed on newly hatched brine shrimp nauplii ( Artemia spp.). P. bernhardus megalopa did not require any gastropod shell or substratum; it developed best in glass vials without any food. C. maenas larvae could be reared most sucessfully in glass vials (ca 20 ml) under a simulated day-night regime (LD 16:8); constant darkness had a detrimental effect on development, leading to prolonged stage-duration times. C. maenas larvae were fed a mixture of newly hatched brine shrimp naupli and rotifers ( Brachionus plicatilis).

Dawirs, R. R.



Comparative strategies of heavy metal accumulation by crustaceans: zinc, copper and cadmium in a decapod, an amphipod and a barnacle  

Microsoft Academic Search

This study investigates the comparative strategies of accumulation under standardised laboratory conditions of the essential metals zinc and copper, and the non-essential metal cadmium by three crustaceans of different taxa; vizPalaemon elegans Rathke (Malacostraca: Eucarida: Decapoda),Echinogammarus pirloti (Sexton & Spooner) (Malacostraca: Peracarida: Amphipoda) and the barnacleElminius modestus Darwin (Cirripedia: Thoracica).

P. S. Rainbow; S. L. White



Conservation of structure, signaling and pharmacology between two serotonin receptor subtypes from decapod crustaceans, Panulirus interruptus and Procambarus clarkii  

PubMed Central

SUMMARY Serotonin (5-HT) plays important roles in the maintenance and modulation of neural systems throughout the animal kingdom. The actions of 5-HT have been well characterized for several crustacean model circuits; however, a dissection of the serotonergic transduction cascades operating in these models has been hampered by the lack of pharmacological tools for invertebrate receptors. Here we provide pharmacological profiles for two 5-HT receptors from the swamp crayfish, Procambarus clarkii: 5-HT2? and 5-HT1?. In so doing, we also report the first functional expression of a crustacean 5-HT1 receptor, and show that it inhibits accumulation of cAMP. The drugs mCPP and quipazine are 5-HT1? agonists and are ineffective at 5-HT2?. Conversely, methiothepin and cinanserin are antagonists of 5-HT2? but do not block 5-HT1?. A comparison of these two receptors with their orthologs from the California spiny lobster, Panulirus interruptus, indicates conservation of protein structure, signaling and pharmacology. This conservation extends beyond crustacean infraorders. The signature residues that form the ligand-binding pocket in mammalian 5-HT receptors are found in the crustacean receptors. Similarly, the protein domains involved in G protein coupling are conserved between the two crustacean receptors and other characterized arthropod and mammalian 5-HT receptors. Considering the apparent conservation of pharmacological properties between crustacean 5-HT receptors, these tools could be applicable to related crustacean physiological preparations.

Spitzer, Nadja; Edwards, Donald H.; Baro, Deborah J.



Immunocytochemical identification of structures containing putative red pigment-concentrating hormone in two species of decapod crustaceans  

Microsoft Academic Search

By use of an antiserum raised against the Nterminal sequence pGlu-Leu-Asn-Phe..., common to red pigment-concentrating hormone (RPCH) of Pandalus borealis and three structurally similar insect neuropeptides, putative RPCH-immunopositive structures were revealed in the eyestalks of Carcinus maenas and Orconectes limosus and in the brain and thoracic ganglion (TG) of C. maenas. In the eyestalks, complete neurosecretory pathways were demonstrated, consisting

Sigrid Mangerich; Rainer Keller; Heinrich Dircksen



Influence of accumulation of cadmium on the content of other microelements of two species of Black Sea decapods  

SciTech Connect

Because the accumulation of cadmium by an organism may be a progressive and long-term process, the investigation of the influence of this trace metal on the balance of other microelements, especially those of key significance for normal biological functioning, is of great interest. Estimation of the accumulation capacity of organs and tissues involved in this process is of great importance as well.

Skwarzec, B.; Kentzer-Baczewska, A.; Styczynska-Jurewicz, E.; Neugebauer, E.



Detection of unconjugated and conjugated steroids in the ovary, eggs, and haemolymph of the decapod crustacean Nephrops norvegicus.  


Gas chromatography/mass spectrometry with selected ion monitoring has been employed to examine extracts from the ovary, eggs, and haemolymph of the marine prawn, Nephrops norvegicus, to demonstrate the presence of steroids. Both free and conjugated steroids were isolated by solvent partitioning and chromatography (lipophilic Sephadex, reversed-phase Sep Pak, and normal phase medium-pressure liquid chromatography) and steroidal conjugates were cleaved enzymatically. Steroids were determined as their methyloxime derivatives, trimethylsilyl (TMS) ethers or methyloxime-TMS ethers. All assignments were based on the detection of characteristic ions and cochromatography with the authentic steroid derivatives. 5 alpha-Dihydrotestosterone, testosterone, pregnenolone, and 20 alpha-hydroxypregn-4-en-3-one were detected in unconjugated form in the ovary. The eggs and haemolymph were found to contain unconjugated 17 beta-estradiol. Conjugated 5 alpha-dihydrotestosterone was detected in both the ovary and haemolymph, but no conjugated steroids were found in the eggs. PMID:2714624

Fairs, N J; Evershed, R P; Quinlan, P T; Goad, L J



Comparative Population Structure of Two Deep-Sea Hydrothermal-Vent-Associated Decapods (Chorocaris sp. 2 and Munidopsis lauensis) from Southwestern Pacific Back-Arc Basins  

PubMed Central

Studies of genetic connectivity and population structure in deep-sea chemosynthetic ecosystems often focus on endosymbiont-hosting species that are directly dependent on chemical energy extracted from vent effluent for survival. Relatively little attention has been paid to vent-associated species that are not exclusively dependent on chemosynthetic ecosystems. Here we assess connectivity and population structure of two vent-associated invertebrates—the shrimp Chorocaris sp. 2 and the squat lobster Munidopsis lauensis—that are common at deep-sea hydrothermal vents in the western Pacific. While Chorocaris sp. 2 has only been observed at hydrothermal vent sites, M. lauensis can be found throughout the deep sea but occurs in higher abundance around the periphery of active vents We sequenced mitochondrial COI genes and deployed nuclear microsatellite markers for both species at three sites in Manus Basin and either North Fiji Basin (Chorocaris sp. 2) or Lau Basin (Munidopsis lauensis). We assessed genetic differentiation across a range of spatial scales, from approximately 2.5 km to more than 3000 km. Population structure for Chorocaris sp. 2 was comparable to that of the vent-associated snail Ifremeria nautilei, with a single seemingly well-mixed population within Manus Basin that is genetically differentiated from conspecifics in North Fiji Basin. Population structure for Munidopsis lauensis was more complex, with two genetically differentiated populations in Manus Basin and a third well-differentiated population in Lau Basin. The unexpectedly high level of genetic differentiation between M. lauensis populations in Manus Basin deserves further study since it has implications for conservation and management of diversity in deep-sea hydrothermal vent ecosystems.

Thaler, Andrew David; Plouviez, Sophie; Saleu, William; Alei, Freddie; Jacobson, Alixandra; Boyle, Emily A.; Schultz, Thomas F.; Carlsson, Jens; Van Dover, Cindy Lee




Microsoft Academic Search

SUMMARY Blood calcium concentrations are elevated during a hypercapnic acidosis in the terrestrial crab Gecarcinus lateralis, but not in the aquatic Callincetes sapidus. The increase occurs concomitantly with a rise in blood HCO3~ and partial restoration of resting blood pH values. It is believed that in G. later- alis that a source of CaCO3, possibly the shell, is being dissolved



Intra- and extracellular osmotic regulation in the hololimnetic Caridea and Anomura: a phylogenetic perspective on the conquest of fresh water by the decapod Crustacea  

Microsoft Academic Search

We investigate extra- and intracellular osmoregulatory capability in two species of hololimnetic Caridea and Anomura: Macrobrachium brasiliense, a palaemonid shrimp, and Aegla franca, an aeglid anomuran, both restricted to continental waters. We also appraise the sharing of physiological characteristics\\u000a by the hololimnetic Decapoda, and their origins and role in the conquest of fresh water. Both species survive salinity exposure\\u000a well.

Samuel Coelho de Faria; Alessandra Silva Augusto; John Campbell McNamara



Epizoites on Marine Invertebrates: With Particular Reference to Those Associated with the Pycnogonid Phoxichilidium Tubulariae Lebour, the Amphipod Caprella Linearis (L.) and the Decapod Corystes Cassivelaunus (Pennant)  

Microsoft Academic Search

An account is given of a preliminary study of epizoites occurring on the pycnogonid Phoxichilidium tubulariae Lebour and the caprellid Caprella linearis (L.) from the southern North Sea; and on the burrowing crab Corystes cassivelaunus (Pennant) from the Solway Firth.Each of these species appears to be associated with a distinctive and restricted epizoic fauna dominated respectively by ciliate and suctorian

A. R. Pipe



The proteasomes of two marine decapod crustaceans, European lobster (Homarus gammarus) and Edible crab (Cancer pagurus), are differently impaired by heavy metals.  


The intracellular ubiquitin-proteasome system is a key regulator of cellular processes involved in the controlled degradation of short-living or malfunctioning proteins. Certain diseases and cellular dysfunctions are known to arise from the disruption of proteasome pathways. Trace metals are recognized stressors of the proteasome system in vertebrates and plants, but their effects on the proteasome of invertebrates are not well understood. Since marine invertebrates, and particularly benthic crustaceans, can be exposed to high metal levels, we studied the effects of in vitro exposure to Hg(2+), Zn(2+), Cu(2+), and Cd(2+) on the activities of the proteasome from the claw muscles of lobsters (Homarus gammarus) and crabs (Cancer pagurus). The chymotrypsin like activity of the proteasome of these two species showed different sensitivity to metals. In lobsters the activity was significantly inhibited by all metals to a similar extent. In crabs the activities were severely suppressed only by Hg(2+) and Cu(2+) while Zn(2+) had only a moderate effect and Cd(2+) caused almost no inhibition of the crab proteasome. This indicates that the proteasomes of both species possess structural characteristics that determine different susceptibility to metals. Consequently, the proteasome-mediated protein degradation in crab C. pagurus may be less affected by metal pollution than that of the lobster H. gammarus. PMID:24721378

Götze, Sandra; Bose, Aneesh; Sokolova, Inna M; Abele, Doris; Saborowski, Reinhard



Immunocytochemical localization of pigment-dispersing hormone (PDH) and its coexistence with FMRFamide-immunoreactive material in the eyestalks of the decapod crustaceans Carcinus maenas and Orconectes limosus  

Microsoft Academic Search

By use of a new antiserum, raised against synthetic pigment-dispersing hormone (PDH) from Uca pugilator, immunoreactive structures were studied at the light-microscopic level in the eyestalk ganglia of Carcinus maenas and Orconectes limosus. PDH-reactivity was mainly found in two types of neurons that were located between the medulla interna (MI) and the medulla terminalis (MT) in both species. Several additional

S. Mangerich; R. Keller; H. Dircksen; K. Ranga Rao; J. P. Riehm



A comparison of stable isotope ratios ( O\\/ O and l3C\\/12C) between two species of hydrothermal vent decapods (Alvinocaris lusca and Munidopsis subsquamosa)  

Microsoft Academic Search

Stable isotope ratios (180\\/160 and I3C\\/12C) in calcium carbonate exoskeletons of shrimp Alvinocaris lusca and galatheid squat lobsters Munidopsis subsquamosa from hydrothermal vents may provide a record of post-molt water temperature and chemistry experienced by each individual. Shrimp and galatheids appear to occupy distinct environmental regimes which are well-defined in terms of 6'80 and 613C values, and which correspond to

Cindy Lee Van Dover



Histones and nucleosomes in Cancer sperm (Decapod: Crustacea) previously described as lacking basic DNA-associated proteins: a new model of sperm chromatin.  


To date several studies have been carried out which indicate that DNA of crustacean sperm is neither bound nor organized by basic proteins and, contrary to the rest of spermatozoa, do not contain highly packaged chromatin. Since this is the only known case of this type among metazoan cells, we have re-examined the composition, and partially the structure, of the mature sperm chromatin of Cancer pagurus, which has previously been described as lacking basic DNA-associated proteins. The results we present here show that: (a) sperm DNA of C. pagurus is bound by histones forming nucleosomes of 170 base pairs, (b) the ratio [histones/DNA] in sperm of two Cancer species is 0.5 and 0.6 (w/w). This ratio is quite lower than the proportion [proteins/DNA] that we found in other sperm nuclei with histones or protamines, whose value is from 1.0 to 1.2 (w/w), (c) histone H4 is highly acetylated in mature sperm chromatin of C. pagurus. Other histones (H3 and H2B) are also acetylated, though the level is much lower than that of histone H4. The low ratio of histones to DNA, along with the high level of acetylation of these proteins, explains the non-compact, decondensed state of the peculiar chromatin in the sperm studied here. In the final section we offer an explanation for the necessity of such decondensed chromatin during gamete fertilization of this species. PMID:18655193

Kurtz, Kathryn; Martínez-Soler, Fina; Ausió, Juan; Chiva, Manel



A comparative immunocytochemical study of the hyperglycaemic, moult-inhibiting and vitellogenesis-inhibiting neurohormone family in three species of decapod crustacea.  


Eyestalks of the palinuran species Jasus lalandii and Panulirus homarus, and the brachyuran species Carcinus maenas, were examined with antisera raised against purified crustacean hyperglycaemic hormone (cHH) of the astacidean species Homarus americanus and Procambarus bouvieri, as well as the brachyuran species Cancer pagurus. Other antisera used in this investigation were raised against purified moult-inhibiting hormone (MIH) of C. pagurus and vitellogenesis-inhibiting hormone (VIH) of H. americanus. Positive immunoreactions to all the antisera were localised in perikarya of the X-organ and the axon terminals in the sinus gland of all the crustaceans investigated. These results illustrate the existence of an immunological similarity, detectable at the immunocytochemical level, between the cHH/MIH/VIH neurohormones of the Astacidae, Palinura and Brachyura infraorders. Furthermore, results from consecutive tissue sections indicate that cHH, MIH and VIH are co-localised in a subpopulation of X-organ neurons. PMID:9931363

Marco, H G; Gäde, G



Comparative Population Structure of Two Deep-Sea Hydrothermal-Vent-Associated Decapods (Chorocaris sp. 2 and Munidopsis lauensis) from Southwestern Pacific Back-Arc Basins.  


Studies of genetic connectivity and population structure in deep-sea chemosynthetic ecosystems often focus on endosymbiont-hosting species that are directly dependent on chemical energy extracted from vent effluent for survival. Relatively little attention has been paid to vent-associated species that are not exclusively dependent on chemosynthetic ecosystems. Here we assess connectivity and population structure of two vent-associated invertebrates-the shrimp Chorocaris sp. 2 and the squat lobster Munidopsis lauensis-that are common at deep-sea hydrothermal vents in the western Pacific. While Chorocaris sp. 2 has only been observed at hydrothermal vent sites, M. lauensis can be found throughout the deep sea but occurs in higher abundance around the periphery of active vents We sequenced mitochondrial COI genes and deployed nuclear microsatellite markers for both species at three sites in Manus Basin and either North Fiji Basin (Chorocaris sp. 2) or Lau Basin (Munidopsis lauensis). We assessed genetic differentiation across a range of spatial scales, from approximately 2.5 km to more than 3000 km. Population structure for Chorocaris sp. 2 was comparable to that of the vent-associated snail Ifremeria nautilei, with a single seemingly well-mixed population within Manus Basin that is genetically differentiated from conspecifics in North Fiji Basin. Population structure for Munidopsis lauensis was more complex, with two genetically differentiated populations in Manus Basin and a third well-differentiated population in Lau Basin. The unexpectedly high level of genetic differentiation between M. lauensis populations in Manus Basin deserves further study since it has implications for conservation and management of diversity in deep-sea hydrothermal vent ecosystems. PMID:24983244

Thaler, Andrew David; Plouviez, Sophie; Saleu, William; Alei, Freddie; Jacobson, Alixandra; Boyle, Emily A; Schultz, Thomas F; Carlsson, Jens; Van Dover, Cindy Lee



Loss of escape responses and giant neurons in the tailflipping circuits of slipper lobsters, Ibacus spp. (Decapoda, Palinura, Scyllaridae)  

Microsoft Academic Search

In many decapod crustaceans, escape tailflips are triggered by lateral giant (LG) and medial giant (MG) interneurons, which connect to motor giant (MoG) abdominal flexor neurons. Several decapods have lost some or all of these giant neurons, however. Because escape-related giant neurons have not been documented in palinurans, I examined tailflipping and abdominal nerve cords for giant neurons in two

Zen Faulkes



Crayfishes of Mexico (Crustacea: Decapoda).  

National Technical Information Service (NTIS)

The present thesis consists of a resume of the studies made concerning the Mexican crayfishes. The crayfishes are freshwater decapod crustaceans which populate a large part of the streams and lacustrine deposits of Guatemala, Mexico, Cuba, and the United ...

A. Villalobos



Who Am I?  

NSDL National Science Digital Library

In this online game, learners identify various animals including rabbits, turtles, and squirrels that live in National Parks, National Seashores and National Preserves. Clues introduce learners to organism characteristics such as invertebrate, decomposer, reptile, decapod, and mammal.

Service, National P.



Phytoplankton, Zooplankton, and Ichthyoplankton in Resurrection Bay, Northern Gulf of Alaska in 1988.  

National Technical Information Service (NTIS)

The report provides information on phytoplankton, zooplankton, decapod larvae, and ichthyoplankton in the Resurrection Bay fjord at the head of the 'Seward line'. The report is based on a preliminary plankton survey of the Resurrection Bay fjord funded by...

A. J. Paul J. M. Paul K. Coyle R. Smith



Trophic relationships at intrannual spatial and temporal scales of macro and megafauna around a submarine canyon off the Catalonian coast (western Mediterranean)  

NASA Astrophysics Data System (ADS)

The spatial and temporal changes of near-bottom macrofauna (suprabenthos and macroplankton) and the trophic relationships of megabenthic decapod crustaceans were analyzed off the Catalonian coasts (western Mediterranean) around Berenguera submarine canyon in four periods (April and December 1991, March and July 1992) and four zones (within Berenguera Canyon at ca. 450 m, and on adjacent slope at ca. 400, 600 m and 1200 m). In March 1992, we found the highest macrofauna abundance and the smallest sizes in the canyon, suggesting a positive effect of river discharges on suprabenthos recruitment. By contrast, macroplankton (decapods, fishes and euphausiids) did not show higher recruitment into canyons. After analyzing the diet of 23 decapod crustaceans, we found a significant segregation between guilds feeding on zooplankton and on benthos. Zooplankton (euphausiids and Pasiphaeidae) and infauna (polychaetes, Calocaris macandreae and ophiuoroids) were consistently the main prey exploited by decapod crustaceans around Berenguera Canyon. We also found some macrophyte ( Posidonia oceanica) consumption, which was higher in periods of water column homogeneity (winter-spring and late autumn). Positive correlations between decapods' gut fullness ( F) and decapod abundance indicate feeding aggregations, while positive correlations were also found between F and Llobregat River (situated ca. 18 km from Berenguera head) flow 1 to 2 months before sampling. Increases in F were delayed only 1 month when zooplankton feeders were analyzed alone, while benthos feeders did not show significant relationships with any environmental variables. That indicates that the response of megabenthic decapods feeding on benthos to environmental shifts is slower than that of zooplankton feeders. The importance of river flows in enhancing food supply of macro- and megabenthos dwelling close to submarine canyons was apparent, with a delay in the fauna response of 0-2 months after river flow peaks.

Cartes, Joan E.; Fanelli, Emanuela; Papiol, Vanesa; Maynou, Francesc



Influence of trophic variables on the depth-range distributions and zonation rates of deep-sea megafauna: the case of the Western Mediterranean assemblages  

NASA Astrophysics Data System (ADS)

We studied in a deep-sea megafaunal community the relationship of different trophic variables to the depth ranges inhabited by and depth zonation of species, after the ordination of fish and decapod crustaceans in feeding guilds. The variables studied included trophic level of species, food sources exploited, mean weight of predators and prey, feeding intensity and dietary diversity of species. We compiled data on the diets of 18 species of fish and 14 species of decapod crustaceans distributed between 862 and 2261 m in the Catalano-Balearic Basin (Western Mediterranean). Feeding guilds were identified for fish and decapods separately and at two depth strata (862-1400 and 1400-2261 m). The zonation rates (degree of depth overlap) between species within each trophic guild differed by guild and taxon (fish and decapods). The three guilds (G1, G2 and G3) of decapod crustaceans showed quite significantly distinct overlap. G1 (plankton feeders) showed the widest overlap (1326-1381 m) and G3 (benthos feeders) the narrowest (330-476 m). Among the four guilds established for fish, G1, comprising larger predators such as sharks, showed the lowest overlap (between 194 and 382 m). Macrourids overlap ranged between 122 and 553 m, the rest of benthopelagic feeders ranged between 423 and 970 m, and G3 (benthos feeders) gave overlaps between 867 and 1067 m. Significant differences were detected between the depth overlap of most feeding guilds excluding the paired comparisons between G1/macrourids, and G2/G3. Among decapods higher zonation rates (=lower depth overlap) were identified in those guilds occupying higher trophic levels (TL), with a similar, though not as general, trend among fish. In the ordination of species in feeding guilds, TL as indicated by ?15N measurements, was significantly correlated with Dimension 1 (D1) of ordination—MDS-analysis, both in fish and decapods at 862-1400 m. However, deeper (at 1400-2261 m), D1 was not significantly correlated with TL but with the mean weight of predator and prey in fish. In general, TL was again the main explanatory variable (accumulated variances, r2, explained by multi-linear regression—MLR-models between 0.54 and 0.69) both of the zonation rates and the depth ranges occupied by megafauna (fish and decapods together) throughout all the depth range studied. Possible relationships between zonation rates /depth distributions and other biological variables (i.e. egg size, fecundity) are also discussed.

Cartes, Joan E.; Carrassón, Maite




EPA Science Inventory

A two year trawling and gill-netting study of vegetated and unvegetated bottoms near Parson's Island, Maryland and near the mouth of the York River, Virginia was carried out to assess the nursery function of submerged vegetation for population of fishes and decapod crustaceans in...


Activation of lipid catabolism by the water-soluble fraction of petroleum in the crustacean Macrobrachium borellii  

Microsoft Academic Search

Little is known about the effect of the water-soluble fraction of crude oil (WSF) on lipid metabolism in invertebrates. The effect of the WSF on the triacylglycerol (TAG) mobilization, fatty acid activation and degradation was evaluated in the decapod Macrobrachium borellii, exposing adult and eggs at different stages of development for 7 days to a sublethal concentration of WSF. Using

S. Lavarías; R. J. Pollero; H. Heras



Occurrence of the autofluorescent pigment, lipofuscin, in polar crustaceans and its potential as an age marker  

Microsoft Academic Search

In crustaceans, the lack of reliable methods often prevents the determination of individual age. The quantification of the autofluorescent age pigment, lipofuscin, has revealed promising results in boreal and tropical species. We studied the presence of morphological lipofuscin and its possible application as an age marker in five Arctic and five Antarctic species, comprising decapods, amphipods and a euphausiid. Lipofuscin

Bodil A. Bluhm; Thomas Brey; Michael Klages; Wolf E. Arntz



A new lobster Paraclytia valashtensis (Crustacea, Decapoda, Nephropidae) from the Late Cretaceous of the central Alborz Range, Iran  

Microsoft Academic Search

Springer-Verlag 2009 Abstract A new species of Late Cretaceous clawed lobster, Paraclytia valashtensis, is described. The discov- ery is a notable addition to the sparse decapod fossil record of Iran, and this is the first record of the genus outside central Europe. The four previously known species of Paraclytia are from Germany and the Czech Republic, so this discovery represents

Lucy Martha Evelyn McCobb; Vachik Hairapetian



Outer Continental Shelf environmental assessment program. Final reports of principal investigators. Volume 53  

SciTech Connect

Contents include: Baffin Island experimental oil spill and dispersant studies. Hydrocarbon bioaccumulation and histopathological and biochemical responses in marine bivalve molluscs; Feeding ecology of juvenile king and Tanner crab in the southeastern Bering Sea; Distribution of larval and juvenile red king crabs (Paralithodes camtschatica) in Bristol Bay; Distribution and abundance of decapod crustacean larvae in the southeastern Bering Sea with emphasis on commercial species.

Not Available



Ancient lakes as evolutionary reservoirs: evidence from the thalassoid gastropods of Lake Tanganyika  

Microsoft Academic Search

Ancient lakes are often collectively viewed as evolutionary hot spots of diversification. East Africa's Lake Tanganyika has long been the subject of scientific interest owing to dramatic levels of endemism in species as diverse as cichlid fishes, paludomid gastropods, decapod and ostracod crustaceans and poriferans. It is the largest and deepest of the African rift lakes, and its endemic fauna

Anthony B. Wilson; Matthias Glaubrecht; Axel Meyer



Structure, patterns, and function of cuticular terraces in recent and fossil arthropods  

Microsoft Academic Search

Cuticular terraces are found in a number of decapod families. In four examples investigations have been made of terrace pattern, terrace morphology, morphogenetic processes, ontogenetic development, and function. InGrapsus grapsus the terrace pattern on carapace and appendages remains constant during ontogeny and the terraces function as frictional resistances in crevices, aiding to escape from avian predators. Histological investigations explain the

Helmut Schmalfuss



RESEARCH ARTICLE Rheb, an activator of target of rapamycin, in the blackback land crab, Gecarcinus lateralis: cloning and effects of molting and unweighting on expression in skeletal muscle  

Microsoft Academic Search

SUMMARY Molt-induced claw muscle atrophy in decapod crustaceans facilitates exuviation and is coordinated by ecdysteroid hormones. There is a 4-fold reduction in mass accompanied by remodeling of the contractile apparatus, which is associated with an 11-fold increase in myofibrillar protein synthesis by the end of the premolt period. Loss of a walking limb or claw causes a loss of mass

Kyle S. MacLea; Ali M. Abuhagr; Natalie L. Pitts; Joseph A. Covi; Brandon D. Bader; Ernest S. Chang; Donald L. Mykles



Ultrastructural study on the release of neurosecretory material from the sinus gland of the land crab, Gecarcinus lateralis  

Microsoft Academic Search

Sites of release of neurosecretory material were examined in a neurohemal organ of decapod crustaceans, the sinus gland of the land crab, Gecarcinus lateralis. Such discharge into the circulation seems to occur primarily at interfaces between the neurosecretory axons and the acellular stromal sheath which is interposed between parenchyma and hemolymph. The evidence obtained from electron micrographs of adult specimens

Mary Weitzman



Characterization of Limb Autotomy Factor Proecdysis (LAFpro), Isolated From Limb Regenerates, That Suspends Molting in the Land Crab Gecarcinus lateralis  

Microsoft Academic Search

Molting and limb regeneration are tightly cou- pled processes, both of which are regulated by ecdysteroid hormone synthesized and secreted by the Y-organs. Regen- eration of lost appendages can affect the timing and duration of the proecdysial, or premolt, stage of the molt cycle. Autotomy of all eight walking legs induces precocious molts in various decapod crustacean species. In the




EPA Science Inventory

Larval development in decapod crustaceans is marked by variable growth patterns and changes in weight and biochemical composition. Larvae of the stone crab, Menippe adina, were mass-reared under laboratory conditions (28?C; 20o/ooS) from hatching to the megalopa stage. Growth in...



EPA Science Inventory

Larval development in decapod crustaceans is marked by variable growth patterns and changes in weight and biochemical composition. Larvae of the stone crab, Menippe adina, were mass-reared under laboratory conditions (28|C; 20o/ooS) from hatching to the megalopal stage. Growth in...


Crustacean fauna (Stomatopoda: Decapoda) associated with the deepwater fishery of Heterocarpus vicarius (Decapoda: Pandalidae) along the Pacific coast of Costa Rica  

Microsoft Academic Search

Commercial bottom trawling is a successful and commonly used method to catch marine shrimps. However, the shrimp fishing gears are poorly selective, and in addition to the target species they catch and retain large quantities of non-target species (bycatch). This study presents data concerning species composition and depth distribution of the crustacean fauna (stomatopods and decapods) associated with Heterocarpus vicarius

Ingo S. Wehrtmann; Silvia Echeverría-Sáenz


Structural re-evaluation of the neurosecretory system in the crayfish eyestalk  

Microsoft Academic Search

The topography of the neurosecretory system in the decapod eyestalk has not been precisely delineated with light microscopy. Cobalt iontophoresis and electron microscopy have proved useful in clarifying the microstructure of this system. The sinus gland (sg) of the crayfish eyestalk consists of aggregated axon terminals which end at or near the blood space, lontophoresing cobalt back through the cut

R. D. Andrew; I. Orchard; A. S. M. Saleuddin



Lactate and malate dehydrogenase in the fan-shell associated shrimp, Pontonia pinnophylax (Otto): Effects of temperature and urea  

Microsoft Academic Search

In Pontonia pinnophylax (Otto), a crustacean decapod inhabiting the mantle cavity of Pinna nobilis L. (Bivalvia: Pteriomorpha), the lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) activity, and their electrophoretic patterns, were compared in relation to heat and urea inactivation. Activity was higher in LDH than in MDH, and the electrophoretic patterns showed a predominance of LDH-A4 and the presence of

G. Laganà; S. Giacobbe; E. Bellocco; C. Mannucci; A. Galtieri; S. Ficarra; A. Kotyk; U. Leuzzi



Carrion-feeding on the sediment surface at nocturnal low tides by the polychaete Phyllodoce mucosa  

Microsoft Academic Search

Harsh physical conditions in the intertidal zone are the cause of an ample amount of dead macroinvertebrates, which constitute a food source for carrion-feeders. In the European Wadden Sea, this trophic guild includes decapod crustaceans and fish when the tide is in, while during nocturnal low tides the polychaete Phyllodoce mucosa is attracted in large numbers by dead mollusks, crabs

C.-G. Lee; M. Huettel; J.-S. Hong; K. Reise



Ecology and taxonomy of a tree-living freshwater crab (Brachyura: Potamoidea: Potamonautidae) from Kenya and Tanzania, East Africa  

Microsoft Academic Search

The ecology and taxonomy of an interesting species of tree-living freshwater crab from the East Usambara mountains, Tanzania, and from the Shimba Hills, Kenya, East Africa is described. This phytotelmic decapod crustacean belongs to a new species of potamonautid freshwater crab in the genus Potamonautes MacLeay, 1838, which is described. This is one of only a few reports of the

Neil Cumberlidge; Marco Vannini



A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples.  


The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species. PMID:21931530

Ströher, Patrícia R; Firkowski, Carina R; Freire, Andrea S; Pie, Marcio R



Effect of temporal variation, gender and size on cuticle polyphenol oxidase activity in deep-water rose shrimp ( Parapenaeus longirostris)  

Microsoft Academic Search

Seasonal changes and physiological factors related to sex, size and spawning period may alter polyphenol oxidase (PPO) activity in crustacean decapods. Given the undesirable effects that the enzyme has on the marketability of shrimps, the cuticles of the valuable deep-water rose shrimp were examined. Monthly measurements of PPO activity in cuticles of juvenile and adult males and females were recorded

Gioacchino Bono; Cinzia Badalucco; Antonino Corrao; Salvatore Cusumano; Luigi Mammina; Giovanni B. Palmegiano



The impact of extreme turbidity events on the nursery function of a temperate European estuary with regulated freshwater inflow  

Microsoft Academic Search

Estuaries are used as nursery grounds by numerous marine species despite being usually subject to strong anthropogenic disturbances. Abundances of marine recruits (fish and crustacean decapods) and their main prey (mysids) were monitored by monthly sampling, from June 1997 to February 2009, in the lower reaches of the Guadalquivir estuary (SW Spain). During that period, unusually high and persistent turbidity

E. González-Ortegón; M. D. Subida; J. A. Cuesta; A. M. Arias; C. Fernández-Delgado; P. Drake



The structure and function of the hepatopancreas of a terrestrial isopod, Armadillidium vulgare.  


The fine structure of the hepatopancreas of the isopod, Armadillidium vulgare was studied in intact and in experimentally treated animals. The gross anatomy of the hepatopancreas of this species is simpler than that of decapods, but microscopically the cells are similar in both. Accordingly, the function of this organ is probably the same in decapods and Armadillidium. Some phylogenetic considerations are also presented. In a previous paper Miyawaki et al. (1984), presented experimental results which indicated that the hepatopancreas of the crayfish, Procambarus clarki, had an important role in the absorption of digested food materials. These results confirmed earlier reports by Yonge (1924) and van Weel (1955) on the decapods, Nephrops norvegicus and Atya spinides, respectively. In the present study, we wished to determine whether the isopod hepatopancreas has a function like that of the decapods. A terrestrial isopod, Armadillidium vulgare collected on the University campus, and reared in the laboratory at room temperature was used. The methods of study were similar to those employed in the study with Procambarus clarki (Miyawaki et al., 1984). PMID:3986923

Miyawaki, M; Yamamoto, Y



Emigration of penaeid shrimp from the once-through cooling lake of Cedar Bayou Steam Electric Generating Station, Baytown, Texas  

Microsoft Academic Search

Migration and distribution of two decapod shrimp, Penaeus setiferus and P. aztecus, in the cooling-water system of a power plant on the Texas coast were investigated, with emphasis on the seaward emigration from the cooling lake. Samples were collected every two weeks for a year by straining water leaving the lake over a drop structure, trawling in the cooling lake,



A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples  

PubMed Central

The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species.

Stroher, Patricia R.; Firkowski, Carina R.; Freire, Andrea S.; Pie, Marcio R.




Microsoft Academic Search

New decapod crustacean fossils collected from Eocene rocks of Algarrobo, Chile, have yielded a new genus and species of callianassid, Melipal chilensis. The large sample size makes it possible to recognize marked sexual dimorphism of the major cheliped and pronounced heterochely in the new taxon. Cretaceous fossils from Algarrobo are referred to Protocallianassa saetosa (Forster and Stinnesbeck, 1987) new combination.

C. E. Schweitzer; R. M. Feldmann; A. Encinas; M. Suárez



A structural and functional comparison of nematode and crustacean PDH-like sequences.  


The elucidation of the whole genome of the nematode Caenorhabditis elegans allowed for the identification of ortholog genes belonging to the pigment dispersing hormone/factor (PDH/PDF) peptide family. Members of this peptide family are known from crustaceans, insects and nematodes and seem to exist exclusively in ecdysozoans where they play a role in different processes, ranging from the dispersion of integumental and eye (retinal) pigments in decapod crustaceans to circadian rhythms in insects and locomotion in C. elegans. Two pdf genes (pdf-1 and pdf-2) encoding three different peptides: PDF-1a, PDF-1b and PDF-2 have been identified in C. elegans. These three C. elegans PDH-like peptides are similar but not identical in primary structure to PDHs from decapod crustaceans. We investigate whether this divergence has an influence on the pigment dispersing function of the peptides in a decapod crustacean, namely the shrimp Palaemon pacificus. We show that C. elegans PDF-1a and b peptides display cross-functional activity by dispersing pigments in the epithelium of P. pacificus at physiological doses. Moreover, by means of a comparative amino acid sequence analysis of nematode and crustacean PDH-like peptides, we can pinpoint several potentially important residues for eliciting pigment dispersing activity in decapod crustaceans. Although there is no sequence information on a receptor for PDH in decapod crustaceans, we postulate that there is general conservation of the PDH/PDF signaling system based on structural similarities of precursor proteins and receptors (including those from a branchiopod crustacean and from C. elegans). PMID:22115566

Meelkop, E; Marco, H G; Janssen, T; Temmerman, L; Vanhove, M P M; Schoofs, L



The microvilli of the midgut epithelium in the freshwater shrimp, Caridina denticulata.  


The ultrastructure of the epithelial cell microvilli of the midgut of a decapod, Caridina denticulata , was studied. The microvilli have an axial bundle of filaments extend from the tip of the microvilli deeply into the interior cytoplasm of the epithelial cells. Basal globules were present at the base of the microvilli in the premolt stage animals. The length and arrangement of the microvilli change during the molting cycle. PMID:6722906

Miyawaki, M; Taketomi, Y



Chemical Ecology and Social Behavior of Anomura  

Microsoft Academic Search

\\u000a Anomura is an extremely diverse assemblage of crustacean decapods with a large variety of forms and lifestyles, which makes\\u000a the taxon ideal for comparative studies of social systems and means of communication. Notwithstanding this, our knowledge\\u000a of Anomura is mostly restricted to the crab–shell relationships in hermit crabs, whereas promising fields of research, such\\u000a as chemical ecology, are still in

Francesca Gherardi; Elena Tricarico


Roles of crustacean hyperglycaemic hormone in ionic and metabolic homeostasis in the Christmas Island blue crab, Discoplax celeste.  


There is a growing body of evidence implicating the involvement of crustacean hyperglycaemic hormone (CHH) in ionic homeostasis in decapod crustaceans. However, little is known regarding hormonally influenced osmoregulatory processes in terrestrial decapods. As many terrestrial decapods experience opposing seasonal demands upon ionoregulatory physiologies, we reasoned that these would make interesting models in which to study the effect of CHH upon these phenomena. In particular, those (tropical) species that also undergo seasonal migrations might be especially informative, as we know relatively little regarding the nature of CHHs in terrestrial decapods, and hormonally mediated responses to seasonal changes in metabolic demands might also be superimposed or otherwise integrated with those associated with ionic homeostasis. Using Discoplax celeste as a model crab that experiences seasonal extremes in water availability, and exhibits diurnal and migratory activity patterns, we identified two CHHs in the sinus gland. We biochemically characterised (cDNA cloning) one CHH and functionally characterised (in terms of dose-dependent hyperglycaemic responses and glucose-dependent negative feedback loops) both CHHs. Whole-animal in situ branchial chamber (22)NaCl perfusion experiments showed that injection of both CHHs increased gill Na(+) uptake in a seasonally dependent manner, and (51)Cr-EDTA clearance experiments demonstrated that CHH increased urine production by the antennal gland. Seasonal and salinity-dependent differences in haemolymph CHH titre further implicated CHH in osmoregulatory processes. Intriguingly, CHH appeared to have no effect on gill Na(+)/K(+)-ATPase or V-ATPase activity, suggesting unknown mechanisms of this hormone's action on Na(+) transport across gill epithelia. PMID:23239894

Turner, Lucy M; Webster, Simon G; Morris, Stephen




Microsoft Academic Search

The controversial interrelationships of the major clades of the reptant decapods are resolved by simultaneous analysis of 16S, 18S, and 28S rRNA sequences in combination with morphology. All major reptant clades are represented including the first molecular data for the controversial Polychelidae, Glypheidae, and Enoplometopidae. Interrelationships of major clades in the shortest morphological cladograms were identical to those based on

Shane T. Ahyong; Denis O'Meally


Expression of recombinant eyestalk crustacean hyperglycemic hormone from the tropical land crab, Gecarcinus lateralis , that inhibits Y-organ ecdysteroidogenesis in vitro  

Microsoft Academic Search

Crustacean hyperglycemic hormone (CHH) is a pleiotropic neuropeptide that regulates carbohydrate and lipid metabolism, molting,\\u000a reproduction, and osmoregulation in decapod crustaceans. CHH elevates glucose levels in the hemolymph by stimulating glycogenolysis\\u000a in target tissues. It also inhibits ecdysteroidogenesis in the molting gland, or Y-organ (YO), possibly as a response to environmental\\u000a stress. CHH acts via binding to a membrane receptor

Tyler P. Zarubin; Ernest S. Chang; Donald L. Mykles



Cloning of a nitric oxide synthase from green shore crab, Carcinus maenas: A comparative study of the effects of eyestalk ablation on expression in the molting glands (Y-organs) of C. maenas, and blackback land crab, Gecarcinus lateralis  

Microsoft Academic Search

Molting in decapod crustaceans is regulated by ecdysteroids produced by a pair of Y-organs (YOs) located in the cephalothorax. YO ecdysteroidogenesis is suppressed by molt-inhibiting hormone (MIH), a neuropeptide produced in the X-organ of the eyestalk (ES) ganglia. MIH signaling may involve nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). A full-length cDNA encoding Carcinus maenas NOS (Cm-NOS; 3836

Audrey A. McDonald; Ernest S. Chang; Donald L. Mykles



Comparative analysis of an excitatory motor unit in crustaceans  

Microsoft Academic Search

1.The leg stretcher muscle motor unit was examined in five different decapod crustaceans (Gecarcinus, Grapsus, Goniopsis, Homarus andPanulirus) with the objective of establishing interrelationships between nerve terminal and muscle fiber properties.2.In each species, nerve terminals varied greatly in their capacity for facilitation of transmitter release (Fe), muscle fibers varied with respect to sarcomere length (SL), and a wide range of

R. G. Sherman



Proteomics and signal transduction in the crustacean molting gland  

Microsoft Academic Search

Synopsis Regulation of the molting cycle in decapod crustaceans involves 2 endocrine organs: the X-organ\\/sinus gland (XO\\/SG) complex located in the eyestalk ganglia and the Y-organ (YO) located in the cephalothorax. Two neuropeptides (molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH)) are produced in the XO\\/SG complex and inhibit ecdysteroidogenesis in the YO. Thus, YO activation is induced by eyestalk

Sung Gu Lee; Donald L. Mykles



Accumulation of Mutagenic Xenobiotics in Fresh Water (Lake Baikal) and Marine (Hornoya Island) Ecosystems  

Microsoft Academic Search

Extracts from tissues of a wide range of aquatic organisms (plants, plankton, decapods, molluscs, fish, Baikal seals, and fish-eating birds and their eggs) from Lake Baikal and from the Selenga River estuary and tissue extracts of birds breeding on Hornoya Island (northern Norway) were assayed for mutagenicity using the Ames Salmonella\\/microsome test. The activities of cytochrome P-450 and the enzymes

Ludmila I. Stepanova; Vadim M. Glaser; Tatiana I. Savinova; Sergey V. Kotelevtsev; Demetris Savva



The feeding habits of three Mediterranean sea anemone species, Anemonia viridis (Forskål), Actinia equina (Linnaeus) and Cereus pedunculatus (Pennant)  

Microsoft Academic Search

The feeding habits of the Mediterranean sea anemonesCereus pedunculatus, Actinia equina andAnemonia viridis were examined mainly by analysing their coelenteron contents. The three species are opportunistic omnivorous suspension feeders.\\u000a Main source of food forA. viridis andC. pedunculatus are crustaceans (mainly amphipods and decapods, respectively), while for the midlittoral speciesA. equina, it is organic detritus. Using the same method, the temporal

Ch. Chintiroglou; A. Koukouras



Mating behavior of Abdopus aculeatus (d’Orbigny 1834) (Cephalopoda: Octopodidae) in the wild  

Microsoft Academic Search

The mating system of Abdopus aculeatus incorporates sneaker matings, mate guarding, sex-specific body patterns, frequent copulations, and male–male competition\\u000a for mates, making it more similar to that of aggregating decapod cephalopods than any previously known octopus social system.\\u000a Large male–female A. aculeatus occupy ‘Adjacent’ (GA) dens and copulate frequently in mate-guarding situations over successive days. Nearby individuals copulate in ‘Temporary

Christine L. Huffard; Roy L. Caldwell; Farnis Boneka



Spatial structure of a leaf-removing crab population in a mangrove of North-Brazil  

Microsoft Academic Search

The leaf-removing decapod crab, Ucides cordatus plays a key role as ecological engineer in Brazilian mangrove ecosystems. We analyzed the spatial distribution of a specific\\u000a population at two different scales to observe how individual behavior could alter spatial population structure. First, we\\u000a conducted a spatial point pattern analysis of the burrow entrances and the Rhizophora mangle prop roots on the

Cyril Piou; Uta Berger; Ilka C. Feller



Molecular Phylogeny of Eastern Pacific Porcelain Crabs, Genera Petrolisthes and Pachycheles, Based on the mtDNA 16S rDNA Sequence: Phylogeographic and Systematic Implications  

Microsoft Academic Search

Porcelain crabs, genera Petrolisthes and Pachycheles, are diverse and abundant members of the eastern Pacific near-shore decapod crustacean community. Morphology-based taxonomic analyses of these crabs have determined groupings of affiliated species, but phylogenetic relationships remain unknown. We used sequence data from the mitochondrial 16S rRNA gene of 46 species of eastern Pacific porcelain crabs to perform phylogenetic analyses by distance

Jonathon H. Stillman; Carol A. Reeb



Seasonal changes of benthic megafauna in the Ría de Muros e Noia (Galicia, North-West Spain)  

Microsoft Academic Search

A community of decapod crustaceans (Brachyura) was sampled seasonally (October 1978–July 1979) from three habitats (raft, middle and beach) in the Ría de Muros e Noia (North-West Spain), with the purpose of studying spatial and temporal changes in the community and comparing with communities in the neighbouring Ría de Arousa, which supports an intense mussel (Mytilus edulis)-raft culture. The Portunidae

E. González-Gurriarán



Tension Receptor Reflexes in the Walking Legs of the Crab Cancer pagurus  

Microsoft Academic Search

THE decapod crustaceans have many advantages for the study of the neuronal mechanisms controlling simple behaviour1-3. Numerous authors have investigated the functions of the walking legs, but models of the control mechanisms have been presented in terms of central programmes and reflexes related simply to the positions and movements of the joints4,5; little attention has been paid to the control

F. Clarac; M. R. Dando



Recovery of rhythmic activity in a central pattern generator: analysis of the role of neuromodulator and activity-dependent mechanisms  

Microsoft Academic Search

The pyloric network of decapods crustaceans can undergo dramatic rhythmic activity changes. Under normal conditions the network\\u000a generates low frequency rhythmic activity that depends obligatorily on the presence of neuromodulatory input from the central\\u000a nervous system. When this input is removed (decentralization) the rhythmic activity ceases. In the continued absence of this\\u000a input, periodic activity resumes after a few hours

Yili Zhang; Jorge Golowasch


Bait-attending fauna of the Kermadec Trench, SW Pacific Ocean: Evidence for an ecotone across the abyssal–hadal transition zone  

Microsoft Academic Search

The bait-attending fauna of the abyssal–hadal transition zone of the Kermadec Trench, SW Pacific Ocean (4329–7966m), was investigated using a baited camera and a trap lander. The abyssal stations (4329–6007m) revealed a typical scavenging fish community comprising macrourids and synaphobranchid eels, as well as natantian decapods. At the hadal depths of 7199 and 7561m, the endemic liparid Notoliparis kermadecensis was

A. J. Jamieson; N. M. Kilgallen; A. A. Rowden; T. Fujii; T. Horton; A.-N. Lörz; K. Kitazawa; I. G. Priede




Microsoft Academic Search

Stomach contents of 2,622 silver hake collected in the Northwest Atlant.ic have been analyzed. Fish were collected on bottom trawl surveys conducted from 1973 to 1976. The mean fish fork length (FL) was 20 em and the average stomach content weight was 1.5 g. Silver hake <20 em FL prey mostly on amphipods. decapod shrimp. and euphausiids. Fish 20 cm




Protistan diseases of commercially important crabs: a review.  


Protists are a diverse group of eukaryotes that possess a unicellular level of organization. As unicellular organisms, the differentiation of cells into tissues does not occur, although when cell differentiation does occur, it is limited to sexual reproduction, alternate vegetative morphologies or quiescent life history stages. Protistan parasites may possess simple or complex life histories that are important factors to consider when investigating protistan diseases of decapods. Unfortunately, the life histories of many protistan parasites of decapods are insufficiently described, resulting in the fact that modes of infection and transmission are often unidentified. This is surprising considering the economic importance of many marine decapods and the ability of protistan parasites to produce significant, but generally transient and area limited mortalities. However, the marine disease landscape is changing and will continue to change as climate change and ocean acidification will play important roles in disease occurrence and distribution. As a result, the following discussion attempts to summarize current knowledge on several crab diseases, their protistan etiological agents, the impact of disease on economically important crab populations and draw attention to areas of needed research. The discussion is not complete as only selected diseases are addressed, or perfect as the Microsporidia are included in the discussion (a traditional error continued in this summary) despite the recent, but controversial placement of the taxon with the fungi. PMID:21215354

Morado, J F



Feeding ecology of the deep-water blue-red shrimp Aristeus antennatus (Decapoda: Aristeidae) in the Greek Ionian Sea (E. Mediterranean)  

NASA Astrophysics Data System (ADS)

The feeding habits of the deep-sea blue-red shrimp Aristeus antennatus were determined based on the analysis of 1047 stomach contents, sampled in the Greek Ionian Sea (E. Mediterranean). The diet of this economically and biologically important decapod was studied in relation to the season, size class and sex. The diet of A. antennatus consisted of 54 different prey categories, and belonged mainly to smaller crustaceans (e.g. natantian decapods, euphausiids, tanaidaceans), molluscs, polychaetes, chaetognaths and, to a lesser extent, fishes. The above prey categories consisted of 71-82% of the relative abundance and total occurrence for males and 61-81% for females. Females seemed to be better fed than males (stomach fullness, food quality). A. antennatus displayed a highly diversified diet and the different feeding patterns were discussed. Diet composition showed slight seasonal fluctuations. The observed slight differences on A. antennatus diet among the western, central and eastern Mediterranean could be attributed to the more oligotrophic character of the eastern part of the basin. The principal factors driving the changes in the feeding strategy of this decapod among the seasons are the increased energy demands related to sexual requirements and the food availability in the marine environment. The ontogenetic changes in the shrimp's diet were relatively clear. Larger individuals exhibited selecting prey with a good swimming capacity (e.g. fishes), while the smaller individuals consumed prey with low mobility (e.g. copepods, ostracods).

Kapiris, Kostas; Thessalou-Legaki, Maria



Abbreviation of larval development and extension of brood care as key features of the evolution of freshwater Decapoda.  


The transition from marine to freshwater habitats is one of the major steps in the evolution of life. In the decapod crustaceans, four groups have colonized fresh water at different geological times since the Triassic, the freshwater shrimps, freshwater crayfish, freshwater crabs and freshwater anomurans. Some families have even colonized terrestrial habitats via the freshwater route or directly via the sea shore. Since none of these taxa has ever reinvaded its environment of origin the Decapoda appear particularly suitable to investigate life-history adaptations to fresh water. Evolutionary comparison of marine, freshwater and terrestrial decapods suggests that the reduction of egg number, abbreviation of larval development, extension of brood care and lecithotrophy of the first posthatching life stages are key adaptations to fresh water. Marine decapods usually have high numbers of small eggs and develop through a prolonged planktonic larval cycle, whereas the production of small numbers of large eggs, direct development and extended brood care until the juvenile stage is the rule in freshwater crayfish, primary freshwater crabs and aeglid anomurans. The amphidromous freshwater shrimp and freshwater crab species and all terrestrial decapods that invaded land via the sea shore have retained ocean-type planktonic development. Abbreviation of larval development and extension of brood care are interpreted as adaptations to the particularly strong variations of hydrodynamic parameters, physico-chemical factors and phytoplankton availability in freshwater habitats. These life-history changes increase fitness of the offspring and are obviously favoured by natural selection, explaining their multiple origins in fresh water. There is no evidence for their early evolution in the marine ancestors of the extant freshwater groups and a preadaptive role for the conquest of fresh water. The costs of the shift from relative r- to K-strategy in freshwater decapods are traded-off against fecundity, future reproduction and growth of females and perhaps against size of species but not against longevity of species. Direct development and extension of brood care is associated with the reduction of dispersal and gene flow among populations, which may explain the high degree of speciation and endemism in directly developing freshwater decapods. Direct development and extended brood care also favour the evolution of social systems, which in freshwater decapods range from simple subsocial organization to eusociality. Hermaphroditism and parthenogenesis, which have evolved in some terrestrial crayfish burrowers and invasive open water crayfish, respectively, may enable populations to adapt to restrictive or new environments by spatio-temporal alteration of their socio-ecological characteristics. Under conditions of rapid habitat loss, environmental pollution and global warming, the reduced dispersal ability of direct developers may turn into a severe disadvantage, posing a higher threat of extinction to freshwater crayfish, primary freshwater crabs, aeglids and landlocked freshwater shrimps as compared to amphidromous freshwater shrimps and secondary freshwater crabs. PMID:22891642

Vogt, Günter



The emergence of lobsters: phylogenetic relationships, morphological evolution and divergence time comparisons of an ancient group (decapoda: achelata, astacidea, glypheidea, polychelida).  


Lobsters are a ubiquitous and economically important group of decapod crustaceans that include the infraorders Polychelida, Glypheidea, Astacidea and Achelata. They include familiar forms such as the spiny, slipper, clawed lobsters and crayfish and unfamiliar forms such as the deep-sea and "living fossil" species. The high degree of morphological diversity among these infraorders has led to a dynamic classification and conflicting hypotheses of evolutionary relationships. In this study, we estimated phylogenetic relationships among the major groups of all lobster families and 94% of the genera using six genes (mitochondrial and nuclear) and 195 morphological characters across 173 species of lobsters for the most comprehensive sampling to date. Lobsters were recovered as a non-monophyletic assemblage in the combined (molecular?+?morphology) analysis. All families were monophyletic, with the exception of Cambaridae, and 7 of 79 genera were recovered as poly- or paraphyletic. A rich fossil history coupled with dense taxon coverage allowed us to estimate and compare divergence times and origins of major lineages using two drastically different approaches. Age priors were constructed and/or included based on fossil age information or fossil discovery, age, and extant species count data. Results from the two approaches were largely congruent across deep to shallow taxonomic divergences across major lineages. The origin of the first lobster-like decapod (Polychelida) was estimated in the Devonian (?409-372 Ma) with all infraorders present in the Carboniferous (?353-318 Ma). Fossil calibration subsampling studies examined the influence of sampling density (number of fossils) and placement (deep, middle, and shallow) on divergence time estimates. Results from our study suggest including at least 1 fossil per 10 operational taxonomic units (OTUs) in divergence dating analyses. [Dating; decapods; divergence; lobsters; molecular; morphology; phylogenetics.]. PMID:24562813

Bracken-Grissom, Heather D; Ahyong, Shane T; Wilkinson, Richard D; Feldmann, Rodney M; Schweitzer, Carrie E; Breinholt, Jesse W; Bendall, Matthew; Palero, Ferran; Chan, Tin-Yam; Felder, Darryl L; Robles, Rafael; Chu, Ka-Hou; Tsang, Ling-Ming; Kim, Dohyup; Martin, Joel W; Crandall, Keith A



Molecular detection of Hematodinium sp. in Northeast Pacific Chionoecetes spp. and evidence of two species in the Northern Hemisphere.  


Hematodinium is a genus of parasitic dinoflagellates that infects crustaceans worldwide including Tanner crabs Chionoecetes bairdi and snow crabs C. opilio in the Northeast Pacific Ocean. The present study describes the optimization of a PCR-based assay for the detection and monitoring of Hematodinium sp. in snow and Tanner crabs. Two fragments, 1682 and 187 bp, were amplified from the 18S ribosomal DNA region of the parasite. The assay performed well in 6 additional decapod species (1 lobster and 5 crabs) infected with Hematodinium spp., suggesting that it could be used to detect Hematodinium spp. in other decapods. We also report Hematodinium spp. infections in the majid crab, Hyas coarctatus, and the lithodid crab, Lithodes couesi. Sequencing of 18S rDNA and the adjacent internal transcribed spacer 1 (ITS1) region of Hematodinium spp. isolated from 7 host species in the present study revealed the presence of 2 Hematodinium clades, one in the blue crab Callinectes sapidus and a second in all other host species. The ITS1 sequences of the 2 clades could not be aligned, but showed a conserved secondary structure that may be related to a functional diversification during a host switch. Comparison of our data with 18S and ITS1 sequence data available in GenBank placed the north Pacific Hematodinium sp. in a clade separate from the Hematodinium sp. infecting the portunoids, C. sapidus, Liocarcinus depurator and Scylla serrata, and within a second clade that infected all other decapod hosts located in the North Pacific and North Atlantic Oceans. PMID:20402233

Jensen, Pamela C; Califf, Katy; Lowe, Vanessa; Hauser, Lorenz; Morado, J Frank



Mass spectral characterization of peptide transmitters/hormones in the nervous system and neuroendocrine organs of the American lobster Homarus americanus  

PubMed Central

The American lobster Homarus americanus is a decapod crustacean with both high economic and scientific importance. To facilitate physiological investigations of peptide transmitter/hormone function in this species, we have used matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and nanoscale liquid chromatography coupled to electrospray ionization quadrupole time-of-flight tandem mass spectrometry (nanoLC-ESI-Q-TOF-MS/MS) to elucidate the peptidome present in its nervous system and neuroendocrine organs. In total, 84 peptides were identified, including 27 previously known H. americanus peptides (e.g. VYRKPPFNGSIFamide [Val1-SIFamide]), 23 peptides characterized previously from other decapods, but new to the American lobster (e.g. pQTFQYSRGWTNamide [Arg7-corazonin]), and 34 new peptides de novo sequenced/detected for the first time in this study. Of particular note are a novel B-type allatostatin (TNWNKFQGSWamide) and several novel FMRFamide-related peptides, including an unsulfated analog of sulfakinin (GGGEYDDYGHLRFamide), two myosuppressins (QDLDHVFLRFamide and pQDLDHVFLRFamide), and a collection of short neuropeptide F isoforms (e.g. DTSTPALRLRFamide, and FEPSLRLRFamide). Our data also include the first detection of multiple tachykinin-related peptides in a non-brachyuran decapod, as well as the identification of potential individual-specific variants of orcokinin and orcomyotropin-related peptide. Taken collectively, our results not only expand greatly the number of known H. americanus neuropeptides, but also provide a framework for future studies on the physiological roles played by these molecules in this commercially and scientifically important species.

Ma, Mingming; Chen, Ruibing; Sousa, Gregory L.; Bors, Eleanor K.; Kwiatkowski, Molly; Goiney, Christopher C.; Goy, Michael F.; Christie, Andrew E.; Li, Lingjun



Retinal anatomy of Chorocaris chacei, a deep-sea hydrothermal vent shrimp from the Mid-Atlantic Ridge.  


Exploration of deep-sea hydrothermal vents over the past quarter century has revealed that they support unique and diverse biota. Despite the harsh nature of the environment, vents along the Mid-Atlantic Ridge are dominated by large masses of highly motile Bresiliid shrimp. Until 1989, when it was discovered that the vent shrimp Rimicaris exoculata possesses a hypertrophied dorsal eye, many believed that animals populating hydrothermal vents were blind. Chorocaris chacei (originally designated Rimicaris chacei) is a Bresiliid shrimp found at hydrothermal vent fields along the Mid-Atlantic Ridge. Like R. exoculata, C. chacei has a hypertrophied retina that appears to be specialized to detect the very small amount of light emitted from the orifices of black smoker hydrothermal vent chimneys. C. chacei lacks the sophisticated compound eyes common to other decapod crustaceans. Instead, it has a smooth cornea, with no dioptric apparatus, apposed by a tightly packed, massive array of photosensitive membrane. Photoreceptors in the C. chacei retina are segmented into a hypertrophied region that contains the photosensitive membrane and an atrophied cell body that is roughly ten times smaller in volume than the photosensitive segment. The microvillar photosensitive membrane is consistent in structure and ultrastructure with the rhabdoms of decapod and other invertebrate retinas. However, the volume density of photosensitive membrane (> or =60%) exceeds that typically observed in invertebrate retinas. The reflecting pigment cells commonly found in decapod retinas are represented in the form of a matrix of white diffusing cells that exhibit Tyndall scattering and form an axial sheath around the photoreceptors. All photoreceptor screening pigment granules and screening pigment cells are restricted to the region below the photoreceptor nuclei and are thereby removed from the path of incident light. No ultrastructural evidence of rhythmic cycling of photosensitive membrane was observed. The morphological adaptations observed in the C. chacei retina suggest that it is a high-sensitivity photodetector that is of functional significance to the animal. PMID:9302103

Lakin, R C; Jinks, R N; Battelle, B A; Herzog, E D; Kass, L; Renninger, G H; Chamberlain, S C



Analysis of the Central Nervous System Transcriptome of the Eastern Rock Lobster Sagmariasus verreauxi Reveals Its Putative Neuropeptidome  

PubMed Central

Neuropeptides have been discovered in many arthropod species including crustaceans. The nature of their biological function is well studied and varies from behavior modulation to physiological regulation of complex biochemical processes such as metabolism, molt and reproduction. Due to their key role in these fundamental processes, neuropeptides are often targeted for modulating these processes to align with market demands in commercially important species. We generated a comprehensive transcriptome of the eyestalk and brain of one of the few commercially important spiny lobster species in the southern Hemisphere, the Eastern rock lobster Sagmariasus verreauxi and mined it for novel neuropeptide and protein hormone-encoding transcripts. We then characterized the predicted mature hormones to verify their validity based on conserved motifs and features known from previously reported hormones. Overall, 37 transcripts which are predicted to encode mature full-length/partial peptides/proteins were identified, representing 21 peptide/protein families/subfamilies. All transcripts had high similarity to hormones that were previously characterized in other decapod crustacean species or, where absent in crustaceans, in other arthropod species. These included, in addition to other proteins previously described in crustaceans, prohormone-3 and prohormone-4 which were previously identified only in insects. A homolog of the crustacean female sex hormone (CFSH), recently found to be female-specific in brachyuran crabs was found to have the same levels of expression in both male and female eyestalks, suggesting that the CFSH female specificity is not conserved throughout decapod crustaceans. Digital gene expression showed that 24 out of the 37 transcripts presented in this study have significant changes in expression between eyestalk and brain. In some cases a trend of difference between males and females could be seen. Taken together, this study provides a comprehensive neuropeptidome of a commercially important crustacean species with novel peptides and protein hormones identified for the first time in decapods.

Ventura, Tomer; Cummins, Scott F.; Fitzgibbon, Quinn; Battaglene, Stephen; Elizur, Abigail



Thalassinoides burrows (decapoda dwelling structures) in lower cretaceous sections of southwestern and central Crimea  

NASA Astrophysics Data System (ADS)

Burrows of Thalassinoides, which are attributed to the group of dwelling structures, occur in all the marine and coastal facies. The Lower Cretaceous sections of southwestern and central Crimea yielded the representative collection of Thalassinoides burrows belonging to the ichnospecies Th. suevicus (Rieth, 1932), which served as an object for this investigation. The burrows are confined to coarse-grained terrigenous, carbonate, and mixed sediments and contain assemblages of ichnofossils indicating coastal and shallow-water marine Skolithos and Cruziana ichnofacies. In the Mesozoic-Cenozoic, the producers of the Thalassinoides burrows were decapods, confirmed by finds of crayfish Hoploparia in them.

Yanin, B. T.; Baraboshkin, E. Yu.



Physiological responses of three crustacean species to infection by the dinoflagellate-like protist Hematodinium (Alveolata: Syndinea).  


This is the first study comparing physiological responses of three decapod species to infection by parasites of the genus Hematodinium, which belongs to the dinoflagellate-like Syndinea. Responses varied profoundly between the crabs Carcinus maenas and Cancer pagurus (Brachyura), but also differed to those of hermit crabs, Pagurus bernhardus (Anomura). Osmoregulatory capacity was reduced significantly in Hematodinium-infected C. maenas, haemolymph pH increased in parasitised C. pagurus and P. bernhardus, and L-lactate concentration decreased in infected P. bernhardus. Changes to tissues and exoskeletons were observed in C. pagurus, but not in C. maenas and P. bernhardus. PMID:20600085

Hamilton, Kristina M; Shaw, Paul W; Morritt, D



Oplophorus oxyluciferin and a model luciferin compound biologically active with Oplophorus luciferase.  


The luciferin of the bioluminescent decapod shrimp, Oplophorus gracilorostris, was purified and studied with respect to u.v. spectrum, fluorescence spectrum, mass spectrum and luminescent cross-reaction with the enzyme luciferase of the bioluminescent ostracod, Cypridina hilgendorfii. On the basis of these results, an empirical formula C10H13N3O3 and an imidazo [1,2-a]pyrazin-3-one structure are proposed for luciferin. Of three model luciferin compounds, 3-hydroxy-2-methylimidazo[1,2-a]pyridine is biologically active with both Oplophorus and Cypridina luciferase, indicating that a pyrazine structure is not essential for biological activity with Cypridina luciferase. PMID:1212217

Yamaguchi, I



Phase response theory extended to nonoscillatory network components  

NASA Astrophysics Data System (ADS)

New tools for analysis of oscillatory networks using phase response theory (PRT) under the assumption of pulsatile coupling have been developed steadily since the 1980s, but none have yet allowed for analysis of mixed systems containing nonoscillatory elements. This caveat has excluded the application of PRT to most real systems, which are often mixed. We show that a recently developed tool, the functional phase resetting curve (fPRC), provides a serendipitous benefit: it allows incorporation of nonoscillatory elements into systems of oscillators where PRT can be applied. We validate this method in a model system of neural oscillators and a biological system, the pyloric network of crustacean decapods.

Sieling, Fred H.; Archila, Santiago; Hooper, Ryan; Canavier, Carmen C.; Prinz, Astrid A.



Phase response theory extended to nonoscillatory network components  

PubMed Central

New tools for analysis of oscillatory networks using phase response theory (PRT) under the assumption of pulsatile coupling have been developed steadily since the 1980s, but none have yet allowed for analysis of mixed systems containing nonoscillatory elements. This caveat has excluded the application of PRT to most real systems, which are often mixed. We show that a recently developed tool, the functional phase resetting curve (fPRC), provides a serendipitous benefit: it allows incorporation of nonoscillatory elements into systems of oscillators where PRT can be applied. We validate this method in a model system of neural oscillators and a biological system, the pyloric network of crustacean decapods.

Sieling, Fred H.; Archila, Santiago; Hooper, Ryan; Canavier, Carmen C.; Prinz, Astrid A.



Molecular characterization and evolution of haemocyanin from the two freshwater shrimps Caridina multidentata (Stimpson, 1860) and Atyopsis moluccensis (De Haan, 1849).  


Haemocyanin (Hc) is a copper-containing respiratory protein, floating freely dissolved in the hemolymph of many arthropod species. A typical haemocyanin is a hexamer or oligohexamer of six identical or similar subunits, with a molecular mass around 75 kDa each. In the crustaceans, the haemocyanins appear to be restricted to the remipedes and the malacostracans. We have investigated the haemocyanins of two freshwater shrimps, the Amano shrimp Caridina multidentata and the bamboo shrimp Atyopsis moluccensis. We obtained three full-length and one partial cDNA sequences of haemocyanin subunits from the Amano shrimp, which were assigned to the ?- and ?-types of decapod haemocyanin subunits. Three complete and two partial haemocyanin cDNA sequences were obtained from the bamboo shrimp, which represent subunit types ?, ? and ?. This is the first time that sequences of all three subunit types of the decapod haemocyanins were obtained from a single species. However, mass spectrometry analyses identified only ?- and ?-type subunits, suggesting that a ?-subunit is not a major component of the native haemocyanin of the bamboo shrimp. Phylogenetic and molecular clock analyses showed that malacostracan haemocyanins commenced to diversify into distinct subunit types already ~515 million years ago. ?-subunits diverged first, followed by ?- and ?-type subunits ~396 million years ago. The haemocyanins of phyllocarids and peracarids form distinct clades within the ?/?-cluster. Within the Caridea, an early divergence of distinct ?-type subunits occurred ~200 MYA. The tree of the ?-subunits suggests a common clade of the Caridea (shrimps) and Penaeidae (prawns). PMID:23338600

Marxen, Julia C; Pick, Christian; Kwiatkowski, Marcel; Burmester, Thorsten



Animal Behavior Frozen in Time: Gregarious Behavior of Early Jurassic Lobsters within an Ammonoid Body Chamber  

PubMed Central

Direct animal behavior can be inferred from the fossil record only in exceptional circumstances. The exceptional mode of preservation of ammonoid shells in the Posidonia Shale (Lower Jurassic, lower Toarcian) of Dotternhausen in southern Germany, with only the organic periostracum preserved, provides an excellent opportunity to observe the contents of the ammonoid body chamber because this periostracum is translucent. Here, we report upon three delicate lobsters preserved within a compressed ammonoid specimen of Harpoceras falciferum. We attempt to explain this gregarious behavior. The three lobsters were studied using standard microscopy under low angle light. The lobsters belong to the extinct family of the Eryonidae; further identification was not possible. The organic material of the three small lobsters is preserved more than halfway into the ammonoid body chamber. The lobsters are closely spaced and are positioned with their tails oriented toward each other. The specimens are interpreted to represent corpses rather than molts. The lobsters probably sought shelter in preparation for molting or against predators such as fish that were present in Dotternhausen. Alternatively, the soft tissue of the ammonoid may have been a source of food that attracted the lobsters, or it may have served as a long-term residency for the lobsters (inquilinism). The lobsters represent the oldest known example of gregariousness amongst lobsters and decapods in the fossil record. Gregarious behavior in lobsters, also known for extant lobsters, thus developed earlier in earth's history than previously known. Moreover, this is one of the oldest known examples of decapod crustaceans preserved within cephalopod shells.

Klompmaker, Adiel A.; Fraaije, Rene H. B.



Housekeeping Mutualisms: Do More Symbionts Facilitate Host Performance?  

PubMed Central

Mutualisms often involve one host supporting multiple symbionts, whose identity, density and intraguild interactions can influence the nature of the mutualism and performance of the host. However, the implications of multiple co-occurring symbionts on services to a host have rarely been quantified. In this study, we quantified effects of decapod symbionts on removal of sediment from their coral host. Our field survey showed that all common symbionts typically occur as pairs and never at greater abundances. Two species, the crab Trapezia serenei and the shrimp Alpheus lottini, were most common and co-occurred more often than expected by chance. We conducted a mesocosm experiment to test for effects of decapod identity and density on sediment removal. Alone, corals removed 10% of sediment, but removal increased to 30% and 48% with the presence of two and four symbionts, respectively. Per-capita effects of symbionts were independent of density and identity. Our results suggest that symbiont density is restricted by intraspecific competition. Thus, increased sediment removal from a coral host can only be achieved by increasing the number of species of symbionts on that coral, even though these species are functionally equivalent. Symbiont diversity plays a key role, not through added functionality but by overcoming density limitation likely imposed by intraspecific mating systems.

Lemer, Sarah; Leray, Matthieu; Mills, Suzanne C.; Osenberg, Craig W.



Idiosyncratic species effects confound size-based predictions of responses to climate change  

PubMed Central

Understanding and predicting the consequences of warming for complex ecosystems and indeed individual species remains a major ecological challenge. Here, we investigated the effect of increased seawater temperatures on the metabolic and consumption rates of five distinct marine species. The experimental species reflected different trophic positions within a typical benthic East Atlantic food web, and included a herbivorous gastropod, a scavenging decapod, a predatory echinoderm, a decapod and a benthic-feeding fish. We examined the metabolism–body mass and consumption–body mass scaling for each species, and assessed changes in their consumption efficiencies. Our results indicate that body mass and temperature effects on metabolism were inconsistent across species and that some species were unable to meet metabolic demand at higher temperatures, thus highlighting the vulnerability of individual species to warming. While body size explains a large proportion of the variation in species' physiological responses to warming, it is clear that idiosyncratic species responses, irrespective of body size, complicate predictions of population and ecosystem level response to future scenarios of climate change.

Twomey, Marion; Brodte, Eva; Jacob, Ute; Brose, Ulrich; Crowe, Tasman P.; Emmerson, Mark C.



New Host Range for Hematodinium in Southern Australia and Novel Tools for Sensitive Detection of Parasitic Dinoflagellates  

PubMed Central

Hematodinium is a parasitic dinoflagellate and emerging pathogen of crustaceans. It preferably manifests in haemolymph of marine decapod crustaceans, killing a large variety of genera with significant impacts on fisheries worldwide. There is, however, evidence that some crustacean stocks harbor high prevalence, low intensity infections that may not result in widespread host mortality and are therefore hard to detect. The most widely used methods for detection of Hematodinium are conventional blood smears and polymerase chain reaction (PCR) against ribosomal RNAs. Blood smears demand a trained investigator, are labor intensive and not readily scalable for high-throughput sampling. PCRs only detect parasite DNA and can also suffer from false negatives and positives. In order to develop alternative detection tools for Hematodinium cells in decapod crustaceans we employed an immunological approach against a newly identified, abundant dinoflagellate-specific nuclear protein—Dinoflagellate/Viral NucleoProtein (DVNP). Both immunofluorescence assay (IFA) and Western blot methods against DVNP showed high sensitivity of detection. The Western blot detects Hematodinium parasites to levels of 25 parasites per milliliter of crustacean haemolymph, with the potential for sample pooling and screening of large samples. Using both PCR and these new tools, we have identified Hematodinium cells present in three new host crab taxa, at high prevalence but with no sign of pathogenesis. This extends the known range of Hematodinium to southern Australia.

Gornik, Sebastian G.; Cranenburgh, Andrea; Waller, Ross F.



Efficient identification of proteins from ovaries and hepatopancreas of the unsequenced edible crab, Cancer pagurus, by mass spectrometry and homology-based, cross-species searching.  


Proteome maps of hepatopancreas (midgut gland) and ovarian tissues of the crustacean, Cancer pagurus (Decapoda; edible crab) have been produced by 2D-PAGE and identification of proteins, following trypsin proteolysis, by electrospray MS/MS and database searching. Owing to the lack of sequence information on proteins and fully sequenced genomes amongst the decapod crustaceans and given the evolutionary distance to the nearest full genome database (Daphnia), it was necessary to adopt a non-conventional identification approach. Thus, a strategy was developed for effective identification of decapod proteins by sequence similarity, homology-based cross-species database searching, using various algorithms and a combination of NCBI Crustacea and Arthropoda databases, together with the Arthropoda PartiGene database (Blaxter, University of Edinburgh). In both hepatopancreas and ovary tissues, the largest group of proteins identified were a variety of enzymes, followed by a smaller number of storage/transport proteins [including vitellogenin (yolk protein), several subunits of hemocyanin, cryptocyanin, ferritin and calreticulin], with fewer structural proteins (actin, tubulin) and heat-shock proteins, in addition to a number of proteins of miscellaneous functions. Such protein identifications allow the development of tools, such as antibodies and RNA/DNA probes, to investigate the functions of the proteins in specific tissues during development. PMID:20656081

Ward, Deborah A; Sefton, Elaine M; Prescott, Mark C; Webster, Simon G; Wainwright, Geoff; Rees, Huw H; Fisher, Michael J



Discovery and Functional Study of a Novel Crustacean Tachykinin Neuropeptide  

PubMed Central

Tachykinin-related peptide (TRP) refers to a large and structurally diverse family of neuropeptides found in vertebrate and invertebrate nervous systems. These peptides have various important physiological functions, from regulating stress in mammals to exciting the gastric mill (food chewing) and pyloric (food filtering) rhythm in the stomatogastric nervous system (STNS) of decapod crustaceans. Here, a novel TRP, which we named CalsTRP (Callinectes sapidus TRP), YPSGFLGMRamide (m/z 1026.52), was identified and de novo sequenced using a multifaceted mass spectrometry-based platform in both the central nervous system (CNS) and STNS of C. sapidus. We also found, using isotopic formaldehyde labeling, that CalsTRP in the C. sapidus brain and commissural ganglion (CoG) was up-regulated after food intake, suggesting that TRPs in the CNS and STNS are involved in regulating feeding in Callinectes. Using imaging mass spectrometry, we determined that the previously identified CabTRP Ia (APSGFLGMRamide) and CalsTRP were colocalized in the C. sapidus brain. Lastly, our electrophysiological studies show that bath-applied CalsTRP and CabTRP Ia each activate the pyloric and gastric mill rhythms in C. sapidus, as shown previously for pyloric rhythm activation by CabTRP Ia in the crab Cancer borealis. In summary, the newly identified CalsTRP joins CabTRP Ia as a TRP family member in the decapod crustacean nervous system, whose actions include regulating feeding behavior.



Regulation of essential heavy metals (Cu, Cr, and Zn) by the freshwater prawn macrobrachium malcolmsonii (Milne Edwards)  

SciTech Connect

Despite the low concentrations of heavy metals in the surrounding medium, aquatic organisms take them up and accumulate them in their soft tissues to concentrations several fold higher than those of ambient levels. Knowledge of accumulation patterns of a particular trace metal is a prerequisite for understanding the significance of an observed metal concentration in a particular animal, especially from the aspect of biomonitoring. Many marine invertebrates accumulate heavy metals without any regulation and the accumulation necessarily being associated with mechanisms to store the metals in a detoxified form. Two detoxification mechanisms have been described, both of which may occur in one specimen. Heavy metals can either be bound up in insoluble metalliferous {open_quote}granules{close_quote}, or are bound to soluble metal-binding ligands, such as metallothioneins. Some marine decapod crustaceans have an innate ability to regulate the internal concentrations of essential but potentially toxic metals within a constant level, presumably to meet their metabolic demands. However, at present, there is no such information relating to freshwater decapod crustaceans, especially shrimps which occupy a totally different environment. Macrobrachium malcolmsonii, a potential aquaculture species for freshwater is found in abundance in one of the major Indian rivers, the Cauvery. In the present study, an attempt was made to determine whether the freshwater prawn, M. malcolmsonlii, is able to regulate the three essential elements, copper, chromium and zinc, over a wide range of dissolved concentrations. These three metals were chosen because the Cauvery River receives pollutants containing these metals.

Vijayram, K. [Periyar E.V.R. College, Tiruchirappalli (India)] [Periyar E.V.R. College, Tiruchirappalli (India); Geraldine, P. [Bharathidasan Univ., Tiruchirappalli (India)] [Bharathidasan Univ., Tiruchirappalli (India)



Diet and scavenging habits of the smooth skate Dipturus innominatus.  


The diet of smooth skate Dipturus innominatus was determined from examination of stomach contents of 321 specimens of 29·3-152·0 cm pelvic length, sampled from research and commercial trawlers at depths of 231-789 m on Chatham Rise, New Zealand. The diet was dominated by the benthic decapods Metanephrops challengeri and Munida gracilis, the natant decapod Campylonotus rathbunae and fishes from 17 families, of which hoki Macruronus novaezelandiae, sea perch Helicolenus barathri, various Macrouridae and a variety of discarded fishes were the most important. Multivariate analyses indicated the best predictors of diet variability were D. innominatus length and a spatial model. The diet of small D. innominatus was predominantly small crustaceans, with larger crustaceans, fishes and then scavenged discarded fishes increasing in importance as D. innominatus got larger. Scavenged discards were obvious as fish heads or tails only, or skeletal remains after filleting, often from pelagic species. Demersal fish prey were most frequent on the south and west Chatham Rise, in areas where commercial fishing was most active. Dipturus innominatus are highly vulnerable to overfishing, but discarding practices by commercial fishing vessels may provide a positive feedback to populations through improved scavenging opportunities. PMID:22497396

Forman, J S; Dunn, M R



Expression of antimicrobial peptides from Hyas araneus haemocytes following bacterial challenge in vitro.  


Circulating haemocytes play major roles in the host defense reactions of decapods, including the synthesis and release of antimicrobial peptides (AMPs). Unlike the AMPs from insects, those in decapods are constitutively expressed. This study aims to establish primary cell cultures of the three main haemocyte types in Hyas araneus haemocytes, and to measure the in vitro expression of AMP genes in the cells following microbial challenge. The haemocyte populations were separated on Percoll gradients and cultured in modified L-15 medium. Expression analysis by real-time RT-PCR showed that the granular cells are the main producers of crustin, hyastatin and arasin 1 AMPs, but the hyaline cells and semigranular cells also show some expression of these genes. Incubating the cell populations with Aerococcus viridans var. homari (a Gram-positive bacterium) or Listonella anguillarum (a Gram-negative pathogen) provoked no dramatic changes in the gene expression of any of the AMP, and although there was a small (single doubling) significant increase in expression of the crustin gene in granular cells 24h after exposure to L. anguillarum, it is unclear if this is biologically relevant under in vitro conditions. The results presented in this study are in accordance with several in vivo studies. PMID:20083137

Sperstad, Sigmund V; Smith, Valerie J; Stensvåg, Klara



The complete mitogenome of the Chinese swamp shrimp Neocaridina denticulata sinensis Kemp 1918 (Crustacea: Decapoda: Atyidae).  


In this study we determined the complete mitochondrial genome (mitogenome) of the Chinese swamp shrimp Neocaridina denticulata sinensis Kemp, 1918 (Decapoda, Atyidae). The mitogenome consists of 15,561?bp encoding 37 genes that are involved in mitochondrial protein synthesis as well as respiration chain/oxidative phosphorylation. Besides, a 672-bp putative control region was identified between the small subunit ribosomal RNA and tRNA-Ile genes, the size and AT content of which is moderate within the Decapoda. The gene arrangement of the mitogenome follows the pancrustacean ancestral pattern shared by the decapod subfamily Dendrobranchiata, pleocyematan infrafamilies Caridea and Palinura. Our results will provide important data for various levels of phylogeny and further evolution. PMID:23795841

Yu, Yan-Qin; Yang, Wei-Jun; Yang, Jin-Shu



The feeding habits of three Mediterranean sea anemone species, Anemonia viridis (Forskål), Actinia equina (Linnaeus) and Cereus pedunculatus (Pennant)  

NASA Astrophysics Data System (ADS)

The feeding habits of the Mediterranean sea anemones Cereus pedunculatus, Actinia equina and Anemonia viridis were examined mainly by analysing their coelenteron contents. The three species are opportunistic omnivorous suspension feeders. Main source of food for A. viridis and C. pedunculatus are crustaceans (mainly amphipods and decapods, respectively), while for the midlittoral species A. equina, it is organic detritus. Using the same method, the temporal and spatial changes in the diet of A. viridis were examined. During the whole year, crustaceans seem to be the main source of food for A. viridis. The diet composition of this species, however, differs remarkably in space, possibly reflecting the different composition of the macrobenthic organismic assemblages in different areas. The data collected are compared with the limited bibliographical information.

Chintiroglou, Ch.; Koukouras, A.



Novel Protocol for the Chemical Synthesis of Crustacean Hyperglycemic Hormone Analogues -- An Efficient Experimental Tool for Studying Their Functions  

PubMed Central

The crustacean Hyperglycemic Hormone (cHH) is present in many decapods in different isoforms, whose specific biological functions are still poorly understood. Here we report on the first chemical synthesis of three distinct isoforms of the cHH of Astacus leptodactylus carried out by solid phase peptide synthesis coupled to native chemical ligation. The synthetic 72 amino acid long peptide amides, containing L- or D-Phe3 and (Glp1, D-Phe3) were tested for their biological activity by means of homologous in vivo bioassays. The hyperglycemic activity of the D-isoforms was significantly higher than that of the L-isoform, while the presence of the N-terminal Glp residue had no influence on the peptide activity. The results show that the presence of D-Phe3 modifies the cHH functionality, contributing to the diversification of the hormone pool.

Mosco, Alessandro; Zlatev, Vientsislav; Guarnaccia, Corrado; Pongor, Sandor; Campanella, Antonella; Zahariev, Sotir; Giulianini, Piero G.



Disease effects on lobster fisheries, ecology, and culture: overview of DAO Special 6.  


Lobsters are prized by commercial and recreational fishermen worldwide, and their populations are therefore buffeted by fishery practices. But lobsters also remain integral members of their benthic communities where predator-prey relationships, competitive interactions, and host-pathogen dynamics push and pull at their population dynamics. Although lobsters have few reported pathogens and parasites relative to other decapod crustaceans, the rise of diseases with consequences for lobster fisheries and aquaculture has spotlighted the importance of disease for lobster biology, population dynamics and ecology. Researchers, managers, and fishers thus increasingly recognize the need to understand lobster pathogens and parasites so they can be managed proactively and their impacts minimized where possible. At the 2011 International Conference and Workshop on Lobster Biology and Management a special session on lobster diseases was convened and this special issue of Diseases of Aquatic Organisms highlights those proceedings with a suite of articles focused on diseases discussed during that session. PMID:23186696

Behringer, Donald C; Butler, Mark J; Stentiford, Grant D



A new species of Eualus Thallwitz, 1892 and new record of Lebbeus antarcticus (Hale, 1941) (Crustacea: Decapoda: Caridea: Hippolytidae) from the Scotia Sea  

NASA Astrophysics Data System (ADS)

Eleven specimens representing two hippolytid genera, EualusThallwitz, 1892 and LebbeusWhite, 1847 were sampled recently from the Scotia Sea (1517-2598 m). Seven specimens are described and illustrated as Eualus amandae sp. nov., and its morphology is compared with those of previously described species. Four female specimens, morphologically consistent with Lebbeus antarcticus (Hale, 1941), are described and illustrated to supplement previous descriptions of this rarely collected bathyal species. Partial COI mtDNA and 18S rDNA sequences were generated for both species. Only limited DNA sequences are available for the Hippolytidae. COI phylogenetic trees are presented to illustrate that the new species is genetically distinct from all other species in GenBank. This record enhances existing knowledge of Antarctic invertebrate biodiversity and species richness of decapod crustaceans in the Southern Ocean.

Nye, Verity; Copley, Jonathan T.; Linse, Katrin



Mitochondrial gene rearrangements confirm the parallel evolution of the crab-like form.  

PubMed Central

The repeated appearance of strikingly similar crab-like forms in independent decapod crustacean lineages represents a remarkable case of parallel evolution. Uncertainty surrounding the phylogenetic relationships among crab-like lineages has hampered evolutionary studies. As is often the case, aligned DNA sequences by themselves were unable to fully resolve these relationships. Four nested mitochondrial gene rearrangements--including one of the few reported movements of an arthropod protein-coding gene--are congruent with the DNA phylogeny and help to resolve a crucial node. A phylogenetic analysis of DNA sequences, and gene rearrangements, supported five independent origins of the crab-like form, and suggests that the evolution of the crab-like form may be irreversible. This result supports the utility of mitochondrial gene rearrangements in phylogenetic reconstruction.

Morrison, C L; Harvey, A W; Lavery, S; Tieu, K; Huang, Y; Cunningham, C W



Food of freshwater drum in western Lake Erie  

USGS Publications Warehouse

The abundance of freshwater drum (Aplodinotus grunniens) suggests they play an important role in the Lake Erie ecosystem. Our analysis of freshwater drum digestive tracts and macrobenthic samples collected from western Lake Erie indicates that drum were selective feeders. Planktonic cladocerans and larval midges (Chironomidae) were the primary prey organisms eaten by drum. Young-of-the-year fed mostly on cladocerans, while yearling and older drum ate both cladocerans and midge larvae. Decapods, pelecypods, and fish were found only in the digestive tracts of drum longer than 250 mm. While the most abundant organisms in benthic samples were cladocerans (ephippial) and oligochaetes (89.5% by number), they constituted less than 1% of the diet. An evaluation of food selectivity, using Ivlev's index of electivity for benthic organisms, indicated that adult drum preferred midges to any other benthic food.

Bur, Michael T.



Trace fossils assemblage and depositional environment of Turonian calcareous sandstones in the southern Benue Trough, Nigeria  

NASA Astrophysics Data System (ADS)

A calcareous sandstone sequence that forms part of the Eze-Aku Formation (Reyment) features an assemblage of ichnofossils in a section exposed on a quarry face. The traces encountered include horizontal burrows, some of which are preserved as casts, lined with organic matter and belonging to the ichnogenera Gyrolithes, Pholeus and Arthrophycus. Three other types of trace fossils are described as horizontal crawling trails, flat impressions and cylindrical shafts without formal names. Gyrolithes are by far the dominant traces in this sequence. The degree of bioturbation is high in every horizon. Body fossils are very rare except for scattered occurrence of fragments of calcitic pelecypod shells. Ichnological and lithological considerations suggest that the sediments were deposited in an aerated shallow shelf environment which supported an assemblage of decapods, worms and other shallow water marine benthos. Deposition was generally below wave base under a continuous but relatively slow rate of sedimentation.

Akpan, Etie B.; Nyong, Eyo E.


North Sea ecosystem change from swimming crabs to seagulls  

PubMed Central

A recent increase in sea temperature has established a new ecosystem dynamic regime in the North Sea. Climate-induced changes in decapods have played an important role. Here, we reveal a coincident increase in the abundance of swimming crabs and lesser black-backed gull colonies in the North Sea, both in time and in space. Swimming crabs are an important food source for lesser black-backed gulls during the breeding season. Inhabiting the land, but feeding mainly at sea, lesser black-backed gulls provide a link between marine and terrestrial ecosystems, since the bottom-up influence of allochthonous nutrient input from seabirds to coastal soils can structure the terrestrial food web. We, therefore, suggest that climate-driven changes in trophic interactions in the marine food web may also have ensuing ramifications for the coastal ecology of the North Sea.

Luczak, C.; Beaugrand, G.; Lindley, J. A.; Dewarumez, J-M.; Dubois, P. J.; Kirby, R. R.



Effects of temperature and salinity on the development of the amphipod crustacean Eogammarus sinensis  

NASA Astrophysics Data System (ADS)

The amphipod crustacean Eogammarus sinensis has useful features that make it suitable for use in the aquaculture of fish and large decapod crustaceans. In this study, we investigated the effects of temperature and salinity on the development, fecundity, survival, and growth rate of E. sinensis. The results show that temperature significantly affected E. sinensis development, but salinity. As temperature increased, the duration of E. sinensis embryonic development decreased. Fecundity was affected significantly by temperature and the combination of temperature and salinity, but by salinity alone. In addition, high temperatures accelerated E. sinensis juvenile growth rates, whereas high salinity reduced it. Therefore, our data suggest that E. sinensis tolerates a wide range of salinities and that temperature has more significant effects than salinity on the embryonic development, fecundity, and growth of E. sinensis. Our results shall be useful for mass production of this species for use in aquaculture.

Xue, Suyan; Fang, Jianguang; Zhang, Jihong; Jiang, Zengjie; Mao, Yuze; Zhao, Fazhen



Complete mitogenome of the deep-sea hydrothermal vent shrimp Alvinocaris chelys Komai and Chan, 2010 (Decapoda: Caridea: Alvinocarididae).  


We reported the complete sequence of the mitochondrial (mt) genome of the deep-sea vent shrimp Alvinocaris chelys. This is the first complete mt genome obtained for the hydrothermal vent shrimp. The gene arrangement of the A. chelys mt genome is identical to the pancrustacean ground pattern as in most of the other caridean shrimp mt genomes available to date. However, there is an exceptionally long intergene spacer (86 bp in length) existed between the ND1 and tRNA(Leu)-CUN genes that is not previously reported. Our results provide further evidence that the mt gene order is highly conserved among caridean shrimp, in contrast to the other decapod infraorder such as Brachyura or Anomura which are of comparable or lower diversity. PMID:22943309

Yang, Chien-Hui; Tsang, Ling Ming; Chu, Ka Hou; Chan, Tin-Yam



Enterospora sp., an intranuclear microsporidian infection of hermit crab Eupagurus bernhardus.  


Recent work at our laboratory has led to the discovery of a new genus of microsporidian parasite residing in the family Enterocytozoonidae. The type species of this new genus, Enterospora canceri, is an intranuclear parasite infecting the hepatopancreatocytes of the decapod crustacean Cancer pagurus. Here we provide the second description of a parasite within the genus Enterospora, this time infecting the hermit crab Eupagurus bernhardus from U.K. waters. The pathological manifestation and ultrastructural features of the hermit crab parasite are very similar to those described for E. canceri. Further taxonomic comparisons based upon ultrastructural and molecular affinities of Enterospora are now required to define firmer links between this new genus within the Enterocytozoonidae and all other microsporidian families. The opportunistic nature of the discovery of a second intranuclear microsporidian within the Crustacea suggests that their presence may be more common than in higher animal groups. PMID:17523545

Stentiford, G D; Bateman, K S



Biorecovery of gold  

USGS Publications Warehouse

Recovery of ionic and metallic gold (Au) from a wide variety of solutions by selected species of bacteria, yeasts, fungi, algae, and higher plants is documented. Gold accumulations were up to 7.0 g/kg dry weight (DW) in various species of bacteria, 25.0 g/kg DW in freshwater algae, 84.0 g/kg DW in peat, and 100.0 g/kg DW in dried fungus mixed with keratinous material. Mechanisms of accumulation include oxidation, dissolution, reduction, leaching, and sorption. Uptake patterns are significantly modified by the physicochemical milieu. Crab exoskeletons accumulate up to 4.9 g Au/kg DW; however, gold accumulations in various tissues of living teleosts, decapod crustaceans, and bivalve molluscs are negligible.

Eisler, R.



Effects of the sandbar breaching on hydrobiological parameters and zooplankton communities in the Senegal River Estuary (West Africa).  


This study describes the changes in hydrology, zooplankton communities and abundance in the Senegal River Estuary (SRE) before and after the breaching of the sandbar in October 2003. Samples were taken in 2003 at 3 stations located upstream (DI), in mid estuary (HY) and downstream (RM), and in 2005 at the same stations (RM becoming Old River Mouth: ORM), plus the new river mouth (NRM) resulting from the morphological evolution of the SRE. The study showed marked seasonal variations that affected the structure and distribution of zooplankton as well as major changes caused by the sandbar opening: increased marine influence throughout the whole SRE, changes in the horizontal gradients, arrival of euryhaline species and increase in meroplankton, in particular decapod larvae, transformation of the ORM area into a slackwater area with limited exchanges and the highest zooplankton numbers during high waters. PMID:24685450

Champalbert, Gisèle; Pagano, Marc; Arfi, Robert; Chevalier, Cristèle



Changes in cardiac performance during hypoxic exposure in the grass shrimp Palaemonetes pugio  

PubMed Central

SUMMARY In hearts of higher invertebrates as well as vertebrates, the work performed by the ventricle is a function of both rate and contractility. Decapod crustaceans experience a hypoxia-induced bradycardia that is thought to result in an overall reduction in cardiac work; however, this hypothesis has not yet been tested and is the primary purpose of this study. In the grass shrimp Palaemonetes pugio, cardiac pressure and area data were obtained simultaneously, and in vivo, under normoxic (20.2 kPa O2) and hypoxic (6.8 or 2.2 kPa O2) conditions and integrated to generate pressure–area (P–A) loops. The area enclosed by the P–A loop provides a measure of stroke work and, when multiplied by the heart rate, provides an estimate of both cardiac work and myocardial O2 consumption. Changes in intra-cardiac pressure (dp/dt) are correlated to the isovolemic contraction phase and provide an indication of stroke work. At both levels of hypoxic exposure, intra-cardiac pressure, dp/dt, stroke work and cardiac work fell significantly. The significant decrease in intra-cardiac pressure provides the primary mechanism for the decrease in stroke work, and, when coupled with the hypoxia-induced bradycardia, it contributes to an overall fall in cardiac work. Compared with normoxic P–A loops, hypoxic P–A loops (at both levels of hypoxia) become curvilinear, indicating a fall in peripheral resistance (which might account for the reduction in intra-cardiac pressure), which would reduce both stroke work and cardiac work and ultimately would serve to reduce myocardial O2 consumption. This is the most direct evidence to date indicating that the hypoxia-induced bradycardia observed in many decapod crustaceans reduces cardiac work and is therefore energetically favorable during acute exposure to conditions of low oxygen.

Guadagnoli, Jutta A.; Tobita, Kimimasa; Reiber, Carl L.



Identification of SYWKQCAFNAVSCFamide: a broadly conserved crustacean C-type allatostatin-like peptide with both neuromodulatory and cardioactive properties  

PubMed Central

Summary The allatostatins comprise three structurally distinct peptide families that regulate juvenile hormone production by the insect corpora allata. A-type family members contain the C-terminal motif –YXFGLamide and have been found in species from numerous arthropod taxa. Members of the B-type family exhibit a –WX6Wamide C-terminus and, like the A-type peptides, appear to be broadly conserved within the Arthropoda. By contrast, members of the C-type family, typified by the unblocked C-terminus –PISCF, a pyroglutamine blocked N-terminus, and a disulfide bridge between two internal Cys residues, have only been found in holometabolous insects, i.e. lepidopterans and dipterans. Here, using transcriptomics, we have identified SYWKQCAFNAVSCFamide (disulfide bridging predicted between the two Cys residues), a known honeybee and water flea C-type-like peptide, from the American lobster Homarus americanus (infraorder Astacidea). Using matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS), a mass corresponding to that of SYWKQCAFNAVSCFamide was detected in the H. americanus brain, supporting the existence of this peptide and its theorized structure. Furthermore, SYWKQCAFNAVSCFamide was detected by MALDI-FTMS in neural tissues from five additional astacideans as well as 19 members of four other decapod infraorders (i.e. Achelata, Anomura, Brachyura and Thalassinidea), suggesting that it is a broadly conserved decapod peptide. In H. americanus, SYWKQCAFNAVSCFamide is capable of modulating the output of both the pyloric circuit of the stomatogastric nervous system and the heart. This is the first demonstration of bioactivity for this peptide in any species.

Dickinson, Patsy S.; Wiwatpanit, Teerawat; Gabranski, Emily R.; Ackerman, Rachel J.; Stevens, Jake S.; Cashman, Christopher R.; Stemmler, Elizabeth A.; Christie, Andrew E.



Abundance, distribution, and feeding patterns of juvenile coho salmon ( Oncorhynchus kisutch) in the Juan de Fuca Eddy  

NASA Astrophysics Data System (ADS)

The Juan de Fuca Eddy is a seasonal, counter-clockwise gyre off the mouth of the Strait of Juan de Fuca between Washington, USA and British Columbia, Canada that may provide favorable feeding habitat for juvenile coho salmon ( Oncorhynchus kisutch) during their early marine existence. In late September 2002, physical and biological sampling was conducted along two transects of the eddy region. Surface rope trawling was conducted to capture juvenile salmon and other nekton, along with bongo and neuston net tows to examine potential mesozooplanktonic salmon prey. Presence of the Juan de Fuca Eddy was confirmed with vertical water profiles. In addition, nutrient and chlorophyll a concentrations collected from 3-m depth were within the range observed in previous studies within the eddy region. In the mesozooplankton community, euphausiids, chaetognaths, and decapod megalopae were common. In the diet of juvenile coho salmon, euphausiids and decapod megalopae were dominant by percent number, and larval and juvenile fish were dominant by percent weight. Feeding intensity (percent body weight) based on stomach contents was variable, but not significantly different among stations. To compare the Juan de Fuca Eddy region with an upwelling area, we sampled along a transect off La Push (LP), Washington, USA which is south of the eddy. The eddy region was found to be less productive than the LP transect. Nutrients were lower, chlorophyll a concentrations were higher, and zooplankton abundance was generally higher along the LP transect than in the eddy region. In addition, more juvenile coho salmon were captured from the LP transect than the eddy region. Prey items in stomachs of salmon from the LP transect were heterogeneous compared to those from the eddy region. Feeding intensity along the LP transect was slightly lower and more variable than in the eddy region, and differences in feeding intensity among LP stations were significant. In addition, feeding intensities among stations nested within regions were significantly different.

Pool, Suzan S.; Brodeur, Richard D.; Goodman, N. Lynn; Daly, Elizabeth A.



Recovery of floral and faunal communities after placement of dredged material on seagrasses in Laguna Madre, Texas  

NASA Astrophysics Data System (ADS)

The objectives of this project were to determine how long alterations in habitat characteristics and use by fishery and forage organisms were detectable at dredged material placement sites in Laguna Madre, Texas. Water, sediment, seagrass, benthos, and nekton characteristics were measured and compared among newly deposited sediments and nearby and distant seagrasses each fall and spring over three years. Over this period, 75% of the estimated total surface area of the original deposits was either re-vegetated by seagrass or dispersed by winds and currents. Differences in water and sediment characteristics among habitat types were mostly detected early in the study. There were signs of steady seagrass re-colonization in the latter half of the study period, and mean seagrass coverage of deposits had reached 48% approximately three years after dredging. Clovergrass Halophila engelmannii was the initial colonist, but shoalgrass Halodule wrightii predominated after about one year. Densities of annelids and non-decapod crustaceans were generally significantly greater in close and distant seagrass habitats than in dredged material habitat, whereas densities of molluscs were not significantly related to habitat type. Nekton (fish and decapod) densities were almost always significantly greater in the two seagrass habitats than in dredged material deposits. Benthos and nekton communities in dredged material deposits were distinct from those in seagrass habitats. Recovery from dredged material placement was nearly complete for water column and sediment components after 1.5 to 3 years, but recovery of seagrasses, benthos, and nekton was predicted to take 4 to 8 years. The current 2 to 5 years dredging cycle virtually insures no time for ecosystem recovery before being disturbed again. The only way to ensure permanent protection of the high primary and secondary productivity of seagrass beds in Laguna Madre from acute and chronic effects of maintenance dredging, while ensuring navigation capability, is to remove dredged materials from the shallow waters of the ecosystem.

Sheridan, P.



Neuropeptides in the crayfish stomatogastric nervous system.  


Neuropeptides are peptides with profound effects on the nervous system. The function of neuropeptides can be studied in detail in the stomatogastric nervous system (STNS). Neuropeptides are ubiquitously distributed in the STNS and it contains well-studied neural circuits that are strongly modulated by neuropeptides. The STNS controls the movements of the foregut in crustaceans and has been studied intensively in a variety of decapod crustaceans including crayfish. This article reviews our knowledge of neuropeptides in the crayfish STNS. Within crayfish, peptides reach the circuits of the STNS as neurohormones released by neurohaemal organs or by putative neurohemal zones located within the STNS. As transmitters, neuropeptides are present in identified motoneurons, interneurons, and sensory neurons (mainly shown by immunocytochemistry), indicating a multiple role of peptides in the plasticity of neural networks. Neuropeptides are not only present in varicosities within the neuropil of ganglia, but also in varicosities on muscles and within small neuropil patches along nerves. This suggests that the muscles of the stomach are under a more direct modulatory control than previously thought, and that information processing can also occur within nerves. In addition to anatomical studies, biochemical and electrophysiological methods were used. For example, MALDI-TOF MS (matrix-assisted laser desorption ionization time of flight mass spectrometry) revealed the presence of four different peptides of the orcokinin family within a single neuron, and electrophysiological experiments demonstrated that the networks of the STNS are not only under excitatory but also inhibitory peptidergic influence. Comparing the similarities and differences between the STNS of crayfish and that of other decapod crustaceans has already contributed to our knowledge about peptides and will further help to unravel peptide function in the plasticity of neural circuits. For example, the identified neurons in the STNS can be used to study co-transmission because neuropeptides are co-localized with classical transmitters, biogenic amines, or other peptides in these neurons. PMID:12539160

Skiebe, Petra



Vertically migrating micronekton and macrozooplankton communities around Guam and the Northern Mariana Islands  

NASA Astrophysics Data System (ADS)

The distribution, biomass, and assemblages of vertically migrating micronekton/macrozooplankton were studied in relation to oceanographic conditions around Guam and the adjacent Northern Mariana Islands during Spring 2010, using 3-m2 Isaacs-Kidd Midwater Trawl (IKMT). The study area was located within the oligotrophic waters of the westward flowing North Equatorial Current (NEC). However, southern stations of the survey were situated close to the northern boundary of the more productive North Equatorial Countercurrent (NECC), where we observed the highest biomass, abundance, species richness, and diversity of pelagic organisms. Overall, we recorded 85 species from 20 families of mostly mesopelagic species in the area, with lanternfishes (Myctophidae—40 species) and dragonfishes (Stomiidae—18 species) being the most taxonomically diverse groups. Three genera of mesopelagic shrimps, Sergestes, Janicella and Sergia, dominated the decapod crustacean component of the micronekton community numerically and by biomass, while the contribution from cephalopods was relatively minor. Assemblages of major micronekton/macrozooplankton groups, based on biomass and abundance showed principal changes with latitude. However, the classification and ordination analysis, based on taxonomically resolved taxa (fishes and decapod shrimps), indicated additional zonal variation, with areas east and west of the island chain showing different community structure. The mean total micronekton biomass for the area near the productive boundary region between the NEC and NECC was 5.8 mg/m3, with a mean biomass of 1.2 mg/m3 obtained for stations in the oligotrophic NEC area. The corresponding biomass of mesopelagic fishes was 0.88 mg/m3 and 0.24 mg/m3 for these two areas, respectively. We reviewed and compared the available information on the quantitative distribution of midwater fish biomass in the western tropical Pacific and outlined major patterns of variation in the equatorial Pacific in general.

Suntsov, Andrey; Domokos, Réka



Synaptic neuropil in nerves of the crustacean stomatogastric nervous system: an immunocytochemical and electron microscopical study.  


Patches of peptide-immunoreactive varicosities have been found in nerves of the stomatogastric nervous system (STNS) of decapod crustaceans. In the present study, these patches were examined in detail in the stomatogastric nerve (stn) and in the superior oesophageal nerve (son) of the crayfish Cherax destructor by using whole-mount immunocytochemical techniques combined with confocal microscopy and, in addition, electron microscopy. Double-labeling experiments with antibodies generated against the peptides allatostatin, FMRFamide and proctolin, combined with an antibody generated against the small vesicle protein synapsin, suggest that each patch contains small synaptic vesicles in addition to all three peptides. The neuropil regions of the ganglia of the STNS were also strongly stained by the synapsin antibody. Synapsin-like immunoreactivity was also studied in the crab Cancer pagurus and the lobster Homarus americanus. A similar pattern of staining was found for all three species, but the distribution within the stn varied. In H. americanus, a lightly stained weblike structure was found on the surface of nerves including the inferior oesophageal nerve, the son, and the anterior stn. By using electron microscopy, synapses were found in the core of the stn-son junction of C. destructor, in the same region where the synapsin-like and the peptide staining was localized. In addition, putative neurohemal release sites were found in the peripheral sheath of the stn. The presynaptic profiles found in the core of the stn seem to correspond to the types of presynaptic profiles found in the neuropil of the stomatogastric ganglion. These findings demonstrate that synaptic neuropil is present in the nerves of the STNS of a decapod crustacean. PMID:10754509

Skiebe, P; Ganeshina, O



Allatostatin-like immunoreactivity in the stomatogastric nervous system and the pericardial organs of the crab Cancer pagurus, the lobster Homarus americanus, and the crayfish Cherax destructor and Procambarus clarkii.  


The distribution of allatostatin (AST)-like immunoreactivity was studied in the stomatogastric nervous system (STNS) and the neurosecretory pericardial organs (PO) of four decapod crustacean species by using wholemount immunocytochemical techniques and confocal microscopy. AST-like immunoreactivity was found within the STNS of all four species; its distribution in each was unique. In all four species, AST-like immunoreactivity was present in the paired commissural ganglia (CoG), in the esophageal ganglion (OG), in the stomatogastric ganglion (STG), and in their connecting nerves. Within the CoGs, numerous cell bodies and neuropil were stained. In the OG, two cell bodies were immunoreactive, although their branching pattern varies between species. In the STG of C. pagurus and H. americanus, neuropil was stained extensively, but no labeled cell bodies were found. Surprisingly, in C. destructor and P. clarkii, cell bodies were stained in the STG, one brightly stained cell body in both species and an additional two to five weakly stained cell bodies in P. clarkii. In all four species, stained gastropyloric receptor cells were present. In contrast to the variable staining within the STNS, all four species have a similar pattern of AST-like immunoreactivity within the PO. Only in C. destructor, AST-immunoreactive varicosities occur on the surface of the circumesophageal connectives and on the postesophageal commissure and suggest another neurohaemal source for AST-like peptides in this species. The pattern of this staining suggests that AST-like peptides are likely utilized as both neurohormones and as neuromodulators in the STNS of decapod crustacea. PMID:10075445

Skiebe, P



A role for oxygen delivery and extracellular magnesium in limiting cold tolerance of the sub-antarctic stone crab Paralomis granulosa?  


A low capacity for regulation of extracellular Mg(2+) has been proposed to exclude reptant marine decapod crustaceans from temperatures below 0°C and thus to exclude them from the high Antarctic. To test this hypothesis and to elaborate the underlying mechanisms in the most cold-tolerant reptant decapod family of the sub-Antarctic, the Lithodidae, thermal tolerance was determined in the crab Paralomis granulosa (Decapoda, Anomura, Lithodidae) using an acute stepwise temperature protocol (-1°, 1°, 4°, 7°, 10°, and 13°C). Arterial and venous oxygen partial pressures (Po(2)) in hemolymph, heartbeat and ventilation beat frequencies, and hemolymph cation composition were measured at rest and after a forced activity (righting) trial. Scopes for heartbeat and ventilation beat frequencies and intermittent heartbeat and scaphognathite beat rates at rest were evaluated. Hemolymph [Mg(2+)] was experimentally reduced from 30 mmol L(-1) to a level naturally observed in Antarctic caridean shrimps (12 mmol L(-1)) to investigate whether the animals remain more active and tolerant to cold (-1°, 1°, and 4°C). In natural seawater, righting speed was significantly slower at -1° and 13°C, compared with acclimation temperature (4°C). Arterial and venous hemolymph Po(2) increased in response to cooling even though heartbeat and ventilation beat frequencies as well as scopes decreased. At rest, ionic composition of the hemolymph was not affected by temperature. Activity induced a significant increase in hemolymph [K(+)] at -1° and 1°C. Reduction of hemolymph [Mg(2+)] did not result in an increase in activity, an increase in heartbeat and ventilation beat frequencies, or a shift in thermal tolerance to lower temperatures. In conclusion, oxygen delivery in this cold-water crustacean was not acutely limiting cold tolerance, and animals may have been constrained more by their functional capacity and motility. In contrast to earlier findings in temperate and subpolar brachyuran crabs, these constraints remained insensitive to changing Mg(2+) levels. PMID:22494984

Wittmann, Astrid C; Pörtner, Hans O; Sartoris, Franz J



Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus.  


White spot syndrome virus (WSSV) is the most important pathogen known to affect the sustainability and growth of the global penaeid shrimp farming industry. Although most commonly associated with penaeid shrimp farmed in warm waters, WSSV is also able to infect, cause disease in and kill a wide range of other decapod crustaceans, including lobsters, from temperate regions. In 2005, the European Union imported US$500 million worth of raw frozen or cooked frozen commodity products, much of which originated in regions positive for white spot disease (WSD). The presence of WSSV within the UK food market was verified by means of nested PCR performed on samples collected from a small-scale survey of supermarket commodity shrimp. Passage trials using inoculum derived from commodity shrimp from supermarkets and delivered by injection to specific pathogen-free Pacific white shrimp Litopenaeus vannamei led to rapid mortality and pathognomonic signs of WSD in the shrimp, demonstrating that WSSV present within commodity shrimp was viable. We exposed a representative European decapod crustacean, the European lobster Homarus gammarus, to a single feeding of WSSV-positive, supermarket-derived commodity shrimp, and to positive control material (L. vannamei infected with a high dose of WSSV). These trials demonstrated that lobsters fed positive control (high dose) frozen raw products succumbed to WSD and displayed pathognomonic signs associated with the disease as determined by means of histology and transmission electron microscopy. Lobsters fed WSSV-positive, supermarket-derived commodity shrimp (low dose) did not succumb to WSD (no mortality or pathognomonic signs of WSD) but demonstrated a low level or latent infection via PCR. This study confirms susceptibility of H. gammarus to WSSV via single feedings of previously frozen raw shrimp products obtained directly from supermarkets. PMID:23186704

Bateman, K S; Munro, J; Uglow, B; Small, H J; Stentiford, G D



Predators alter community organization of coral reef cryptofauna and reduce abundance of coral mutualists  

NASA Astrophysics Data System (ADS)

Coral reefs are the most diverse marine systems in the world, yet our understanding of the processes that maintain such extraordinary diversity remains limited and taxonomically biased toward the most conspicuous species. Cryptofauna that live deeply embedded within the interstitial spaces of coral reefs make up the majority of reef diversity, and many of these species provide important protective services to their coral hosts. However, we know very little about the processes governing the diversity and composition of these less conspicuous but functionally important species. Here, we experimentally quantify the role of predation in driving the community organization of small fishes and decapods that live embedded within Pocillopora eydouxi, a structurally complex, reef-building coral found widely across the Indo-Pacific. We use surveys to describe the natural distribution of predators, and then, factorially manipulate two focal predator species to quantify the independent and combined effects of predator density and identity on P. eydouxi-dwelling cryptofauna. Predators reduced abundance (34 %), species richness (20 %), and modified species composition. Rarefaction revealed that observed reductions in species richness were primarily driven by changes in abundance. Additionally, the two predator species uniquely affected the beta diversity and composition of the prey assemblage. Predators reduced the abundance and modified the composition of a number of mutualist fishes and decapods, whose benefit to the coral is known to be both diversity- and density-dependent. We predict that the density and identity of predators present within P. eydouxi may substantially alter coral performance in the face of an increased frequency and intensity of natural and anthropogenic stressors.

Stier, A. C.; Leray, M.



A comparative study on mesozooplankton abundance and diversity between a protected and an unprotected coastal area of Andaman Islands.  


The study was carried out to understand the variability in phytoplankton production (Chlorophyll a) and mesozooplankton diversity from two different shallow coastal regions of south Andaman viz. Port Blair Bay (PBB), the only real urban area among the islands and Mahatma Gandhi Marine National Park, a Marine Protected Area (MPA) at Wandoor. Seasonal sampling was carried out during the Northeast monsoon (NEM-November 2005), Intermonsoon (IM-April 2006), and Southwest monsoon (SWM-August 2006). Significant (P?decapod larvae were more abundant at MPA. A total of 20 and 21 copepod families was recorded from PBB and MPA, respectively. Eleven species of chaetognaths were observed as common at both areas. Larval decapods were found to be predominant at MPA with 20 families; whereas, at PBB, only 12 families were recorded. In the light of the recent reports on various changes occurring in the coastal waters of the Andaman Islands, it is suspected that the difference in Chl. a as well as the mesozooplankton standing stock and community structure observed between the two study areas may be related to the various anthropogenic events influencing the coastal waters. PMID:24729177

Pillai, Honey U K; Jayalakshmy, K V; Biju, A; Jayalakshmi, K J; Paulinose, V T; Devi, C B L; Nair, V R; Revichandran, C; Menon, N R; Achuthankutty, C T; Panampunnayil, S U



Pigment-dispersing hormone in Daphnia interneurons, one type homologous to insect clock neurons displaying circadian rhythmicity.  


We report identification of a beta-type pigment-dispersing hormone (PDH) identical in two water flea species, Daphnia magna and Daphnia pulex. It has been identified by cloning of precursors, chromatographic isolation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. The peptide is restricted to a complex system of distinct interneurons in the brain and visual ganglia, but does not occur in neurosecretory cells projecting to neurohemal organs as in decapod crustaceans. Thirteen neuron types individually identified and reconstructed by immunohistochemistry were almost identical in terms of positions and projection patterns in both species. Several neurons invade and form plexuses in visual ganglia and major brain neuropils including the central body. Five neuron types show contralateral pathways and form plexuses in the lateral, dorsal, or postlateral brain neuropils. Others are local interneurons, and a tritocerebral neuron connects the protocerebrum with the neuropil of the locomotory second antenna. Two visual ganglia neuron types lateral to the medulla closely resemble insect medulla lateral circadian clock neurons containing pigment-dispersing factor based upon positional and projectional criteria. Experiments under 12:12 h light/dark cycles and constant light or darkness conditions showed significant circadian changes in numbers and activities of one type of medulla lateral PDH neuron with an acrophase in the evening. This simple PDH system shows striking homologies to PDH systems in decapod crustaceans and well-known clock neurons in several insects, which suggests evolutionary conservation of an ancient peptidergic interneuronal system that is part of biological clocks. PMID:21365282

Strauss, Johannes; Zhang, Qian; Verleyen, Peter; Huybrechts, Jurgen; Neupert, Susanne; Predel, Reinhard; Pauwels, Kevin; Dircksen, Heinrich



The 'Ventral Organs' of Pycnogonida (Arthropoda) Are Neurogenic Niches of Late Embryonic and Post-Embryonic Nervous System Development  

PubMed Central

Early neurogenesis in arthropods has been in the focus of numerous studies, its cellular basis, spatio-temporal dynamics and underlying genetic network being by now comparably well characterized for representatives of chelicerates, myriapods, hexapods and crustaceans. By contrast, neurogenesis during late embryonic and/or post-embryonic development has received less attention, especially in myriapods and chelicerates. Here, we apply (i) immunolabeling, (ii) histology and (iii) scanning electron microscopy to study post-embryonic ventral nerve cord development in Pseudopallene sp., a representative of the sea spiders (Pycnogonida), the presumable sister group of the remaining chelicerates. During early post-embryonic development, large neural stem cells give rise to additional ganglion cell material in segmentally paired invaginations in the ventral ectoderm. These ectodermal cell regions – traditionally designated as ‘ventral organs’ – detach from the surface into the interior and persist as apical cell clusters on the ventral ganglion side. Each cluster is a post-embryonic neurogenic niche that features a tiny central cavity and initially still houses larger neural stem cells. The cluster stays connected to the underlying ganglionic somata cortex via an anterior and a posterior cell stream. Cell proliferation remains restricted to the cluster and streams, and migration of newly produced cells along the streams seems to account for increasing ganglion cell numbers in the cortex. The pycnogonid cluster-stream-systems show striking similarities to the life-long neurogenic system of decapod crustaceans, and due to their close vicinity to glomerulus-like neuropils, we consider their possible involvement in post-embryonic (perhaps even adult) replenishment of olfactory neurons – as in decapods. An instance of a potentially similar post-embryonic/adult neurogenic system in the arthropod outgroup Onychophora is discussed. Additionally, we document two transient posterior ganglia in the ventral nerve cord of Pseudopallene sp. and evaluate this finding in light of the often discussed reduction of a segmented ‘opisthosoma’ during pycnogonid evolution.

Brenneis, Georg; Scholtz, Gerhard



A contribution to the life history and distribution of Atlantic species of the deep-sea fish genus Conocara (Alepocephalidae)  

NASA Astrophysics Data System (ADS)

The bathyal-abyssal alepocephalid genus Conocara comprises six Atlantic species. These species have broad but spotty distributions. Conocara macropterum and C. murrayi are known only from the Atlantic. The remaining species also occur in other oceans. In Bahamian basins C. macropterum occurs between 1239 and 2166 m. Mean population density between 1300 and 1500 m is 243 fish km -2, mean biomass is 13,396 g km -2. Over its Bahamian depth range of 1363-2404 m, C. fiolenti displays a mean population density of 0.9 fish km -2 and a mean biomass of 3.1 g km -2. Reproduction in C. macropterum appears to be aseasonal. Mature ova are large (6 mm diameter) and fecundity is low (57-490 ova), both typically alepocephalid features. Overall, females outnumber males 1.9:1. Mature C. fiolenti have 5 mm ova, and fecundities of 113-170. Females in C. macropterum attain a larger size than males. Standard length at first maturity in males is 225 mm, in females 268 mm. Maximum length is 368 mm. The length frequency distribution of Bahamian C. macropterum is bimodal. Modes in abundance occur over intervals of 50-150 mm (early juveniles) and 250-350 mm (mature adults). This pattern suggests high juvenile mortality coupled with rapid growth to full adult size. Rapid growth to adult size would be selectively advantageous, both in terms of predator avoidance and efficiency in feeding and locomotion. Species of Conocara have a varied diet. Small C. macropterum consume mostly polychaetes, copepods, and ostracods; large fish feed heavily on decapod crustaceans and teleosts. Salps are consumed by all size classes, and sediment ingestion is frequent. Dietary range in C. fiolenti is similar, except that decapod crustaceans and teleosts are not eaten, and sediment is unimportant. Salps were the dominant food item in C. fiolenti.

Crabtree, Roy E.; Sulak, Kenneth J.



An evolutionary analysis of flightin reveals a conserved motif unique and widespread in Pancrustacea.  


Flightin is a thick filament protein that in Drosophila melanogaster is uniquely expressed in the asynchronous, indirect flight muscles (IFM). Flightin is required for the structure and function of the IFM and is indispensable for flight in Drosophila. Given the importance of flight acquisition in the evolutionary history of insects, here we study the phylogeny and distribution of flightin. Flightin was identified in 69 species of hexapods in classes Collembola (springtails), Protura, Diplura, and insect orders Thysanura (silverfish), Dictyoptera (roaches), Orthoptera (grasshoppers), Pthiraptera (lice), Hemiptera (true bugs), Coleoptera (beetles), Neuroptera (green lacewing), Hymenoptera (bees, ants, and wasps), Lepidoptera (moths), and Diptera (flies and mosquitoes). Flightin was also found in 14 species of crustaceans in orders Anostraca (water flea), Cladocera (brine shrimp), Isopoda (pill bugs), Amphipoda (scuds, sideswimmers), and Decapoda (lobsters, crabs, and shrimps). Flightin was not identified in representatives of chelicerates, myriapods, or any species outside Pancrustacea (Tetraconata, sensu Dohle). Alignment of amino acid sequences revealed a conserved region of 52 amino acids, referred herein as WYR, that is bound by strictly conserved tryptophan (W) and arginine (R) and an intervening sequence with a high content of tyrosines (Y). This motif has no homologs in GenBank or PROSITE and is unique to flightin and paraflightin, a putative flightin paralog identified in decapods. A third motif of unclear affinities to pancrustacean WYR was observed in chelicerates. Phylogenetic analysis of amino acid sequences of the conserved motif suggests that paraflightin originated before the divergence of amphipods, isopods, and decapods. We conclude that flightin originated de novo in the ancestor of Pancrustacea > 500 MYA, well before the divergence of insects (~400 MYA) and the origin of flight (~325 MYA), and that its IFM-specific function in Drosophila is a more recent adaptation. Furthermore, we propose that WYR represents a novel myosin coiled-coil binding motif. PMID:24271855

Soto-Adames, Felipe N; Alvarez-Ortiz, Pedro; Vigoreaux, Jim O



Megafaunal responses to strong oxygen gradients on the Pakistan margin of the Arabian Sea  

NASA Astrophysics Data System (ADS)

The Arabian Sea oxygen minimum zone (OMZ), which intersects the continental margin between approximately 100 and 1200 m, is one of the world's largest deep-water oxygen-deficient water masses. We analysed megafaunal organisms seen in images obtained using a wide-angle survey photographic (WASP) system at nine sites (140-1850 m water depth) across the OMZ on the Pakistan Margin during the late-monsoon period (August-September 2003). The visible megafauna comprised: (1) the megabenthos sensu strictu ( s.s.), (2) large polychaetes and (3) the benthopelagic megafauna (fish, natant decapods and octopods). Large protozoans, mainly the foraminiferan Pelosina sp., were counted but not included in the megafauna. The megabenthos s.s. were rare at the seasonally hypoxic 140-m site (O 2=0.11 ml l -1), entirely absent in the OMZ core and most of the lower transition zone (300-900 m; O 2=0.12-0.15 ml l -1), but peaked in abundance (27.94 indiv. m -2) at 1000 m (O 2=0.16 ml l -1). Densities were much lower at 1100 and 1200 m (0.52-0.69 indiv. m -2; O 2=0.25-0.38 ml l -1), and declined to minimal values (0.01 indiv. m -2) at 1850 m (O 2=1.68 ml l -1). There was no correlation with depth, dissolved-oxygen concentration or sediment organic chemistry variables (%C org, %Total N, C:N, ?13C, ?15N). Pelosina sp. was the only strictly benthic organism visible at 400 and 700 m. Fish and natant decapods were fairly common at 300 m, and fish were the only metazoans seen in photographs from 700 m. Large polychaetes, almost certainly Linopherus sp., were very abundant in photographs from 900 m, where megabenthos s.s. were absent, and somewhat less abundant at 1000 m. Suspension-feeding cnidarians and tunicates were abundant at 1100 and 1200 m, respectively. The number of megabenthos s.s. species visible at each site ranged from six (1000 and 1850 m) to 11 (1100 and 1200 m). Diversity ( H'(log e)) was the lowest at 1000 and 1850 m and the highest at 1100 m, with intermediate values at 140 and 1200 m. Dominance was the highest (>99%) at 1000 m, high (87%) at 1200 m and lower (32-50%) at 140, 1100 and 1850 m. Benthopelagic megafauna appeared more tolerant of dysoxia than the megabenthos s.s., although densities peaked at 1100 m, slightly deeper than for the megabenthos s.s.. The presence of uneaten carrion (dead fish and natant decapods) between 300 and 900 m suggests that scavengers were either not active or not present within the OMZ. The megabenthos s.s. appeared to respond to oxygen concentrations above a threshold value (˜0.15-0.16 ml l -1). The ophiuroid-dominated abundance peak at 1000 m, and the abrupt changes in megabenthic assemblage composition between 1000 and 1200 m, were probably expressions of an 'edge effect', known from other OMZs and believed to reflect a threshold release from physiological oxygen limitation accompanied by an abundant food supply.

Murty, Sarah J.; Bett, Brian J.; Gooday, Andrew J.



Influence of environmental variables on the spatio-temporal dynamics of bentho-pelagic assemblages in the middle slope of the Balearic Basin (NW Mediterranean)  

NASA Astrophysics Data System (ADS)

The spatio-temporal dynamics of benthic and bentho-pelagic assemblages of megafauna from the middle slope of the Catalan Sea (NW Mediterranean Sea) were studied. Nineteen bottom trawls were performed to collect megafauna on 5 cruises between February 2007 and February 2008. Samples were obtained from three depth strata, including a submarine canyon. Simultaneously, environmental variables were recorded and three levels of bottom-boundary layer macrofauna (infauna, suprabenthos and zooplankton), potential prey of megafauna, were sampled. Fish and decapod assemblages were explored individually. Depth was the main factor structuring megafaunal assemblages, with larger organisms usually observed at greater depths (based on mean individual weight). Nevertheless, in April, coinciding with the reproductive period of the dominant species, larger fish and decapods were observed inside the submarine canyon rather than at greater depths. Assemblages inside and outside the submarine canyons differed in species abundance and biomass, rather than in species composition; larger densities of endobenthic species were found inside the canyon. Also, higher abundance and biomass of megafauna were recorded inside the canyon on all cruises, generally linked to higher prey availability there. A seasonal trend related to size was also observed, associated with the stratification (?Tsurface-bottom water=8.37±0.33 °C for summer-autumn) versus homogeneity (?Tsurface-bottom water=2.09±1.76 °C for winter-spring) of the water column. Larger amounts of smaller species feeding at lower trophic levels were found in periods of homogeneity, while assemblages during periods of stratification were characterised by larger species feeding at higher trophic levels. Environmental variables most strongly explaining changes in megafaunal assemblages (from Spearman rank correlation and generalised linear models) were temperature (T) and salinity (S) close to the sea bottom, river discharges and turbidity above the sea bottom. Also, micronekton biomass explained changes in fish assemblages, while Polychaeta biomass and surface primary production were explanatory for decapods. All these variables directly or indirectly affect availability of trophic resources at bathyal depths. T and S are intrinsically related to depth, and are the variables to which organisms may be actually responding. Prey biomass plays an important role in the bathymetric and the topographic distribution of megafauna. T and S are also linked to the stratification or homogeneity of water masses. Peaks of surface primary production (SPP) in February and maximum river discharge in April corresponded to a maximum in megafaunal biomass in summer after ca. 3-5 months. High river discharges, channelled to bathyal depths through submarine canyons, were related to increases in water turbidity, associated with resuspension of organic matter (food for low trophic levels). On the other hand, low turbidity coincided with minimum river discharges, favouring deposition of organic matter in the sediments. Peaks in abundance and biomass of megafauna were observed after peaks in key prey (zooplankton, micronekton and benthic infauna) with a lag of ca. 2 months. Diversity of megafaunal assemblages was coupled to food availability.

Papiol, V.; Cartes, J. E.; Fanelli, E.; Maynou, F.



Food web structure of deep-sea macrozooplankton and micronekton off the Catalan slope: Insight from stable isotopes  

NASA Astrophysics Data System (ADS)

Food web structure of the macroplankton/micronekton fauna on the continental slope of the Catalan Sea (Balearic basin, NW Mediterranean) was investigated using carbon and nitrogen stable isotope tracers on a total of 34 taxa. Samples were collected close to Barcelona, Spain, on the middle slope, at a seasonal scale. Mean ? 13C values ranged from - 22.1‰ ( Salpa maxima) to - 16.9‰ (the mysid Eucopia hanseni). Values of ? 15N ranged from 2.5‰ (the hyperiid Vibilia armata) to 9.8‰ (the pelagic polychaete Tomopteris sp.). The stable isotope ratios of this fauna displayed a continuum of values over the ? 15N range of 7‰, confirming a wide spectrum of feeding strategies (from filter feeders to predators). High annual mean ? 15N values were found among carnivorous large zooplankton and micronekton, including species that prey on gelatinous plankton (i.e. salps, siphonophores), euphausiids, natantian decapod crustaceans and fish (i.e. myctophids and stomiiformes). In agreement with the available information on diets of planktonic taxa, the lowest isotope ratios were found for filter feeders ( V. armata, S. maxima, the pteropods Cymbulia peroni and Cavolinia inflexa, ostracods and the thaliacean Pyrosoma atlanticum), all of which feed on particulate organic matter. We found three trophic levels in macroplankton/micronekton food webs based on a 15N-enrichment factor of ~ 2.5‰ per level. The range of ? 13C was particularly wide among carnivores (- 20.7‰ to - 16.6‰), suggesting predation on a variety of prey from gelatinous zooplankton (which displayed more depleted ? 13C signatures) to small fishes and decapods. Correlation between ? 13C-? 15N was generally weak, likely due to the consumption of different kinds of sinking particles (e.g. marine snow, phytodetritus), some constituted of multiply recycled particulate organic matter (POM). However, higher ? 13C-? 15N correlations were observed during winter and spring, periods of water column homogenization, suggesting that the planktonic community assimilates pulses of new production from the photic zone (peaking in January-February). Low correlations were observed during periods of water column stratification, particularly in summer, when production is especially low, suggesting that in this period macroplankton-micronekton community rely on sources other than surface primary production such as POM derived from river discharge.

Fanelli, E.; Cartes, J. E.; Papiol, V.



Material properties of zooplankton and nekton from the California current  

NASA Astrophysics Data System (ADS)

This study measured the material properties of zooplankton, Pacific hake (Merluccius productus), Humboldt squid (Dosidicus gigas), and two species of myctophids (Symbolophorus californiensis and Diaphus theta) collected from the California Current ecosystem. The density contrast (g) was measured for euphausiids, decapods (Sergestes similis), amphipods (Primno macropa, Phronima sp., and Hyperiid spp.), siphonophore bracts, chaetognaths, larval fish, crab megalopae, larval squid, and medusae. Morphometric data (length, width, and height) were collected for these taxa. Density contrasts varied within and between zooplankton taxa. The mean and standard deviation for euphausiid density contrast were 1.059 +/- 0.009. Relationships between zooplankton density contrast and morphometric measurements, geographic location, and environmental conditions were investigated. Site had a significant effect on euphausiid density contrast. Density contrasts of euphausiids collected in the same geographic area approximately 4-10 days apart were significantly higher (p < 0.001). Sound speed contrast (h) was measured for euphausiids and pelagic decapods (S. similis) and it varied between taxa. The mean and standard deviation for euphausiid sound speed were 1.019 +/- 0.009. Euphausiid mass was calculated from density measurements and volume, and a relationship between euphausiid mass and length was produced. We determined that euphausiid from volumes could be accurately estimated two dimensional measurements of animal body shape, and that biomass (or biovolume) could be accurately calculated from digital photographs of animals. Density contrast (g) was measured for zooplankton, pieces of hake flesh, myctophid flesh, and of the following Humboldt squid body parts: mantle, arms, tentacle, braincase, eyes, pen, and beak. The density contrasts varied within and between fish taxa, as well as among squid body parts. Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast (h) was measured for Pacific hake flesh, myctophid flesh, Humboldt squid mantle, and Humboldt squid braincase. Sound speed varied within and between nekton taxa. The material properties reported in this study can be used to improve target strength estimates from acoustic scattering models which would increase the accuracy of biomass estimates from acoustic surveys for these zooplankton and nekton.

Becker, Kaylyn


DIRS1-like retrotransposons are widely distributed among Decapoda and are particularly present in hydrothermal vent organisms  

PubMed Central

Background Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. Considering their mutational abilities, TEs can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. DIRS1-like retrotransposons are a particular group of retrotransposons according to their mode of transposition that implies a tyrosine recombinase. To date, they have been described in a restricted number of species in comparison with the LTR retrotransposons. In this paper, we determine the distribution of DIRS1-like elements among 25 decapod species, 10 of them living in hydrothermal vents that correspond to particularly unstable environments. Results Using PCR approaches, we have identified 15 new DIRS1-like families in 15 diverse decapod species (shrimps, lobsters, crabs and galatheid crabs). Hydrothermal organisms show a particularly great diversity of DIRS1-like elements with 5 families characterized among Alvinocarididae shrimps and 3 in the galatheid crab Munidopsis recta. Phylogenic analyses show that these elements are divergent toward the DIRS1-like families previously described in other crustaceans and arthropods and form a new clade called AlDIRS1. At larger scale, the distribution of DIRS1-like retrotransposons appears more or less patchy depending on the taxa considered. Indeed, a scattered distribution can be observed in the infraorder Brachyura whereas all the species tested in infraorders Caridea and Astacidea harbor some DIRS1-like elements. Conclusion Our results lead to nearly double both the number of DIRS1-like elements described to date, and the number of species known to harbor these ones. In this study, we provide the first degenerate primers designed to look specifically for DIRS1-like retrotransposons. They allowed for revealing for the first time a widespread distribution of these elements among a large phylum, here the order Decapoda. They also suggest some peculiar features of these retrotransposons in hydrothermal organisms where a great diversity of elements is already observed. Finally, this paper constitutes the first essential step which allows for considering further studies based on the dynamics of the DIRS1-like retrotransposons among several genomes.

Piednoel, Mathieu; Bonnivard, Eric



Neuropeptide Action in Insects and Crustaceans*  

PubMed Central

Physiological processes are regulated by a diverse array of neuropeptides that coordinate organ systems. The neuropeptides, many of which act through G protein–coupled receptors, affect the levels of cyclic nucleotides (cAMP and cGMP) and Ca2+ in target tissues. In this perspective, their roles in molting, osmoregulation, metabolite utilization, and cardiovascular function are highlighted. In decapod crustaceans, inhibitory neuropeptides (molt-inihibiting hormone and crustacean hyperglycemic hormone) suppress the molting gland through cAMP- and cGMP-mediated signaling. In insects, the complex movements during ecdysis are controlled by ecdysis-triggering hormone and a cascade of downstream neuropeptides. Adipokinetic/hypertrehalosemic/hyperprolinemic hormones mobilize energy stores in response to increased locomotory activity. Crustacean cardioacceleratory (cardioactive) peptide, proctolin, and FMRFamide-related peptides act on the heart, accessory pulsatile organs, and excurrent ostia to control hemolymph distribution to tissues. The osmoregulatory challenge of blood gorging in Rhodnius prolixus requires the coordinated release of serotonin and diuretic and antidiuretic hormones acting on the midgut and Malpighian tubules. These studies illustrate how multiple neuropeptides allow for flexibility in response to physiological challenges.

Mykles, Donald L.; Adams, Michael E.; Gade, Gerd; Lange, Angela B.; Marco, Heather G.; Orchard, Ian



The peroxinectin of white shrimp Litopenaeus vannamei is synthesised in the semi-granular and granular cells, and its transcription is up-regulated with Vibrio alginolyticus infection.  


Peroxinectin mRNA expression in the different types of haemocytes of white shrimp Litopenaeus vannamei was studied by in situ hybridisation using digoxigenin-UTP-labelled riboprobes and reverse transcription-polymerase chain reaction (RT-PCR). Granular cells (GC) and a mixture of semi-granular cells (SGC) and hyaline cells (HC) were separated by 70% Percoll gradient centrifugation. Peroxinectin was synthesised in both GC and the mixture of SGC-HC. An in situ hybridisation assay indicated that peroxinectin mRNA expression occurred in GC and SGC, but not in HC. Peroxinectin transcript up-regulated significantly, whereas haemocyte count decreased significantly at 6, 12 and 24 h post Vibrio alginolyticus-injection with slower restoration as compared to that of saline-injected shrimp. The RT-PCR assay indicated that peroxinectin exists extensively in several species of decapod crustaceans including L. vannamei, freshwater prawn Macrobrachium rosenbergii, common caridina Caridina pseudodenticulata, stone crab Thalamita crenata and mud crab Scylla serrata suggesting that this protein plays an important role in defence against pathogens. PMID:15683919

Liu, Chun-Hung; Cheng, Winton; Chen, Jiann-Chu



A year in Barkley Canyon: A time-series observatory study of mid-slope benthos and habitat dynamics using the NEPTUNE Canada network  

NASA Astrophysics Data System (ADS)

Understanding long-term trends in species abundance and distribution represents an important challenge for future research in the deep sea, particularly as management of human impacts becomes a more important concern. However, until natural higher frequency variability is better understood, it will be difficult to interpret any long-term trends that may be apparent in data sets. We present here the results of the first year of observations at the NEPTUNE Canada cabled observatory site in Barkley Canyon, off the coast of Vancouver Island, in the northeast Pacific Ocean. Presence/absence and abundance data for 28 faunal groups were extracted from daily video records from an observatory camera. Concurrent CTD and current meter data were collected from co-located instruments. Water mass properties, currents and faunal community composition exhibited notable seasonal trends. Distinct seasonal faunal groupings were observed, together with summer and winter trends in temperature, salinity and current patterns. Variations in abundance of decapod crustaceans and fishes were responsible for most differences between faunal groups. We suggest that faunal composition may have been responding to seasonal variations in food availability, together with direct and indirect physical influences on predator and prey abundance.

Juniper, S. Kim; Matabos, Marjolaine; Mihály, Steven; Ajayamohan, R. S.; Gervais, Françoise; Bui, Alice O. V.



PCB, PCDD/F and PBDE levels and profiles in crustaceans from the coastal waters of Brittany and Normandy (France).  


Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analysed in the muscle of various edible marine crustaceans (spider crab, edible crab, velvet swimming crab and Norway lobster) from the Brittany and Normandy coasts (France). The highest concentrations were measured in species collected from Antifer (Seine Bay). PCB and PBDE patterns in crustacean muscles were similar and independent of the geographical area with the predominance of the high chlorinated PCBs (CB153, 138, 118 and 180), and of a few PBDE congeners (BDE47, BDE99, BDE100 and BDE28). Oppositely, dioxin contamination differed with site. The major component in crustaceans from the Seine Bay was 2378-TCDF, whereas specimens from cleaner areas had higher relative concentrations of OCDD. Finally, the comparison of the spider crab contaminant profiles to those measured in mussel and sea bass highlighted two different trends: decapod crustaceans possess relatively strong capacity to metabolise PCBs and PBDEs; however these species might be used as bioindicators for dioxin pollution monitoring in the marine coastal environment. PMID:17434539

Bodin, N; Abarnou, A; Fraisse, D; Defour, S; Loizeau, V; Le Guellec, A-M; Philippon, X



A new morphometric implemented video-image analysis protocol for the study of social modulation in activity rhythms of marine organisms.  


Video-image analysis can be an efficient tool for microcosm experiments portraying the modulation of individual behaviour based on sociality. The Norway lobster, Nephrops norvegicus is a burrowing decapod the commercial capture of which occurs by trawling only when animals are engaged in seabed excursions. Emergence behaviour is modulated by the day-night cycle but a further modulation occurs upon social interaction in a still unknown fashion. Here, we present a novel automated protocol for the tracking of the movement of different animals at once based on a multivariate morphometric approach. Four black and white tags were customized according to a precise geometric design. Shape Matching and Complex Fourier Descriptors analyses were used to track tag displacement through consecutive frames in a 7-day experiment under monochromatic blue light (480 nm)-darkness conditions. Shape Matching errors were evaluated in relation to tag geometry. Time series of centroid coordinates in pixels were transformed in centimetres. The FD analysis was slightly less efficient than the Shape Matching, although more rapid (i.e. up to 20 times faster). Nocturnal rhythms were reported for all animals. Waveform analysis indicated marked differences in the amplitude of activity phases as proof of interindividual interaction. Total diel activity presented a decrease in the rate of out of burrow locomotion as the testing progressed. N. norvegicus is a nocturnal species and present observations sustain the efficiency and fidelity of our automated tracking system. PMID:19619586

Menesatti, Paolo; Aguzzi, Jacopo; Costa, Corrado; García, José Antonio; Sardà, Francesc



Emigration of penaeid shrimp from the once-through cooling lake of Cedar Bayou Steam Electric Generating Station, Baytown, Texas  

SciTech Connect

Migration and distribution of two decapod shrimp, Penaeus setiferus and P. aztecus, in the cooling-water system of a power plant on the Texas coast were investigated, with emphasis on the seaward emigration from the cooling lake. Samples were collected every two weeks for a year by straining water leaving the lake over a drop structure, trawling in the cooling lake, and flushed from the intake screen. Shrimp catches at the drop structure were positively correlated with the standing population in the cooling lake. Significantly more shrimp passed over the drop structure nocturnally than diurnally. Shrimp caught at the drop structure diurnally averaged either smaller or similar in size to the shrimp taken there at night. The passage of a cold front enhanced migration and initially increased and then reduced the mean size of shrimp passing the drop structure. Higher percentages of the shrimp population in the cooling lake emigrated near new moon than full moon. The moon-phase effects appeared to be due to the moon cycle itself rather than to the intinsity of moon light. Significantly more shrimp of both species emigrated during the hours of ebbing than incoming tide. As the lake surface was above high tide level, an endogenous timing mechanism rather than evironmental factors associated with tidal rhythms controlled this emigration pattern. A temperature drop of up to 0.23 C/hour significantly increased P. aztecus emigration.

Chen, Y.L.



Road and stream network connectivity and potential: northeastern Puerto Rico, an exploratory analysis  

NASA Astrophysics Data System (ADS)

Interactions between road and stream networks are complex and are influenced by a range of environmental and road design characteristics. These interactions are not clearly understood and are the subjects of current research. To increase understanding of these interactions we explore the concepts of Road and Stream Network Connectivity (R/S Connectivity) and Road and Stream Network Connectivity Potential (RSNCP). Lastly we provide a methodology for study and analysis of R/S connectivity. This study focuses on road induced alterations to sediment and water flow processes, which are important road effects of R/S connectivity. For 25 river road crossings (RRC) in the Rio Mameyes and Rio Espiritu watersheds of Northeastern Puerto Rico, a multi-scale Geographic Information Systems (GIS) database measuring environmental and road characteristic variables was developed specifically to measure variables influencing sediment and water flow. Multivariate analysis methods were used to select the environmental and road characteristic variables which were used in multiple linear regression models for three biota variables (Decapod Richness, Adult Fish Richness, and Total Richness), and four stream habitat geomorphology variables (Median Channel Grain Size, Active Channel Maximum Depth, Pool Volume, and Active Channel Width). Explained variance (R2) from modeling results ranged from 0.22 to 0.86, demonstrating that the GIS derived variables can successfully be used to model important stream biota and geomorphology response variables.

Sherrill, K. R.; Laituri, M. J.; Helmer, E. H.; Ramirez, J. A.; Blanco, J. F.; Hein, K.; Pike, A. S.



[Feeding changes for three Sphoeroides species (Tetraodontiformes: Tetraodontidae) after Isidore hurricane impact in Carbonera Inlet, Southeastern Gulf of Mexico].  


The coexistence of ecologically similar species may occur because of resources distribution, such as prey and habitat type and segregation time, that minimizes the interspecific competition. The changes brought about by Hurricane Isidore in the distribution of food resources by three coexisting fish species of the family Tetraodontidae (Sphoeroides nephelus, S. spengleri and S testudineus), were analyzed at the Carbonera Inlet. Sphoeroides spp. based their food on benthic organisms; principally, they consume mussels (Brachidontes sp.), barnacles (Balanus sp.) and gastropods (Crepidula sp). Before hurricane impact, the three species share the available food resources in different proportions (bivalves, gastropods, barnacles and decapods), according to different strategies that enabled them to coexist and reduce interspecific competition. After the impact, the abundance of available prey decreased and the interespecific competition for food increased, leading to S. testudines and S. nephelus change their trophic spectrum (xiphosurans, amphipods, isopods and detritus) and displacing S. splengleri of the inlet. The distribution of food resources was conditioned by the abundance and diversity of prey, as well as the adaptive response of each species. PMID:21250477

Palacios-Sánchez, Sonia Eugenia; Vega-Cendejas, María Eugenia



Paragonimiasis in KwaZulu-Natal Province, South Africa.  


Nine cases of paragonimiasis have been reported from cats (4), dogs (2) and children (3) in South Africa, with an additional suspected case in an adult female patient. Details of these cases are reviewed. All nine cases, and perhaps the adult case as well, were from the province of KwaZulu-Natal but locality data are only available for six of them. These six cases represent four localities which all lie below 100 m above sea level in the province's lowlands, suggesting that there may be a focus of transmission here. The molluscan first intermediate host must be one of the two prosobranch snail species present in the area, Melanoides tuberculata or Tomichia natalensis, and the decapod second intermediate host the common river crab Potamonautes sidneyi. All infected cats and dogs had pulmonary infections, while two human cases for which there is sufficient information had extrapulmonary infections. Transmission appears to be ongoing but the invasive snail Tarebia granifera may be competing with both M. tuberculata and T. natalensis. If so, this may bring transmission to an end. PMID:23253517

Appleton, C C



How do mandibles sense? The sensory apparatus of larval mandibles in Palaemon elegans Rathke, 1837 (Decapoda, Palaemonidae).  


The mandibles of decapod zoea-I larvae are robustly built masticating mouthparts equipped with several processes and spines. Superficial examination of these sturdy, inflexible structures can suggest that they are lacking sensory receptors. However, detailed TEM analysis of their ultrastructure revealed up to 11 sensillar cell clusters on the gnathal edges of the mandibles of the zoea-I in Palaemon elegans Rathke, 1837. Based on ultrastructural criteria we distinguish 7 types of sensilla: mechanoreceptors, chemoreceptors and mechano- and chemoreceptors. One sensory unit located at the base of the 'lacinia mobilis' exhibits the typical features of a crustacean mechanosensitive sensillum with an external seta and corresponding ultrastructure. Another unit shows features indicating bimodal contact chemosensitivity. A third one is similar to known olfactory chemoreceptors. Using the concept of modality-specific structures we analyse the structure and functional morphology of each sensillum, and give a comprehensive overview of the sensory abilities of zoea mandibles. We take a closer look at the ultrastructure of the 'lacinia mobilis', providing further features to trace its evolutionary history in Decapoda, and thus contributing to a better understanding of malacostracan phylogeny. PMID:23010507

Geiselbrecht, Hannes; Melzer, Roland R



Expression of recombinant eyestalk crustacean hyperglycemic hormone from the tropical land crab, Gecarcinus lateralis, that inhibits Y-organ ecdysteroidogenesis in vitro.  


Crustacean hyperglycemic hormone (CHH) is a pleiotropic neuropeptide that regulates carbohydrate and lipid metabolism, molting, reproduction, and osmoregulation in decapod crustaceans. CHH elevates glucose levels in the hemolymph by stimulating glycogenolysis in target tissues. It also inhibits ecdysteroidogenesis in the molting gland, or Y-organ (YO), possibly as a response to environmental stress. CHH acts via binding to a membrane receptor guanylyl cyclase, which is expressed in most tissues, including the YO. Large amounts of biologically active neuropeptide are required to investigate the mechanism of CHH signaling in the YO. Consequently, the eyestalk ganglia CHH (EG-CHH) isoform was cloned into a yeast (Pichia pastoris) expression vector to express recombinant mature peptide (rEG-CHH) with or without a C-terminal c-Myc/polyhistidine tag. Yeast cultures with untagged or tagged rEG-CHH inhibited ecdysteroidogenesis in YOs from European green crab (Carcinus maenas) 36% (P < 0.002) and 51% (P < 0.006), respectively. Purified tagged EG-CHH inhibited YO ecdysteroidogenesis 32% (P < 0.002), but lacked hyperglycemic activity in vivo. This is the first report of recombinant EG-CHH inhibiting YO ecdysteroidogenesis. The data suggest that the tagged recombinant peptide can be used to elucidate the CHH signaling pathway in the crustacean molting gland. PMID:18595002

Zarubin, Tyler P; Chang, Ernest S; Mykles, Donald L



Characterization of limb autotomy factor-proecdysis (LAF(pro)), isolated from limb regenerates, that suspends molting in the land crab Gecarcinus lateralis.  


Molting and limb regeneration are tightly coupled processes, both of which are regulated by ecdysteroid hormone synthesized and secreted by the Y-organs. Regeneration of lost appendages can affect the timing and duration of the proecdysial, or premolt, stage of the molt cycle. Autotomy of all eight walking legs induces precocious molts in various decapod crustacean species. In the land crab Gecarcinus lateralis, autotomy of a partially regenerated limb bud before a critical period during proecdysis (regeneration index <17) delays molting so that a secondary limb bud (2 degrees LB) forms and the animal molts with a complete set of walking legs. It is hypothesized that 2 degrees LBs secrete a factor, termed limb autotomy factor-proecdysis (LAF(pro)), that inhibits molting by suppressing the Y-organs from secreting ecdysone. Molting was induced by autotomy of eight walking legs; autotomy of primary (1 degrees ) LBs reduced the level of ecdysteroid hormone in the hemolymph 73% by one week after limb bud autotomy (LBA). Injection of extracts from 2 degrees LBs, but not 1 degrees LBs, inhibited 1 degrees LB growth in proecdysial animals, thus having the same effect on molting as LBA. The inhibitory activity in 2 degrees LB extracts was stable after boiling in water for 15 min, but was destroyed by boiling 15 min in 0.1 N acetic acid or incubation with proteinase K. These results support the hypothesis that LAF(pro) is a peptide that resembles a molt-inhibiting hormone. PMID:12086991

Yu, Xiaoli; Chang, Ernest S; Mykles, Donald L



Comparative Ultrastructure and Carbohydrate Composition of Gastroliths from Astacidae, Cambaridae and Parastacidae Freshwater Crayfish (Crustacea, Decapoda)  

PubMed Central

Crustaceans have to cyclically replace their rigid exoskeleton in order to grow.Most of them harden this skeleton by a calcification process. Some decapods (land crabs, lobsters and crayfish) elaborate calcium storage structures as a reservoir of calcium ions in their stomach wall, as so-called gastroliths. For a better understanding of the cyclic elaboration of these calcium deposits, we studied the ultrastructure of gastroliths from freshwater crayfish by using a combination of microscopic and physical techniques. Because sugars are also molecules putatively involved in the elaboration process of these biomineralizations, we also determined their carbohydrate composition. This study was performed in a comparative perspective on crayfish species belonging to the infra-order Astacidea (Decapoda, Malacostraca): three species from the Astacoidea superfamily and one species from the Parastacoidea superfamily. We observed that all the gastroliths exhibit a similar dense network of protein-chitin fibers, from macro- to nanoscale, within which calcium is precipitated as amorphous calcium carbonate. Nevertheless, they are not very similar at the molecular level, notably as regards their carbohydrate composition. Besides glucosamine, the basic carbohydrate component of chitin, we evidenced the presence of other sugars, some of which are species-specific like rhamnose and galacturonic acid whereas xylose and mannose could be linked to proteoglycan components.

Luquet, Gilles; Fernandez, Maria S.; Badou, Aicha; Guichard, Nathalie; Roy, Nathalie Le; Corneillat, Marion; Alcaraz, Gerard; Arias, Jose L.



Crystal Structure of the Shrimp Proliferating Cell Nuclear Antigen: Structural Complementarity with WSSV DNA Polymerase PIP-Box  

PubMed Central

DNA replication requires processivity factors that allow replicative DNA polymerases to extend long stretches of DNA. Some DNA viruses encode their own replicative DNA polymerase, such as the white spot syndrome virus (WSSV) that infects decapod crustaceans but still require host replication accessory factors. We have determined by X-ray diffraction the three-dimensional structure of the Pacific white leg shrimp Litopenaeus vannamei Proliferating Cell Nuclear Antigen (LvPCNA). This protein is a member of the sliding clamp family of proteins, that binds DNA replication and DNA repair proteins through a motif called PIP-box (PCNA-Interacting Protein). The crystal structure of LvPCNA was refined to a resolution of 3 Å, and allowed us to determine the trimeric protein assembly and details of the interactions between PCNA and the DNA. To address the possible interaction between LvPCNA and the viral DNA polymerase, we docked a theoretical model of a PIP-box peptide from the WSSV DNA polymerase within LvPCNA crystal structure. The theoretical model depicts a feasible model of interaction between both proteins. The crystal structure of shrimp PCNA allows us to further understand the mechanisms of DNA replication processivity factors in non-model systems.

Carrasco-Miranda, Jesus S.; Lopez-Zavala, Alonso A.; Arvizu-Flores, Aldo A.; Garcia-Orozco, Karina D.; Stojanoff, Vivian; Rudino-Pinera, Enrique; Brieba, Luis G.; Sotelo-Mundo, Rogerio R.



Diversification of epithelial adherens junctions with independent reductive changes in cadherin form: identification of potential molecular synapomorphies among bilaterians.  


The adherens junction (AJ) is the most universal junction found in bilaterian epithelia and may represent one of the earliest types of cell-cell junctions. The adhesion molecules responsible for forming AJs are the classic cadherins (referred to simply as cadherins), whose extracellular domain organization displays marked variety among species examined so far. In this study, we attempted to reconstruct the evolution of cadherin by analyzing new data from several arthropods (two insects, one non-insect hexapod, three crustaceans, and one chelicerate) and previously published sequences for Drosophila melanogaster and other animals. The results of comparative analyses using the BLAST tool and immunohistochemical analyses revealed that the extracellular domain organizations of a decapod, an isopod, a spider, and a starfish cadherin, which are present at AJs in the embryonic epithelia are homologous. Independent reductive changes from the ancestral state were evident in the epithelia of hexapods+branchiopod, vertebrates+urochordates, and a cephalochordate. The form of cadherins in hexapods is more closely related to that of a branchiopod than to that of malacostracan crustaceans, and one of those of vertebrates is more closely related to that of urochordates than to that of a cephalochordate. Although the sampling of taxa is limited at this stage of research, we hypothesize that the reductive events in cadherin structure related to AJ formation in the epithelia may possess information about bilaterian relationships as molecular synapomorphies. PMID:16174032

Oda, Hiroki; Tagawa, Kunifumi; Akiyama-Oda, Yasuko



Purification and characterization of a cadmium-induced metallothionein from the shore crab Carcinus maenas (L.).  

PubMed Central

Two metallothionein variants were purified from the midgut gland of crabs (Carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). One of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). The purification method involved acetone precipitation, gel filtration and reversed-phase h.p.l.c. The complete amino acid sequences of both variants have been elucidated by m.s. and automated sequence analysis on S-methylated proteins or fragments produced by cleavage of the S-methylated proteins with Staphylococcus aureus proteinase. The two variants from crabs exposed to the high cadmium concentration differed only by a single residue of methionine at the N-terminus. The single variant isolated from crabs exposed to the low cadmium concentration was the one without the N-terminal methionine, indicating that high cadmium concentrations either inhibit the processing enzymes and/or that the processing enzymes cannot keep pace with the increased metallothionein synthesis when cadmium availability is high. Cadmium-induced metallothionein from C. maenas shows a high degree of structural similarity to metallothioneins from the decapod crustaceans Scylla serrata and Homarus americanus.

Pedersen, K L; Pedersen, S N; H?jrup, P; Andersen, J S; Roepstorff, P; Knudsen, J; Depledge, M H



How multiple conductances determine electrophysiological properties in a multicompartment model  

PubMed Central

Most neurons have large numbers of voltage- and time-dependent currents that contribute to their electrical firing patterns. Because these currents are nonlinear, it can be difficult to determine the role each current plays in determining how a neuron fires. The LP neuron of the stomatogastric ganglion of decapod crustaceans has been extensively studied biophysically. We constructed ~600,000 versions of a four-compartment model of the LP neuron, and distributed 11 different currents into the compartments. From these, we selected ~1300 models that match well the electrophysiological properties of the biological neuron. Interestingly, correlations that were seen in the expression of channel mRNA in biological studies were not found across the ~1300 admissible LP neuron models, suggesting that the electrical phenotype does not require these correlations. We used cubic fits of the function from maximal conductances to a series of electrophysiological properties to ask which conductances predominantly influence input conductance, resting membrane potential, resting spike rate, phasing of activity in response to rhythmic inhibition, and several other properties. In all cases, multiple conductances contribute to the measured property, and the combinations of currents that strongly influence each property differ. These methods can be used to understand how multiple currents in any candidate neuron interact to determine the cell’s electrophysiological behavior.

Goaillard, Jean-Marc; Marder, Eve



Composition and Dynamics of the Black Sea Benthopelagic Plankton and Its Contribution to the Near-Shore Plankton Communities  

PubMed Central

At a shallow (7 m) near-shore sampling site in the Black Sea we analyzed composition, abundance, and biomass of benthopelagic organisms and the contribution these animals make to the total plankton. The site was monitored across several years (1996–2001; 2006–2007) whilst for 1999–2000 the seasonal variations were analysed. A total of 321 samples from Golubaja Bay near Novorossiysk (44°34?31.04? N, 37°58?45.11? E) in 1996–2007 were taken with a Judey net. The benthopelagic fauna was represented by 69 taxa, a diversity comparable to similar shelf areas. The benthopelagic component played an important role in near-shore plankton communities in the Black Sea accounting for 50% of the total zooplankton biomass at night during all seasons. Abundance and biomass of the benthopelagic animals showed seasonal fluctuations, the highest biomass being recorded during winter (>75% of the total zooplankton biomass) and early spring due to large amphipods, whilst the highest abundances occur during late summer because of numerous young stages of various taxa. Amphipods, mysids, and decapods are the main contributors to the plankton biomass and abundances. Both night and daytime samples are strongly recommended for the adequate description of the near-shore plankton communities.

Vereshchaka, Alexander L.; Anokhina, Ludmila L.



Differential uptake of MRI contrast agents indicates charge-selective blood-brain interface in the crayfish.  


This study provides a new perspective on the long-standing problem of the nature of the decapod crustacean blood-brain interface. Previous studies of crustacean blood-brain interface permeability have relied on invasive histological, immunohistochemical and electrophysiological techniques, indicating a leaky non-selective blood-brain barrier. The present investigation involves the use of magnetic resonance imaging (MRI), a method for non-invasive longitudinal tracking of tracers in real-time. Differential uptake rates of two molecularly distinct MRI contrast agents, namely manganese (Mn(II)) and Magnevist® (Gd-DTPA), were observed and quantified in the crayfish, Cherax destructor. Contrast agents were injected into the pericardium and uptake was observed with longitudinal MRI for approximately 14.5 h. Mn(II) was taken up quickly into neural tissue (within 6.5 min), whereas Gd-DTPA was not taken up into neural tissue and was instead restricted to the intracerebral vasculature or excreted into nearby sinuses. Our results provide evidence for a charge-selective intracerebral blood-brain interface in the crustacean nervous system, a structural characteristic once considered too complex for a lower-order arthropod. PMID:22526631

Otopalik, Adriane G; Shin, Jane; Beltz, Barbara S; Sandeman, David C; Kolodny, Nancy H



Phylogenetic relationships within the snapping shrimp genus Synalpheus (Decapoda: Alpheidae).  


The snapping shrimp genus Synalpheus (Alpheidae) is one of the most speciose decapod genera, with over 160 described species worldwide. Most species live in symbiotic relationships with other marine organisms, such as sponges, corals and crinoids, and some sponge-dwelling species have a highly organized, social structure. The present study is the first worldwide molecular phylogenetic analysis of Synalpheus, based on >2200bp of sequence data from two mitochondrial (COI and 16S) and two nuclear (PEPCK and 18S) loci. Our molecular data show strong support for monophyly of three out of six traditionally recognized morphology-based species groups: the S. brevicarpus, S. comatularum and S. gambarelloides groups. The remaining three species groups (S. paulsoni, S. neomeris and S. coutierei groups) are non-monophyletic in their current composition and will need to be either abandoned or taxonomically redefined. We also identified potential cryptic species of Synalpheus in our dataset, using intraspecific and interspecific sequence variation in COI from the taxonomically well-studied S. gambarelloides group to establish a genetic divergence threshold. We then used both genetic divergence and tree-based criteria (reciprocal monophyly) to identify potential cryptic species in the remaining taxa of the genus. Our results suggest the presence of multiple cryptic lineages in Synalpheus, underlining the need for more integrative taxonomic studies-including morphological, ecological, molecular, and color pattern data-in this biologically interesting genus. PMID:24680914

Hultgren, Kristin M; Hurt, Carla; Anker, Arthur



Ichnology of Upper Cretaceous deep-sea thick-bedded flysch sandstones: Lower Istebna Beds, Silesian Unit (Outer Carpathians, southern Poland)  

NASA Astrophysics Data System (ADS)

The Ophiomorpha rudis ichnosubfacies of the Nereites ichnofacies was recognized in thick- and very thick-bedded sandstones of the Lower Istebna Beds (Campanian-Maastrichtian), which were deposited mainly in deep-sea clastic ramps and aprons. It contains mainly Ophiomorpha rudis (produced by deeply burrowing decapod crustaceans) and rarely Zoophycos isp. and Chondrites isp. The impoverished Paleodictyon ichnosubfacies of the Nereites ichnofacies is present in the medium- and thin-bedded packages of flysch sandwiched between the thick- and very thick-bedded sandstones. They contain Chondrites isp., Phycosiphon incertum, Planolites isp., Arthrophycus strictus, Thalassinoides isp., Ophiomorpha annulata, O. rudis, Scolicia strozzii and Helminthorhaphe flexuosa. The relatively low diversity of this assemblage is influenced by limited areas covered by muddy substrate, which favours deep-sea tracemakers, and partly by a lowered oxygenation in the sediment.

Rajchel, Jacek; Uchman, Alfred



Bilateral symmetry in crayfish behavioral reactions.  


The crayfish, Procambarus cubensis, placed in the central area of a plus-maze preferred to go forward in about 50% of trials; they chose the right or left arm in 20.7 and 18.9% of the trials, respectively. In a T-maze, the difference between right and left directions was also insignificant. When exploring a plus-maze, the crayfish turned to 180 degrees at the end of the arms, then turned to 90 degrees going to the next arm. The mean difference between the right and left U-turns, and the right and left turns was insignificant though some animals demonstrated a left or right preference. There was a strong correlation between the direction of U-turns and following turns ensuring the clockwise or anti-clockwise movements of the crayfish. Also we examined a possible preference of the right or left claw in the feeding behavior of the crayfish. The crayfish caught a small bloodworm given from above equally with the right or left claw. The crayfish conditioned to take a bloodworm with a claw did not demonstrate any stable preference of left or right claw in the course of the experiments. The question of bilateral asymmetries within the decapod crustaceans is discussed. PMID:18652389

Shuranova, Zhanna



Evidence of secondary consumption of invertebrate prey by Double-crested Cormorants  

USGS Publications Warehouse

The piscivorous nature of the Double-crested Cormorant (Phalacrocorax auritus) is well documented. However, many researchers who have used regurgitated pellets to describe the diet of cormorants report that invertebrates compose a small but consistent portion of the diet. We examined the hypothesis that invertebrates found in pellets are primarily the result of secondary consumption. We used odds ratio analysis to examine associations in 2,846 individual pellets between the presence of specific invertebrate prey and the presence of fish species known to consume those invertebrate taxa. Significant (P < 0.05) relationships occurred between gastropods and pumpkinseed (Lepomis gibbosus) and ictalurids, and between decapods and rock bass (Ambloplites rupestris) and smallmouth bass (Micropterus dolomieu). Significant (P < 0.05) relationships were also found between pelecypods and pumpkinseed and ictalurids. We suggest that the invertebrate prey we observed in pellets were present in the digestive tracts of fish that were consumed by Double-crested Cormorants and hence represent secondary consumption by cormorants. We conclude that consumption of invertebrates by Double-crested Cormorants may be overestimated in the literature in instances where the diet was described using pellets.

Johnson, J. H.; Ross, R. M.; Smith, D. R.



Characterization of red pigment concentrating hormone (RPCH) in the female mud crab (Scylla olivacea) and the effect of 5-HT on its expression.  


Red pigment concentrating hormone (RPCH) is a member of the chromatophorotropic hormones and, in crustaceans, it is synthesized in the eyestalk. We have isolated a full-length cDNA for a RPCH preprohormone gene (Scyol-RPCH) from the eyestalks of female mud crabs, Scylla olivacea. The open reading frame consists of 642 nucleotides, and encodes a deduced 108 amino acid precursor protein, which includes a signal peptide, the RPCH (pQLNFSPGWamide), and an associated peptide. We show that the mud crab RPCH peptide exhibits 100% identity with 15 other decapods. Expression of Scyol-RPCH within adult mud crab takes place in the eyestalk, brain, and ventral nerve cord, comprising subesophageal ganglion, thoracic ganglion, and abdominal ganglion. In situ hybridization demonstrates specific expression within neuronal clusters 1, 2, 3, and 4 of the eyestalk X-organ, clusters 6, 8, 9, 10, and 17 of the brain, and in neuronal clusters of the ventral nerve cord. We found that administration of 5-HT up-regulates RPCH gene expression in the eyestalk, suggesting that RPCH may play a role as a downstream hormone of 5-HT. PMID:23376531

Kornthong, Napamanee; Chotwiwatthanakun, Charoonroj; Chansela, Piyachat; Tinikul, Yotsawan; Cummins, Scott F; Hanna, Peter J; Sobhon, Prasert



Brachyuran and anomuran crabs associated with Schizoporella unicornis (Ectoprocta, Cheilostomata) from southeastern Brazil.  


The main goals of this investigation were to describe the community structure of anomuran and brachyuran crabs inhabiting reefs constituted by colonies of Schizoporella unicornis, and to provide a species importance ranking for this community. Collections were carried out on S. unicornis reefs at two-month intervals from May 2003 to May 2004, in the rocky sublittoral of the southeastern Brazilian coast. Relative abundance and occurrence were used to rank these species in the hierarchy importance. A total of 2,018 individuals were obtained, in 11 families, 22 genera and 31 species. Porcellanidae and Pilumnidae were the most abundant families, comprising respectively almost 60% and 15% of individuals sampled. The species ranking indicated four main groups A, B, C and D, with group A subdivided. Subgroup A1 contained 9 species, including the species of greatest ecological importance for community regarding abundance and occurrence. The great abundance of crabs associated with S. unicornis seems to be the result of its recognized importance during the crab developmental cycle, and as shelter and food for some Decapod species. These observations reveal the importance of conserving the areas occupied by these reef colonies, which appear to be an important environment for maintaining local biodiversity. PMID:23538959

Alves, Douglas F R; Barros-Alves, Samara P; Lima, Daniel J M; Cobo, Valter J; Negreiros-Fransozo, Maria Lucia



Ichnofauna from the Harbans Bed of the Badhaura Formation (Sterlitmakian), Rajasthan, India  

NASA Astrophysics Data System (ADS)

In the first ever systematic study of trace fossils from the Badhaura Formation, the authors described a nesting burrow, which they ascribed to a stomatopod. The purpose of this paper is two-fold: primarily, to document ichnofauna from (post-glacial marine late Palaeozoic rocks of peninsular India) the Badhaura Formation (Sterlitmakian) representing marine rocks deposited following the Late Palaeozoic glaciation and secondly to contribute to the data on post-glacial ichnofauna from constituent continents of the Gondwanaland. Trace fossils described here are from the Harbans Bed, the topmost lithounit of the Badhaura Formation. The ichnofauna includes Arenicolites tenuis, Beaconites isp., Curvolithus isp., Cylindrichnus concentricus, Didymaulichnus lyelli, Ophiomorpha isp., Palaeophycus tubularis, Planolites beverleyensis, P. montanus, Rosselia chonoides, R. socialis, Skolithos linearis, Taenidium cameronensis, Thalassinoides paradoxicus, Thalassinoides isp. and a flask-shaped brood chamber assigned to a stomatopod crustacean. This mixed assemblage is assigned to distal Skolithos ichnofacies and is suggestive of a period of relatively quiet, shallow water conditions of deposition. The ichnofauna, when viewed in context of peri-gondwanic ichnofaunas, mainly consisting of simple tracks and trails, from late Palaeozoic post-glacial deposits of other Gondwanan continents, is interesting due to dominance of domichnia. Profusion of brood chambers along with Thalassinoides in the Badhaura Formation validates the concept of pre-Mesozoic Thalassinoides being non-decapod in origin and suggestive of adaptive convergence.

Kulkarni, Kantimati G.; Borkar, Vidyadhar D.



Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities  

PubMed Central

The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO2 (425–1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO2 tolerances derived from laboratory experiments. High CO2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs.

Fabricius, K. E.; De'ath, G.; Noonan, S.; Uthicke, S.



Geographical Information System Based Evaluation of Benthic MACRO Fauna in Thondi Coastal Environment, South East Coast of India Rethna Priya. E, Anbuchezhian. R and Ravichandran. S. Centre of Advanced Study in Marine Biology, Annamalai University, Portonovo, India  

NASA Astrophysics Data System (ADS)

Seasonal and frequency difference of the macro fauna have been related to variation in the morpho dynamics and the population dynamics of dominant species. The aim of this article is to describe the seasonal and spatial variation of the macro fauna at 12 different samplings stations with distinct environmental conditions in Thondi coastal area. The samples were collected monthly from September 2010 to September 2011. Macro benthic invertebrates are numerically important components of coastal ecosystems and represents indicators of fishery potentials, intertidal ecology and environmental degradation. Sampling stations were fixed by GPS. 54 species were recorded, of this 24 species belonging to gastropods, 15 species of bivalves, 5 species of amphipods, 6 species of decapods and 4 species of echinoderms. In the present study the abdunce of benthic fauna greatly depends on physical and chemical properties of the substratum. The diversity, seasonal variations, dominances, influence of ecological parameters have been studied geographically by using GIS software for a period of one year from September 2010 to September 2011The macro fauna at all sites showed a arresting seasonal variation in density and diversity. Keywords: Macro fauna, GIS software, environmental degradation, morpho dynamics.

Priya, R.; Ramasamy, A.; Ravichandran, R.; Anbuchezhian. E.



Molecular phylogeny of Eastern Pacific porcelain crabs, genera Petrolisthes and Pachycheles, based on the mtDNA 16S rDNA sequence: phylogeographic and systematic implications.  


Porcelain crabs, genera Petrolisthes and Pachycheles, are diverse and abundant members of the eastern Pacific near-shore decapod crustacean community. Morphology-based taxonomic analyses of these crabs have determined groupings of affiliated species, but phylogenetic relationships remain unknown. We used sequence data from the mitochondrial 16S rRNA gene of 46 species of eastern Pacific porcelain crabs to perform phylogenetic analyses by distance and parsimony methods. Our results are used to compare the taxonomic significance of morphological and molecular characters, to examine sequence divergence rates of crab 16S rRNA genes, and to analyze the phylogeographic history of these crabs. Our phylogenetic trees indicate that the genus Petrolisthes is divided into two main clades, reflecting morphological features. One clade contains primarily tropical species, and the other contains species from throughout the eastern Pacific, as well as species in the genera Allopetrolisthes and Liopetrolisthes. Phylogenetic trees of Pachycheles suggest an antitropical distribution; north and south temperate species form one clade and tropical species form a second clade. Sequence divergence rates of the 16S rRNA gene from three pairs of geminate species can be used to date divergence times, and we discuss porcelain crab phylogeographic patterns in relation to paleogeographic events. PMID:11341806

Stillman, J H; Reeb, C A



Dancing for Food in the Deep Sea: Bacterial Farming by a New Species of Yeti Crab  

PubMed Central

Vent and seep animals harness chemosynthetic energy to thrive far from the sun's energy. While symbiont-derived energy fuels many taxa, vent crustaceans have remained an enigma; these shrimps, crabs, and barnacles possess a phylogenetically distinct group of chemosynthetic bacterial epibionts, yet the role of these bacteria has remained unclear. We test whether a new species of Yeti crab, which we describe as Kiwa puravida n. sp, farms the epibiotic bacteria that it grows on its chelipeds (claws), chelipeds that the crab waves in fluid escaping from a deep-sea methane seep. Lipid and isotope analyses provide evidence that epibiotic bacteria are the crab's main food source and K. puravida n. sp. has highly-modified setae (hairs) on its 3rd maxilliped (a mouth appendage) which it uses to harvest these bacteria. The ?- and ?- proteobacteria that this methane-seep species farms are closely related to hydrothermal-vent decapod epibionts. We hypothesize that this species waves its arm in reducing fluid to increase the productivity of its epibionts by removing boundary layers which may otherwise limit carbon fixation. The discovery of this new species, only the second within a family described in 2005, stresses how much remains undiscovered on our continental margins.

Thurber, Andrew R.; Jones, William J.; Schnabel, Kareen



Survey of genome size in 28 hydrothermal vent species covering 10 families.  


Knowledge of genome size is a useful and necessary prerequisite for the development of many genomic resources. To better understand the origins and effects of DNA gains and losses among species, it is important to collect data from a broad taxonomic base, but also from particular ecosystems. Oceanic thermal vents are an interesting model to investigate genome size in very unstable environments. Here we provide data estimated by flow cytometry for 28 vent-living species among the most representative from different hydrothermal vents. We also report the genome size of closely related coastal decapods. Haploid C-values were compared with those previously reported for species from corresponding orders or infraorders. This is the first broad survey of 2C values in vent organisms. Contrary to expectations, it shows that certain hydrothermal vent species have particularly large genomes. The vent squat lobster Munidopsis recta has the largest genome yet reported for any anomuran: 2C=31.1 pg=30.4x10(9) bp. In several groups, such as Brachyura, Phyllodocida, and Veneroida, vent species have genomes that clearly rank at the high end of published values for each group. We also describe the highest DNA content yet recorded for the Brachyura (coastal crabs Xantho pilipes and Necora puber). Finally, analysis of genome size variation across populations revealed unexpected intraspecific variation in the vent shrimp Mirocaris fortunata that could not be attributed simply to ploidy changes. PMID:19483771

Bonnivard, Eric; Catrice, Olivier; Ravaux, Juliette; Brown, Spencer C; Higuet, Dominique



Composition and dynamics of the black sea benthopelagic plankton and its contribution to the near-shore plankton communities.  


At a shallow (7 m) near-shore sampling site in the Black Sea we analyzed composition, abundance, and biomass of benthopelagic organisms and the contribution these animals make to the total plankton. The site was monitored across several years (1996-2001; 2006-2007) whilst for 1999-2000 the seasonal variations were analysed. A total of 321 samples from Golubaja Bay near Novorossiysk (44°34'31.04? N, 37°58'45.11? E) in 1996-2007 were taken with a Judey net. The benthopelagic fauna was represented by 69 taxa, a diversity comparable to similar shelf areas. The benthopelagic component played an important role in near-shore plankton communities in the Black Sea accounting for 50% of the total zooplankton biomass at night during all seasons. Abundance and biomass of the benthopelagic animals showed seasonal fluctuations, the highest biomass being recorded during winter (>75% of the total zooplankton biomass) and early spring due to large amphipods, whilst the highest abundances occur during late summer because of numerous young stages of various taxa. Amphipods, mysids, and decapods are the main contributors to the plankton biomass and abundances. Both night and daytime samples are strongly recommended for the adequate description of the near-shore plankton communities. PMID:24945680

Vereshchaka, Alexander L; Anokhina, Ludmila L



Seasonal changes in the demersal nekton community off the Changjiang River estuary  

NASA Astrophysics Data System (ADS)

The diversity, community structure and seasonal variation in demersal nekton off the Changjiang (Yangtze) River estuary was evaluated using monthly trawl survey data, collected between December 2008 and November 2009. A total of 95 species (56 teleosts, 11 cephalopods, and 28 decapod crustaceans) from 69 genera, 49 families and 15 orders were collected. These species could be classified into six groups on the basis of temporal distribution patterns. The resident crab Ovalipes punctatus dominated the community, both in number and biomass. A clear seasonal succession was observed in the species composition. Cluster analysis revealed three primary seasonal groups corresponding to the samples collected in winter-spring, late spring-summer and late summer-autumn. The highest biomass and lowest diversity were observed in summer, while the lowest biomass and highest diversity in winter. The abundance-biomass comparison curves and community composition suggested that the investigated community was moderately disturbed. The results suggest that reduction in fishing pressure and in the degree of seasonal hypoxia are essential for sustainable resource management off the Changjiang River estuary.

Jiang, Yazhou; Ling, Jianzhong; Li, Jiansheng; Yang, Linlin; Li, Shengfa



Conservation in the first internal transcribed spacer region (ITS1) in Hematodinium species infecting crustacean hosts found in the UK and Newfoundland.  


Parasitic dinoflagellates in the genus Hematodinium infect a number of decapod crustaceans in waters off the UK, including the Norway lobster Nephrops norvegicus and the edible crab Cancer pagurus. This study investigated sequence variability in the first internal transcribed spacer (ITS1) region of the ribosomal RNA complex of Hematodinium spp. infecting N. norvegicus, C. pagurus, and Pagurus bernhardus from 4 locations in the UK and from the Hematodinium sp. infecting Chionoecetes opilio from the province of Newfoundland and Labrador, Canada. Phylogenetic analysis of the Hematodinium ITS1 sequences from N. norvegicus, C. pagurus, P. bernhardus and C. opilio suggest that these crustaceans are infected with the same species of Hematodinium. Length variability of the ITS1 region was observed (324 to 345 bp) and attributed to 4 variable microsatellite regions (CATG)n' (GCC)nTCCGC(TG)n' (TA)n' and (GAA)n(GGA)n within the sequenced ITS1 fragment. The observed variation may be due to co-infection of the host crustacean with several different strains of Hematodinium or differences among copies of ITS1 region within the genome of a single parasite cell. The Hematodinium ITS1 sequence from N. norvegicus, C. pagurus, P. bernhardus and C. opilio isolates was sufficiently conserved in primer binding regions targeted by previous molecular diagnostic assays; therefore, we suggest that this assay could be used to screen for Hematodinium infections in these crustacean hosts. PMID:17629120

Small, H J; Shields, J D; Moss, J A; Reece, K S



Four differentially expressed cDNAs in Callinectes sapidus containing the Rebers-Riddiford consensus sequence.  


Decapod crustaceans such as Callinectes sapidus, the blue crab, provide unique opportunities to study proteins involved in biomineralization. Subsequent to each molt, the previously deposited soft cuticle is calcified while the postecdysial layers are simultaneously deposited and mineralized. Though the majority of the exoskeleton hardens, morphologically similar cuticle at the joints, called arthrodial membrane, remains flexible. It seems reasonable that hypodermal cells producing these cuticle types should be synthesizing proteins that regulate mineralization. Data presented here are consistent with this hypothesis, showing that transcripts coding for proteins containing the chitin-binding Rebers-Riddiford (RR) consensus sequence (Gx(8)Gx(7)YxAxExGYx(7)Px(2)P) are differentially expressed. Two RR-containing transcripts, CsAMP8.1 and CsAMP6.0, are found only in arthrodial membrane and are expressed uniformly both before and after ecdysis. They have high sequence homology with RR-containing proteins from uncalcified portions of the cuticle of Cancer pagurus, Penaeus japonicus, and Homarus americanus. The other two transcripts, CsCP8.5 and CsCP8.2, are expressed solely in premolt and in hypodermis depositing calcifying cuticle rather than arthrodial membrane. They have high sequence homology with calcification-associated peptides containing the RR sequence obtained from the calcified cuticle of Procambarus clarkii. This suggests possible involvement in the postmolt mineralization of the pre-ecdysial cuticle. PMID:15939643

Wynn, Anna; Shafer, Thomas H



Effect of air exposure on nitrogen metabolism in the crab Cancer pagurus.  


In C. pagurus exposed to air for 18 h, blood ammonia content decreased within the 2 first hours, then increased at a relatively constant rate (25 microM/h); blood urate content increased at a lower rate (10 microM/h) and a classical blood acidosis was observed. In the cheliped muscle, a transient 22% decrease in GDH activity for ammonia formation and a 48% increase in GDH activity in the reverse reaction (glutamate synthesis) occurred following 6 and 12 h of emersion, respectively. Changes in LDH activity, used as an indicator of anaerobic potential of muscle, were not observed, except for an 18% increase in crabs exposed to air for 24 h. The increase in blood urate content, not known as a response to emersion in decapods, appeared to be different from that observed in response to hypoxia. The relatively low blood ammonia overload and the GDH increased activity for glutamate synthesis suggested that part of the produced ammonia was stored under a bound form in some tissues. The response of C. pagurus to air exposure is discussed on account of the Storey and Storey ('90) theory. PMID:1460435

Regnault, M



Cancer pagurus bacilliform virus (CpBV) infecting juvenile European edible crabs C. pagurus from UK waters.  


This study provides the first description of an intranuclear bacilliform virus infecting the hepatopancreatic epithelial cells of juvenile European edible crab Cancer pagurus from the English Channel, UK. This is the first field report of a virus infecting a member of the Cancer genus and follows a report of a different virus infection detected in C. pagurus held under experimental conditions. We have named the virus Cancer pagurus bacilliform virus (CpBV). The morphology and size of the nucleocapsid and the complete virion align the virus most closely with intranuclear bacilliform viruses reported from other decapod species. The virus was only observed in juvenile C. pagurus with carapace widths ranging between 20 and 70 mm. Viral infection was not observed in crabs above the minimum landing size of 140 mm carapace width. Due to the importance of C. pagurus as a fisheries target, the increasing relative reliance on crustacean fisheries in Europe and the relative dearth of information on diseases of this species, it is pertinent to consider the effects that infections such as CpBV may have on mortality of juvenile crabs and on the sustainability of the fishery as a whole. PMID:18500031

Bateman, K S; Stentiford, G D



Haplosporidium littoralis sp. nov.: a crustacean pathogen within the Haplosporida (Cercozoa, Ascetosporea).  


Previously, we described the pathology and ultrastructure of an apparently asporous haplosporidian-like parasite infecting the common shore crab Carcinus maenas from the European shoreline. In the current study, extraction of genomic DNA from the haemolymph, gill or hepatopancreas of infected C. maenas was carried out and the small subunit ribosomal DNA (SSU rDNA) of the pathogen was amplified by PCR before cloning and sequencing. All 4 crabs yielded an identical 1736 bp parasite sequence. BLAST analysis against the NCBI GenBank database identified the sequence as most similar to the protistan pathogen group comprising the order Haplosporida within the class Ascetosporea of the phylum Cercozoa Cavalier-Smith, 1998. Parsimony analysis placed the crab pathogen within the genus Haplosporidium, sister to the molluscan parasites H. montforti, H. pickfordi and H. lusitanicum. The parasite infecting C. maenas is hereby named as Haplosporidium littoralis sp. nov. The presence of a haplosporidian parasite infecting decapod crustaceans from the European shoreline with close phylogenetic affinity to previously described haplosporidians infecting molluscs is intriguing. The study provides important phylogenetic data for this relatively understudied, but commercially significant, pathogen group. PMID:23999708

Stentiford, G D; Bateman, K S; Stokes, N A; Carnegie, R B



The timing and pattern of biotic recovery following the end-Permian mass extinction  

NASA Astrophysics Data System (ADS)

The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of >90% species globally. The crisis was triggered by a number of physical environmental shocks (global warming, acid rain, ocean acidification and ocean anoxia), and some of these were repeated over the next 5-6 Myr. Ammonoids and some other groups diversified rapidly, within 1-3 Myr, but extinctions continued through the Early Triassic period. Triassic ecosystems were rebuilt stepwise from low to high trophic levels through the Early to Middle Triassic, and a stable, complex ecosystem did not re-emerge until the beginning of the Middle Triassic, 8-9 Myr after the crisis. A positive aspect of the recovery was the emergence of entirely new groups, such as marine reptiles and decapod crustaceans, as well as new tetrapods on land, including -- eventually -- dinosaurs. The stepwise recovery of life in the Triassic could have been delayed either by biotic drivers (complex multispecies interactions) or physical perturbations, or a combination of both. This is an example of the wider debate about the relative roles of intrinsic and extrinsic drivers of large-scale evolution.

Chen, Zhong-Qiang; Benton, Michael J.



Identification and characterization of a serine protease inhibitor (PtSerpin) in the swimming crab Portunus trituberculatus.  


Serine protease inhibitors (Serpins) play a key role in diverse immune biological processes. A serine protease inhibitor (Serpin), namely PtSerpin, was identified from the haemocyte cDNA library of swimming crab Portunus trituberculatus. The full-length PtSerpin cDNA was 1593 bp, including an open reading frame (ORF) of 1227 bp encoding a polypeptide of 408 amino acids with estimated molecular mass of 45.048 kDa and theoretical isoelectric point of 7.23. Predicted tertiary structure of PtSerpin contained three ?-sheets and nine ?-helices. Multiple sequence alignment revealed that deduced amino acid sequence of PtSerpin shared the highest similarity with serpin SPI from green mud crab Scylla paramamosain (SpSerpin). Phylogenetic analysis supported PtSerpin and SpSerpin were closely related to serpins from Penaeus monodon and Daphnia pulex while other decapods formed a separate group. Although the mRNA transcripts of PtSerpin could be detected in all the examined tissues, the higher levels were present in haemocytes and gills which are the major organs respond to pathogenic microorganism. After challenged by Vibrio alginolyticus, Micrococcus luteus and Pichia pastoris, the temporal expression of PtSerpin gene in haemocytes showed different activation times against bacteria and fungi within the experimental period of 72 h. These findings suggest that PtSerpin is involved in the antibacterial defense mechanism of P. trituberculatus crab. PMID:22245590

Wang, Shuangyan; Cui, Zhaoxia; Liu, Yuan; Li, Qianqian; Song, Chengwen



Tunneling trilobites: Habitual infaunalism in an Ordovician carbonate seafloor  

NASA Astrophysics Data System (ADS)

Asaphus trilobites preserved in tunnel systems of the trace fossil Thalassinoides from the mid-Ordovician (ca. 465 Ma) Holen Limestone, Sweden, are interpreted as the trace makers, enabled by shallow carbonate firm grounds to construct open tunnel networks and develop habitual infaunal behavior. Their in situ preservation confirms an infaunal ethology inferred for some trilobite taxa from functional morphology. We suggest that predation pressure from large omnivorous nautiloid cephalopods (“Orthoceras” Limestone facies) may have triggered ecologic opportunism. In trilobites well adapted for predatory-scavenging behavior as well as excavation, the tunnel networks functioned primarily for protection, possibly assisting in feeding, breathing, and breeding strategies. Previously, “trilobite burrows” have referred to seafloor traces of locomotion, feeding, and resting (Cruziana, Rusophycus). Infaunal, tunneling trilobites provide new evidence of mid-Ordovician partitioning of the skeletal benthos, adding to an ecologic and trophic tier hitherto interpreted as occupied by soft-bodied organisms. Such trilobites also provide an identity for Thalassinoides tracemakers prior to Devonian evolution of decapod crustaceans.

Cherns, Lesley; Wheeley, James R.; Karis, Lars



Differential acid-base regulation in various gills of the green crab Carcinus maenas: Effects of elevated environmental pCO2.  


Euryhaline decapod crustaceans possess an efficient regulation apparatus located in the gill epithelia, providing a high adaptation potential to varying environmental abiotic conditions. Even though many studies focussed on the osmoregulatory capacity of the gills, acid-base regulatory mechanisms have obtained much less attention. In the present study, underlying principles and effects of elevated pCO(2) on acid-base regulatory patterns were investigated in the green crab Carcinus maenas acclimated to diluted seawater. In gill perfusion experiments, all investigated gills 4-9 were observed to up-regulate the pH of the hemolymph by 0.1-0.2 units. Anterior gills, especially gill 4, were identified to be most efficient in the equivalent proton excretion rate. Ammonia excretion rates mirrored this pattern among gills, indicating a linkage between both processes. In specimen exposed to elevated pCO(2) levels for at least 7 days, mimicking a future ocean scenario as predicted until the year 2300, hemolymph K(+) and ammonia concentrations were significantly elevated, and an increased ammonia excretion rate was observed. A detailed quantitative gene expression analysis revealed that upon elevated pCO(2) exposure, mRNA levels of transcripts hypothesized to be involved in ammonia and acid-base regulation (Rhesus-like protein, membrane-bound carbonic anhydrase, Na(+)/K(+)-ATPase) were affected predominantly in the non-osmoregulating anterior gills. PMID:23022520

Fehsenfeld, Sandra; Weihrauch, Dirk



Histology of the hepatopancreas of the freshwater prawn Palaemonetes argentinus (Crustacea, Caridea).  


The aim of this study is to describe the histological structure of the hepatopancreas of P. argentinus in intermoult stage in order to provide a baseline for future analysis of its modifications as indicator of environmental stress. Adults at sexual rest of both sexes were collected from Sotelo stream, tributary of Mar Chiquita lagoon, Argentina (38 degrees S 55 degrees W). P. argentinus hepatopancreas was studied by using histological techniques. The hepatopancreas is a bilaterally bilobed brown-yellowish organ. The structure is formed by a mass of blind tubules, with scarce intertubular space. Each tubule consists of a cylindrical epithelial layer surrounded by a basal lamina and myoepithelial cells. Four cellular types were recognized which represent E (embryonic), F (fibrillar), R (resorptive) and B (blisterlike) cells of other decapods. E-cells were found in mitosis and some F-cells had signs of cellular death. B-cells were observed in different phases of holocrine secretion and some groups of desquamated cells appeared at medial and proximal zones, revealing an important cellular turnover rate. According to these observations F, R and B cells are differentiated independently from E-cells. PMID:11201654

Sousa, L G; Petriella, A M



Changes in the hepatopancreas histology of Palaemonetes argentinus (Crustacea, Caridea) during moult.  


The present work describes the histological changes in the hepatopancreas of Palaemonetes argentinus during the moulting cycle. The hepatopancreas of individuals at different moult stages were dissected and studied using histological techniques. The hepatopancreas in intermoult presents four typical cell types (E, F, R and B) and follows the general plan of the rest of decapods. During early premoult (D1), there is an important secretory activity and many R-cells have several subapical vacuoles and are highly columnar. In early postmoult (A), B-cells are confined to the proximal zone of the tubules. Some of the tubules show a folded basal lamina in late premoult and postmoult. Degenerative desquamation occurs at the proximal zone of the tubules in all the stages, this zone being replenished by mitosis of E cells. Mucopolysaccharides and glycogen reserves are more abundant in premoult than in the rest of the cycle. Cellular height increased in premoult and decreased towards the intermoult, stage of more stability. R-cells are the most abundant, and F-cells do not change significantly through the cycle. The observations suggest that the hepatopancreas of P. argentinus undergoes a significant dynamic and cellular turn over rate in relation to moult. PMID:11813543

Sousa, L G; Petriella, A M



Suspension feeding in adult Nephrops norvegicus (L.) and Homarus gammarus (L.) (decapoda)  

NASA Astrophysics Data System (ADS)

Suspension feeding in adults of the Norway lobster Nephrops norvegicus (40-74 g) and the European lobster Homarus gammarus (280-350 g) was tested in experiments offering planktonic food items of different sizes from 200 to 600 ?m and measuring the clearing capacity. Both lobster species were found to effectively clear water of food particles comprising nauplii of the brine shrimp Artemia salina of about 600 ?m in size. These were reduced to 50% of the initial concentration within 5 h and to 90% within 12 h. When N. norvegicus was offered food particles averaging 200 ?m, a significant reduction in average size occurred, indicating that the minimum retention size is around 200 ?m. Fluorescently dyed Artemia salina were recovered in the stomach and intestine of lobsters proving that the filtered particles are passed to the digestive tract. Results from other experiments, using the blood pigment (haemocyanin) concentration as an index of nutritional state, indicated that the lobsters can get some nutritional advantage from suspension feeding. Suspension feeding in larger decapods has not been described previously, so the significance of this finding is discussed with respect to changes in behavioural and ecological role.

Loo, Lars-Ove; Pihl Baden, Susanne; Ulmestrand, Mats


Feeding habits and ontogenetic diet shifts of Bombay duck, Harpadon nehereus  

NASA Astrophysics Data System (ADS)

Based on two bottom trawl surveys conducted in autumn 2000 and 2001, a total of 1106 stomach samples of Bombay duck Harpadon nehereus between 23-278 mm fork length were collected and analyzed. The results show that Bombay duck prey items consisted of 11 groups or 32 species, of which Apogon lineatus, Leptochela gracilis, Acetes chinensis, and Euphausia pacifi ca were the dominant prey species. Ontogenetic variations were found in feeding habits and feeding activity of Bombay duck. Feeding activity was highest in fish smaller than 50 mm, lowest in fish between 50 and 99 mm, and then increased with increasing size thereafter. As Bombay duck size increased, fish prey increased in importance, whereas euphausiids and decapods decreased in importance. Different trophic guilds were observed in feeding habits across the examined size range. Bombay duck smaller than 50 mm were zooplanktivores, mainly feeding on zooplankton and fish larva; those between 50 and 149 mm were generalist predators, mainly feeding on pelagic shrimps, demersal shrimps and fishes; and those larger than 150 mm were piscivores, mainly feeding on fishes.

Zhang, Bo; Jin, Xianshi



Depth zonation and bathymetric trends of deep-sea megafaunal scavengers of the Hawaiian Islands  

NASA Astrophysics Data System (ADS)

The deep sea has been shown to exhibit strong depth zonation in species composition and abundance. Examination of these patterns can offer ecological insight into how organisms adapt and respond to changing environmental parameters that co-occur with depth. Here we provide the first tropical study on bathymetric zonation and other depth-related trends (size, abundance, and species richness) spanning shelf to abyssal depths of scavenging megafauna. Baited time-lapse free-vehicle cameras were used to examine the deep-sea benthic and demersal scavenging communities of the Hawaiian Islands, an area for which the biology and ecology have remained poorly studied below 2000 m. Twenty-two deployments ranging in depth from 250 to 4783 m yielded 37 taxa attracted to bait, including the first known occurrence of the family Zoarcidae in the Hawaiian Islands. Cluster analysis of Bray-Curtis similarity of species peak abundance ( nmax) revealed four main faunal zones (250-500, 1000, 1500-3000, and ?4000 m) with significant separation (ANOSIM, global R=0.907, p=0.001) between designated depth groups. A major faunal break was identified at the 500-1000 m transition where species turnover was greatest, coinciding with the location of the local oxygen minimum zone. Dominance in species assemblage shifted from decapod crustaceans to teleosts moving from shallow to deeper faunal zones. Significant size differences in total length with depth were found for two of the four fish species examined. A logarithmic decline was observed in scavenger relative abundance with depth. Evidence of interaction between scavenging species was also noted between Synaphobranchus affinis and Neolithodes sp. (competition) and Histiobranchus sp. and aristeid shrimp (predation), suggesting that interactions between scavengers could influence indices of abundance generated from baited camera data.

Yeh, John; Drazen, Jeffrey C.



Reproductive biology and recruitment of the deep-sea fish community from the NW Mediterranean continental margin  

NASA Astrophysics Data System (ADS)

Temporal patterns in deep-sea fish reproduction are presently unknown for the majority of deep continental margins. A series of seasonal trawling surveys between depths of 300 to 1750 m in the Blanes submarine canyon and its adjacent open slope (NW Mediterranean) were conducted. The bathymetric size distributions and reproductive cycles of the most abundant species along the NW Mediterranean margin were analyzed to assess the occurrence of (i) temporal patterns in reproduction (i.e., spawning season) along a bathymetric gradient and (ii) preferential depth strata for recruitment. The fish assemblages were grouped in relation to their bathymetric distribution: upper slope, middle slope and lower slope species. Middle-slope species (i.e., 800-1350 m) showed short (i.e., highly seasonal) reproductive activity compared to the upper (300-800 m) and lower (1350-1750 m) ones. Our results, together with those previously published for megabenthic crustacean decapods in the area, suggest a cross-phyla depth-related trend of seasonality in reproduction. In the middle and lower slope species, the reproductive activity reached a maximum in the autumn-winter months and decreased in the spring. The observed seasonal spawning patterns appear to be ultimately correlated with changes in the downward transport of organic particles and with seasonal changes in the physicochemical characteristics of the surrounding water masses. The distribution of juveniles was associated with the bathymetric stratum where intermediate nepheloid layers interact with the continental margins, indicating that this stratum acts as a deep-sea fish nursery area.

Fernandez-Arcaya, U.; Rotllant, G.; Ramirez-Llodra, E.; Recasens, L.; Aguzzi, J.; Flexas, M. M.; Sanchez-Vidal, A.; López-Fernández, P.; García, J. A.; Company, J. B.



Molecular characterization of three crustin genes in the morotoge shrimp, Pandalopsis japonica.  


Crustins are among the most important antimicrobial peptides (AMPs) found in decapod crustaceans. They are small cationic AMPs (5-7 kDa) characterized by a proline-rich amino-terminal domain and a cysteine-rich carboxyl-terminal domain. Here, the first 3 crustin-like cDNAs (Pj-crus Ia, Ib, and II) were identified from the morotoge shrimp, Pandalopsis japonica. The full-length cDNAs of Pj-crus Ia, Ib, and II consisted of 1135, 580, and 700 nucleotides and encoded putative proteins containing 109, 119, and 186 amino acids residues, respectively. All 3 identified Pj-crus sequences exhibited the conserved domain organization for crustins, including a signal sequence, a cysteine-containing region, a glycine-rich region, and a whey-acidic protein (WAP) domain. Amino acid sequence comparisons and phylogenetic analysis revealed that the Pj-crus Ia and Ib belong to type I crustins (e.g., carcinin), which have been mostly identified from Brachyura and Astacidea, whereas Pj-crus II was classified as belonging to the type II crustins, which are mainly found in Dendrobranchiata. An analysis of the organization of these 3 Pj-crus genes revealed that the splicing site within the WAP domain may be an important key for classifying types I and II crustin family members. The tissue distribution profile results showed that the Pj-crus I genes were expressed in a tissue-specific manner but that the Pj-crus II gene was expressed ubiquitously, suggesting that these crustins may play different roles in various tissues or under different physiological conditions. The bacterial challenge results suggested that the Pj-crus genes may be transcriptionally influenced by different bacterial types. This comparative study of various crustin family members will help extend the knowledge on the crustacean innate immune response, which will provide important basic information for controlling shrimp immunity against various pathogens. PMID:22613817

Kim, MeeSun; Jeon, Jeong-Min; Oh, Chul-Woong; Kim, Young Mog; Lee, Dae Sung; Kang, Chang-Keun; Kim, Hyun-Woo



Transcriptome Analysis of the Oriental River Prawn, Macrobrachium nipponense Using 454 Pyrosequencing for Discovery of Genes and Markers  

PubMed Central

Background The oriental river prawn, Macrobrachium nipponense, is an economically and nutritionally important species of the Palaemonidae family of decapod crustaceans. To date, the sequencing of its whole genome is unavailable as a non-model organism. Transcriptomic information is also scarce for this species. In this study, we performed de novo transcriptome sequencing to produce the first comprehensive expressed sequence tag (EST) dataset for M. nipponense using high-throughput sequencing technologies. Methodology and Principal Findings Total RNA was isolated from eyestalk, gill, heart, ovary, testis, hepatopancreas, muscle, and embryos at the cleavage, gastrula, nauplius and zoea stages. Equal quantities of RNA from each tissue and stage were pooled to construct a cDNA library. Using 454 pyrosequencing technology, we generated a total of 984,204 high quality reads (338.59Mb) with an average length of 344 bp. Clustering and assembly of these reads produced a non-redundant set of 81,411 unique sequences, comprising 42,551 contigs and 38,860 singletons. All of the unique sequences were involved in the molecular function (30,425), cellular component (44,112) and biological process (67,679) categories by GO analysis. Potential genes and their functions were predicted by KEGG pathway mapping and COG analysis. Based on our sequence analysis and published literature, many putative genes involved in sex determination, including DMRT1, FTZ-F1, FOXL2, FEM1 and other potentially important candidate genes, were identified for the first time in this prawn. Furthermore, 6,689 SSRs and 18,107 high-confidence SNPs were identified in this EST dataset. Conclusions The transcriptome provides an invaluable new data for a functional genomics resource and future biological research in M. nipponense. The molecular markers identified in this study will provide a material basis for future genetic linkage and quantitative trait loci analyses, and will be essential for accelerating aquaculture breeding programs with this species.

Ma, Keyi; Qiu, Gaofeng; Feng, Jianbin; Li, Jiale



Cross-shelf transport of pink shrimp larvae: Interactions of tidal currents, larval vertical migrations and internal tides  

USGS Publications Warehouse

Transport and behavior of pink shrimp Farfantepenaeus duorarum larvae were investigated on the southwestern Florida (SWF) shelf of the Gulf of Mexico between the Dry Tortugas spawning grounds and Florida Bay nursery grounds. Stratified plankton samples and hydrographic data were collected at 2 h intervals at 3 stations located on a cross-shelf transect. At the Marquesas station, midway between Dry Tortugas and Florida Bay, internal tides were recognized by anomalously cool water, a shallow thermocline with strong density gradients, strong current shear, and a high concentration of pink shrimp larvae at the shallow thermocline. Low Richardson numbers occurred at the pycnocline depth, indicating vertical shear instability and possible turbulent transport from the lower to the upper layer where myses and postlarvae were concentrated. Analysis of vertically stratified plankton suggested that larvae perform vertical migrations and the specific behavior changes ontogenetically; protozoeae were found deeper than myses, and myses deeper than postlarvae. Relative concentrations of protozoea in the upper, middle and bottom layers were consistent with a diel vertical migration, whereas that of postlarvae and myses were consistent with the semidiurnal tides in phase with the flood tide. Postlarvae, the shallowest dwellers that migrate with a semidiurnal periodicity, experienced the largest net onshore flux and larval concentrations were highly correlated with the cross-shelf current. These results provide the first evidence of an onshore tidal transport (a type of selective tidal stream transport, STST), in decapod larvae migrating in continental shelf waters offshore, ca. 100 km from the coast and at a depth of 20 m, while approaching the coastal nursery grounds. Longer time series would be necessary to establish whether internal tides play any role in the larval onshore transport of this species and determine if the STST is the dominant onshore transport mechanism. ?? Inter-Research 2007 .

Criales, M. M.; Browder, J. A.; Mooers, C. N. K.; Robblee, M. B.; Cardenas, H.; Jackson, T. L.



Proteomics and signal transduction in the crustacean molting gland.  


Regulation of the molting cycle in decapod crustaceans involves 2 endocrine organs: the X-organ/sinus gland (XO/SG) complex located in the eyestalk ganglia and the Y-organ (YO) located in the cephalothorax. Two neuropeptides [molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH)] are produced in the XO/SG complex and inhibit ecdysteroidogenesis in the YO. Thus, YO activation is induced by eyestalk ablation (ESA), which removes the primary source of MIH and CHH. Cyclic nucleotides (cAMP and cGMP) and nitric oxide (NO) appear to mediate neuropeptide suppression of the YO. Proteomics was used to identify potential components of signal transduction pathways ("targeted" or cell-map proteomics) as well as assess the magnitude of protein changes in response to activation ("global" or expression proteomics) in the tropical land crab, Gecarcinus lateralis. Total proteins in YOs from intact and ES-ablated animals were separated by two-dimensional gel electrophoresis and expression profiles were assessed by image analysis and gene clustering software. ESA caused a >3-fold increase in the levels of 170 proteins and >3-fold decrease in the levels of 89 proteins; a total of 543 proteins were quantified in total YO extracts. ESA induced significant changes in the levels of 3 groups of proteins eluting from a phosphoprotein column and detected with phosphoprotein staining of two-dimensional gels; ?17 kDa and ?150 kDa phosphoproteins increased in activated YOs, while ?12 kDa phosphoproteins decreased. A ?150 kDa phosphoprotein, which was isolated only from activated YO, was identified as NO synthase by western blotting and mass spectrometry of trypsin peptides. These data show that phosphorylation of NO synthase is associated with activation of the YO. A neuropeptide signaling pathway involving NO synthase and NO-sensitive guanylyl cyclase is proposed. PMID:21672800

Lee, Sung Gu; Mykles, Donald L



Molecular characterization of an ecdysone inducible gene E75 of Chinese shrimp Fenneropenaeus chinensis and elucidation of its role in molting by RNA interference.  


Ecdysone inducible gene, E75 is a primary target of ecdysone receptor (EcR), and is found to play a critical role in the molting process of arthropods. In this study, a cDNA encoding the E75 of Chinese shrimp Fenneropenaeus chinensis (FcE75) was cloned using RT-PCR and RACE techniques. FcE75 cDNA was 3611bp in length with an ORF of 2394bp. The deduced amino acid sequence of FcE75 had the highest sequence identity to E75 from a land crab Gecarcinus lateralis and E75 of the shrimp Metapenaeus ensis. Quantitative real-time PCR revealed a prominently high expression of FcE75 mRNA in the whole body RNA extract of late premolt period (D3) juvenile shrimp. The role of E75 in the process of shrimp molting was investigated using the RNA interference technique. Long double-stranded RNA corresponding to the FcE75 (dsE75) efficiently silenced the FcE75 transcript levels in juvenile F. chinensis. Further, injection with dsE75 completely arrested the molting process in experimental shrimp which eventually caused death. Setogenic analysis of the uropods from molt-arrested shrimp, showed defective epidermal retraction, poor development of setae and new cuticle. These results indicate that E75 might be related to the molting process and is essential for proper molting and survival of shrimp. This is the first report demonstrating the use of double stranded RNA to elucidate the possible role of E75 in the molting of decapod crustaceans. PMID:20184963

Priya, T A Jose; Li, Fuhua; Zhang, Jiquan; Yang, Changjian; Xiang, Jianhai



Ubiquitin and actin expression in claw muscles of land crab, Gecarcinus lateralis, and American lobster, Homarus americanus: differential expression of ubiquitin in two slow muscle fiber types during molt-induced atrophy.  


The closer muscle of large-clawed decapod crustaceans undergoes a proecdysial (premolt) atrophy to facilitate withdrawal of the appendage at ecdysis. This atrophy involves the activation of both calcium-dependent (calpains) and ubiquitin (Ub)/proteasome-dependent proteolytic systems that break down proteins to reduce muscle mass. Moreover, the large slow-twitch (S(1)) fibers undergo a greater atrophy than the small slow-tonic (S(2)) fibers. Both polyUb mRNA and Ub-protein conjugates increase during claw muscle atrophy. In this study in situ hybridization and RT-PCR were used to determine the temporal and spatial expression of polyUb and alpha-actin. A cDNA encoding the complete sequence of lobster muscle alpha-actin was characterized; a probe synthesized from the cDNA provided a positive control for optimizing RT-PCR and in situ hybridization. PolyUb was expressed at low levels in claw closer muscle from anecdysial (intermolt) land crab. By early proecdysis (premolt; stage D(0)), polyUb mRNA levels increased in medial fibers that insert along the midline of the apodeme, with greater expression in S(1) than S(2), while levels remained low in peripheral fibers. By late proecdysis, polyUb mRNA decreased in central fibers, while mRNA increased in peripheral S(1) fibers. In contrast, alpha-actin was expressed in lobster claw muscles at relatively constant levels during the intermolt cycle. These results suggest that Ub/proteasome-dependent proteolysis contributes to enhanced turnover of myofibrillar proteins during claw closer muscle atrophy. Furthermore, atrophy is not synchronous within the muscle; it begins in medial fibers and then progresses peripherally. PMID:12115927

Koenders, Annette; Yu, Xiaoli; Chang, Ernest S; Mykles, Donald L



Epi-benthic megafaunal zonation across an oxygen minimum zone at the Indian continental margin  

NASA Astrophysics Data System (ADS)

The Arabian Sea oxygen minimum zone (OMZ) impinges upon the Indian continental margin at bathyal depths (150-1500 m) producing changes in ambient oxygen availability and sediment geochemistry across the seafloor. The influence of these environmental changes upon the epi-benthic megafaunal assemblage was investigated by video survey at six stations spanning the OMZ core (540 m), lower boundary (800-1100 m) and below the OMZ (2000 m), between September and November 2008. Structural changes in the megafaunal assemblage were observed across the six stations, through changes in both megafaunal abundance and lebensspuren (biogenic traces). Most megafauna were absent in the OMZ core (540 m), where the assemblage was characterised by low densities of fishes (0.02-0.03 m -2). In the lower OMZ boundary, megafaunal abundance peaked at 800 m, where higher densities of ophiuroids (0.20-0.44 m -2) and decapods (0.11-0.15 m -2) were present. Total abundance declined with depth between 800 and 2000 m, as the number of taxa increased. Changes in the megafaunal assemblage were predicted by changes in abundance of seven taxonomic groups, correlated to both oxygen availability and sediment organic matter quality. Lebensspuren densities were highest in the OMZ boundary (800-1100 m) but traces of large infauna (e.g., echiurans and enteropneusts) were only observed between 1100 and 2000 m station, where the influence of the OMZ was reduced. Thus, changes in the megafaunal assemblage across the Indian margin OMZ reflect the responses of specific taxa to food availability and oxygen limitation.

Hunter, William R.; Oguri, Kazumasa; Kitazato, Hiroshi; Ansari, Zakir A.; Witte, Ursula



Climate Change and Trophic Response of the Antarctic Bottom Fauna  

PubMed Central

Background As Earth warms, temperate and subpolar marine species will increasingly shift their geographic ranges poleward. The endemic shelf fauna of Antarctica is especially vulnerable to climate-mediated biological invasions because cold temperatures currently exclude the durophagous (shell-breaking) predators that structure shallow-benthic communities elsewhere. Methodology/Principal Findings We used the Eocene fossil record from Seymour Island, Antarctic Peninsula, to project specifically how global warming will reorganize the nearshore benthos of Antarctica. A long-term cooling trend, which began with a sharp temperature drop ?41 Ma (million years ago), eliminated durophagous predators—teleosts (modern bony fish), decapod crustaceans (crabs and lobsters) and almost all neoselachian elasmobranchs (modern sharks and rays)—from Antarctic nearshore waters after the Eocene. Even prior to those extinctions, durophagous predators became less active as coastal sea temperatures declined from 41 Ma to the end of the Eocene, ?33.5 Ma. In response, dense populations of suspension-feeding ophiuroids and crinoids abruptly appeared. Dense aggregations of brachiopods transcended the cooling event with no apparent change in predation pressure, nor were there changes in the frequency of shell-drilling predation on venerid bivalves. Conclusions/Significance Rapid warming in the Southern Ocean is now removing the physiological barriers to shell-breaking predators, and crabs are returning to the Antarctic Peninsula. Over the coming decades to centuries, we predict a rapid reversal of the Eocene trends. Increasing predation will reduce or eliminate extant dense populations of suspension-feeding echinoderms from nearshore habitats along the Peninsula while brachiopods will continue to form large populations, and the intensity of shell-drilling predation on infaunal bivalves will not change appreciably. In time the ecological effects of global warming could spread to other portions of the Antarctic coast. The differential responses of faunal components will reduce the endemic character of Antarctic subtidal communities, homogenizing them with nearshore communities at lower latitudes.

Aronson, Richard B.; Moody, Ryan M.; Ivany, Linda C.; Blake, Daniel B.; Werner, John E.; Glass, Alexander



Morphology and Histochemistry of the Aesthetasc-Associated Epidermal Glands in Terrestrial Hermit Crabs of the Genus Coenobita (Decapoda: Paguroidea)  

PubMed Central

Crustaceans have successfully adapted to a variety of environments including fresh- and saltwater as well as land. Transition from an aquatic to a terrestrial lifestyle required adaptations of the sensory equipment of an animal, particularly in olfaction, where the stimulus itself changes from hydrophilic to mainly hydrophobic, air-borne molecules. Hermit crabs Coenobita spp. (Anomura, Coenobitidae) have adapted to a fully terrestrial lifestyle as adults and have been shown to rely on olfaction in order to detect distant food items. We observed that the specialized olfactory sensilla in Coenobita, named aesthetascs, are immersed in a layer of mucous-like substance. We hypothesized that the mucous is produced by antennal glands and affects functioning of the aesthetascs. Using various microscopic and histochemical techniques we proved that the mucous is produced by aesthetasc-associated epidermal glands, which we consider to be modified rosette-type aesthetasc tegumental glands known from aquatic decapods. These epidermal glands in Coenobita are multicellular exocrine organs of the recto-canal type with tubulo-acinar arrangement of the secretory cells. Two distinct populations of secretory cells were clearly distinguishable with light and electron microscopy. At least part of the secretory cells contains specific enzymes, CUB-serine proteases, which are likely to be secreted on the surface of the aesthetasc pad and take part in antimicrobial defense. Proteomic analysis of the glandular tissue corroborates the idea that the secretions of the aesthetasc-associated epidermal glands are involved in immune responses. We propose that the mucous covering the aesthetascs in Coenobita takes part in antimicrobial defense and at the same time provides the moisture essential for odor perception in terrestrial hermit crabs. We conclude that the morphological modifications of the aesthetasc-associated epidermal glands as well as the functional characteristics of their secretions are important adaptations to a terrestrial lifestyle.

Muller, Carsten H. G.; Wielsch, Natalie; Hupfer, Yvonne; Svatos, Ales; Grosse-Wilde, Ewald; Hansson, Bill S.



Phylogeny and evolutionary patterns in the Dwarf crayfish subfamily (Decapoda: Cambarellinae).  


The Dwarf crayfish or Cambarellinae, is a morphologically singular subfamily of decapod crustaceans that contains only one genus, Cambarellus. Its intriguing distribution, along the river basins of the Gulf Coast of United States (Gulf Group) and into Central México (Mexican Group), has until now lacked of satisfactory explanation. This study provides a comprehensive sampling of most of the extant species of Cambarellus and sheds light on its evolutionary history, systematics and biogeography. We tested the impact of Gulf Group versus Mexican Group geography on rates of cladogenesis using a maximum likelihood framework, testing different models of birth/extinction of lineages. We propose a comprehensive phylogenetic hypothesis for the subfamily based on mitochondrial and nuclear loci (3,833 bp) using Bayesian and Maximum Likelihood methods. The phylogenetic structure found two phylogenetic groups associated to the two main geographic components (Gulf Group and Mexican Group) and is partially consistent with the historical structure of river basins. The previous hypothesis, which divided the genus into three subgenera based on genitalia morphology was only partially supported (P?=?0.047), resulting in a paraphyletic subgenus Pandicambarus. We found at least two cases in which phylogenetic structure failed to recover monophyly of recognized species while detecting several cases of cryptic diversity, corresponding to lineages not assigned to any described species. Cladogenetic patterns in the entire subfamily are better explained by an allopatric model of speciation. Diversification analyses showed similar cladogenesis patterns between both groups and did not significantly differ from the constant rate models. While cladogenesis in the Gulf Group is coincident in time with changes in the sea levels, in the Mexican Group, cladogenesis is congruent with the formation of the Trans-Mexican Volcanic Belt. Our results show how similar allopatric divergence in freshwater organisms can be promoted through diverse vicariant factors. PMID:23155379

Pedraza-Lara, Carlos; Doadrio, Ignacio; Breinholt, Jesse W; Crandall, Keith A



Cytoarchitecture and Ultrastructure of Neural Stem Cell Niches and Neurogenic Complexes Maintaining Adult Neurogenesis in the Olfactory Midbrain of Spiny Lobsters, Panulirus argus  

PubMed Central

New interneurons are continuously generated in small proliferation zones within neuronal somata clusters in the olfactory deutocerebrum of adult decapod crustaceans. Each proliferation zone is connected to a clump of cells containing one neural stem cell (i.e., adult neuroblast), thus forming a “neurogenic complex.” Here we provide a detailed analysis of the cytoarchitecture of neurogenic complexes in adult spiny lobsters, Panulirus argus, based on transmission electron microscopy and labeling with cell-type-selective markers. The clump of cells is composed of unique bipolar clump-forming cells that collectively completely envelop the adult neuroblast and are themselves ensheathed by a layer of processes of multipolar cell body glia. An arteriole is attached to the clump of cells, but dye perfusion experiments show that hemolymph has no access to the interior of the clump of cells. Thus, the clump of cells fulfills morphological criteria of a protective stem cell niche, with clump-forming cells constituting the adult neuroblast’s microenvironment together with the cell body glia processes separating it from other tissue components. Bromodeoxyuridine pulse-chase experiments with short survival times suggest that adult neuroblasts are not quiescent but rather cycle actively during daytime. We propose a cell lineage model in which an asymmetrically dividing adult neuroblast repopulates the pool of neuronal progenitor cells in the associated proliferation zone. In conclusion, as in mammalian brains, adult neurogenesis in crustacean brains is fueled by neural stem cells that are maintained by stem cell niches that preserve elements of the embryonic microenvironment and contain glial and vascular elements.

Schmidt, Manfred; Derby, Charles D.



The Fauna Of Two New Discovered Hydrothermal Fields At 5°S And 9°33'S On The Mid-Atlantic-Ridge  

NASA Astrophysics Data System (ADS)

Before April 2005 there was a zoogeographical puzzle to solve: Are there any hydrothermal vent communities south of the equator the Atlantic Ocean, and if so, what will be their characteristics? Are they similar with those of the northern Atlantic Ocean or will they differ? Before the cruise 169 of the British "Charles Darwin" research vessel started, no vent site was discovered on the southern Atlantic Ridge. Using an autonomous underwater vehicle from WHOI, the first hydrothermal active vent site was found at 5°S in April 2005. With the support by British and American colleagues(Chris German and Tim Shank) the scientific crew of Meteor cruise M64/1 sampled this site at 5° first with the ROV "Quest 4000" from Marum, University Bremen. But far in excess of this success one more vent site was discovered and investigated by the Meteor cruise M64/1: the Lilliput Field at 9°33S on the Mid-Atlantic-Ridge. Our first results indicate that the identified taxa of the hydrothermal fields at 5°S and 9°33S resemble the northern Logatchev community (Gebruk et al. 2000) in most elements. Remarkable is the missing of following typical hydrothermal taxa: Decapods of the families Alvinocaridae, like Chorocaris, and Galatheidae, echinoderms like Ophiuridae and Ventfishes of the family Zoarcidae. Obviously the Romanch Fracture Zone act only partly as a physical barrier between vent fauna assemblages of the North and South Atlantic Oceans (see Shank 2004). Gebruk, A.V., Chevaldonne, P., Shank, T., Lutz, R.A. & Vrijenhoek, R.C. (2000): Deep-sea hydrothermal vent communities of the Logatchev area (14°45'N, Mid-Atlantic Ridge): diverse biotopes and high biomass. J. Mar. Biol. Assoc. U. K. 80: 383-393. Shank, T. (2004): The evolutionary puzzle of seafloor life. - Oceanus Magazine Vol. 42, No.2

Stecher, J. E.



Diversity and Distribution of Deep-Sea Shrimps in the Ross Sea Region of Antarctica  

PubMed Central

Although decapod crustaceans are widespread in the oceans, only Natantia (shrimps) are common in the Antarctic. Because remoteness, depth and ice cover restrict sampling in the South Ocean, species distribution modelling is a useful tool for evaluating distributions. We used physical specimen and towed camera data to describe the diversity and distribution of shrimps in the Ross Sea region of Antarctica. Eight shrimp species were recorded: Chorismus antarcticus; Notocrangon antarcticus; Nematocarcinus lanceopes; Dendrobranchiata; Pasiphaea scotiae; Pasiphaea cf. ledoyeri; Petalidium sp., and a new species of Lebbeus. For the two most common species, N. antarcticus and N. lanceopes, we used maximum entropy modelling, based on records of 60 specimens and over 1130 observations across 23 sites in depths from 269 m to 3433 m, to predict distributions in relation to environmental variables. Two independent sets of environmental data layers at 0.05° and 0.5° resolution respectively, showed how spatial resolution affected the model. Chorismus antarcticus and N. antarcticus were found only on the continental shelf and upper slopes, while N. lanceopes, Lebbeus n. sp., Dendrobranchiata, Petalidium sp., Pasiphaea cf. ledoyeri, and Pasiphaea scotiae were found on the slopes, seamounts and abyssal plain. The environmental variables that contributed most to models for N. antarcticus were depth, chlorophyll-a concentration, temperature, and salinity, and for N. lanceopes were depth, ice concentration, seabed slope/rugosity, and temperature. The relative ranking, but not the composition of these variables changed in models using different spatial resolutions, and the predicted extent of suitable habitat was smaller in models using the finer-scale environmental layers. Our modelling indicated that shrimps were widespread throughout the Ross Sea region and were thus likely to play important functional role in the ecosystem, and that the spatial resolution of data needs to be considered both in the use of species distribution models.

Basher, Zeenatul; Bowden, David A.; Costello, Mark J.



Mobile demersal megafauna at artificial structures in the German Bight - Likely effects of offshore wind farm development  

NASA Astrophysics Data System (ADS)

Within the next few decades, large underwater structures of thousands of wind turbines in the northern European shelf seas will substantially increase the amount of habitat available for mobile demersal megafauna. As a first indication of the possible effects of this large scale habitat creation on faunal stocks settling on hard substrata, we compared selected taxa of the mobile demersal megafauna (decapods and fish) associated with the foundation of an offshore research platform (a wind-power foundation equivalent) with those of five shipwrecks and different areas of soft bottoms in the southern German Bight, North Sea. When comparing the amount of approximately 5000 planned wind-power foundations (covering 5.1 × 106 m2 of bottom area) with the existing number of at least 1000 shipwrecks (covering 1.2 × 106 m2 of bottom area), it becomes clear that the southern North Sea will provide about 4.3 times more available artificial hard substratum habitats than currently available. With regard to the fauna found on shipwrecks, on soft substrata and on the investigated wind-power foundation, we predict that the amount of added hard substrata will allow the stocks of substrata-limited mobile demersal hard bottom species to increase by 25-165% in that area. The fauna found at the offshore platform foundations is very similar to that at shipwrecks. Megafauna abundances at the foundations, however, are lower compared to those at the highly fractured wrecks and are irregularly scattered over the foundations. The upper regions of the platform construction (5 and 15 m depth) were only sparsely colonized by mobile fauna, the anchorages, however, more densely. The faunal assemblages from the shipwrecks and the foundations, respectively, as well as from the soft bottoms clearly differed from each other. We predict that new wind-power foundations will support the spread of hard bottom fauna into soft bottom areas with low wreck densities.

Krone, R.; Gutow, L.; Brey, T.; Dannheim, J.; Schröder, A.



Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude  

NASA Astrophysics Data System (ADS)

Phenotypic plasticity is an important but often ignored ability that enables organisms, within species-specific physiological limits, to respond to gradual or sudden extrinsic changes in their environment. In the marine realm, the early ontogeny of decapod crustaceans is among the best known examples to demonstrate a temperature-dependent phenotypic response. Here, we present morphometric results of larvae of the hairy crab Cancer setosus, the embryonic development of which took place at different temperatures at two different sites (Antofagasta, 23°45' S; Puerto Montt, 41°44' S) along the Chilean Coast. Zoea I larvae from Puerto Montt were significantly larger than those from Antofagasta, when considering embryonic development at the same temperature. Larvae from Puerto Montt reared at 12 and 16°C did not differ morphometrically, but sizes of larvae from Antofagasta kept at 16 and 20°C did, being larger at the colder temperature. Zoea II larvae reared in Antofagasta at three temperatures (16, 20, and 24°C) showed the same pattern, with larger larvae at colder temperatures. Furthermore, larvae reared at 24°C, showed deformations, suggesting that 24°C, which coincides with temperatures found during strong EL Niño events, is indicative of the upper larval thermal tolerance limit. C. setosus is exposed to a wide temperature range across its distribution range of about 40° of latitude. Phenotypic plasticity in larval offspring does furthermore enable this species to locally respond to the inter-decadal warming induced by El Niño. Morphological plasticity in this species does support previously reported energetic trade-offs with temperature throughout early ontogeny of this species, indicating that plasticity may be a key to a species’ success to occupy a wide distribution range and/or to thrive under highly variable habitat conditions.

Weiss, Monika; Thatje, Sven; Heilmayer, Olaf



Hematodinium sp. and its bacteria-like endosymbiont in European brown shrimp (Crangon crangon)  

PubMed Central

Background Parasitic dinoflagellates of the genus Hematodinium are significant pathogens affecting the global decapod crustacean fishery. Despite this, considerable knowledge gaps exist regarding the life history of the pathogen in vivo, and the role of free living life stages in transmission to naïve hosts. Results In this study, we describe a novel disease in European brown shrimp (Crangon crangon) caused by infection with a parasitic dinoflagellate of the genus Hematodinium. This is the second example host within the Infraorder Caridea (shrimp) and significantly, the first description within the superfamily Crangonoidea. Based upon analysis of the rRNA gene (SSU) and spacers (ITS1), the parasite in C. crangon is the same as that previously described infecting Nephrops norvegicus and Cancer pagurus from European seas, and to the parasite infecting several other commercially important crab species in the Northern Hemisphere. The parasite is however distinct from the type species, H. perezi, found infecting type hosts (Carcinus maenas and Liocarcinus depurator) from nearby sites within Europe. Despite these similarities, the current study has also described for the first time, a bacteria-like endosymbiont within dinospore stages of the parasite infecting shrimp. The endosymbionts were either contained individually within electron lucent vacuoles within the parasite cell cytoplasm, or remained in direct contact with the parasite cytoplasm or in some cases, the nucleoplasm. In all of these cases, no apparent detrimental effects of colonization were observed within the parasite cell. Conclusions The presence of bacteria-like endosymbionts within dinospore life stages presumes that the relationship between the dinoflagellate and the bacteria is extended beyond the period of liberation of spores from the infected host shrimp. In this context, a potential role of endosymbiosis in the survival of free-living stages of the parasite is possible. The finding offers a further intriguing insight into the life history of this enigmatic pathogen of marine crustacean hosts and highlights a potential for mixotrophy in the parasitic dinoflagellates contained within the genus Hematodinium.



The Global Diversity of Parasitic Isopods Associated with Crustacean Hosts (Isopoda: Bopyroidea and Cryptoniscoidea)  

PubMed Central

Parasitic isopods of Bopyroidea and Cryptoniscoidea (commonly referred to as epicarideans) are unique in using crustaceans as both intermediate and definitive hosts. In total, 795 epicarideans are known, representing ?7.7% of described isopods. The rate of description of parasitic species has not matched that of free-living isopods and this disparity will likely continue due to the more cryptic nature of these parasites. Distribution patterns of epicarideans are influenced by a combination of their definitive (both benthic and pelagic species) and intermediate (pelagic copepod) host distributions, although host specificity is poorly known for most species. Among epicarideans, nearly all species in Bopyroidea are ectoparasitic on decapod hosts. Bopyrids are the most diverse taxon (605 species), with their highest diversity in the North West Pacific (139 species), East Asian Sea (120 species), and Central Indian Ocean (44 species). The diversity patterns of Cryptoniscoidea (99 species, endoparasites of a diverse assemblage of crustacean hosts) are distinct from bopyrids, with the greatest diversity of cryptoniscoids in the North East Atlantic (18 species) followed by the Antarctic, Mediterranean, and Arctic regions (13, 12, and 8 species, respectively). Dajidae (54 species, ectoparasites of shrimp, mysids, and euphausids) exhibits highest diversity in the Antarctic (7 species) with 14 species in the Arctic and North East Atlantic regions combined. Entoniscidae (37 species, endoparasites within anomuran, brachyuran and shrimp hosts) show highest diversity in the North West Pacific (10 species) and North East Atlantic (8 species). Most epicarideans are known from relatively shallow waters, although some bopyrids are known from depths below 4000 m. Lack of parasitic groups in certain geographic areas is likely a sampling artifact and we predict that the Central Indian Ocean and East Asian Sea (in particular, the Indo-Malay-Philippines Archipelago) hold a wealth of undescribed species, reflecting our knowledge of host diversity patterns.

Williams, Jason D.; Boyko, Christopher B.



Reproductive plasticity in Petrolisthes armatus (Anomura, Porcellanidae): a comparison between a Pacific and an Atlantic population  

NASA Astrophysics Data System (ADS)

The porcellanid crab Petrolisthes armatus, with a known geographic distribution covering a wide range of latitudes, was selected to conduct a comparative study on egg production and reproductive output between two populations from Pacific and Atlantic coasts. Ovigerous females were collected between September and November 2005 in Punta Morales, Pacific coast of Costa Rica ( n = 137) and from March 2005 to July 2006 in Araçá region, São Paulo, Brazil ( n = 46). The mean size of females was statistically different between both populations with larger females from Brazil than Costa Rica (7.9 ± 1.31 and 6.6 ± 0.95 mm CW, respectively). Likewise, egg production was significantly different in both populations and started in Pacific Costa Rica at a smaller female size than in Brazil. Specimens from Pacific Costa Rica produced roughly three times more eggs than equally sized females from Brazil, while newly extruded embryos were larger in Brazil than in Costa Rica (0.045 and 0.039 mm3, respectively). Egg volume increased during embryogenesis by 112.8 and 164.5% in Costa Rican and Brazilian populations, respectively. The egg water content increased steadily in both populations; however, eggs produced in Brazil contained always more water than those from the same developmental stage in Costa Rica. Average reproductive output (based on dry weight) was substantially lower in Brazil (0.031) than in Costa Rica (0.065). Our results confirm an impressive intraspecific plasticity of reproductive features in an intertidal decapod. The observed phenotypical variability might be related to local environmental conditions as well as to the location of the studied population concerning its geographic range of distribution.

Wehrtmann, Ingo S.; Miranda, Ivana; Lizana-Moreno, Claudia A.; Hernáez, Patricio; Barrantes-Echandi, Vera; Mantelatto, Fernando L.



Identifying exoskeleton proteins in the blue crab from an expressed sequence tag (EST) library.  


A blue crab (Callinectes sapidus) expressed sequence tag project was designed for multiple purposes including discovery of genes for cuticular (exoskeletal) proteins, some of which may regulate mineralization. One of the expression libraries sequenced was from the hypodermis (the epithelium depositing the cuticle). RNAs used for cDNA synthesis were pooled from arthrodial and mid-dorsal hypodermis at both pre-ecdysis and post-ecdysis. This ensured representation from both calcifying and non-calcifying regions and from layers of cuticle deposited both before and after ecdysis. The EST database was mined for cuticular protein sequences in three ways. First, we searched for sequences coding for known cuticle-specific motifs like the Rebers-Riddiford chitin-binding sequence and a motif known only from proteins extracted from mineralized exoskeletons of other decapods. Second, we checked the associated annotations in the EST project for similarity to known cuticular proteins, often from insects. Third, BLAST was used to search the EST data for significant homology to published cuticular protein sequences from other crustaceans. In all, the database contains at least 73 contigs or singlets representing transcripts of cuticular proteins. Forty-five of these distribute among ten clusters of very similar transcripts, possibly representing alternative splicing or recent gene duplications. The rest share less similarity. We have obtained complete sequences for 25 of the transcripts, have produced phylogenetics trees comparing them with similar proteins from insects and other crustaceans, and have determined expression patterns across the molt in calcifying versus non-calcifying cuticle. The combination of homology analysis and gene expression analysis allows us to infer putative functions in cuticle synthesis and calcification. PMID:21672801

Shafer, Thomas H; McCartney, Michael A; Faircloth, Lindsay M



Pyloric neuron morphology in the stomatogastric ganglion of the lobster, Panulirus interruptus.  


The pyloric network of decapod crustaceans has been intensively studied electrophysiologically in the infraorders Astacidea, Brachyura, and Palinura. The morphology of some or all pyloric neurons has been well described in Astacidea and Brachyura, but less so in Palinura. Given the large evolutionary distance between these three groups, and the large amount of electrophysiology that has been performed in palinuroid species, it is important to fill this gap. We describe here the gross morphology of all six pyloric neuron types in a palinuroid, P. interruptus. All pyloric neurons had complicated, extended dendritic trees that filled the majority of the neuropil, with most small diameter processes present in a shell near the surface of the ganglion. Certain neuron types showed modest preferences for somata location in the ganglion, but these differences were too weak to use as identifying characteristics. Quantitative measurements of secondary branch number, maximum branch order, total process length, and neuron somata diameter were also, in general, insufficient to distinguish among the neurons, although AB and LP neuron somata diameters differed from those of the other types. One neuron type (VD) had a distinctive neurite branching pattern consisting of a small initial branch followed shortly by a bifurcation of the main neurite. The processes arising from these two branches occupied largely non-overlapping neuropil. Electrophysiological recordings showed that each major branch had its own spike initiation zone and that, although the zones fired correlated spikes, they generated spikes independently. VD neurons in the other infraorders have similar morphologies, suggesting that having two arbors is important for the function of this neuron. These data are similar to those previously obtained in Brachyura and Astacidea. It thus appears that, despite their long evolutionary separation, neuron morphology in these three infraorders has not greatly diverged. PMID:19223685

Thuma, Jeffrey B; White, William E; Hobbs, Kevin H; Hooper, Scott L



Prediction of the first neuropeptides from a member of the Remipedia (Arthropoda, Crustacea).  


The Remipedia is a small, recently described crustacean class that inhabits submerged marine/anchialine cave systems. Phylogenetic and morphological investigations support a sister group relationship between these animals and the hexapods. The recent deposition of numerous (>100,000) transcriptome shotgun assembly sequences for Speleonectes cf. tulumensis provides a unique resource to identify proteins of interest from a member of the Remipedia. Here, this dataset was mined for sequences encoding putative neuropeptide pre/preprohormones, with the mature peptides predicted from the deduced precursors using an established workflow. The structures of 40 mature peptides were obtained via this strategy, including members of 11 well-known arthropod peptide families (adipokinetic hormone/corazonin-like peptide [ACP], allatostatin A, allatostatin C, diuretic hormone 31, eclosion hormone, ion transport peptide/crustacean hyperglycemic hormone, neuropeptide F, proctolin, SIFamide, sulfakinin and tachykinin-related peptide); these are the only peptides thus far described from any member of the Remipedia. Comparison of the Speleonectes isoforms with those from other crustaceans and hexapods revealed the peptidome of this species to have characteristics of both subphyla (e.g. it possesses the stereotypical decapod crustacean SIFamide and tachykinin-related peptide isoforms, while simultaneously being the only crustacean with an insect AKC). Moreover, BLAST searches in which the deduced Speleonectes precursors were compared to the pancrustacean protein database most frequently returned insect homologs as the closest matches. The peptidomic analyses presented here are consistent with the hypothesized phylogenetic position of the Remipedia within the Pancrustacea, and serve as a foundation from which to launch future investigations of peptidergic signaling in remipedes. PMID:24530630

Christie, Andrew E



Birth, survival and differentiation of neurons in an adult crustacean brain.  


Life-long neurogenesis is a characteristic feature of many vertebrate and invertebrate species. In decapod crustaceans, new neurons are added throughout life to two cell clusters containing local (cluster 9) and projection (cluster 10) interneurons in the olfactory pathway. Adult-born neurons in clusters 9 and 10 in crayfish have the anatomical properties and chemistry of mature neurons by 6 months after birth. Here we use 5-bromo-2'-deoxyuridine (BrdU) incorporation to pulse label mitotically active cells in these cell clusters, followed by a survival time of up to 8 months, during which crayfish (Cherax destructor) were sacrificed at intervals and the numbers of BrdU-labeled cells quantified. We find a decrease in the numbers of BrdU-labeled cells in cell cluster 10 between the first and second weeks following BrdU exposure, suggesting a period of cell death shortly after proliferation. Additional delayed cell divisions in both cell clusters are indicated by increases in labeled cells long after the BrdU clearing time. The differentiation time of these cells into neurons was defined by detection of the first immunoreactivity for the transmitter SIFamide in cluster 10 BrdU-labeled cells, which begins at 4 weeks after BrdU labeling; the numbers of SIFamide-labeled cells continues to increase over the following month. Experiments testing whether proliferation and survival of Cluster 10 cells are influenced by locomotor activity provided no evidence of a correlation between activity levels and cell proliferation, but suggest a strong influence of locomotor activity on cell survival. PMID:24339155

Kim, Youngmi Faith; Sandeman, David C; Benton, Jeanne L; Beltz, Barbara S



Retinal anatomy of a new species of bresiliid shrimp from a hydrothermal vent field on the Mid-Atlantic Ridge.  


A new species of shrimp (Rimicaris sp.) was recently collected from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge. Until the discovery in 1989 that the deep-sea, hydrothermal vent species, Rimicaris exoculata, possessed a hypertrophied dorsal eye, everyone believed that animals recovered from vent environments were blind. Like R. exoculata, Rimicaris sp., a small orange bresiliid shrimp, has an enlarged dorsal eye specialized for detecting light in a very dim environment instead of the expected compound eye. The individual lenses characteristic of a compound eye adapted for imaging have been replaced in Rimicaris sp. by a smooth cornea underlain by a massive array of photosensitive membrane. The number of ommatidia in this species is about the same as in shrimp species that live at the surface; however, the photoreceptors are larger in the deep-sea species and the shape of the photoreceptors is markedly different. The light-sensitive region of the photoreceptor is much larger than those of other shrimp and the rest of the receptor is much smaller than normal. All screening pigment has moved out of the path of incident light to a position below the retina, and the reflecting pigment cells have adapted to form a bright white diffusing screen between and behind the photoreceptors. The ultrastructure of the microvillar array comprising the rhabdom is typical for decapod crustaceans; however, there is a much greater volume density of rhabdom (80% to 85%) than normal. There is no ultrastructural evidence for cyclic rhabdom shedding or renewal. Rimicaris sp. has apparently adapted its visual system to detect the very dim light emitted from the throats of the black smoker chimneys around which it lives. PMID:8852633

Nuckley, D J; Jinks, R N; Battelle, B A; Herzog, E D; Kass, L; Renninger, G H; Chamberlain, S C



Diversity and distribution of deep-sea shrimps in the ross sea region of antarctica.  


Although decapod crustaceans are widespread in the oceans, only Natantia (shrimps) are common in the Antarctic. Because remoteness, depth and ice cover restrict sampling in the South Ocean, species distribution modelling is a useful tool for evaluating distributions. We used physical specimen and towed camera data to describe the diversity and distribution of shrimps in the Ross Sea region of Antarctica. Eight shrimp species were recorded: Chorismus antarcticus; Notocrangon antarcticus; Nematocarcinus lanceopes; Dendrobranchiata; Pasiphaea scotiae; Pasiphaea cf. ledoyeri; Petalidium sp., and a new species of Lebbeus. For the two most common species, N. antarcticus and N. lanceopes, we used maximum entropy modelling, based on records of 60 specimens and over 1130 observations across 23 sites in depths from 269 m to 3433 m, to predict distributions in relation to environmental variables. Two independent sets of environmental data layers at 0.05° and 0.5° resolution respectively, showed how spatial resolution affected the model. Chorismus antarcticus and N. antarcticus were found only on the continental shelf and upper slopes, while N. lanceopes, Lebbeus n. sp., Dendrobranchiata, Petalidium sp., Pasiphaea cf. ledoyeri, and Pasiphaea scotiae were found on the slopes, seamounts and abyssal plain. The environmental variables that contributed most to models for N. antarcticus were depth, chlorophyll-a concentration, temperature, and salinity, and for N. lanceopes were depth, ice concentration, seabed slope/rugosity, and temperature. The relative ranking, but not the composition of these variables changed in models using different spatial resolutions, and the predicted extent of suitable habitat was smaller in models using the finer-scale environmental layers. Our modelling indicated that shrimps were widespread throughout the Ross Sea region and were thus likely to play important functional role in the ecosystem, and that the spatial resolution of data needs to be considered both in the use of species distribution models. PMID:25051333

Basher, Zeenatul; Bowden, David A; Costello, Mark J



Deep-water zooplankton of the Guaymas basin hydrothermal vent field  

NASA Astrophysics Data System (ADS)

Zooplankton from the Guaymas Basin deep-sea vent field were collected with a 1 m 2 MOCNESS to examine the distribution of total standing stock, taxonomic composition, size-frequency distribution of zooplankton, and the species composition of calanoid copepods. Low altitude (˜ 100 m above the bottom) horizontal tows along and across the axis of the basin's southern trough, and oblique tows from the bottom of the basin (˜ 2000 m) to the surface were made. Total biomass in near-bottom samples (range: 13-46 cc/1000 m 3) was only about a factor of 10 lower than in the upper 100 m. However, there was little or no evidence for enrichment of biomass in the ˜ 100 m zone above the vent site relative to biomass at the same depth horizon over non-vent areas. Total numbers of individuals ranged between 2600 and 4800/1000 m 3. Calanoid copepods consistently ranked first in abundance of counts of the taxa, followed by cyclopoid copepods, ostracods, chaetognaths, and amphipods. Other less abundant taxa, but in some cases important contributors to total biomass, were coelenterates (siphonophores, medusae), decapod shrimp, and polychaetes. Size-frequency analysis of individuals from each taxon indicated that the biomass and abundance spectra do not fit the theoretically expected spectra based on weight-dependent metabolism and growth. The pyramid of biomass was substantially different from the pyramid of numbers in this deep-sea community. Of the 67 species of copepods identified in two samples taken on low altitude tows, only 15 co-occurred in both samples. Many of the species in this relatively diverse community remain to be described. Larval and post-larval forms of benthic clams, gastropods, polychaetes, and crustaceans associated with the vents were collected 100-200 m above the southern trough, indicating the post-larvae may play an active role in dispersal of hydrothermal vent species.

Wiebe, Peter H.; Copley, Nancy; Van Dover, Cindy; Tamse, Armando; Manrique, Fernando



Community structure of zooplankton in the main entrance of Bahía Magdalena, México during 1996.  


The zooplankton community structure, including copepods, euphausiids, chaetognaths, and decapod larvae, was monitored during six circadian cycles using Bongo net (500 microns mesh net) samples from Bahía Magdalena, on the southwest coast of Baja California, México. Samples were obtained during three oceanographic surveys (March, July, and December 1996) to describe the changes in the zooplankton community structure throughout the main mouth of Bahía Magdalena. The zooplankton community structure showed strong changes with a close relation to environmental conditions. During March, a well-mixed water column with low temperature and salinity indicated an influence of the California Current water and local upwelling processes. During July, temperature increased and a wide salinity range was recorded. The stratification of the water column was intense during summer, enhancing the thermocline. The highest temperatures and salinity were recorded in December, related to the presence of the Costa Rica Coastal Current (CRCC). The thermocline deepened as water temperature increased. A typical temperate community structure with low specific richness dominated by Calanus pacificus, Nyctiphanes simplex, and Acartia clausi and high zooplankton biomass (average 9.3 and 5.5 ml 1000 m-3 respectively) during March and July shifted to a more complex tropical community structure with a low zooplankton biomass in December (average 0.37 ml 1000 m-3). The mouth of Bahía Magdalena has a vigorous exchange of water caused by tidal currents. The zooplankton community structure was not significantly different between the central part of Bahía Magdalena and the continental shelf outside the bay for all months. The results suggest a more dynamic inside-outside interaction of zooplankton assemblages than first thought. PMID:11935905

Gómez-Gutiérrez, J; Palomares-García, R; Hernández-Trujillo, S; Carballido-Carranza, A



Evidence for the presence of serotonin in Mysidacea (Crustacea, Peracarida) as revealed by fluorescence immunohistochemistry.  


In crustaceans, serotonin (5-HT) exerts a wide range of physiological actions on many tissues. However, 5-HT has not been detected to date in Mysidacea (Crustacea, Peracarida). We have investigated the presence of 5-HT in the brain and the eyestalks of two Mysida (Leptomysis lingvura, Hemimysis margalefi) and one Lophogastrida (Lophogaster typicus) species by using the immunohistofluorescence technique. 5-HT-like immunopositive areas exhibit a similar pattern in the three species. 5-HT-like immunostaining is present in the retinular photosensitive cells, except in the deep-living species L. typicus. 5-HT-like cell bodies and fibres are observed in the lamina ganglionaris and in the three medullae. In the sinus gland, only 5-HT-like endings are detected. In the eyestalks, 5-HT-like fibres detected in the optic tract link with the protocerebrum, in which 5-HT-like somata and their extensions are found. Some neurones are detected in the anterior median cell cluster, in the protocerebral bridge and in the central body. In the deutocerebrum, the paracentral lobes are connected by immunoreactive fibres that run along the deutocerebral commissure. The glomeruli of the olfactory lobes exhibit strong diffuse immunostaining. Beside and in the median part of the deutocerebrum, at least two large serotoninergic neurones project their axons into the olfactory lobe cell cluster. Immunoreactive fibres are also found in the antennular neuropiles. Our results demonstrate the presence of 5-HT-like cell bodies and fibres in Mysidacea. The distribution patterns of the 5-HT immunoreactivity found herein are compared with those of other peracarids and decapods. PMID:12457235

Moreau, X; Benzid, D; De Jong, L; Barthélémy, R-M; Casanova, J-P



Enterospora canceri n. gen., n. sp., intranuclear within the hepatopancreatocytes of the European edible crab Cancer pagurus.  


Only 1 genus (Nucleospora) within 1 family (Enterocytozoonidae) of the Microsporidia contains species that are parasitic within the nuclei of their host cells; to date, all described intranuclear Nucleospora spp. parasitise fish. This study describes the first intranuclear microsporidian parasite of an invertebrate, the European edible crab Cancer pagurus L. (Decapoda: Cancridae). Infected crabs displayed no obvious external signs, and maximum apparent prevalence of infection within a monthly sample was 3.45%. Infected hepatopancreatic tubules were characterised by varying numbers of hypertrophic and eosinophilic nuclei within epithelial cells. Parasite stages appeared as eosinophilic granular accumulations causing margination of host chromatin. In advanced cases, the tubule epithelia degenerated, with parasites and sloughed epithelial cells appearing in tubule lumens. All life stages of the parasite were observed within host nuclei. Uninucleate meronts were not detected, although binucleate stages were observed. Multinucleate plasmodia (sporogonal plasmodia) contained up to 22 nuclei in section, and late-stage plasmodia contained multiple copies of apparatus resembling the polar filament and anchoring disk, apparently associated with individual plasmodial nuclei. As such, aggregation and early assembly of sporoblast components took place within the intact sporogonial plasmodium, a feature unique to the Enterocytozoonidae. Liberation of sporoblasts from plasmodia or the presence of liberated sporoblasts was not observed in this study. However, large numbers of maturing and mature spores (measuring 1.3 +/- 0.02 x 0.7 +/- 0.01 microm) were frequently observed in direct contact with the host nucleoplasm. Considering the shared features of this parasite with microsporidians of the family Enterocytozoonidae, and the unique presence of this parasite within the nucleoplasm of decapod crustacean hepatopancreatocytes, this parasite (Enterospora canceri) is proposed as the type species of a new genus (Enterospora) of microsporidian. Molecular taxonomic work is now required, comparing Enterospora to Enterocytozoon and Nucleospora, the 2 other genera within the Enterocytozoonidae. PMID:17523544

Stentiford, G D; Bateman, K S; Longshaw, M; Feist, S W



Species sympatry and horizontal transfers of Mariner transposons in marine crustacean genomes.  


Mariner-like elements (MLEs) have been widely detected in terrestrial species. The first complete MLE isolated from a marine invertebrate was detected in the genome of the hydrothermal crab Bythograea thermydron by Halaimia-Toumi et al. [Halaimia-Toumi, N., Casse, N., Demattei, M.V., Renault, S., Pradier, E., Bigot, Y., Laulier, M., 2004. The GC-rich transposon Bytmar1 from the deep-sea hydrothermal crab, Bythograea thermydron, may encode three transposase isoforms from a single ORF. J. Mol. Evol. 59, 747-760] and called Bytmar1. Here, we report the isolation of three new Bytmar1 relatives from the genomes of one hydrothermal amphipod Ventiella sulfuris (Vensmar1) and two coastal crustacea, Maia brachydactila (Maibmar1) and Cancer pagurus (Canpmar1). Like Bytmar1, these MLEs have an unusually high GC content, a high CpG ratio, and a low TpA ratio. Their consensus sequence encodes a transposase that is preceded by an N-flag, as in Bytmar1, which could be a marine feature. Only one of the 19 clones obtained, Vensmar1.3, encoded for a full-length transposase. The phylogenetic analyses revealed that all these Bytmar1-related elements can be differentiated into two clusters, corresponding to the coastal or hydrothermal origin of their hosts. They also confirmed that the irritans sub-family comprises at least four lineages that seem to depend on the taxonomical position and habitat of their hosts. Finally, we observed that elements coding for two potentially complete transposases exhibiting 99.5% similarity, Bytmar1.11 and Vensmar1.3, were present in the genome of two distantly related hydrothermal crustacea, one Amphipod and one Decapod. The hypothesis of horizontal transfers is discussed in the light of the sequence similarities observed. PMID:16690328

Casse, N; Bui, Q T; Nicolas, V; Renault, S; Bigot, Y; Laulier, M



The impact of extreme turbidity events on the nursery function of a temperate European estuary with regulated freshwater inflow  

NASA Astrophysics Data System (ADS)

Estuaries are used as nursery grounds by numerous marine species despite being usually subject to strong anthropogenic disturbances. Abundances of marine recruits (fish and crustacean decapods) and their main prey (mysids) were monitored by monthly sampling, from June 1997 to February 2009, in the lower reaches of the Guadalquivir estuary (SW Spain). During that period, unusually high and persistent turbidity events (HPTEs) were observed twice. Both HPTEs started with strong and sudden freshwater discharges after relatively long periods of very low freshwater inflow. Data from this time-series were used to test the hypothesis that HPTEs may negatively impact the nursery function of estuaries either by decreasing prey availability or by decreasing survival/arrival of marine recruits. During HPTEs, the commonest mysid ( Mesopodopsis slabberi), a key species in the estuarine food web, showed a significant decrease in abundance. Likewise, some marine recruits that prey on M. slabberi and whose peaks of abundance within the estuary occur in summer-autumn ( Engraulis encrasicolus and Pomadasys incisus) were less abundant during HPTEs. It is also suggested that HPTEs might have triggered a shift in the distribution of the most euryhaline prey ( Neomysis integer) and predator ( Dicentrarchus punctatus and Crangon crangon) species, towards more saline waters. This could have contributed to an increase in the inter-specific competition (for food/habitat) within the estuarine nursery area. The results discussed in this study call attention to the need to reduce as much as possible the anthropogenic pressures that may stimulate the occurrence of high and persistent turbidity events (HPTEs) in order to preserve the nursery function of temperate estuaries.

González-Ortegón, E.; Subida, M. D.; Cuesta, J. A.; Arias, A. M.; Fernández-Delgado, C.; Drake, P.



Inorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the hydrothermal vent host-shrimp Rimicaris exoculata.  


The shrimp Rimicaris exoculata dominates several hydrothermal vent ecosystems of the Mid-Atlantic Ridge and is thought to be a primary consumer harbouring a chemoautotrophic bacterial community in its gill chamber. The aim of the present study was to test current hypotheses concerning the epibiont's chemoautotrophy, and the mutualistic character of this association. In-vivo experiments were carried out in a pressurised aquarium with isotope-labelled inorganic carbon (NaH(13)CO(3) and NaH(14)CO(3)) in the presence of two different electron donors (Na(2)S(2)O(3) and Fe(2+)) and with radiolabelled organic compounds ((14)C-acetate and (3)H-lysine) chosen as potential bacterial substrates and/or metabolic by-products in experiments mimicking transfer of small biomolecules from epibionts to host. The bacterial epibionts were found to assimilate inorganic carbon by chemoautotrophy, but many of them (thick filaments of epsilonproteobacteria) appeared versatile and able to switch between electron donors, including organic compounds (heterotrophic acetate and lysine uptake). At least some of them (thin filamentous gammaproteobacteria) also seem capable of internal energy storage that could supply chemosynthetic metabolism for hours under conditions of electron donor deprivation. As direct nutritional transfer from bacteria to host was detected, the association appears as true mutualism. Import of soluble bacterial products occurs by permeation across the gill chamber integument, rather than via the digestive tract. This first demonstration of such capabilities in a decapod crustacean supports the previously discarded hypothesis of transtegumental absorption of dissolved organic matter or carbon as a common nutritional pathway. PMID:22914596

Ponsard, Julie; Cambon-Bonavita, Marie-Anne; Zbinden, Magali; Lepoint, Gilles; Joassin, André; Corbari, Laure; Shillito, Bruce; Durand, Lucile; Cueff-Gauchard, Valérie; Compère, Philippe





Unrestrained crabs instrumented with probes for ultrasonic measurement of arterial haemolymph flow were subjected to 6 h of hypoxic exposure. During this interval, the inhalant O2 partial pressure was reduced in steps from 18 to 3 kPa. Measurement of haemolymph flow through all arteries leaving the heart allowed direct calculation of cardiac output, stroke volume and the distribution of cardiac output for both non-stressed and hypoxic animals. Resting levels of cardiac output were low compared with previously reported values for this and other species of decapod crustaceans. During exposure to the most severe level of hypoxia tested, haemolymph flow through the anterior arteries decreased while flow through the posterior aorta and sternal artery increased by 55 % and 27 % respectively. Cardiac output increased from a control value of 9.8±1.6 to 11.9±1.2 ml kg-1 min-1 despite a decrease in heart-beat frequency. Scaphognathite beat frequency increased from 82.1±4.3 min-1 to more than 120 min-1 after 90 min of hypoxic exposure and remained at this level for the duration of the exposure period. The decrease in haemolymph flow, via the anterior arteries, to the antero-dorsal region of the animal concurrent with an increase in flow to the posterior and antero-ventral regions, via the posterior aorta and sternal artery, implicates an active mechanism for redistribution of haemolymph flow during hypoxic exposure. The high rate of scaphognathite pumping, presumably to maximise O2 uptake during experimental hypoxia, was probably made possible by an increased blood supply to these organs, which are perfused by downstream branches of the sternal artery. PMID:9317266

Airriess; Mcmahon



Biodiversity of the Deep-Sea Continental Margin Bordering the Gulf of Maine (NW Atlantic): Relationships among Sub-Regions and to Shelf Systems  

PubMed Central

Background In contrast to the well-studied continental shelf region of the Gulf of Maine, fundamental questions regarding the diversity, distribution, and abundance of species living in deep-sea habitats along the adjacent continental margin remain unanswered. Lack of such knowledge precludes a greater understanding of the Gulf of Maine ecosystem and limits development of alternatives for conservation and management. Methodology/Principal Findings We use data from the published literature, unpublished studies, museum records and online sources, to: (1) assess the current state of knowledge of species diversity in the deep-sea habitats adjacent to the Gulf of Maine (39–43°N, 63–71°W, 150–3000 m depth); (2) compare patterns of taxonomic diversity and distribution of megafaunal and macrofaunal species among six distinct sub-regions and to the continental shelf; and (3) estimate the amount of unknown diversity in the region. Known diversity for the deep-sea region is 1,671 species; most are narrowly distributed and known to occur within only one sub-region. The number of species varies by sub-region and is directly related to sampling effort occurring within each. Fishes, corals, decapod crustaceans, molluscs, and echinoderms are relatively well known, while most other taxonomic groups are poorly known. Taxonomic diversity decreases with increasing distance from the continental shelf and with changes in benthic topography. Low similarity in faunal composition suggests the deep-sea region harbours faunal communities distinct from those of the continental shelf. Non-parametric estimators of species richness suggest a minimum of 50% of the deep-sea species inventory remains to be discovered. Conclusions/Significance The current state of knowledge of biodiversity in this deep-sea region is rudimentary. Our ability to answer questions is hampered by a lack of sufficient data for many taxonomic groups, which is constrained by sampling biases, life-history characteristics of target species, and the lack of trained taxonomists.

Kelly, Noreen E.; Shea, Elizabeth K.; Metaxas, Anna; Haedrich, Richard L.; Auster, Peter J.



Molecular characterization and expression of a crustin-like gene from Chinese mitten crab, Eriocheir sinensis.  


Crustin is a cysteine-rich antibacterial peptide which widely distributes within decapod crustaceans. In the present study, the cDNA encoding crustin-like peptide (designated CrusEs) was cloned from Chinese mitten crab Eriocheir sinensis by using rapid amplification of cDNA ends (RACE) approaches and expressed sequence tag analysis. The full-length cDNA of CrusEs was of 796bp, containing a 5' untranslated region (UTR) of 214bp, a 3' UTR of 267bp with a poly(A) tail, and an open reading frame (ORF) of 315bp encoding a polypeptide of 104 amino acids including a putative signal peptide of 21 amino acids. A WAP domain and the consensus framework existing in class I crustins were both identified in CrusEs, suggesting that CrusEs is a new member of type I crustins. Quantitative real-time RT-PCR was employed to examine the expression of CrusEs, and its mRNA transcript was mainly detected in haemocytes and gill. The CrusEs mRNA transcript in haemocytes was down-regulated after the challenge with Gram-positive bacteria Micrococcus luteus, while Gram-negative bacteria Listonella anguillarum did not induce significant variation of CrusEs mRNA. The mature peptide of CrusEs was cloned into pET-21a(+) with a C-terminal hexa-histidine tag fused in-frame, and expressed in Escherichia coli, and the recombinant CrusEs inhibited the growth of Gram-positive bacteria with low MIC. The results indicate that CrusEs is a potent antibacterial protein against Gram-positive bacteria infection, and it may play an important role in innate immune response of E. sinensis. PMID:20144896

Mu, Changkao; Zheng, Peilin; Zhao, Jianmin; Wang, Lingling; Zhang, Huan; Qiu, Limei; Gai, Yunchao; Song, Linsheng



New insights into mercury bioaccumulation in deep-sea organisms from the NW Mediterranean and their human health implications.  


A number of studies have found high levels of mercury (Hg) in deep-sea organisms throughout the world's oceans, but the underlying causes are not clear as there is no consensus on the origin and cycling of Hg in the ocean. Recent findings suggested that Hg accumulation may increase with increasing forage depth and pointed to the deep-water column as the origin of most Hg in marine biota, especially its organic methylmercury (MeHg) form. In the present study, we determined the total mercury (THg) levels in 12 deep-sea fish species and a decapod crustacean and investigated their relationship with the species' nitrogen stable isotope ratio (?(15)N) as an indicator of their trophic level, average weight and habitat depth. THg levels ranged from 0.27 to 4.42 ?g/g w.w. and exceeded in all, except one species, the recommended 0.5 ?g/g w.w. guideline value. While THg levels exhibited a strong relationship with ?(15)N values and to a lesser extent with weight, the habitat depth, characterized as the species' depth of maximum abundance (DMA), had also a significant effect on Hg accumulation. The fish species with a shallower depth range exhibited lower THg values than predicted by their trophic level (?(15)N) and body mass, while measured THg values were higher than predicted in deeper-dwelling fish. Overall, the present results point out a potential risk for human health from the consumption of deep-sea fish. In particular, for both, the red shrimp Aristeus antennatus, which is one of the most valuable fishing resources of the Mediterranean, as well as the commercially exploited fish Mora moro, THg levels considerably exceeded the recommended 0.5?g/g w.w. limit and should be consumed with caution. PMID:23178837

Koenig, Samuel; Solé, Montserrat; Fernández-Gómez, Cristal; Díez, Sergi



Spatial, temporal and ontogenetic variation in diet of anchovy ( Engraulis encrasicolus) on the Algerian coast (SW Mediterranean)  

NASA Astrophysics Data System (ADS)

The diet of anchovy Engraulis encrasicolus was studied in three regions (Béjaia, Bénisaf and Ghazaouet) along the Algerian coast. Ontogenetic, spatial and seasonal variations in anchovy diet were investigated using multivariate analyses and analysed in relation with sea surface temperature and chlorophyll- a. 46 prey taxa of varying size between 0.57 mm ( Euterpina acutifrons) and 6.8 mm (fish larvae) were recorded. Whatever the season, the region or the fish size, anchovy is exclusively zooplanktivorous and copepods were the most present prey, constituting 87% by number of the prey taken and found in 98% of the anchovy stomachs examined. However, their occurrence and number varied according to the different areas, seasons and fish size. During its first year of life, anchovy feeds almost exclusively on copepods (mainly small and medium size prey). As anchovy grows, copepods are gradually substituted by large crustaceans such as decapods and amphipods. Hierarchical cluster analysis, analysis of similarities (ANOSIM) and similarities percentage (SIMPER) indicated a distinct diet of anchovy of the bay of Bejaia from those of the bays of Bénisaf and Ghazaouet probably due to differences in hydrologic conditions. Diet differences also occurred between seasons. Summer and spring have distinct prey assemblages each and showed low diet similarities with the two other seasons. More prey species were found in the diet during winter (36) and autumn (30) and the vacuity index was lower in winter. Temporal variability in satellite-derived chlorophyll- a matched the seasonal variability in the diversity of the anchovy prey and feeding intensity as reflected by the vacuity index, suggesting further investigation of the potential use of satellite-derived chlorophyll- a data as a proxy for anchovy feeding intensity.

Bacha, M.; Amara, R.



Characterization of a membrane-bound angiotensin-converting enzyme isoform in crayfish testis and evidence for its release into the seminal fluid.  


In the present study, an isoform of angiotensin-converting enzyme was characterized from the testis of a decapod crustacean, the crayfish Astacus leptodactylus. Angiotensin-converting enzyme cDNA, obtained by 3'- to 5' RACE of testis RNAs, codes for a predicted one-domain protein similar to the mammalian germinal isoform of angiotensin-converting enzyme. All amino acid residues involved in enzyme activity are highly conserved, and a potential C-terminus transmembrane anchor may be predicted from the sequence. Comparison of this testicular isoform with angiotensin-converting enzyme from other crustaceans, namely Carcinus maenas, Homarus americanus (both reconstituted for this study from expressed-sequence tag data) and Daphnia pulex, suggests that membrane-bound angiotensin-converting enzyme occurs widely in crustaceans, conversely to other invertebrate groups where angiotensin-converting enzyme is predominantly a soluble protein. In situ hybridization and immunohistochemistry performed on testis sections show that angiotensin-converting enzyme mRNA is mainly localized in spermatogonias, whereas protein is present in spermatozoids. By contrast, in vas deferens, immunoreactivity is detected in the seminal fluid rather than in germ cells. Accordingly, angiotensin-converting enzyme activity assays of testis and vas deferens extracts demonstrate that the enzyme is present in the membrane fraction in testis, but in the soluble fraction in vas deferens. Taken together, the results obtained in the present study suggest that, during the migration of spermatozoids from testis to vas deferens, the enzyme is cleaved from the membrane of the germ cells and released into the seminal fluid. To our knowledge, this present study is the first to report such a maturation process for angiotensin-converting enzyme outside of mammals. PMID:19656189

Simunic, Juraj; Soyez, Daniel; Kamech, Nédia



Pre-Partum Diet of Adult Female Bearded Seals in Years of Contrasting Ice Conditions  

PubMed Central

Changing patterns of sea-ice distribution and extent have measurable effects on polar marine systems. Beyond the obvious impacts of key-habitat loss, it is unclear how such changes will influence ice-associated marine mammals in part because of the logistical difficulties of studying foraging behaviour or other aspects of the ecology of large, mobile animals at sea during the polar winter. This study investigated the diet of pregnant bearded seals (Erignathus barbatus) during three spring breeding periods (2005, 2006 and 2007) with markedly contrasting ice conditions in Svalbard using stable isotopes (?13C and ?15N) measured in whiskers collected from their newborn pups. The ?15N values in the whiskers of individual seals ranged from 11.95 to 17.45 ‰, spanning almost 2 full trophic levels. Some seals were clearly dietary specialists, despite the species being characterised overall as a generalist predator. This may buffer bearded seal populations from the changes in prey distributions lower in the marine food web which seems to accompany continued changes in temperature and ice cover. Comparisons with isotopic signatures of known prey, suggested that benthic gastropods and decapods were the most common prey. Bayesian isotopic mixing models indicated that diet varied considerably among years. In the year with most fast-ice (2005), the seals had the greatest proportion of pelagic fish and lowest benthic invertebrate content, and during the year with the least ice (2006), the seals ate more benthic invertebrates and less pelagic fish. This suggests that the seals fed further offshore in years with greater ice cover, but moved in to the fjords when ice-cover was minimal, giving them access to different types of prey. Long-term trends of sea ice decline, earlier ice melt, and increased water temperatures in the Arctic are likely to have ecosystem-wide effects, including impacts on the forage bases of pagophilic seals.

Hindell, Mark A.; Lydersen, Christian; Hop, Haakon; Kovacs, Kit M.



Antarctic Crabs: Invasion or Endurance?  

PubMed Central

Recent scientific interest following the “discovery” of lithodid crabs around Antarctica has centred on a hypothesis that these crabs might be poised to invade the Antarctic shelf if the recent warming trend continues, potentially decimating its native fauna. This “invasion hypothesis” suggests that decapod crabs were driven out of Antarctica 40–15 million years ago and are only now returning as “warm” enough habitats become available. The hypothesis is based on a geographically and spatially poor fossil record of a different group of crabs (Brachyura), and examination of relatively few Recent lithodid samples from the Antarctic slope. In this paper, we examine the existing lithodid fossil record and present the distribution and biogeographic patterns derived from over 16,000 records of Recent Southern Hemisphere crabs and lobsters. Globally, the lithodid fossil record consists of only two known specimens, neither of which comes from the Antarctic. Recent records show that 22 species of crabs and lobsters have been reported from the Southern Ocean, with 12 species found south of 60°S. All are restricted to waters warmer than 0°C, with their Antarctic distribution limited to the areas of seafloor dominated by Circumpolar Deep Water (CDW). Currently, CDW extends further and shallower onto the West Antarctic shelf than the known distribution ranges of most lithodid species examined. Geological evidence suggests that West Antarctic shelf could have been available for colonisation during the last 9,000 years. Distribution patterns, species richness, and levels of endemism all suggest that, rather than becoming extinct and recently re-invading from outside Antarctica, the lithodid crabs have likely persisted, and even radiated, on or near to Antarctic slope. We conclude there is no evidence for a modern-day “crab invasion”. We recommend a repeated targeted lithodid sampling program along the West Antarctic shelf to fully test the validity of the “invasion hypothesis”.

Griffiths, Huw J.; Whittle, Rowan J.; Roberts, Stephen J.; Belchier, Mark; Linse, Katrin



The reaction of European lobster larvae (Homarus gammarus) to different quality food: effects of ontogenetic shifts and pre-feeding history.  


Young larval stages of many organisms represent bottlenecks in the life-history of many species. The high mortality commonly observed in, for example, decapod larvae has often been linked to poor nutrition, with most studies focussing on food quantity. Here, we focus instead on the effects of quality and have investigated its effects on the nutritional condition of lobster larvae. We established a tri-trophic food chain consisting of the cryptophyte Rhodomonas salina, the calanoid copepod Acartia tonsa and larvae of the European lobster Homarus gammarus. In a set of experiments, we manipulated the C:N:P stoichiometry of the primary producers, and accordingly those of the primary consumer. In a first experiment, R. salina was grown under N- and P-limitation and the nutrient content of the algae was manipulated by addition of the limiting nutrient to create a food quality gradient. In a second experiment, the effect on lobster larvae of long- and short-term exposure to food of varying quality during ontogenetic development was investigated. The condition of the lobster larvae was negatively affected even by subtle N- and P-nutrient limitations of the algae. Furthermore, younger lobster larvae were more vulnerable to nutrient limitation than older ones, suggesting an ontogenetic shift in the capacity of lobster larvae to cope with low quality food. The results presented here might have substantial consequences for the survival of lobster larvae in the field, as, in the light of future climate change and re-oligotrophication of the North Sea, lobster larvae might face marked changes in temperature and nutrient conditions, thus significantly altering their condition and growth. PMID:24072442

Schoo, Katherina L; Aberle, Nicole; Malzahn, Arne M; Schmalenbach, Isabel; Boersma, Maarten



Effects of cadmium on lipid storage and metabolism in the freshwater crab Sinopotamon henanense.  


Since environmental effects of molecular traits are often questioned we analyze here the molecular effects of cadmium (Cd) on lipid pathways and their effects on tissues development. Lipids are an important energy source for the developing embryo, and accumulate in the ovary and hepatopancreas of decapod crustaceans. The extend of Cd affecting lipid storage and metabolism, is studied here with the freshwater crabs Sinopotamon henanense. Crabs were exposed to water-born Cd at 1.45, 2.9, 5.8 mg/l for 10, 15, and 20 days. With significantly increased Cd accumulation in exposed crabs, lipid content in hepatopancreas and ovary showed a time-dependent and concentration-dependent reduction, being at least one of the reasons for a lower ovarian index (OI) and hepatopancreatic index (HI). After 10-day exposure increased triglyceride (TG) level in hemolymph and up-regulation of pancreatic lipase (PL) activity in the hepatopancreas suggested an increased nutritional lipid uptake. However, two processes led to lower lipid levels upon Cd exposure: an increased utilization of lipids and a down-regulated lipoprotein lipase (LPL) led to insufficient lipid transport. 10-day Cd exposure also triggered the production of ?-nicotinamide adenine dinucleotide 2'-phosphate reduced tetrasodium salt hydrate (NADPH), as well as to the synthesis of adenosine triphosphate (ATP) and fatty acids. With increasing exposure time, the crabs at 15 and 20-day exposure contained less lipid and TG, suggesting that more energy was consumed during the exposure time. Meanwhile, the level of NADPH, ATP and the activity of PL, LPL, fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC) activity was down-regulated suggesting an impairment of the crab metabolism by Cd in addition to causing a lower lipid level. PMID:24130894

Yang, Jian; Liu, Dongmei; Jing, Weixin; Dahms, Hans-Uwe; Wang, Lan



Modifications to the bottomless lift net for sampling nekton in tidal mangrove forests  

USGS Publications Warehouse

Sampling fishes in vegetated intertidal wetlands is logistically challenging. We modified the 2 ?? 3-m2 bottomless lift net developed for sampling nekton (fish and decapod crustaceans) on the surface of salt marshes for use in tidal mangrove forests with a woody (as opposed to herbaceous) underground root system. As originally designed (Rozas, Mar Ecol Prog Ser 89:287-292, 1992), the lift net was buried directly in the marsh substrate. The net was raised at slack high tide thereby encircling nekton within the enclosed area. A chain-line on the net bottom prevented escape under the net once deployed. However, when we used this same design in tidal mangrove forests, the extensive woody roots and occasional slumping sediments resulted in uneven trenches that could not be cleared effectively during sample recovery. We made 3 modifications to the original net design: (i) lined the peat trenches with aluminum channels of uniform width and depth; (ii) replaced the previous chain-line with Velcro closures that directly attached the net to the inner face of the outer wall of the aluminum channel; and (iii) removed the subtidal pan previously used for concentrating the enclosed nekton at low tide, and filled in those depressions with on-site peat. In the modified version, the aluminum trench became the only subtidal refuge available to nekton, and it was from here that we collected the sample after the forest drained. These modifications permitted high clearing efficiency (93-100%) of fin-clipped individuals of two common species of estuarine resident fishes, Kryptolebias marmoratus (mangrove rivulus) and Bathygobius soporator (frillfin goby). Additionally, the density estimates of grass shrimp (Palaemonetes spp.) increased 10-fold post-modification. ?? 2010 US Government.

McIvor, C. C.; Silverman, N. L.



Geomorphological, trophic and human influences on the bamboo coral Isidella elongata assemblages in the deep Mediterranean: To what extent does Isidella form habitat for fish and invertebrates?  

NASA Astrophysics Data System (ADS)

We analyzed what are the best ecological conditions for megafauna associated with the bamboo coral Isidella elongata based on the geomorphological, physical and trophic information taken in 3 stations (St1, St2, St3) off the southern Catalonian coasts at 620 m depth in June 2011. Results were compared with assemblage compositions recorded in past cruises (May 1992, 1994) at the same 3 stations. St1 was in a fishing ground exploited since the 1940s over a relatively wide slope at ca. 22 km from the nearest canyon head; St2 and St3 were on a narrower slope closer to canyon heads and to the Ebro river mouth than St1. I. elongata had formed (to May 1994, at least) a dense coral forest at St2-St3 (to ca. 255 colonies/ha at St3), and some isolated colonies (to ca. 0.9 colonies/ha) were still collected in 2011. Fish and invertebrate communities significantly differed between St1 and St2/St3, with two macrourid fishes (Trachrhynchus trachyrhynchus and Nezumia aequalis) and two decapods (Plesionika martia and Plesionika acanthonotus) more abundant at St2/St3. The following ecological indicators imply better food conditions for megafauna at St2-St3 and for I. elongata itself: (i) greater density of zooplankton (copepods, euphausiids, and others) as potential prey for planktivores (including I. elongata); (ii) greater biomass and mean weight of epifaunal and infaunal deposit feeders; (iii) higher feeding intensity, F, at St3 for benthos feeders (Phycis blennoides, N. aequalis and Aristeus antennatus). Also, at St2-St3 we found higher near-bottom turbidity (indicating particle resuspension: food for suspension feeders) and finer and more reduced (Eh) sediments. The results let us suggest that corals and accompanying fauna preferently found optimal ecological conditions in the same habitat, while habitat-forming capacity by I. elongata seemed weak to generate these conditions. Coral forests may enhance detritus accumulations around them, improving habitat conditions for benthos feeders (e.g. macrourid fish). At St3 our side-scan sonar recorded three types of tracks produced by trawler doors, which match with three identified vessels occasionally operating in the area. After this low fishing activity off the Ebro Delta since the mid-1990s, almost all colonies of I. elongata has been removed. However, this impact has hardly altered fish and invertebrate composition without any significant loss of diversity, pointing also toward a rather low capacity of I. elongata facies in forming habitat for megafauna on muddy bottoms of the Mediterranean slope.

Cartes, J. E.; LoIacono, C.; Mamouridis, V.; López-Pérez, C.; Rodríguez, P.



Proteins of crustacean exoskeleton: IV. Partial amino acid sequences of exoskeletal proteins from the Bermuda land crab, Gecarcinus lateralis, and comparisons to certain insect proteins.  


As in all decapod Crustacea, the exoskeleton of the land crab Gecarcinus lateralis consists of four layers. Prior electrophoretic analysis of proteins extracted from these layers revealed an abundance of small M(r) proteins with acidic pIs are found in insect cuticle (O'Brien et al. [1991 Biol. Bull., 181:427-441). Further, immunological cross-reactivity between crab exoskeletal proteins and insect cuticular proteins has been demonstrated (Kumari and Skinner [1993] J. Exp. Zool., 265:195-210). Partial amino acid sequences of a number of proteins from the four exoskeletal layers are described here. Proteins were electrophoresed on two-dimensional (2D) gels, transferred to polyvinylidene difluoride (PVDF) membranes, and stained; individual spots were recovered and their N-termini were sequenced. In addition, a 14-kDa protein (pI = 5.4) from membranous layer (ML14) was eluted from 2D gels and digested with endoproteinase Lys-C; N-termini of its constituent peptides were sequenced. The two epicuticular proteins differed from each other. Three proteins with identical electrophoretic mobility isolated from exocuticle, endocuticle, and membranous layer appeared to have identical N termini, while another electrophoretically identical set from the three layers appeared identical with each other but differed in three positions from the first set. Two proteins from the membranous layer both had a mass of 25 kDa but different isoelectric points. Their sequences were indistinguishable from each other but clearly distinct from another membranous layer protein. Another distinct sequence was found in a 14-kDa protein from endocuticle, while a less acidic pair of 14-kDa proteins from endocuticle and membranous layer were quite similar to one another. The three internal peptide fragments from ML14 were distinct, but one had regions similar to the ML14 N terminus. One crab exoskeletal protein sequence was similar to some structural proteins of vertebrates, whereas others had motifs found in insect cuticular proteins. The sequence similarities identified did not account for the antibody cross-reactivity. PMID:8576695

Kumari, S S; Willis, J H; Skinner, D M



Cloning of a nitric oxide synthase from green shore crab, Carcinus maenas: a comparative study of the effects of eyestalk ablation on expression in the molting glands (Y-organs) of C. maenas, and blackback land crab, Gecarcinus lateralis.  


Molting in decapod crustaceans is regulated by ecdysteroids produced by a pair of Y-organs (YOs) located in the cephalothorax. YO ecdysteroidogenesis is suppressed by molt-inhibiting hormone (MIH), a neuropeptide produced in the X-organ of the eyestalk (ES) ganglia. MIH signaling may involve nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). A full-length cDNA encoding Carcinus maenas NOS (Cm-NOS; 3836 base pairs) of 1164 amino acid residues (estimated mass 131,833 Da) was cloned with 88% identity to Gecarcinus lateralis NOS (Gl-NOS). End-point reverse transcription-polymerase chain reaction (RT-PCR) showed that Cm-NOS was expressed at varying levels in the YO, testis, ovary, hepatopancreas, midgut, hindgut, heart, thoracic ganglion, and skeletal muscle and was not detected in the gill. Immunofluorescence microscopy showed localization of NOS and cGMP in the steroidogenic cells and the surrounding connective tissue layer of the C. maenas YO. ES ablation (ESA) induced molting in G. lateralis; hemolymph ecdysteroid titers increased during premolt and reached a peak of about 400 pg/?L at 20 days and 24 days post-ESA. By contrast, ESA did not induce molting in C. maenas; hemolymph ecdysteroid titers increased about 2-fold (53 to 121 pg/?L) by 3 days post-ESA and remained at that level at 7 days post-ESA. Real time PCR was used to quantify the effects of ESA on the expression of NOS in C. maenas and G. lateralis YOs. ESA caused 32-fold and 5-fold increases in Gl-NOS and Cm-NOS transcripts by 24 days and 7 days post-ESA, respectively, which were correlated with hemolymph ecdysteroid levels. In addition, GC-I catalytic subunit (Gl-GC-I?) mRNA level increased 7.4-fold by 24 days post-ESA, but there was no significant effect of ESA on membrane GC (Gl-GC-II) mRNA level. These data indicate that the YO up-regulates NO signaling components in response to withdrawal of ES neuropeptides. PMID:20959144

McDonald, Audrey A; Chang, Ernest S; Mykles, Donald L



Molt cycle regulation of protein synthesis in skeletal muscle of the blackback land crab, Gecarcinus lateralis, and the differential expression of a myostatin-like factor during atrophy induced by molting or unweighting.  


In decapod crustaceans, claw muscle undergoes atrophy in response to elevated ecdysteroids while thoracic muscle undergoes atrophy in response to unweighting. The signaling pathways that regulate muscle atrophy in crustaceans are largely unknown. Myostatin is a negative regulator of muscle growth in mammals, and a myostatin-like cDNA is preferentially expressed in muscle of the land crab, Gecarcinus lateralis (Gl-Mstn). Contrary to prediction, levels of Gl-Mstn mRNA decreased dramatically in both the claw closer and weighted thoracic muscles when molting was induced by either eyestalk ablation (ESA) or multiple limb autotomy (MLA). However, the effect of molt induction was greater in the claw muscle. By late premolt, Gl-Mstn mRNA in the claw muscle decreased 81% and 94% in ESA and MLA animals, respectively, and was negatively correlated with ecdysteroids. Gl-Mstn mRNA in thoracic muscle decreased 68% and 82% in ESA and MLA animals, respectively, but was only weakly correlated with ecdysteroid. Claw and thoracic muscles also differed to varying extents in the expression of ecdysteroid receptor (Gl-EcR and Gl-RXR), elongation factor-2 (Gl-EF-2), and calpain T (Gl-CalpT) in response to molt induction, but levels of the four transcripts were not correlated with ecdysteroid. The downregulation of Gl-Mstn expression in premolt claw muscle coincided with 11- and 13-fold increases in protein synthesis in the myofibrillar and soluble protein fractions, respectively. Furthermore, the rate of the increase in the synthesis of soluble proteins was greater than that of myofibrillar proteins during early premolt (1.4:1, soluble:myofibrillar), but the two were equivalent during late premolt. By contrast, Gl-Mstn mRNA increased 3-fold and Gl-CalpT mRNA decreased 40% in unweighted thoracic muscle; there was little or no effect on Gl-EF-2, Gl-EcR, and Gl-RXR mRNA levels. These data indicate that Gl-Mstn expression is negatively regulated by both ecdysteroids and load-bearing contractile activity. The downregulation of Gl-Mstn in claw muscle may induce the elevated protein turnover associated with remodeling of the contractile apparatus during molt-induced atrophy. The upregulation of Gl-Mstn in unweighted thoracic muscle suggests that this factor is also involved in disuse atrophy when hemolymph ecdysteroid levels are low. PMID:20008374

Covi, J A; Bader, B D; Chang, E S; Mykles, D L



Differences in cytochrome P450 enzyme activities between fish and crustacea: relationship with the bioaccumulation patterns of polychlorobiphenyls (PCBs).  


Variations in cytochrome P450 enzyme (CYPs) distribution and function between animal groups could result in differential metabolism and elimination kinetics for certain contaminants. Although a number of studies have suggested that differences in polychlorobiphenyl (PCB) accumulation profiles between crustacea and fish might result from differential CYP patterns, the relationship between PCB bioaccumulation and CYP capacities has not been demonstrated in these organisms. In the present study we investigated the hepatic microsomal catalytic activities in three deep-sea fish species, Alepocephalus rostratus (Alepocephalidae), Coelorinchus mediterraneus (Macrouridae), and Lepidion lepidion (Moridae), and the decapod crustacean Aristeus antennatus (Decapoda), using six fluorescent CYP-mediated substrates, namely ER (7-ethoxyresorufin), PR (7-pentoxyresorufin), BR (7-benzyloxyresorufin), CEC (3-cyano-7-ethoxycoumarin), DBF (dibenzylfluorescein) and BFC (7-benzyloxy-4-trifluoromethylcoumarin). Furthermore, we related the metabolic activities to the accumulation patterns of 41 PCB congeners in the muscle of these organisms. The results indicated a marked difference in the presence and activities of CYP isoforms between fish and the crustacean A. antennatus. Liver microsomes of the three selected fish species were capable of metabolizing all six CYP-mediated substrates and enzymes were identified as primarily belonging to CYP1A and CYP3A subfamilies. In contrast, hepatopancreas microsomes from A. antennatus only showed activity for PR and DBF substrates, generally related to mammalian CYP2-like enzymes. Furthermore, a direct relationship between metabolic activities and PCB accumulation profiles could be established. Results revealed that A. antennatus accumulated significantly higher proportions of PCBs 28, 52, 118, 138, 158 and 169 than fish, which is in accordance with the previously observed lack of CYP1A-like biotransformation capacities. Moreover, A. antennatus exhibited lower levels of PCBs 87, 149, 153, 170, 180, 183, 194 and 206 indicating that this crustacean is able to metabolize congeners considered mammalian CYP2B inducers. Hence, the present findings highlight the role of CYP-mediated metabolism in the congener-specific accumulation of PCBs in aquatic organisms and stress the need to further investigate quantitative and qualitative differences in xenobiotic metabolism among animal groups. PMID:22093813

Koenig, Samuel; Fernández, Pilar; Solé, Montserrat



Viral diseases of marine invertebrates  

NASA Astrophysics Data System (ADS)

Approximately 40 viruses are known from marine sponges; turbellarian and monogenetic flatworms; cephalopod, bivalve, and gastropod mollusks; nereid polychaetes; and isopod and decapod crustaceans. Most of the viruses can be tentatively assigned to the Herpesviridae, Baculoviridae, Iridoviridae, Adenoviridae, Papovaviridae, Reoviridae, “Birnaviridae”, Bunyaviridae, Rhabdoviridae, and Picornaviridae. Viruslike particles found in oysters might be representatives of the Togaviridae and Retroviridae. Enveloped single-stranded RNA viruses from crustaceans have developmental and morphological characteristics intermediate between families, and some show evidence of relationships to the Paramyxoviridae as well as the Bunyaviridae or Rhabdoviridae. Certain small viruses of shrimp cannot be assigned, even tentatively, to a particular family. Some viruses cause disease in wild and captive hosts, others are associated with disease states but may not be primary instigators, and many occur in apparently normal animals. The frequency of viral disease in natural populations of marine invertebrates is unknown. Several viruses that cause disease in captive animals, with or without experimental intervention, have also been found in diseased wild hosts, including herpeslike viruses of crabs and oysters, iridovirus of octopus, and reolike and bunyalike viruses of crabs. Iridolike viruses have been implicated in massive mortalities of cultured oysters. Baculoviruses, and IHHN virus, which is of uncertain affinities, cause economically damaging diseases in cultured penaeid shrimp. Double or multiple viral infection is common in crabs. For example, a reolike virus and associated rhabdolike virus act synergistically to cause paralytic and fatal disease in Callinectes sapidus. Information on host range, most susceptible stage, and viral latency is available only for viruses of shrimp. One baculovirus attacks five species of New World penaeid shrimp. IHHN virus infects three species of Penaeus and causes catastrophic mortalities in P. stylirostris, but usually exhibits only inapparent infection in P. vannamei. Some shrimp viruses apparently are latent in larvae, causing disease only when shrimp have reached the postlarval or juvenile stages. Others are equally or more pathogenic in larvae. Studies of shrimp viruses and iridovirus-associated disease in cultured oysters point up the need for rapid and accurate diagnostic methods. Until appropriate cell cultures from marine invertebrates are devised, the viral identifications necessary for understanding of epizootiology, rapid containment of epizootics in cultured animals, and decisions regarding introductions of exotic species will be difficult or impossible.

Johnson, P. T.



Climatic changes in hydrological and biological characteristics of the North-Western Black Sea region  

NASA Astrophysics Data System (ADS)

The last decades have shown considerable climatic changes in all components of the Earth System. In particular, a hydrological regime of river runoffs in the North-Western Black Sea (NWBS) shows changes on seasonal and interannual scales. A general reduction in annual runoff occurs, while winter flow increases and spring flow decreases. This can be explained by the fact that the snow cover becomes less important with regional warming. Changes in the hydrological regime affect the vertical thermohaline structure and circulation in the NWBS. Observations in coastal waters show that both the temperature and salinity changed remarkably for the winter, while there are no significant variations for the summer season. Moreover, for the winter season, temperature has increased by about 2?C within the upper layer of 0-10 m and more than 3?C in the benthonic layer. Changes of salinity in the upper and benthonic layers are of opposite signs leading to weakening of the vertical water exchange between two layers. The changes in hydrological environment lead to consequent changes of diversity and population of hydrobiota. Biological components are less sensitive to the interannual changes and work like a natural filter smoothing this temporal scale and emphasizing longer fluctuations. Due to the warming, the spring peak of phytoplankton has moved from May to late March - early April and its population during the last decade considerably increased. The major contribution of this growth is associated with the green and blue-green seaweed microalgae, coming into the NWBS with river runoff. The increasing amount of microalgae while decreasing the biomass means the degradation of macrocells species of microalgae. The peaks of population and biomass of zooplankton follow in 2-4 weeks after microalgae, which is the forage reserve. Diversity and amount of zooplankton have been degradated in the past decades. The spring peak associated with the zooplankton has especially decreased during last decade. Some species of decapods larvae disappeared totally. Thus, the basic signature of destabilization in hydrobiology environment during climate changes is the reduction of diversity in favour of simplest species and the increase of seasonal amplitude of their population.

Kovalyshyna, S.; Ivanov, S.; Matygin, A.



Serotonin-immunoreactive neurons in scorpion pectine neuropils: similarities to insect and crustacean primary olfactory centres?  


The pectines of scorpions are a single pair of mechano- and chemosensory appendages located ventrally behind the most posterior pair of walking legs. They are used for probing the substrate in behaviours such as prey tracking and courtship. The sensory afferents on the pectines supply large segmental neuropils with a conspicuous glomerular structure. The pectine neuropils thus bear similarities to insect and crustacean deutocerebral chemosensory centres associated with the antennae, but they also possess idiosyncratic features. One characteristic property of many insect and decapod crustacean olfactory neuropils is their innervation by single, or very few, large serotonergic (inter-) neurons. This feature, among others, has been proposed to support homology of the olfactory lobes in the two arthropod groups. A possible serotonergic innervation of the scorpion pectine neuropils has not yet been studied, despite its apparent diagnostic and functional importance. We thus examined serotonin-immunoreactivity in the pectine neuropils of Androctonus australis and Pandinus imperator. Both scorpion species yielded similar results. The periphery of the neuropil and the matrix between the glomeruli are supplied by a dense network of serotonin-immunoreactive (5-HT-ir) arborisations and varicosities, while the glomeruli themselves are mostly free of 5-HT-ir fibres. The 5-HT-ir supply of the pectine neuropils has two origins. The first is a pair of neurons on each body side, up to 30 ?m in diameter and thus slightly larger than the surrounding somata. These cell bodies are and associated with the neuromeres of the genital and pectine segments. The situation is reminiscent of the 5-HT supply of insect and crustacean olfactory and antennal neuropils. The second 5-HT innervation of the pectine neuropils is from a group of some 10-20 ipsilateral neuronal somata of slightly smaller size (15-20 ?m). These are part of a much larger 5-HT-ir group comprising 70-90 somata. The whole group is located more anteriorly than the single soma mentioned above, and associated with the neuromere of the last (4th) walking leg. When compared to data from other arthropods, our findings may suggest that glomerular organisation is an ancestral feature of primary chemosensory centres innervated by arthropod appendages. This idea needs further scrutiny, although supporting evidence may have been overlooked previously, due to the small size of chemosensory neuropils in walking legs and in reduced segmental appendages. PMID:22445574

Wolf, Harald; Harzsch, Steffen



Toxicity of organic compounds to marine invertebrate embryos and larvae: a comparison between the sea urchin embryogenesis bioassay and alternative test species.  


This study investigated the toxic effects of the insecticides lindane and chlorpyrifos, the herbicide diuron, the organometallic antifoulant tributyltin (TBT), and the surfactant sodium dodecyl sulfate (SDS) on the early life stages of Paracentrotus lividus (Echinodermata, Euechinoidea), Ciona intestinalis (Chordata, Ascidiacea), Maja squinado and Palaemon serratus (Arthropoda, Crustacea) in laboratory acute toxicity tests. The assays studied embryogenesis success from fertilized egg to normal larvae in P. lividus (48 h incubation at 20 degrees C) and C. intestinalis (24 h incubation at 20 degrees C), and larval mortality at 24 and 48 h in M. squinado and P. serratus. For P. lividus, the median effective concentrations (EC50) reducing percentages of normal larvae by 50% were: 350 microg l(-1) for chlorpyrifos, 5500 microg l(-1) for diuron, 4277 microg l(-1) for SDS, and 0.309 microg l(-1) for TBT. For C. intestinalis, the EC50 values affecting embryogenesis success were 5666 microg l(-1) for chlorpyrifos, 24,397 microg (l-1) for diuron, 4412 microg l(-1) for lindane, 5145 microg I(-1) for SDS, and 7.1 microg l(-1) for TBT. The median lethal concentrations (LC50) for M. squinado larval survival were 0.84 microg l(-1) (24 h) and 0.79 microg l(-1) (48 h) for chlorpyrifos, 2.23 microg(l(-1) (24 h) and 2.18 microg l(-1) (48 h) for lindane, and 687 microg l(-1) (48 h) for SDS. For P. serratus the LC50 values obtained were 0.35 microg l(-1) (24 h) and 0.22 microg l(-1) (48 h) for chlorpyrifos, 3011 microg l(-1) (24 h) and 3044 microg l(-1) (48 h) for diuron, 5.20 microg l(-1) (24 h) and 5.59 microg l(-1) (48 h) for lindane, and 22.30 microg l(-1) (24 h) and 17.52 microg l(-1) (48 h) for TBT. Decapod larvae, as expected, were markedly more sensitive to the insecticides than sea urchins and ascidians, and SDS was the least toxic compound tested for these organisms. Lowest observed effect concentrations (LOEC) of TBT for sea urchin and ascidian embryos, chlorpyrifos and lindane for crustacean larvae, and SDS, were similar to those found in many coastal areas indicating that there would be a risk to invertebrate embryos and larvae from exposure in the field to these pollutants. PMID:15943109

Bellas, Juan; Beiras, Ricardo; Mariño-Balsa, José Carlos; Fernández, Nuria



Uptake and loss of dissolved 109Cd and 75Se in estuarine macroinvertebrates.  


Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), followed by exposure to radionuclide-free water for 189 h (loss phase). The whole body uptake rates of (75)Se by pygmy mussels, semaphore crabs and soldier crabs were 1.9, 2.4 and 4.1 times higher than (109)Cd, respectively. There were no significant (P>0.05) differences between the uptake rates of (75)Se and (109)Cd for ghost shrimps and polychaetes. The uptake rates of (109)Cd and (75)Se were highest in pygmy mussels; about six times higher than in soldier crabs for (109)Cd and in polychaetes for (75)Se - the organisms with the lowest uptake rates. The loss rates of (109)Cd and (75)Se were highest in semaphore crabs; about four times higher than in polychaetes for (109)Cd and nine times higher than in ghost shrimps for (75)Se - the organisms with the lowest loss rates. The loss of (109)Cd and (75)Se in all organisms was best described by a two (i.e. short and a longer-lived) compartment model. In the short-lived, or rapidly exchanging, compartment, the biological half-lives of (75)Se (16-39 h) were about three times greater than those of (109)Cd (5-12h). In contrast, the biological half-lives of (109)Cd in the longer-lived, or slowly exchanging compartment(s), were typically greater (1370-5950 h) than those of (75)Se (161-1500 h). Semaphore crabs had the shortest biological half-lives of both radionuclides in the long-lived compartment, whereas polychaetes had the greatest biological half-life for (109)Cd (5950 h), and ghost shrimps had the greatest biological half-life for (75)Se (1500 h). This study provides the first reported data for the biological half-lives of Se in estuarine decapod crustaceans. Moreover, it emphasises the importance of determining metal(loid) accumulation and loss kinetics in keystone prey items, which consequently influences their trophic transfer potential to higher-order predators. PMID:17182081

Alquezar, Ralph; Markich, Scott J; Twining, John R



Effect of meal type on specific dynamic action in the green shore crab, Carcinus maenas.  


The effect of meal type on specific dynamic action was investigated in the green shore crab, Carcinus maenas. When the crabs were offered a meal of fish, shrimp, or mussel of 3 % of their body mass the duration of the SDA response and thus the resultant SDA was lower for the mussel, compared with the shrimp or fish meals. In feeding behaviour experiments the crabs consumed almost twice as much mussel compared with fish or shrimp. When the animals were allowed to feed on each meal until satiated, the differences in the SDA response were abolished. The mussel was much softer (compression test) than the fish or shrimp meal, and meal texture is known to affect the SDA response in amphibians and reptiles. When the crabs were offered a meal of homogenized fish muscle or whole fish muscle, the SDA for the homogenized meal was approximately 35 % lower. This suggested that a significant portion of the SDA budget in decapod crustaceans may be related to mechanical digestion. This is not unexpected since the foregut is supplied by over forty muscles which control the cutting and grinding movements of the gastric mill apparatus. There were slight, but significant differences in protein, lipid, moisture and total energy content of each meal type. Three prepared meals that were high in either protein, lipid or carbohydrate were offered to the crabs to determine if the nutrient content was also a contributing factor to the observed differences in the SDA. The crabs did not eat the prepared meals as readily as the natural food items and as they are messy feeders there was a large variation in the amount of food eaten. The lack of significant differences in the SDA response as a function of nutrient content was likely due to differences in amount of food eaten, which is a major factor determining the SDA response. The differences in SDA when consuming natural food items were likely due to a combination of the costs of mechanical digestion, variation in nutrient content and food preference: determining how each of these factors contributes to the overall SDA budget remains a pressing question for comparative physiologists. PMID:24531572

McGaw, Iain J; Penney, Chantelle M



Mercury bioaccumulation in cartilaginous fishes from Southern New England coastal waters: Contamination from a trophic ecology and human health perspective.  


This study examined total mercury (Hg) concentrations in cartilaginous fishes from Southern New England coastal waters, including smooth dogfish (Mustelus canis), spiny dogfish (Squalus acanthias), little skate (Leucoraja erinacea), and winter skate (Leucoraja ocellata). Total Hg in dogfish and skates were positively related to their respective body size and age, indicating Hg bioaccumulation in muscle tissue. There were also significant inter-species differences in Hg levels (mean ± 1 SD, mg Hg/kg dry weight, ppm): smooth dogfish (3.3 ± 2.1 ppm; n = 54) > spiny dogfish (1.1 ± 0.7 ppm; n = 124) > little skate (0.4 ± 0.3 ppm; n = 173) ? winter skate (0.3 ± 0.2 ppm; n = 148). The increased Hg content of smooth dogfish was attributed to its upper trophic level status, determined by stable nitrogen (?(15)N) isotope analysis (mean ?(15)N = 13.2 ± 0.7‰), and the consumption of high Hg prey, most notably cancer crabs (0.10 ppm). Spiny dogfish had depleted ?(15)N signatures (11.6 ± 0.8‰), yet demonstrated a moderate level of contamination by foraging on pelagic prey with a range of Hg concentrations, e.g., in order of dietary importance, butterfish (Hg = 0.06 ppm), longfin squid (0.17 ppm), and scup (0.11 ppm). Skates were low trophic level consumers (?(15)N = 11.9-12.0‰) and fed mainly on amphipods, small decapods, and polychaetes with low Hg concentrations (0.05-0.09 ppm). Intra-specific Hg concentrations were directly related to ?(15)N and carbon (?(13)C) isotope signatures, suggesting that Hg biomagnifies across successive trophic levels and foraging in the benthic trophic pathway increases Hg exposure. From a human health perspective, 87% of smooth dogfish, 32% of spiny dogfish, and <2% of skates had Hg concentrations exceeding the US Environmental Protection Agency threshold level (0.3 ppm wet weight). These results indicate that frequent consumption of smooth dogfish and spiny dogfish may adversely affect human health, whereas skates present minimal risk. PMID:25081850

Taylor, David L; Kutil, Nicholas J; Malek, Anna J; Collie, Jeremy S



Distribution and habitat preferences of two grapsid crab species in Mar Chiquita Lagoon (Province of Buenos Aires, Argentina)  

NASA Astrophysics Data System (ADS)

Cyrtograpsus angulatus and Chasmagnathus granulata (Grapsidae) are the two dominant decapod crustacean species in the outer parts of Mar Chiquita Lagoon, the southernmost in a series of coastal lagoons that occur along the temperate Atlantic coasts of South America. Distribution and habitat preferences (water and sediment type) in these crab species were studied in late spring. There is evidence of ontogenetic changes in habitat selection of both species. Recruitment of C. angulatus takes place mainly in crevices of tube-building polychaete ( Ficopomatus enigmaticus) “reefs” and, to a lesser extent, also in other protected microhabitats (under stones). In the latter, mostly somewhat larger juveniles were found, suggesting that these are used as a refuge for growing individuals. Adults are most frequently found on unprotected muddy and sandy beaches. C. angulatus was found in all parts of Mar Chiquita Lagoon, including freshwater, brackish, and marine habitats. C. granulata, in contrast, was restricted to the lower parts of the lagoon, where brackish water predominates and freshwater or marine conditions occur only exceptionally. It showed highest population density on “dry mud” flats and in Spartina densiflora grassland, where it can build stable burrows and where high contents of organic matter occur in the sediment. Such habitats are characterized by mixed populations of juveniles (including newly settled recruits) and adults, males and females (including a high percentage of ovigerous). Unstable “wet mud” as well as stony sand were found to be inhabited by chiefly adult populations, with only few ovigerous females. In “dry mud” flats, the proportion of males increased vertically with increasing level in the intertidal zone, showing a significantly increasing trend also in their average body size. These observations may be explained by higher resistance of males, in particular of large individuals, to desiccation, salinity, and temperature stress occurring in the upper intertidal. However, an opposite, or no such, tendency was found in the distribution of ovigerous and non-ovigerous females, respectively. With increasing distance from the water edge, salinity increased and pH decreased significantly in C. granulata burrows, whereas temperature showed no consistent tendency within the intertidal gradient. A highly significant linear relationship (r=-0.794; P<0.001) between salinity and pH in water from crab burrows is described. This regression line is significantly different from one that had been observed in water from the lagoon, indicating consistently lower pH values at any salinity level in burrow water. This is interpreted as a result of crab and/or microbial respiration.

Spivak, E.; Anger, K.; Luppi, T.; Bas, C.; Ismael, D.



Isotopic composition of carbon and nitrogen of suprabenthic fauna in the NW Balearic Islands (western Mediterranean)  

NASA Astrophysics Data System (ADS)

Stable isotope (? 13C and ? 15N) analyses were performed on suprabenthic fauna collected in the western Mediterranean (NW Balearic Islands), at depths ranging between 350 and 780 m. Samples were collected seasonally at bi-monthly intervals during six cruises performed between August 2003 and June 2004, using a Macer-GIROQ suprabenthic sledge (0.5 mm mesh size). Twenty-four separate species (5 mysids, 12 amphipods, 2 cumaceans, 2 isopods, 1 euphausiid, 1 decapod and 1 fish) and bulk copepods were analyzed on a seasonal basis for stable carbon and nitrogen isotopes. Stable nitrogen isotope ratios (? 15N) ranged from 2.3‰ (the amphipod Lepechinella manco in September 2003) to 13.0‰ (the amphipod Rhachotropis caeca in August 2003). ? 13C values ranged from - 24.2 (the cumacean Campylaspis sulcata in June 2004) to - 16.1 (the amphipod Bruzelia typica in November 2006). Both ? 13C and ? 15N values suggest that there are three trophic levels within the suprabenthic community. However, considering the bathymetric range of the species, the results suggest that the deepest assemblage supported only two trophic levels. The stable isotope ratios of suprabenthic fauna displayed a continuum of values and confirmed a wide spectrum of feeding types (from filter-feeders to predators). In general, and in spite of the poor knowledge about diets available for most suprabenthic species, higher ? 15N were found for carnivorous amphipods (e.g. Rhachotropis spp., Nicippe tumida) consuming copepods. Low overlap for ? 13C and ? 15N values was observed, though ? 15N values where less variable than ? 13C, which suggests high resource partitioning in this assemblage. Seasonal variations in isotopic composition for both ? 13C and ? 15N were low (less than 1‰ and 3‰, respectively) and variable depending on species. Low correlations between ? 13C and ? 15N of suprabenthic fauna were found for all periods studied, though increasing from February 2004 to June 2004 (after the main peak of primary production in surface). C:N ratio (indicator of lipid content) showed higher values in summer than in winter. This suggests that lipid content may explain the seasonal patterns of ? 13C variability and, due to the increase of storage products in phytoplankton and zooplankton, it possibly indicates the peak of primary production at the surface.

Madurell, T.; Fanelli, E.; Cartes, J. E.


Towing large nets by single warp at abyssal depths: methods and biological results  

NASA Astrophysics Data System (ADS)

Adequately sampling deep-water nekton is difficult because of the great time required for tows, avoidance of nets by larger animals, and the sparse fauna. These problems have been compounded by the small nets usually used for such sampling. This paper describes the equipment, techniques, difficulties, and results of towing large midwater and bottom trawls single warp at depths below 2000 m from chartered commercial fishing vessels. Use of large nets (107 m 2 mouth pelagic rope trawl and 29.6 m headrope otter trawl) is a method which minimizes the effects on sample sizes and compositions of the above factors. Tows with large opening-closing midwater trawls and otter trawls between 2000 and 4300 m off northern California collected specimens of rare species and unusually large individuals of other species. Included among these are five fish species not previously reported from off California: Bathysaurus mollis (Synodontidae), Barathronus pacificus (Aphyonidae), Echinomacrurus occidentalis (Macrouridae), Dysalotus oligoscolus (Chiasmodontidae), and Bellocia alvifrons (Alepocephalidae). Fishes decreased with depth by numbers of species, numbers of individuals, and by weight. Decapod crustaceans did not show similar trends. Cephalopods were uncommon at all depths sampled. Coryphaenoides filifer (Macrouridae), a nominally benthic fish species, was unexpectedly abundant in midwater between 2000 and 3100 m. It constituted 54.6% of the fish biomass collected at these depths. Its abundance did not appear to be related to sex, size, or reproduction. Food habits of Coryphaenoides armatus and C. yaquinae (Macrouridae), the most abundant benthic fish species, differed. The former ate primarily nekton; the latter, benthic infauna. Occurrence in stomachs of beaks from shallow living squid and of epipelagic barnacles suggests that carrion may form a significant part of the diets of these species. One ripe and five ripening female C. armatus, all longer than 740 mm TL, were collected. Estimated fecundity of the ripest was 6.2 × 10 6 eggs. Based on these and previous captures, C. armatus females mature at a large size, have a high fecundity relative to other macrourids, may not spawn simultaneously, and may be semelparous.

Stein, David L.



Characterization of the putative farnesoic acid O-methyltransferase (LvFAMeT) cDNA from white shrimp, Litopenaeus vannamei: Evidence for its role in molting.  


Methyl farnesoate (MF) is the crustacean homolog of the insect juvenile hormone and is believed to regulate growth and reproduction in crustaceans. Farnesoic acid O-methyltransferase (FAMeT) catalyzes the conversion of farnesoic acid (FA) to MF. Here we report the cloning and characterization of two forms of FAMeTs (i.e. LvFAMeT-S and LvFAMeT-L) from the shrimp Litopenaeus vannamei. LvFAMeT transcript has a wide tissue distribution pattern in L. vannamei and is also expressed in nauplius, zoea, mysis, post-larval stages and adults. Unlike FAMeTs reported in other decapods, transcripts of two different sizes were detected in L. vannamei. We postulate that the wide distribution of LvFAMeT expression may be related to its role in growth and regulation of molting. To study the functions of LvFAMeT in molting, the RNA interference (RNAi) technique was used. Injection of double stranded RNA (dsRNA) for LvFAMeT knocked down the expression of LvFAMeT in shrimp for at least 3 days and the shrimp did not advance to the final stage of molt cycle. Furthermore, the expression of the molt-related genes encoding cathepsin-L and the hemocyanin gene was disturbed. Subsequently, 100% mortality of the shrimp was observed in the LvFAMeT dsRNA-injected shrimp. In contrast, control shrimp completed their molt and proceeded to the next molt cycle. We postulate that, as an important enzyme for the conversion of FA to MF, RNAi injection knocked down the expression of LvFAMeT which could potentially result in a decrease in the production of MF and subsequently, could affect the molting process. The newly identified LvFAMeT may be involved in the control of molting in shrimp. The results of this study demonstrate the potential use of the RNA interference technique to study other putative genes identified in crustaceans. PMID:18226425

Hui, Jerome Ho Lam; Tobe, Stephen S; Chan, Siu-Ming



Coherence of long-term variations of zooplankton in two sectors of the California Current System  

NASA Astrophysics Data System (ADS)

We analyzed long-term (56-year) variations in springtime biomass of the zooplankton of the California Current System from two primary regions sampled by CalCOFI: Southern California (SC) and Central California (CC) waters. All organisms were enumerated from the plankton samples and converted to organic carbon biomass using length-carbon relationships, then aggregated into 19 major taxa. Planktonic copepods dominate the carbon biomass in both SC (59%) and CC (46%), followed by euphausiids (18% and 25% of mean biomass in SC and CC, respectively). Pelagic tunicates, especially salps and doliolids, constituted a higher fraction of the biomass in CC (13%) than in SC (5%). There was no long-term trend detectable in total zooplankton carbon biomass, in marked contrast to a decline in zooplankton displacement volume in both regions. The difference between these biomass metrics is accounted for by a long-term decline in pelagic tunicates (particularly salps), which have a relatively high ratio of biovolume:carbon. The decline in pelagic tunicates was accompanied by a long-term increase in water column density stratification. No other taxa showed a decline over the duration of the study, apart from salps and pyrosomes in SC and doliolids in CC. Some zooplankton taxa showed compensatory increases over the same time period (ostracods, large decapods, and calycophoran siphonophores in both SC and CC; appendicularians and polychaetes in SC). Two tests for ecosystem shifts, a sequential algorithm and the cumulative sum of anomalies (CuSum) approach, failed to detect changes in 1976-1977 in total carbon biomass, displacement volume, or most individual major taxa, suggesting that aggregated biomass is an insensitive indicator of climate forcing. In contrast, both techniques revealed a cluster of step-like changes associated with the La Niña of 1999. The major El Niño’s in the past half century have consistently depressed total zooplankton biomass and biomass of many major taxa in both SC and CC, although such effects are transitory. Much, but not all, of the interannual variability in zooplankton is shared between the Southern and Central California sectors of the California Current System.

Lavaniegos, Bertha E.; Ohman, Mark D.



Molt regulation in green and red color morphs of the crab Carcinus maenas: gene expression of molt-inhibiting hormone signaling components.  


In decapod crustaceans, regulation of molting is controlled by the X-organ/sinus gland complex in the eyestalks. The complex secretes molt-inhibiting hormone (MIH), which suppresses production of ecdysteroids by the Y-organ (YO). MIH signaling involves nitric oxide and cGMP in the YO, which expresses nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). Molting can generally be induced by eyestalk ablation (ESA), which removes the primary source of MIH, or by multiple leg autotomy (MLA). In our work on Carcinus maenas, however, ESA has limited effects on hemolymph ecdysteroid titers and animals remain in intermolt at 7 days post-ESA, suggesting that adults are refractory to molt induction techniques. Consequently, the effects of ESA and MLA on molting and YO gene expression in C. maenas green and red color morphotypes were determined at intermediate (16 and 24 days) and long-term (~90 days) intervals. In intermediate-interval experiments, ESA of intermolt animals caused transient twofold to fourfold increases in hemolymph ecdysteroid titers during the first 2 weeks. In intermolt animals, long-term ESA increased hemolymph ecdysteroid titers fourfold to fivefold by 28 days post treatment, but there was no late premolt peak (>400 pg ?l(-1)) characteristic of late premolt animals and animals did not molt by 90 days post-ESA. There was no effect of ESA or MLA on the expression of Cm-elongation factor 2 (EF2), Cm-NOS, the beta subunit of GC-I (Cm-GC-I?), a membrane receptor GC (Cm-GC-II) and a soluble NO-insensitive GC (Cm-GC-III) in green morphs. Red morphs were affected by prolonged ESA and MLA treatments, as indicated by large decreases in Cm-EF2, Cm-GC-II and Cm-GC-III mRNA levels. ESA accelerated the transition of green morphs to the red phenotype in intermolt animals. ESA delayed molting in premolt green morphs, whereas intact and MLA animals molted by 30 days post treatment. There were significant effects on YO gene expression in intact animals: Cm-GC-I? mRNA increased during premolt and Cm-GC-III mRNA decreased during premolt and increased during postmolt. Cm-MIH transcripts were detected in eyestalk ganglia, the brain and the thoracic ganglion from green intermolt animals, suggesing that MIH in the brain and thoracic ganglion prevents molt induction in green ESA animals. PMID:24198255

Abuhagr, Ali M; Blindert, Jennifer L; Nimitkul, Sukkrit; Zander, Ian A; Labere, Stefan M; Chang, Sharon A; Maclea, Kyle S; Chang, Ernest S; Mykles, Donald L



Climate-dependent evolution of Antarctic ectotherms: An integrative analysis  

NASA Astrophysics Data System (ADS)

The paper explores the climate-dependent evolution of marine Antarctic fauna and tries to identify key mechanisms involved as well as the driving forces that have caused the physiological and life history characteristics observed today. In an integrative approach it uses the recent concept of oxygen and capacity limited thermal tolerance to identify potential links between molecular, cellular, whole-organism, and ecological characteristics of marine animal life in the Antarctic. As a generalized pattern, minimization of baseline energy costs, for the sake of maximized growth in the cold, appears as one over-arching principle shaping the evolution and functioning of Antarctic marine ectotherms. This conclusion is supported by recent comparisons with (sub-) Arctic ectotherms, where elevated levels of energy turnover result at unstable, including cold temperatures, and are related to wide windows of thermal tolerance and associated metabolic features. At biochemical levels, metabolic regulation at low temperatures in general, is supported by the cold compensation of enzyme kinetic parameters like substrate affinities and turnover numbers, through minute structural modifications of the enzyme molecule. These involve a shift in protein folding, sometimes supported by the replacement of individual amino acids. The hypothesis is developed that efficient metabolic regulation at low rates in Antarctic marine stenotherms occurs through high mitochondrial densities at low capacities and possibly enhanced levels of Arrhenius activation energies or activation enthalpies. This contrasts the more costly patterns of metabolic regulation at elevated rates in cold-adapted eurytherms. Energy savings in Antarctic ectotherms, largely exemplified in fish, typically involve low-cost, diffusive oxygen distribution due to high density of lipid membranes, loss of haemoglobin, myoglobin and the heat shock response, reduced anaerobic capacity, large myocytes with low ion exchange activities, and the use of lipid body stores for neutral buoyancy. Important trade-offs result from obligatory energy savings in the permanent cold: low metabolic rates support cold-compensated growth but imply narrow windows of thermal tolerance and reduced scopes for activity. The degree of thermal specialization is not uniformly defined by cold temperature but varies with life style characteristics and activity levels and associated aerobic scope. Trade-offs for the sake of cold compensated growth parallel reduced capacities for exercise performance, exacerbated by the effect of high haemolymph magnesium levels in crustaceans and, possibly, other invertebrates. High magnesium levels likely exclude the group of reptant decapod crustaceans from Antarctic waters below 0 °C. The hypothesis is developed that energy savings imposed by the permanent cold bear specific life history consequences. Due to effects of allometry, energy savings are exacerbated at small body size, favouring passive lecithotrophic larvae. At all stages of life history, reduced energy turnover for the sake of growth causes delays and low rates in other higher functions, with the result of late maturity, fecundity and offspring release, as well as extended development. As a consequence, extended life spans evolved due to life history requirements. At the same time, polar gigantism is enabled by a combination of elevated oxygen levels in cold waters, of reduced metabolism and of extended periods of growth at slow developmental rates.

Pörtner, Hans O.



Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?  

PubMed Central

Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.



Rheb, an activator of target of rapamycin, in the blackback land crab, Gecarcinus lateralis: cloning and effects of molting and unweighting on expression in skeletal muscle.  


Molt-induced claw muscle atrophy in decapod crustaceans facilitates exuviation and is coordinated by ecdysteroid hormones. There is a 4-fold reduction in mass accompanied by remodeling of the contractile apparatus, which is associated with an 11-fold increase in myofibrillar protein synthesis by the end of the premolt period. Loss of a walking limb or claw causes a loss of mass in the associated thoracic musculature; this unweighting atrophy occurs in intermolt and is ecdysteroid independent. Myostatin (Mstn) is a negative regulator of muscle growth in mammals; it suppresses protein synthesis, in part, by inhibiting the insulin/metazoan target of rapamycin (mTOR) signaling pathway. Signaling via mTOR activates translation by phosphorylating ribosomal S6 kinase (s6k) and 4E-binding protein 1. Rheb (Ras homolog enriched in brain), a GTP-binding protein, is a key activator of mTOR and is inhibited by Rheb-GTPase-activating protein (GAP). Akt protein kinase inactivates Rheb-GAP, thus slowing Rheb-GTPase activity and maintaining mTOR in the active state. We hypothesized that the large increase in global protein synthesis in claw muscle was due to regulation of mTOR activity by ecdysteroids, caused either directly or indirectly via Mstn. In the blackback land crab, Gecarcinus lateralis, a Mstn-like gene (Gl-Mstn) is downregulated as much as 17-fold in claw muscle during premolt and upregulated 3-fold in unweighted thoracic muscle during intermolt. Gl-Mstn expression in claw muscle is negatively correlated with hemolymph ecdysteroid level. Full-length cDNAs encoding Rheb orthologs from three crustacean species (G. lateralis, Carcinus maenas and Homarus americanus), as well as partial cDNAs encoding Akt (Gl-Akt), mTOR (Gl-mTOR) and s6k (Gl-s6k) from G. lateralis, were cloned. The effects of molting on insulin/mTOR signaling components were quantified in claw closer, weighted thoracic and unweighted thoracic muscles using quantitative polymerase chain reaction. Gl-Rheb mRNA levels increased 3.4-fold and 3.9-fold during premolt in claw muscles from animals induced to molt by eyestalk ablation (ESA) and multiple leg autotomy (MLA), respectively, and mRNA levels were positively correlated with hemolymph ecdysteroids. There was little or no effect of molting on Gl-Rheb expression in weighted thoracic muscle and no correlation of Gl-Rheb mRNA with ecdysteroid titer. There were significant changes in Gl-Akt, Gl-mTOR and Gl-s6k expression with molt stage. These changes were transient and were not correlated with hemolymph ecdysteroids. The two muscles differed in terms of the relationship between Gl-Rheb and Gl-Mstn expression. In thoracic muscle, Gl-Rheb mRNA was positively correlated with Gl-Mstn mRNA in both ESA and MLA animals. By contrast, Gl-Rheb mRNA in claw muscle was negatively correlated with Gl-Mstn mRNA in ESA animals, and no correlation was observed in MLA animals. Unweighting increased Gl-Rheb expression in thoracic muscle at all molt stages; the greatest difference (2.2-fold) was observed in intermolt animals. There was also a 1.3-fold increase in Gl-s6k mRNA level in unweighted thoracic muscle. These data indicate that the mTOR pathway is upregulated in atrophic muscles. Gl-Rheb, in particular, appears to play a role in the molt-induced increase in protein synthesis in the claw muscle. PMID:22279066

MacLea, Kyle S; Abuhagr, Ali M; Pitts, Natalie L; Covi, Joseph A; Bader, Brandon D; Chang, Ernest S; Mykles, Donald L



Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna  

NASA Astrophysics Data System (ADS)

The Pakistan Margin is characterised by a strong mid-water oxygen minimum zone (OMZ) that intercepts the seabed at bathyal depths (150-1300 m). We investigated whether faunal abundance and diversity trends were similar among protists (foraminiferans and gromiids), metazoan macrofauna and megafauna along a transect (140-1850 m water depth) across the OMZ during the 2003 intermonsoon (March-May) and late/post-monsoon (August-October) seasons. All groups exhibited some drop in abundance in the OMZ core (250-500 m water depth; O 2: 0.10-0.13 mL L -1=4.46-5.80 ?M) but to differing degrees. Densities of foraminiferans >63 ?m were slightly depressed at 300 m, peaked at 738 m, and were much lower at deeper stations. Foraminiferans >300 ?m were the overwhelmingly dominant macrofaunal organisms in the OMZ core. Macrofaunal metazoans reached maximum densities at 140 m depth, with additional peaks at 850, 940 and 1850 m where foraminiferans were less abundant. The polychaete Linopherus sp. was responsible for a macrofaunal biomass peak at 950 m. Apart from large swimming animals (fish and natant decapods), metazoan megafauna were absent between 300 and 900 m (O 2 <0.14-0.15 mL L -1=6.25-6.69 ?M) but were represented by a huge, ophiuroid-dominated abundance peak at 1000 m (O 2 ˜0.15-0.18 mL L -1=6.69-8.03 ?M). Gromiid protists were confined largely to depths below 1150 m (O 2 >0.2 mL L -1=8.92 ?M). The progressively deeper abundance peaks for foraminiferans (>63 ?m), Linopherus sp. and ophiuroids probably represent lower OMZ boundary edge effects and suggest a link between body size and tolerance of hypoxia. Macro- and megafaunal organisms collected between 800 and 1100 m were dominated by a succession of different taxa, indicating that the lower part of the OMZ is also a region of rapid faunal change. Species diversity was depressed in all groups in the OMZ core, but this was much more pronounced for macrofauna and megafauna than for foraminiferans. Oxygen levels strongly influenced the taxonomic composition of all faunal groups. Calcareous foraminiferans dominated the seasonally and permanently hypoxic sites (136-300 m); agglutinated foraminiferans were relatively more abundant at deeper stations where oxygen concentrations were >0.13 mL L -1(=5.80 ?M). Polychaetes were the main macrofaunal taxon within the OMZ; calcareous macrofauna and megafauna (molluscs and echinoderms) were rare or absent where oxygen levels were lowest. The rarity of larger animals between 300 and 700 m on the Pakistan Margin, compared with the abundant macrofauna in the OMZ core off Oman, is the most notable contrast between the two sides of the Arabian Sea. This difference probably reflects the slightly higher oxygen levels and better food quality on the western side.

Gooday, A. J.; Levin, L. A.; Aranda da Silva, A.; Bett, B. J.; Cowie, G. L.; Dissard, D.; Gage, J. D.; Hughes, D. J.; Jeffreys, R.; Lamont, P. A.; Larkin, K. E.; Murty, S. J.; Schumacher, S.; Whitcraft, C.; Woulds, C.



River-Borne Sediment Exports, Sedimentation Rates, and Influence on Benthos and Leaflitter Breakdown in Southern Caribbean Mangroves (uraba, Colombia)  

NASA Astrophysics Data System (ADS)

Deposition of river-borne sediments is a major issue in coastal ecosystems worldwide, but no study has been conducted in Neotropical mangroves. Mangroves in the Urabá Gulf (Southern Caribbean coast of Colombia) receive one of the highest sediment loads (<0.10-0.77 x 106 ton yr-1) of the Caribbean region from rivers crossing an extensive banana crop district. Annual sedimentation rates were computed based in monthly samplings (2009-2010) in mangrove fringes across the Turbo River Delta using bottom-fixed 1L-cylinders (n=15). A significant spatial variation (0.04-0.9 ton m-2 yr-1) was observed among sampling stations within the delta, but the highest trapping occurred on river's main channel (2.54 ton m-2 yr-1). Temporal variation was smaller than spatial variation. Monitoring (twenty 1-m2 quadrats x 3 sites x 12 months) of a dominant mangrove-floor gastropod (Neritina virginea) observed a positive increase of density (4-125 ind. m-2: One-way ANOVA: p<0.001) along a sedimentation gradient (monthly means for low and high sedimentation sites: 3-69 kg m-2 yr-1). The role of N. virginea on leaflitter breakdown relative to sedimentation level was experimentally tested in a black mangrove (Avicennia germinans) stand by using 180 wire-mesh cages (15 x 15 x 25 cm) placed on the forest floor as experimental units, to prevent snail and crab access. After clearing existing snails and litter from the muddy bottom, each cage was placed and 1 senescent leaf of A. germinans and 7 snails were introduced (previously weighed) (snail abundance was similar to background densities). Three levels of area-weighed sedimentation rates (1, 3 and 18 g per cage) were daily added to test the impacts of the field-observed sedimentation gradient. The experiment was carried out during one month. Fresh leaf mass was different among treatments during the first week, increasing in proportion to the sedimentation rate probably due to leaf soaking. However, there was no difference in fresh leaf weight loss (average: 67%) among sediment levels after one month. Fresh weight loss (range: 81.6-4.4%) was observed in the snails during the early stage of the experiment. Significant differences were observed but not related to sediment levels. After one month, the snails gained weight (<1, 5, and 12%) in proportion to increased sediment levels (1, 3 and 18 g per day and cage). These results suggested that sedimentation levels observed in the study area are not detrimental for N. virginea populations and for their feeding activities. They also suggested that this species may cope with increased sedimentation by shifting feeding from leaflitter to sediments. However, the dominance by N. virginea (in number and biomass) in the study area may indicate that siltation is harmful for sensitive gastropods and for the entire benthic community, also including bivalves, decapods and polychaetes.

Blanco, J. F.; Taborda, A.; Arroyave, A.



On two reports associated with James Wood-Mason and Alfred William Alcock published by the Indian Museum and the Indian Marine Survey between 1890 and 1891: implications for malacostracan nomenclature.  


Two rare documents associated with the Indian Museum and the Indian Marine Survey for the administrative year April 1890 to March 1891 have been examined and found to have nomenclatural consequences for malacostracan crustaceans. Even though they constitute available published works according to the International Code for Zoological Nomenclature, these reports have rarely been cited. Dating these two publications is of importance as they make decapod scientific names available and, in a few instances, describe the same taxa. After searching the collections deposited in the Asian and African Room, British Library, the Administration Report of the Indian Marine for the year April 1890 to March 1891 could be dated with some degree of certainty as 25 August 1891. In contrast, dating the Indian Museum Annual Report proved more difficult because after examination of copies held by the General Library in the Natural History Museum, London, it was evident that not all of these reports were consistently published on time to meet an end of year deadline. However, the publication of volume XXII of the Indian Museum Annual Report for the year April 1890 to March 1891 appeared to be contemporary with the year printed at the bottom of the title page. As no exact date could be established with confidence, the publication date for this volume was fixed as 31 December 1891 in accordance with ICZN Art. 21.3.2. Therefore the Administration Report of the Indian Marine (published 25 August 1891) is considered to take precedence over the Indian Museum Annual Report (published 31 December 1891) and as such the names made available in the former take priority. As original copies of the Administration Report of the Indian Marine are not readily available in most libraries and few scientists have actually had access to these publications, the relevant Appendix No. XIII, in which the names of several malacostracan taxa are made available, is reproduced here. Since the appendix is not conclusively attributable to a specific author, it is considered to be written anonymously and should therefore be cited as Anonymous (1891). A number of names in Appendix No. XIII are available since they are accompanied by a brief description of the taxa they denote, and are either attributable to James Wood-Mason or remain with anonymous authorship; others are nomina nuda without a diagnosis or indication, or have been diagnosed previously in the "Natural History Notes from H.M. Indian Marine Survey Steamer Investigator". The nomenclatural implications for eight names made available in Anonymous (1891) are discussed: Glyphocrangon caeca, Glyphocrangon sculptus var. coecescens, Psalidopodidae, Psalidopus, Psalidopus mirabilis, Psathyrocaris, Psathyrocaris fragilis and Psopheticus crepitans. The nomenclatural history of various other taxa, initially denoted by unavailable names in Anonymous (1891), is also documented. The authorships of the various crustacean taxa collected by the Indian Marine Survey Steamer Investigator during the seasons 1889-1890 and 1890-1891, and published in two series of connected parts in the Annals and Magazine of Natural History, are also re-assessed and summarised. A rare document containing the list of R.I.M.S. Investigator stations for the period 1884-1913 is reproduced for the future benefit of the scientific community.  PMID:24869963

Huys, Rony; Low, Martyn E Y; De Grave, Sammy; Ng, Peter K L; Clark, Paul F



Trophic ecology of Lampanyctus crocodilus on north-west Mediterranean Sea slopes in relation to reproductive cycle and environmental variables.  


This study examined the population structure, reproductive cycle and feeding pattern of the lanternfish Lampanyctus crocodilus in the Balearic Basin (north-west Mediterranean Sea) from a depth of 450 to 1800?m and at a seasonal scale. Juveniles were mainly located at shallower depths, but also at deepest stations in autumn, while adults mostly inhabited intermediate depths with their centre of population density (CPD) located at 800-1000?m of depth. The migration of adults to deeper depths was detected in late summer to autumn, probably linked to the occurrence of nepheloid layers at c. 1200?m, which in turn enhances the biomass of the zooplankton prey. The diet was mainly based on euphausiids and mysids, with marked seasonal variations both on the upper (450-800 m) and lower (1000-1800 m), where suprabenthic gammariids and pelagic decapods were also dominant. Stomach fullness increased from winter to autumn on the US, while it had a maximum in spring on the LS, in parallel with high consumption of gelatinous zooplankton, which is probably more available after the phytoplankton bloom in late winter. Reproduction occurred in winter, confirmed by the higher percentage of mature females and high gonadosomatic indices (I(G)) at both depth ranges. Hepatosomatic indices (I(H)) showed an inverse trend to I(G) on the US, except in autumn, and was almost parallel on the LS, probably attributable to the migration of adults, which determined different temporal schemes in energy use and storage for reproduction on the US v. LS. Consistent with the different patterns observed at the two depth ranges, environmental drivers of fullness (i.e. feeding intensity) and I(G) (as a proxy of reproductive cycle) differed on the US and LS. The biomass of mysids and euphausiids was the greatest explanatory variables of fullness on the US and LS, pointing to the increasing feeding intensity when a resource was more available. I(H) also explained fullness, suggesting that greater feeding intensity in pre-reproductive periods enabled energy storage in the liver. I(G) was linked directly (i.e. mysids) or indirectly (i.e. surface primary production recorded 2 months before sampling) to food availability, implying a rapid response to vertical food inputs by deep-sea predators. Also, I(G) in L. crocodilus was related to population density, which suggests aggregations for reproduction. Estimates of L. crocodilus trophic levels, and of other accompanying mesopelagic fishes, indicated that the species feed through a continuum spanning the third trophic level, confirming the key role of mesopelagic fishes in transferring organic carbon between trophic levels. Trophic niche segregation among mesopelagic species was pronounced and non-overlapping groups could be distinguished because of the different vertical distribution and migratory behaviour. The study highlights the important role of the benthic boundary layer in sustaining benthopelagic communities in the deep Mediterranean Sea and the need to study the biology of a species throughout its whole depth range and not just at exploited depths (i.e. fishing grounds). PMID:24786723

Fanelli, E; Papiol, V; Cartes, J E; Rodriguez-Romeu, O



Food-web structure and trophodynamics of mesopelagic-suprabenthic bathyal macrofauna of the Algerian Basin based on stable isotopes of carbon and nitrogen  

NASA Astrophysics Data System (ADS)

The trophodynamics of mesopelagic (macrozooplankton/micronekton) and benthic boundary layer (suprabenthos=hyperbenthos) faunas from the Algerian Basin were characterized on a seasonal scale through stable carbon and nitrogen isotopic analyses of a total of 34 species and two broad taxa (Copepoda and Cumacea). This is the first study simultaneously focused on trophodynamics of deep-sea zooplankton and suprabenthos. Samples were collected southeast of Mallorca (Algerian Basin, Western Mediterranean), on the continental slope close to Cabrera Archipelago, at 650-780 m depths, ca. bi-monthly between August 2003 and June 2004. Mean ? 13C values of suprabenthos ranged from -21.1‰ ( Munnopsurus atlanticus) to -16.7‰ ( Cyclaspis longicaudata). Values of ? 15N ranged from 2.8‰ ( Lepechinella manco) to 9.9‰ (larvae of Gnathia sp.). The stable isotope ratios of suprabenthic fauna displayed a continuum of values, confirming a wide spectrum of feeding guilds (from filter feeders/surface deposit feeders to predators). According to the available information on diets for suprabenthic species, the highest annual mean ? 15N values were found for the hematophagous isopod Gnathia sp. parasite on fish (represented by Praniza larvae) and carnivorous amphipods (e.g. Rhachotropis spp., Nicippe tumida) consuming copepods, and the lowest ? 15N values were found for two cumaceans ( Cyclaspis longicaudata and Platysympus typicus) feeding on detritus. Assuming a 15N-enrichment factor of 2.5‰ and deposit feeders as baseline, we found three trophic levels in suprabenthic food webs. ? 13C ranges were particularly wide among deposit feeders (ranging from -21.8% to -17.3‰) and omnivores (from -20.5% to -18.8‰), suggesting exploitation of particulate organic matter (POM) of different characteristics. Our isotopic analyses revealed lower ranges of ? 13C and ? 15N for macrozooplankton/micronekton, compared with suprabenthos. ? 13C values of zooplankton taxa ranged from -21.1‰ (the hyperiid Phrosina semilunata) to -19.9‰ (the decapod Pasiphaea multidentata), while ? 15N values ranged from 3.9‰ ( P. semilunata) to 7.5‰ ( P. multidentata). Among zooplankton, more enriched ? 15N values were found among carnivores (e.g. the fish Cyclothone spp. and Pasiphaea multidentata) preying on copepods, hyperiids, euphausiids and small fish. The lowest ? 15N values were found for hyperiids that feed on the mucus nets of salps (e.g. Vibilia armata). After contrasting isotope analysis with dietary data, we conclude there were two trophic levels among zooplankton/micronekton. Strong correlation between the mean annual ? 15N and ? 13C values was found for zooplankton ( R2=0.7), but not for suprabenthos, which suggests a single source of carbon for plankton. We found a general seasonal trend for ? 13C enrichment from late autumn (November) to late winter-spring (February-April) for both suprabenthos and zooplankton. The ? 13C enrichment in February-April was correlated in zooplankton with higher surface chlorophyll a concentration 1 month before sampling. As evidenced by ? 13C-? 15N correlations, the response of zooplankton to the peak of surface primary production was almost immediate (an increase of ? 13C-? 15N correlations in February), and stronger than for suprabenthos. The response among suprabenthos was weak, with slight increase in ? 13C-? 15N relationships in April-June.

Fanelli, E.; Cartes, J. E.; Rumolo, P.; Sprovieri, M.



Dynamics of suprabenthos-zooplankton communities around the Balearic Islands (western Mediterranean): Influence of environmental variables and effects on the biological cycle of Aristeus antennatus  

NASA Astrophysics Data System (ADS)

Dynamics of suprabenthos and zooplankton were analyzed in two areas located in the NW (off Sóller harbour) and S (off Cabrera Archipelago) of Mallorca (Balearic Islands, western Mediterranean) at depths ranging between 135-780 m. Four stations situated respectively at 150 m (shelf-slope break), and at bathyal depths of 350, 650 and 750 m were sampled at bi-monthly intervals during six cruises performed between August 2003 and June 2004. Suprabenthos showed maximum biomass in both areas from late spring to summer (April to August), while minimum biomass was found in autumn (September-November). Though variable, temporal dynamics of zooplankton showed peaks of biomass in late winter and summer (February and June), while minimals occurred in autumn (August-September) and, at bathyal depths, in April. Suprabenthos (abundance; MDS analyses) showed a sample aggregation as a function of depth (3 groups corresponding to the shelf-slope break, upper slope — over 350 m; and the middle, deeper part of the slope — over 650-750 m), without any separation of hauls by season. By contrast, zooplankton samples were separated by season and not by depth. There was evidence of three seasonal groups corresponding to summer (June 2004-August 2003), autumn-winter (September and November 2003, February 2004), and spring (April 2004), being especially well established off Sóller. In general, suprabenthos was significantly correlated with the sediment variables (e.g. total organic matter content (% OM), potential REDOX), whereas zooplankton was almost exclusively dependent on Chl a at the surface, which suggests two different food sources for suprabenthos and zooplankton. The increase of suprabenthos abundance in April-June was paralleled by a sharp increase ( ca. 2.8 times) in the %OM on sediment during the same period, coupled ca. 1-2 months of delay with the peak of surface Chl a recorded in February-March (from satellite imagery data). Suprabenthos biomass was also correlated with salinity close to the bottom, suggesting a link between suprabenthos abundance and changes in the oceanographic condition of water masses close to the bottom. It is suggested that a higher suprabenthos biomass recorded off Sóller in comparison to that off Cabrera in June could, in turn, be related to a seasonal inflow of Levantine Intermediate Water (LIW) in April-June in this area at mid bathyal depths (350-650 m). This trend would be based on: 1) it was evident only at mid-slope depths between 350-750 m, coinciding with the LIW distribution, and 2) it was not recorded among zooplankton (collected throughout the water column). The possible effect of the fluctuations of suprabenthos and zooplankton on higher trophic levels has been explored studying the diet and food consumption rates of the red shrimp Aristeus antennatus, as indicator species by its dominance in bathyal communities. A. antennatus increased its food consumption from February to April-June 2004 off Sóller, which in the case of large (CL > 40 mm) specimens was found in both areas. In addition, there was a shift of diet from winter to spring-early summer. In this last period, A. antennatus preyed upon euphausiids and mesopelagic decapods and fish, while benthos (e.g. polychaetes and bivalves) decreased in the diet. This indicates an increase in the food consumption and probably in the caloric content of the diet in pre-spawning females in April-June 2004, which is synchronized with the period when gonad development begins in A. antennatus females (May-June). Anyway, macrozooplankton, and not suprabenthos, is crucial as a high energetic food source in the coupling between food intake and reproduction in the red shrimp.

Cartes, J. E.; Madurell, T.; Fanelli, E.; López-Jurado, J. L.


Growth patterns, chemical composition and oxygen consumption in early juvenile Hyas araneus (Decapoda: Majidae) reared in the laboratory  

NASA Astrophysics Data System (ADS)

Early (instar I and II) juveniles of the spider crab Hyas araneus were reared under constant conditions (12 °C, 32‰S) in the laboratory, and their growth, biochemical composition, and respiration were studied. Every second day, dry weight (W), ash-free dry weight (AFW), and contents of ash, organic and inorganic carbon (C), nitrogen (N), hydrogen (H), protein, chitin, lipid, and carbohydrates were measured, as well as oxygen consumption. Changes in the absolute amounts of W. AFW, and C, N, and H during the moulting cycle are described with various regression equations as functions of age within a given instar. These patterns of growth differ in part from those that have been observed during previous studies in larval stages of the same and some other decapod species, possibly indicating different growth strategies in larvae and juveniles. There were clear periodic changes in ash (% of W) and inorganic C (as % of total C), with initially very low and then steeply increasing values in postmoult, a maximum in intermoult, and decreasing figures during the premoult phase of each moulting cycle. Similar patterns were observed in the chitin fraction, reaching a maximum of 16% of W (31% of AFW). Ash, inorganic C, and chitin represent the major components of the exoskeleton and hence, changes in their amounts are associated with the formation and loss of cuticle material. Consequently, a high percentage of mineral matter was lost with the exuvia (76% of the late premoult [LPM] ash content, 74% of inorganic C), but relatively small fractions of LPM organic matter (15% of AFW, 11% of organic C, 5 6% of N and H). These cyclic changes in the cuticle caused an inverse pattern of variation in the percentage values (% of W) of AFW, organic C, N, H, and biochemical constituents other than chitin. When these measures of living biomass were related to, exclusively, the organic body fraction (AFM), much less variation was found during individual moulting cycles, with values of about 43 52% in organic C, 9 10% in N, 6 9% H, 31 49% of AFW in protein, 3 10% in lipid, and <1% in carbohydrates. All these constituents showed, on the average, a decreasing tendency during the first two crab instars, whereas N remained fairly constant. It cannot be explained at present, what other elements and biochemical compounds, respectively, might replace these decreasing components of AFW. Decreasing tendencies during juvenile growth were observed also in the organic C/N and in the lipid/protein weight ratios, both indicating that the proportion of lipid decreased at a higher rate than that of protein. Changes were observed also in the composition of inorganic matter, with significantly lower inorganic C in early postmoult (2 4% of ash) than in later stages of the moult cycle (about 9%). This reflected probably an increase in the degree of calcification, i.e. in the calcium carbonate content of the exoskeleton. As a fraction of total C, inorganic C reached maximum values of 17 and 20% in the crab I and II instars, respectively. The energy content of juvenile spider crabs was estimated independently from organic C and biochemical constituents, with a significant correlation between these values. However, the former estimates of energy were, on the average, significantly lower than the latter (slope of the regression ?1). Since organic C should be a reliable integrator of organic substances, but the sum of protein, lipid, chitin, and carbohydrates amounted to only 60 91% of AFW, it is concluded that the observed discrepancy between these two estimates of energy was caused by energy from biochemical constituents that had not been determined in our analyses. Thus, energy values obtained from these biochemical fractions alone may underestimate the actual amount of organic matter and energy. Respiration per individual in juvenile spider crabs was higher than that in larval stages of the same species (previous studies), but their W-specific values of oxygen consumption (QO2) were lower than in conspecific larvae (0.6 2?g O2·[mg W]-1). QO2 showed a consiste

Anger, K.; Harms, J.; Christiansen, M. E.; Süsens, U.; Wilmes, B.