Science.gov

Sample records for conrad gastropoda vetigastropoda

  1. Miocene Vetigastropoda and Neritimorpha (Mollusca, Gastropoda) of central Chile

    NASA Astrophysics Data System (ADS)

    Nielsen, Sven N.; Frassinetti, Daniel; Bandel, Klaus

    2004-09-01

    Species of Vetigastropoda (Fissurellidae, Turbinidae, Trochidae) and one species of Neritimorpha (Neritidae) from the Navidad area, south of Valparaı´so, and the Arauco Peninsula, south of Concepción, are described. Among these, the Fissurellidae comprise Diodora fragilis n. sp., Diodora pupuyana n. sp., two additional unnamed species of Diodora, and a species resembling Fissurellidea. Turbinidae are represented by Cantrainea sp., and Trochidae include Tegula (Chlorostoma) austropacifica n. sp., Tegula (Chlorostoma) chilena n. sp., Tegula (Chlorostoma) matanzensis n. sp., Tegula (Agathistoma) antiqua n. sp., Bathybembix mcleani n. sp., Gibbula poeppigii [Philippi, 1887] n. comb., Diloma miocenica n. sp., Fagnastesia venefica [Philippi, 1887] n. gen. n. comb., Fagnastesia matanzana n. gen. n. sp., Calliostoma mapucherum n. sp., Calliostoma kleppi n. sp., Calliostoma covacevichi n. sp., Astele laevis [Sowerby, 1846] n. comb., and Monilea riorapelensis n. sp. The Neritidae are represented by Nerita (Heminerita) chilensis [Philippi, 1887]. The new genus Fagnastesia is introduced to represent low-spired trochoideans with a sculpture of nodes below the suture, angulated whorls, and a wide umbilicus. This Miocene Chilean fauna includes genera that have lived at the coast and in shallow, relatively warm water or deeper, much cooler water. This composition therefore suggests that many of the Miocene formations along the central Chilean coast consist of displaced sediments. A comparison with different fossil and Recent faunas from around the Pacific and South America indicates that the vetigastropod and neritid fauna from the Miocene of Chile has only minor affinities with taxa living near New Zealand, Argentina, and the tropical eastern Pacific at that time.

  2. Joseph Conrad: International Narrator

    ERIC Educational Resources Information Center

    Walker, George

    2004-01-01

    This article discusses the contribution made by Joseph Conrad's fictional writing to our understanding of cultural awareness. Never comfortable with his adopted English culture, Conrad used his experiences in different parts of the world during his career in the merchant navy to explore in his writing aspects of cultural dissonance and cultural…

  3. Conrad Unfurls Flag

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Apollo 12 astronaut Charles 'Pete' Conrad stands beside the United States flag after is was unfurled on the lunar surface during the first extravehicular activity (EVA-1), on November 19, 1969. Several footprints made by the crew can be seen in the photograph.

  4. CONRAD Software Architecture

    NASA Astrophysics Data System (ADS)

    Guzman, J. C.; Bennett, T.

    2008-08-01

    The Convergent Radio Astronomy Demonstrator (CONRAD) is a collaboration between the computing teams of two SKA pathfinder instruments, MeerKAT (South Africa) and ASKAP (Australia). Our goal is to produce the required common software to operate, process and store the data from the two instruments. Both instruments are synthesis arrays composed of a large number of antennas (40 - 100) operating at centimeter wavelengths with wide-field capabilities. Key challenges are the processing of high volume of data in real-time as well as the remote mode of operations. Here we present the software architecture for CONRAD. Our design approach is to maximize the use of open solutions and third-party software widely deployed in commercial applications, such as SNMP and LDAP, and to utilize modern web-based technologies for the user interfaces, such as AJAX.

  5. Conrad Gessner's Paratexts.

    PubMed

    Blair, Ann

    2016-01-01

    Throughout his prolific publishing career Conrad Gessner composed abundant paratexts which offer valuable insight into his methods of working. Gessner wrote many dedications, only a minority of which were addressed to major patrons of his day. Instead he used them to thank dozens of physicians and scholars for sending him information, images, and manuscripts for his ongoing projects. Gessner acknowledged new arrivals in successive publications and invited further contributions explicitly. In "to the readers" and other passages Gessner called attention to his future publication plans and his skill in working with printers and in editing manuscripts of recently deceased scholars, thereby also encouraging new commissions. Gessner was also a master indexer and innovated especially in drawing up the first index of authors cited for his edition of Stobaeus in 1543 and a new all-purpose index in his Stobaeus of 1549. Many other aspects of Gessner's paratexts warrant further study. PMID:27349033

  6. Joseph Conrad's tormented Rescue (fantasy).

    PubMed

    Freedman, William

    2014-02-01

    Joseph Conrad was a notoriously tormented writer for whom the creative act was often a punishment severe enough to drive him into paralyzing depressions that delayed the completion of his novels, sometimes for years. By far the most agonizing of these projects was The Rescue, a novel he began in 1898, abandoned a year later, tried unsuccessfully to continue several times over the next two decades, but was only able to resume in 1918 and to complete, after another tortured two-year struggle, in 1920. An explanation for this incapacity, that is powerfully suggested by the novel's evocative title and perhaps unintentionally ironic subtitle (A Romance of the Shallows) has not yet been explored. Using Freud's 1910 essay on the rescue fantasy, "Contributions to the Psychology of Love: A Special Type of Choice of Object Made by Men," and Emanuel Berman's instructive revision and expansion of the concept in his 2003 American Imago essay, "Ferenczi, Rescue, and Utopia," I argue that a substantial explanation for Conrad's tormented history with The Rescue is ascribable to its quite remarkably faithful treatment of a rescue fantasy with deep and disabling resonance for its author. More specifically, the difficulty was compounded by the novel's dramatization of the soul-crushing conflict between two such fantasies: one in the service of the masculine ideal of unflinching dedication to a heroic purpose, the other promising satisfaction to the equally potent demands of emotional and sexual desire. Features of Conrad's narrative fit so tightly and consistently with the theory as Freud (and Abraham) proposed and as Berman elaborated it that The Rescue offers itself as one of those rare and reinforcing instances wherein the literary text seems to validate the psychoanalytic theory at least as persuasively as the theory "understands" the text. PMID:24555549

  7. Conrad: gene prediction using conditional random fields.

    PubMed

    DeCaprio, David; Vinson, Jade P; Pearson, Matthew D; Montgomery, Philip; Doherty, Matthew; Galagan, James E

    2007-09-01

    We present Conrad, the first comparative gene predictor based on semi-Markov conditional random fields (SMCRFs). Unlike the best standalone gene predictors, which are based on generalized hidden Markov models (GHMMs) and trained by maximum likelihood, Conrad is discriminatively trained to maximize annotation accuracy. In addition, unlike the best annotation pipelines, which rely on heuristic and ad hoc decision rules to combine standalone gene predictors with additional information such as ESTs and protein homology, Conrad encodes all sources of information as features and treats all features equally in the training and inference algorithms. Conrad outperforms the best standalone gene predictors in cross-validation and whole chromosome testing on two fungi with vastly different gene structures. The performance improvement arises from the SMCRF's discriminative training methods and their ability to easily incorporate diverse types of information by encoding them as feature functions. On Cryptococcus neoformans, configuring Conrad to reproduce the predictions of a two-species phylo-GHMM closely matches the performance of Twinscan. Enabling discriminative training increases performance, and adding new feature functions further increases performance, achieving a level of accuracy that is unprecedented for this organism. Similar results are obtained on Aspergillus nidulans comparing Conrad versus Fgenesh. SMCRFs are a promising framework for gene prediction because of their highly modular nature, simplifying the process of designing and testing potential indicators of gene structure. Conrad's implementation of SMCRFs advances the state of the art in gene prediction in fungi and provides a robust platform for both current application and future research. PMID:17690204

  8. Astronaut Charles Conrad using the bicycle ergometer

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Charles Conrad Jr., Skylab 2 commander, during an exercise session on the bicycle ergometer in the crew quarters of the Skylab Orbital Workshop (OWS) in the Skylab 2 space station cluster in Earth orbit.

  9. Conrad Hal Waddington: the last Renaissance biologist?

    PubMed

    Slack, Jonathan M W

    2002-11-01

    Conrad Hal Waddington was a leading embryologist and geneticist from the 1930s to the 1950s. He is remembered mainly for his concepts of the 'epigenetic landscape' and 'genetic assimilation'. This article reviews his life and work, and enquires to what extent his ideas are relevant tools for understanding the biological problems of today. PMID:12415319

  10. The British Novel: Conrad to the Present.

    ERIC Educational Resources Information Center

    Wiley, Paul L.

    Intended for advanced undergraduate and graduate students who desire a useful research tool, this bibliography cites the works of and about British novelists, beginning with Joseph Conrad and terminating in 1950. The listings are selective with proper emphasis given to less celebrated but distinctive writers. A preface explaining the numerous…

  11. Astronauts Weitz and Conrad suit up during prelaunch activity

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Paul J. Weitz, prime crew pilot of the first manned Skylab mission, is suited up in bldg 5 at JSC during prelaunch training activity. He is assisted by Astronaut Charles Conrad Jr., prime crew commander. The man in the left background is wearing a face mask to insure that Conrad, Joseph Kerwin, and Weitz are not exposed to disease prior to launch.

  12. CONRAD Evaluation Code: Development Status and Perspectives

    NASA Astrophysics Data System (ADS)

    Archier, P.; De Saint Jean, C.; Litaize, O.; Noguère, G.; Berge, L.; Privas, E.; Tamagno, P.

    2014-04-01

    CONRAD is an object-oriented code developed at CEA Cadarache since 2005 to treat issues occurring during the data assimilation process. The last new features of the code in terms of experimental, theoretical and interface aspects are presented in this paper. The experimental descriptions capabilities have been enhanced thanks to the implementation of both analytical (Chi-Square, Gaussian) and Monte-Carlo resolution functions which are required for neutron resonance shape analysis. On the theoretical aspects, efforts have been focused on the fast energy region with the wrapping of the ECIS and TALYS codes and the management of optical model and statistical parameters. These new features make it possible for CONRAD to currently perform evaluations from 0 to 20 MeV. Concerning the interfacing developments, a multigroup cross-sections generating tool and an ENDF parser have been recently improved to produce multigroup cross-section covariance matrices in the frame of the JEFF project. Several examples and comparisons with other codes (SAMMY, REFIT) are provided to validate each development.

  13. Neutron tomography instrument CONRAD at HZB

    NASA Astrophysics Data System (ADS)

    Kardjilov, N.; Hilger, A.; Manke, I.; Strobl, M.; Dawson, M.; Williams, S.; Banhart, J.

    2011-09-01

    The neutron tomography instrument CONRAD has been in operation since 2005 at the Hahn-Meitner research reactor at Helmholtz-Zentrum Berlin (HZB). Over the last 5 years, significant developmental work has been performed to expand the radiographic and tomographic capabilities of the beamline [1-3]. New techniques have been implemented, including imaging with polarized neutrons [4-9], Bragg-edge mapping [10,11], high-resolution neutron imaging and grating interferometry [12-15]. These methods have been provided to the user community as tools to help address scientific problems over a broad range of topics such as superconductivity, materials research, life sciences [16,17], cultural heritage and paleontology [18,19]. Industrial applications including fuel cell research [20-27] have also been improved through these new developments. Descriptions and parameters of the developed options will be presented, along with prominent examples.

  14. Astronaut Conrad tweaks Astronaut Cooper's beard for the cameramen

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut Charles Conrad Jr. tweaks Astronaut L. Gordon Cooper's eight-day growth of beard for the cameramen while onboard the prime recovery vessel after their Gemini 5 flight. The NASA Headquarter alternative photo number is 65-H-680.

  15. ["Trema, apophany, apocalypse"--is Conrad's phase model empirically founded?].

    PubMed

    Hambrecht, M; Häfner, H

    1993-12-01

    Among several phase models of beginning schizophrenia, the study by Conrad ("Die beginnende Schizophrenie. Versuch einer Gestaltanalyse des Wahns") was particularly impressive in German psychiatry. The ABC-Schizophrenia-study with its representative sample of 267 first-admissions and a careful retrospective assessment of emerging symptomatology made it possible to test the empirical basis of Conrad's model. In this operationalization "trema" was confirmed as the frequent first stage of the disease process, whereas Conrad's hypothesized order of the two following phrases (first "apophany", then "apocalypse") could not be validated. Therefore, Conrad's model cannot completely be generalized. Because the methods employed so far have some limitations, analyses of additional data (especially reports by significant others) may control and probably enhance the presented results. PMID:8112705

  16. Astronaut Charles Conrad checks out Human Vestibular Function experiment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Charles Conrad Jr., commander of the first manned Skylab mission, checks out the Human Vestibular Function, Experiment M131, during Skylab training at JSC. Conrad is in the work and experiments compartment of the crew quarters of the Skylab Orbital Workshop (OWS) trainer at JSC. The reference sphere with a magnetic rod is used by the astronaut to indicate body orientation non-visually. The litter chair in which he is seated can be rotated by a motor at its base or, when not being rotated, can tilt forward, backward or to either side.

  17. APOLLO 12: C.Conrad Jr. collects geological samples

    NASA Technical Reports Server (NTRS)

    1974-01-01

    APOLLO 12: 'Pete' Conrad collects samples from the lunar surface, while at the same time adjusting to, and remarking on, the working conditions. From the film documentary 'APOLLO 12: 'Pinpoint for Science'', part of a documentary series on the APOLLO missions made in the early '70's and narrated by Burgess Meredith. APOLLO 12: Second manned lunar landing and return with Charles 'Pete' Conrad, Jr., Richard F. Gordon, and Alan F. Bean. Landed in the Ocean of Storms on November 19, 1969; deployed television camera and ALSEP experiments; two EVA's performed; collected core samples and lunar materials; photographed and retrieved parts from surveyor 3 spacecraft. Mission duration 244hrs 36min 24sec

  18. Astronaut Charles Conrad following exercise session on bicycle ergometer

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Charles Conrad Jr., commander of the first manned Skylab mission, wipes perspiration from his face following an exercise session on the bicycle ergometer during Skylab training at JSC. Conrad is in the work and experiments compartment of the crew quarters of the Skylab Orbital Workshop (OWS) trainer at JSC. In addition to being the prime exercise for the crewmen, the ergometer is also used for the vector-cardiogram test and the metabolic activity experiment. The bicycle ergometer produces measured work loads for use in determining man's metabolic effectiveness.

  19. Astronauts Conrad and Kerwin practice Human Vestibular Function experiment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Charles Conrad Jr., commander of the first manned Skylab mission, checks out the Human Vestibular Function, Experiment M131, during Skylab training at JSC. Scientist-Astronaut Joseph P. Kerwin, science pilot of the mission, goes over a checklist. The two men are in the work and experiments compartment of the crew quarters of the Skylab Orbital Workshop (OWS) trainer at JSC.

  20. Astronauts Conrad and Gordon demonstrate tethering procedures for news media

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronauts Charles Conrad (left), command pilot, and Richard F. Gordon (right), pilot, demonstrate tether procedure between their Gemini 11 spacecraft and the Agena Target Docking Vehicle at the post flight press conference. They use models of their spacecraft and its Agena to illustrate maneuvers.

  1. Astronauts Conrad and Gordon demonstrate tethering procedures for news media

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronauts Charles Conrad (center), command pilot, and Richard F. Gordon (right), pilot, demonstrate tether procedure between their Gemini 11 spacecraft and the Agena Target Docking Vehicle at the post flight press conference. They use models of their spacecraft and its Agena to illustrate maneuvers. At left is George Low, Deputy Director, Manned Spacecraft Center, Houston.

  2. Astronaut Charles Conrad during visual acuity experiments over Laredo

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut Charles Conrad Jr., pilot for the prime crew on the Gemini 5 space flight, takes pictures of predetermined land areas during visual acuity experiments over Laredo, Texas. The experiments will aid in learning to identify known terrestrial features under controlled conditions.

  3. Astronauts Cooper and Conrad prepare cameras during visual acuity tests

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronauts L. Gordon Cooper Jr. (left), command pilot, and Charles Conrad Jr., pilot, the prime crew of the Gemini 5 space flight, prepare their cameras while aboard a C-130 aircraft flying near Laredo. The two astronauts are taking part in a series of visual acuity experiments to aid them in learning to identify known terrestrial features under controlled conditions.

  4. The origins of Michael Conrad's research programs (1964-1979).

    PubMed

    Pattee, H H

    2002-01-01

    This paper summarizes Michael Conrad's academic and professional career from the time he began his Ph.D. studies in 1964 to his appointment at Wayne State University in 1979. It describes the origins of several of his major research interests and presents a personal evaluation of how this early work continues to be of fundamental importance. PMID:11755483

  5. Astronaut Joseph Kerwin takes blood sample from Astronaut Charles Conrad

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Scientist-Astronaut Joseph P. Kerwin (right), Skylab 2 science pilot and a doctor of medicine, takes a blood sample from Astronaut Charles Conrad Jr., Sylab 2 commander, as seen in this reproduction taken from a color television transmission made by a TV camera aboard the Skylab 1 and 2 space station cluster in Earth orbit. The blood sampling was part of the Skylab Hematology and Immunology Experiment M110 series.

  6. Astronaut Charles Conrad trims hair of Astronaut Paul Weitz

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Charles Conrad Jr., Skylab 2 commander, trims the hair of Astronaut Paul J. Weitz, Skylab 2 pilot, during the 28-day Skylab 2 mission in Earth orbit. They are in the crew quarters wardroom of the Orbital Workshop of the Skylab 1 and 2 space station. Weitz is holding a vacuum hose in his right hand. This picture was taken by Scientist-Astronaut Joseph P. Kerwin, Skylab 2 science pilot.

  7. Joseph Conrad's Empathy for Exploited Africans in "The Heart of Darkness."

    ERIC Educational Resources Information Center

    Farley, Ena L.

    1990-01-01

    Seemingly contradictory positions of J. Conrad as both a racist and an opponent of race-based imperial practices are discussed with reference to "The Heart of Darkness." It is argued that Conrad made a conscious effort to shake off the racial theories of the time and to deplore imperial racism. (SLD)

  8. Astronauts Alan Bean and Charles Conrad on Lunar Surface

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The second manned lunar landing mission, Apollo 12 launched from launch pad 39-A at Kennedy Space Center in Florida on November 14, 1969 via a Saturn Five launch vehicle. The Saturn V vehicle was developed by the Marshall Space Flight Center (MSFC) under the direction of Dr. Wernher von Braun. Aboard Apollo 12 was a crew of three astronauts: Alan L. Bean, pilot of the Lunar Module (LM), Intrepid; Richard Gordon, pilot of the Command Module (CM), Yankee Clipper; and Spacecraft Commander Charles Conrad. The LM, Intrepid, landed astronauts Conrad and Bean on the lunar surface in what's known as the Ocean of Storms while astronaut Richard Gordon piloted the CM, Yankee Clipper, in a parking orbit around the Moon. Their lunar soil activities included the deployment of the Apollo Lunar Surface Experiments Package (ALSEP), finding the unmanned Surveyor 3 that landed on the Moon on April 19, 1967, and collecting 75 pounds (34 kilograms) of rock samples. In this photograph, one of the astronauts on the Moon's surface is holding a container of lunar soil. The other astronaut is seen reflected in his helmet. Apollo 12 safely returned to Earth on November 24, 1969.

  9. Skylab beverage container filled with orange juice held by Astronaut Conrad

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An accordian-style beverage dispenser filled with orange juice is held by Astronaut Charles Conrad Jr., Skylab 2 commander, in this close-up view which is a reproduction taken from a color television transmission made by a TV camera aboard the Skylab 1 and 2 space station cluster in Earth orbit. Conrad (head and face not in view) is seated at the wardroom table in the crew quarters of the Orbital Workshop. The dispenser contained beverage crystals, and Conrad has just added the prescribed amount of water to make the orange drink.

  10. Recent Developments in the CONRAD Code regarding Experimental Corrections

    NASA Astrophysics Data System (ADS)

    Archier, P.; De Saint Jean, C.; Kopecky, S.; Litaize, O.; Noguère, G.; Schillebeeckx, P.; Volev, K.

    2013-03-01

    The CONRAD code is an object-oriented software tool developed at CEA Cadarache since 2005 to deal with problems arising during the evaluation process (data assimilation and analysis, physical modelling, propagation of uncertainties…). This paper will present recent developments concerning the experimental corrections, which are required when a neutron resonance shape analysis is performed. Several experimental aspects are detailed in this work: the possibility to use spectra in energy as well as in time, the implementation of both analytical (Chi-Square) and Monte-Carlo resolution functions, the sample homogeneity corrections using log-normal distributions. Each development aspect is illustrated with several examples and comparisons with other resonance analysis codes (SAMMY, REFIT).

  11. The CONRAD approach to biokinetic modeling of DTPA decorporation therapy.

    PubMed

    Breustedt, Bastian; Blanchardon, Eric; Bérard, Philippe; Fritsch, Paul; Giussani, Augusto; Lopez, Maria Antonia; Luciani, Andrea; Nosske, Dietmar; Piechowski, Jean; Schimmelpfeng, Jutta; Sérandour, Anne-Laure

    2010-10-01

    Diethylene Triamine Pentaacetic Acid (DTPA) is used for decorporation of plutonium because it is known to be able to enhance its urinary excretion for several days after treatment by forming stable Pu-DTPA complexes. The decorporation prevents accumulation in organs and results in a dosimetric benefit, which is difficult to quantify from bioassay data using existing models. The development of a biokinetic model describing the mechanisms of actinide decorporation by administration of DTPA was initiated as a task in the European COordinated Network on RAdiation Dosimetry (CONRAD). The systemic biokinetic model from Leggett et al. and the biokinetic model for DTPA compounds of International Commission on Radiological Protection Publication 53 were the starting points. A new model for biokinetics of administered DTPA based on physiological interpretation of 14C-labeled DTPA studies from literature was proposed by the group. Plutonium and DTPA biokinetics were modeled separately. The systems were connected by means of a second order kinetics process describing the chelation process of plutonium atoms and DTPA molecules to Pu-DTPA complexes. It was assumed that chelation only occurs in the blood and in systemic compartment ST0 (representing rapid turnover soft tissues), and that Pu-DTPA complexes and administered forms of DTPA share the same biokinetic behavior. First applications of the CONRAD approach showed that the enhancement of plutonium urinary excretion after administration of DTPA was strongly influenced by the chelation rate constant. Setting it to a high value resulted in a good fit to the observed data. However, the model was not yet satisfactory since the effects of repeated DTPA administration in a short time period cannot be predicted in a realistic way. In order to introduce more physiological knowledge into the model several questions still have to be answered. Further detailed studies of human contamination cases and experimental data will be needed in

  12. Gemini 11 Commander Conrad and Pilot Gordon at post flight press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 11 Commander Charles Conrad, Jr (left) and Pilot Richard F. Gordon, Jr describe mission activities during their post flight press conference at JSC. Gordon at the microphone talks about the extravehicular activity (EVA) photo projected behind the two crewmembers. During the EVA Gordon attached a tether to the Agena and retrieved a nuclear emulsion experiment package.

  13. Astronauts Conrad and Cooper slice cake on U.S.S. Lake Champlain

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronauts Charles Conrad Jr. (left) and L. Gordon Cooper Jr. prepate to slice into the huge cake prepared for them by the cooks onboard the aircraft carrier U.S.S. Lake Champlain. They are using ornamental Navy swords for knives.

  14. Holocene polar front migrations over the Conrad Rise in the Indian sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Ikehara, M.; Katsuki, K.; Yokoyama, Y.; Yamane, M.; Khim, B.

    2011-12-01

    The Southern Ocean has played a significant role in the global climate system during the geologic past. In order to understand the paleoceanographic variations with the polar front system and Antarctic Circumpolar Current (ACC), we conducted two cruises KH-07-4 and KH-10-7 in the Indian sector of the Southern Ocean. Two piston cores were collected from the Conrad Rise. We examined centennial-scale changes of diatom assemblages and stable isotopic ratios in planktic foraminifera during the Holocene in a high-accumulation-rate sediment core from the Conrad Rise. Although abundances of dominant diatom taxa (Fragilariopsis kerguelensis and Thalassiothrix antarctica) are comparatively constant, relative abundances of secondary taxa fluctuate. Before ca 9900 cal. yr BP, winter sea-ice and cold water covered the Conrad Rise. Following deglaciation the sea-ice retreated from the Conrad Rise. The Polar Front moved southward during the early Holocene optimum and north Antarctic Zone waters covered the Conrad Rise for about 650 yr. After 9300 cal. yr BP, solar insolation strongly influenced sea surface temperature and primary productivity in the Southern Ocean. In the high-latitude Indian Sector, productivity increased 1500 yr after the onset of late Holocene neoglaciation. Periodic δ18O and cold-water diatom taxa spikes (at intervals of 200 and 300-500 yr, respectively) occurred after 9300 cal. yr BP, probably associated with solar activity. Fluctuations in short-term sea surface temperature and cold-water taxa are synchronous with changes in dD observed in an east Antarctic ice core.

  15. Being a Stranger and the Strangeness of Being: Joseph Conrad's "The Secret Sharer" as an Allegory of Being in Education

    ERIC Educational Resources Information Center

    Schwieler, Elias

    2013-01-01

    Joseph Conrad's "The Secret Sharer" has often been associated with what can be called initiation stories. However, in this article I argue that Conrad's text is more than that. It can, I suggest, be read as an allegory of the inaccessibility to reveal the essence of being in command, being in education, and also the…

  16. Polarized neutron imaging at the CONRAD instrument at Helmholtz Centre Berlin

    NASA Astrophysics Data System (ADS)

    Manke, Ingo; Kardjilov, Nikolay; Hilger, André; Strobl, Markus; Dawson, Martin; Banhart, John

    2009-06-01

    Neutrons are highly sensitive to magnetic fields because of their intrinsic magnetic moment. At the same time, their zero net electrical charge allows them to penetrate thick layers of matter. In combination with standard radiographic and tomographic imaging techniques, these properties have been exploited to visualize magnetic fields in free space and within the bulk of solid, massive, opaque samples. In this paper, the basic principle of this new technique and its realization at the CONRAD instrument at the Helmholtz Centre Berlin (formerly Hahn-Meitner Institute Berlin) are explained. Two application examples will be given: the visualization of the magnetic field around a permanent magnet and the investigation of the displacement of the current density from the core of a conductor to the surface (the skin effect).

  17. Circulation of images and graphic practices in Renaissance natural history: the example of Conrad Gessner.

    PubMed

    Egmond, Florike; Kusukawa, Sachiko

    2016-01-01

    Conrad Gessner's Historia animalium is a compilation of information from a variety of sources: friends, correspondents, books, broadsides, drawings, as well as his own experience. The recent discovery of a cache of drawings at Amsterdam originally belonging to Gessner has added a new dimension for research into the role of images in Gessner's study of nature. In this paper, we examine the drawings that were the basis of the images in the volume of fishes. We uncovered several cases where there were multiple copies of the same drawing of a fish (rather than multiple drawings of the samefish), which problematizes the notion of unique "original" copies and their copies. While we still know very little about the actual mechanism of, or people involved in, commissioning or generating copies of drawings, their very existence suggests that the images functioned as an important medium in the circulation of knowledge in the early modern period. PMID:27349032

  18. The mitochondrial genome of Pomacea maculata (Gastropoda: Ampullariidae).

    PubMed

    Yang, Qianqian; Liu, Suwen; Song, Fan; Li, Hu; Liu, Jinpeng; Liu, Guangfu; Yu, Xiaoping

    2016-07-01

    The golden apple snail, Pomacea maculata Perry, 1810 (Gastropoda: Ampullariidae) is one of the most serious invasive alien species from the native range of South America. The mitochondrial genome of P. maculata (15 516 bp) consists of 37 genes (13 protein-coding genes, two rRNAs, and 22 tRNAs) and a non-coding region with a 16 bp repeat unit. Most mitochondrial genes of P. maculata are distributed on the H-strand, except eight tRNA genes, which are encoded on the L-strand. A phylogenetic analysis showed that there was a close relationship between P. maculata and another invasive golden apple snail species, Pomacea canaliculata (Lamarck, 1822). PMID:26099974

  19. Subsurface temporal variation of radon at the Conrad Geophysical Observatory, Austria

    NASA Astrophysics Data System (ADS)

    Leonhardt, Roman; Steinitz, Gideon; Piatibratova, Oksana

    2015-04-01

    The Conrad Observatory (COBS) housed the national geophysical observatory of Austria and is located 50 km south west of Vienna within the carbonate sequence of the "Wettersteinkalk". Parameters monitored at the facility comprise environmental data, seismic signals, gravity, geomagnetic components and also natural gamma rays. A subsurface tunnel, 150 meters long and oriented E-W is driven into the calcareous sequence at a depth of 50 meters. The tunnel is lined with a concrete carapace, ~20 cm thick. The tunnel observatory is separated from the external atmosphere by 3 tight doors, resulting in a stable temperature of 6.85±0.04°C. A gamma detector (3×3", NaI, SCA) is used measure the variation of the gamma radiation from radon in the air of the tunnel, at a resolution of 1 minute, which is accumulated to form a 15-minute count rate. The sensor is placed on a concrete block at 135 meters. Several SSNTD measurements in the tunnel indicated radon level in the level of 1.5 kBq/m^3. The background gamma radiation, due probably mainly to sources in the concrete is in the order to 2×105 counts (per 15-minutes). A long term variation of radon is reflected as an annual radon signal with large amplitude (2×105 counts) and a maximum in summer. Small to large (2×105 counts) non periodic multi-day signals lasting from two to several tens of days are superimposed. Daily periodic signals of much lower amplitude are observed, with amplitudes generally up to 4×104 counts. The amplitude of the non-periodic multi-day is coupled to amplitude of the annual signal, and the amplitude of the periodic daily signal is modulated by the multi-day variation. The source of the radon in the air of the tunnel is from the concrete lining the floor and walls of the tunnel. The variation patterns and their systematic characteristics cannot be ascribed to local variations of pressure and temperature (stable). These limitations indicate that other driver(s), external to the tunnel, are forcing

  20. Descriptions of three new species of Mitridae (Mollusca: Gastropoda) from South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Baoquan; Zhang, Suping; Li, Xinzheng

    2005-03-01

    Three new species of Family Mitridae (Mollusca: Gastropoda) from the South China Sea are described in the present paper. They are Ziba aglais sp. nov. B. LI & S. ZHANg, Neocancilla daidaleosa sp. nov. B. LI & X. LI, and Mitra holkosa sp. nov. B. LI. Their systematic positions are also discussed.

  1. The new cold neutron radiography and tomography instrument CONRAD at HMI Berlin

    NASA Astrophysics Data System (ADS)

    Hilger, A.; Kardjilov, N.; Strobl, M.; Treimer, W.; Banhart, J.

    2006-11-01

    The new cold neutron radiography instrument CONRAD is a multifunctional facility for radiography and tomography with cold neutrons at Hahn-Meitner Institut, Berlin. It is located at the end of a curved neutron guide, which faces the cold-neutron source of the BER-II research reactor. The geometry provides a cold-neutron beam with wavelengths between 2 and 12 Å. Two measuring positions are available for radiography and tomography investigations. The first one is placed at the end of the guide and it is optimized for in situ experiments in which a high neutron flux is required. The available flux at this position is approximately 10 8 cm -2 s -1. The second measuring position uses a pin-hole geometry which allows better beam collimation ( L/ D up to 1000) and higher image resolution in the range of 200 μm in the CCD based detector system (10×10 cm 2). The use of cold neutrons for radiography purposes increases the image contrast and improves the sensibility e.g., the detection of small amounts of water and hydrogen-containing materials in metal matrixes. On the other hand the cold-neutron beam can be modified easily by using diffraction and neutron optical techniques. This enables to perform radiography and tomography experiments with more sophisticated measuring techniques. Recent examples of research and industrial applications will be presented.

  2. Gravity Variations Induced by Changing Snowpack Observed at Conrad Observatory (Austria)

    NASA Astrophysics Data System (ADS)

    Ressl, Hans; Dorninger, Manfred; Meurers, Bruno

    2016-04-01

    Hydrological processes are usually associated with mass transport. This induces gravity variations observed by superconducting gravimeter (SG) masking the pure geodynamical signal. The present study focusses specifically on gravity variations due to snow accumulation and melting. Measurements of the gravity signal are taken from the SG GWR C025 located at the Conrad Observatory (Austria) in an underground laboratory at about 1000m altitude. In snow rich winters a snowpack of one meter in depth or even more can be observed at this location. Snow height is measured at three different locations to get an idea of its variability. At one place additionally the weight of the snow pack is determined which allows to calculate the snow water equivalent. Gravitational signals are rather different for the accumulation and ablation phase, not only due to the different time scales of these processes but also due to the complex way path of melting water entering the ground beneath of the SG. Two methods, rainfall admittance function and Bouguer reduction, are used to account for the effect of the snow pack. Both have their strengths and weaknesses. They work better for short-term mass transports than for long lasting ones because in the latter case interference with signals of other environmental processes gets more prominent. A few case studies including both accumulation and ablation of snow on different time scales will be discussed.

  3. COMPARISON OF AQUEOUS AND SOLID-PHASE UPTAKE FOR HEXACHLOROBENZENE IN THE TELLINID CLAM MACOMA NASUTA (CONRAD): A MASS BALANCE APPROACH

    EPA Science Inventory

    The uptake of sediment-associated hexachlorobenzene (HCB) by the deposit-feeding clam Macoma nasuta (Conrad) was determined using a clam ventilation chamber. lams were exposed to [14C]HCB-dosed sediment, and the 14C amounts were measured in inhalant and exhalant waters, fecal pel...

  4. Rigorous noise test and calibration check of strong-motion instrumentation at the Conrad Observatory in Austria.

    NASA Astrophysics Data System (ADS)

    Steiner, R.; Costa, G.; Lenhardt, W.; Horn, N.; Suhadolc, P.

    2012-04-01

    In the framework of the European InterregIV Italy/Austria project: "HAREIA - Historical and Recent Earthquakes in Italy and Austria" the Central Institute for Meteorology and Geodynamics (ZAMG) and Mathematic and Geosciences Department of University of Trieste (DMG) are upgrading the transfrontier seismic network of South-Eastern Alps with new 12 accelerometric stations to enhance the strong motion instrument density near the Austria/Italy border. Various public institutions of the provinces Alto Adige (Bolzano Province), Veneto (ARPAV) and Friuli Venezia Giulia (Regional Civil Defense) in Italy and in the Austrian province of Tyrol are involved in the project. The site selection was carried out to improve the present local network geometry thus meeting the needs of public Institutions in the involved regions. In Tyrol and Alto Adige some strategic buildings (hospitals and public buildings) have been selected, whereas in Veneto and Friuli Venezia Giulia the sites are in the free field, mainly located near villages. The instruments will be installed in an innovative box, designed by ZAMG, that provides electric and water isolation. The common choice regarding the instrument selection has been the new Kinemetrics Basalt ® accelerograph to guarantee homogeneity with the already installed instrumentation and compatibility with the software already in use at the different seismic institutions in the area. Prior to deployment the equipment was tested at the Conrad Observatory and a common set-up has been devised. The Conrad Observatory, seismically particularly quiet, permits to analyze both the sensor and the acquisition system noise. The instruments were connected to the network and the data sent in real-time to the ZAMG data center in Vienna and the DMG data center in Trieste. The data have been collected in the database and analyzed using signal processing modules PQLX and Matlab. The data analysis of the recordings at the ultra-quiet Conrad Observatory pointed out

  5. Generation of 238U Covariance Matrices by Using the Integral Data Assimilation Technique of the CONRAD Code

    NASA Astrophysics Data System (ADS)

    Privas, E.; Archier, P.; Bernard, D.; De Saint Jean, C.; Destouche, C.; Leconte, P.; Noguère, G.; Peneliau, Y.; Capote, R.

    2016-02-01

    A new IAEA Coordinated Research Project (CRP) aims to test, validate and improve the IRDF library. Among the isotopes of interest, the modelisation of the 238U capture and fission cross sections represents a challenging task. A new description of the 238U neutrons induced reactions in the fast energy range is within progress in the frame of an IAEA evaluation consortium. The Nuclear Data group of Cadarache participates in this effort utilizing the 238U spectral indices measurements and Post Irradiated Experiments (PIE) carried out in the fast reactors MASURCA (CEA Cadarache) and PHENIX (CEA Marcoule). Such a collection of experimental results provides reliable integral information on the (n,γ) and (n,f) cross sections. This paper presents the Integral Data Assimilation (IDA) technique of the CONRAD code used to propagate the uncertainties of the integral data on the 238U cross sections of interest for dosimetry applications.

  6. The epigenetic landscape in the course of time: Conrad Hal Waddington's methodological impact on the life sciences.

    PubMed

    Baedke, Jan

    2013-12-01

    It seems that the reception of Conrad Hal Waddington's work never really gathered speed in mainstream biology. This paper, offering a transdisciplinary survey of approaches using his epigenetic landscape images, argues that (i) Waddington's legacy is much broader than is usually recognized--it is widespread across the life sciences (e.g. stem cell biology, developmental psychology and cultural anthropology). In addition, I will show that (ii) there exist as yet unrecognized heuristic roles, especially in model building and theory formation, which Waddington's images play within his work. These different methodological facets envisioned by Waddington are used as a natural framework to analyze and classify the manners of usage of epigenetic landscape images in post-Waddingtonian 'landscape approaches'. This evaluation of Waddington's pictorial legacy reveals that there are highly diverse lines of traditions in the life sciences, which are deeply rooted in Waddington's methodological work. PMID:23932231

  7. Bathymetric distribution patterns of Southern Ocean macrofaunal taxa: Bivalvia, Gastropoda, Isopoda and Polychaeta

    NASA Astrophysics Data System (ADS)

    Brandt, Angelika; Linse, Katrin; Schüller, Myriam

    2009-11-01

    The aim of this study is to compare the depth distributions of four major Southern Ocean macrobenthic epi- and infaunal taxa, the Bivalvia, Gastropoda, Isopoda, and Polychaeta, from subtidal to abyssal depth. All literature data up to summer 2008, as well as the unpublished data from the most recent ANDEEP I-III (Antarctic benthic deep-sea biodiversity: colonisation history and recent community patterns) expeditions to the Southern Ocean deep sea are included in the analysis. Benthic invertebrates in the Southern Ocean are known for their wide bathymetric ranges. We analysed the distributions of four of the most abundant and species-rich taxa from intertidal to abyssal (5200 m) depths in depth zones of 100 m. The depth distributions of three macrofaunal classes (Bivalvia, Gastropoda, Polychaeta) and one order (Isopoda) showed distinct differences. In the case of bivalves, gastropods and polychaetes, the number of species per depth zone decreased from the shelf to the slope at around 1000 m depth and then showed stable low numbers. The isopods showed the opposite trend; they were less species rich in the upper 1000 m but increased in species numbers from the slope to bathyal and abyssal depths. Depth ranges of families of the studied taxa (Bivalvia: 31 families, Gastropoda: 60, Isopoda: 32, and Polychaeta: 46 families) were compiled and illustrated. At present vast areas of the deep sea in the Southern Ocean remain unexplored and species accumulation curves showed that only a fraction of the species have been discovered to date. We anticipate that further investigations will greatly increase the number of species known in the Southern Ocean deep sea.

  8. Vertical density contrast and mapping of basement, Conrad and Moho morphologies through 2D spectral analysis of gravity data in and around Odisha, India

    NASA Astrophysics Data System (ADS)

    Kumar, Arbind; S. Roy, P. N.; Das, L. K.

    2016-07-01

    Power spectrum analysis of Complete Bouguer Anomaly (CBA) map of Eastern Ghat Mobile Belt (EGMB) and its surroundings in India through Two Dimensional (2D) spectral analysis has provided estimates of the ensemble average depths for the density discontinuities which represent crustal inhomogeneities. The spectral analysis method has helped to estimate the depths of a perturbing body sources which are obtained from the negative slopes of the linear relationship between the logarithmic power spectrum and the wave-numbers of the gravity field. The detailed analysis reveals three horizontal discontinuities (i) Phanerozoic sediment thickness (ii) Basement depth and (iii) Conrad discontinuity. The average thickness of Phanerozoic sediments is estimated to be 3 km whereas depth of basement and Conrad discontinuity are at 7 km and 14.5 km respectively. Additionally Mohorovicic discontinuity also estimated at a depth of 32.8 km in the study region.

  9. Pyramided QTL underlying tolerance to Phytophthora root rot in mega-environments from soybean cultivars 'Conrad' and 'Hefeng 25'.

    PubMed

    Li, Xiuping; Han, Yingpeng; Teng, Weili; Zhang, Shuzheng; Yu, Kangfu; Poysa, Vaino; Anderson, Terry; Ding, Junjie; Li, Wenbin

    2010-08-01

    Phytophthora root rot (PRR) of soybean (Glycine max (L.) Merr.) is the second most important cause of yield loss by disease in North America, surpassed only by soybean cyst nematode (Wrather et al. in Can J Plant Pathol 23:115-121, 2001). Tolerance can provide economically useful disease control, conditioning partial resistance of soybean to PRR. The aims of this study were to identify new quantitative trait loci (QTL) underlying tolerance to PRR, and to evaluate the effects of pyramided or stacked loci on the level of tolerance. A North American cultivar 'Conrad' (tolerant to PRR) was crossed with a northeastern China cultivar 'Hefeng 25' (tolerant to PRR). Through single-seed descent, 140 F2:5 and F2:6 recombinant inbred lines were advanced. A total of 164 simple sequence repeat (SSR) markers were used to construct a genetic linkage map. The percentage of seedling death was measured over 2 years (2007 and 2008) in the field at four naturally infested locations in Canada and China following additional soil infestation and in the greenhouse following inoculation with Phytophthora sojae isolate. A total of eight QTL underlying tolerance to PRR were identified, located in five linkage groups (F, D1b+w, A2, B1, and C2). The phenotypic variation contributed by the loci ranged from 4.24 to 27.98%. QPRR-1 (anchored in the interval of SSR markers Satt325 and Satt343 of LG F), QPRR-2 (anchored in the interval of Satt005 and Satt600 of LG D1b+w), and QPRR-3 (anchored in the interval of Satt579 and Sat_089 of LG D1b+w) derived their beneficial allele from 'Conrad'. They were located at chromosomal locations known to underlie PRR tolerance in diverse germplasm. Five QTL that derived beneficial alleles from 'Hefeng 25' were identified. The QTL (QPRR-1 to QPRR-7) that were detected across at least three environments were selected for loci stacking and to analyze the relationship between number of tolerance loci and disease loss percentage. The accumulation of tolerance loci was

  10. From sea to land and beyond – New insights into the evolution of euthyneuran Gastropoda (Mollusca)

    PubMed Central

    2008-01-01

    Background The Euthyneura are considered to be the most successful and diverse group of Gastropoda. Phylogenetically, they are riven with controversy. Previous morphology-based phylogenetic studies have been greatly hampered by rampant parallelism in morphological characters or by incomplete taxon sampling. Based on sequences of nuclear 18S rRNA and 28S rRNA as well as mitochondrial 16S rRNA and COI DNA from 56 taxa, we reconstructed the phylogeny of Euthyneura utilising Maximum Likelihood and Bayesian inference methods. The evolution of colonization of freshwater and terrestrial habitats by pulmonate Euthyneura, considered crucial in the evolution of this group of Gastropoda, is reconstructed with Bayesian approaches. Results We found several well supported clades within Euthyneura, however, we could not confirm the traditional classification, since Pulmonata are paraphyletic and Opistobranchia are either polyphyletic or paraphyletic with several clades clearly distinguishable. Sacoglossa appear separately from the rest of the Opisthobranchia as sister taxon to basal Pulmonata. Within Pulmonata, Basommatophora are paraphyletic and Hygrophila and Eupulmonata form monophyletic clades. Pyramidelloidea are placed within Euthyneura rendering the Euthyneura paraphyletic. Conclusion Based on the current phylogeny, it can be proposed for the first time that invasion of freshwater by Pulmonata is a unique evolutionary event and has taken place directly from the marine environment via an aquatic pathway. The origin of colonisation of terrestrial habitats is seeded in marginal zones and has probably occurred via estuaries or semi-terrestrial habitats such as mangroves. PMID:18294406

  11. Original molluscan radula: comparisons among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian fossil Wiwaxia corrugata.

    PubMed

    Scheltema, Amélie H; Kerth, Klaus; Kuzirian, Alan M

    2003-08-01

    As the original molluscan radula is not known from direct observation, we consider what the form of the original radula may have been from evidence provided by neomenioid Aplacophora (Solenogastres), Gastropoda, Polyplacophora, and the Cambrian fossil Wiwaxia corrugata (Matthews). Conclusions are based on direct observation of radula morphology and its accessory structures (salivary gland ducts, radular sac, anteroventral radular pocket) in 25 species and 16 genera of Aplacophora; radula morphogenesis in Aplacophora; earliest tooth formation in Gastropoda (14 species among Prosobranchia, Opisthobranchia, and Pulmonata); earliest tooth formation in four species of Polyplacophora; and the morphology of the feeding apparatus in W. corrugata. The existence of a true radula membrane and of membranoblasts and odontoblasts in neomenioids indicates that morphogenesis of the aplacophoran radula is homologous to that in other radulate Mollusca. We conclude from p redness of salivary gland ducts, a divided radular sac, and a pair of anteroventral pockets that the plesiomorphic state in neomenioids is bipartite, formed of denticulate bars that are distichous (two teeth per row) on a partially divided or fused radula membrane with the largest denticles lateral, as occurs in the genus Helicoradomenia. The tooth morphology in Helicoradomenia is similar to the feeding apparatus in W. corrugata. We show that distichy also occurs during early development in several species of gastropods and polyplacophorans. Through the rejection of the null hypothesis that the earliest radula was unipartite and had no radula membrane, we conclude that the original molluscan radula was similar to the radula found in Helicoradomena species. PMID:12833382

  12. Migration of the Antarctic Circumpolar Current in the Late Neogene: reconstruction from sediment wave on the Conrad Rise, Indian Sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Oiwane, H.; Ikehara, M.; Suganuma, Y.; Nakamura, Y.; Nogi, Y.; Miura, H.; Sato, T.

    2012-12-01

    ACC is the largest and strongest ocean current in the world. It is important for the interoceanic exchange of water, exchange of gases to the atmosphere, and thermal isolation of the Antarctic continent. Fluctuation of the ACC has been reconstructed from several methods such as microfossils, anisotropy of magnetic susceptibilities, and statistical analysis of Ice-Rafted Debris. On the other hand, sediment waves are investigated and interpreted to reconstruct the fluctuation of the bottom- and contour currents. In this study, we tried reconstructing the ACC using sediment waves based on multidisciplinary survey on the Conrad Rise in the Indian sector of the Southern Ocean. The Conrad Rise is a topographic high that is elevated ca. 3000 m from the ocean floor. We conducted multibeam bathymetry, seismic reflection, and sediment coring on the southwestern slope of the rise. Seismic units on the Conrad Rise are divided into three units, A, B, and C in descending order. Unit A shows transparent to low amplitude with sediment wave structure. Sediment waves don't show systematic changes of its dimension and thickness. Sedimentary core showed that the surface sediment is composed of diatom ooze. Unit B shows higher amplitude than that of unit A, and shows planar, parallel configuration. Unit C has high-amplitude reflectors at its top and shows chaotic facies below. Based on morphological characteristics of the sediment waves, oceanographic setting of the Conrad Rise, and components of the surface sediment, it is most likely that the sedimentary structure and component of the Unit A is significantly constrained by the ACC. On the other hand, the Unit B shows planar configuration suggesting deposition without current effect. Additionally, higher amplitude suggests different component form that of the Unit A. These a series of evidence represent difference of sedimentary environment between units A and B, especially on the point of the influence of the ACC. Accordingly, onset

  13. Cytogenetic characterisation of the razor shells Ensis directus (Conrad, 1843) and E. minor (Chenu, 1843) (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    González-Tizón, Ana M.; Rojo, Verónica; Vierna, Joaquín; Jensen, K. Thomas; Egea, Emilie; Martínez-Lage, Andrés

    2013-03-01

    The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric-submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric-submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua.

  14. Use of axonal projection patterns for the homologisation of cerebral nerves in Opisthobranchia, Mollusca and Gastropoda

    PubMed Central

    2013-01-01

    Introduction Gastropoda are guided by several sensory organs in the head region, referred to as cephalic sensory organs (CSOs). These CSOs are innervated by distinct nerves. This study proposes a unified terminology for the cerebral nerves and the categories of CSOs and then investigates the neuroanatomy and cellular innervation patterns of these cerebral nerves, in order to homologise them. The homologisation of the cerebral nerves in conjunction with other data, e.g. ontogenetic development or functional morphology, may then provide insights into the homology of the CSOs themselves. Results Nickel-lysine axonal tracing (“backfilling”) was used to stain the somata projecting into specific nerves in representatives of opisthobranch Gastropoda. Tracing patterns revealed the occurrence, size and relative position of somata and their axons and enabled these somata to be mapped to specific cell clusters. Assignment of cells to clusters followed a conservative approach based primarily on relative location of the cells. Each of the four investigated cerebral nerves could be uniquely identified due to a characteristic set of soma clusters projecting into the respective nerves via their axonal pathways. Conclusions As the described tracing patterns are highly conserved morphological characters, they can be used to homologise nerves within the investigated group of gastropods. The combination of adequate number of replicates and a comparative approach allows us to provide preliminary hypotheses on homologies for the cerebral nerves. Based on the hypotheses regarding cerebral nerve homology together with further data on ultrastructure and immunohistochemistry of CSOs published elsewhere, we can propose preliminary hypotheses regarding homology for the CSOs of the Opisthobranchia themselves. PMID:23597272

  15. Neuromuscular development in Patellogastropoda (Mollusca: Gastropoda) and its importance for reconstructing ancestral gastropod bodyplan features

    PubMed Central

    Kristof, Alen; de Oliveira, André Luiz; Kolbin, Konstantin G.; Wanninger, Andreas

    2015-01-01

    Within Gastropoda, limpets (Patellogastropoda) are considered the most basal branching taxon and its representatives are thus crucial for research into evolutionary questions. Here, we describe the development of the neuromuscular system in Lottia cf. kogamogai. In trochophore larvae, first serotonin-like immunoreactivity (lir) appears in the apical organ and in the prototroch nerve ring. The arrangement and number of serotonin-lir cells in the apical organ (three flask-shaped, two round cells) are strikingly similar to those in putatively derived gastropods. First, FMRFamide-lir appears in veliger larvae in the Anlagen of the future adult nervous system including the cerebral and pedal ganglia. As in other gastropods, the larvae of this limpet show one main and one accessory retractor as well as a pedal retractor and a prototroch muscle ring. Of these, only the pedal retractor persists until after metamorphosis and is part of the adult shell musculature. We found a hitherto undescribed, paired muscle that inserts at the base of the foot and runs towards the base of the tentacles. An apical organ with flask-shaped cells, one main and one accessory retractor muscle is commonly found among gastropod larvae and thus might have been part of the last common ancestor. PMID:26869747

  16. The complete mitochondrial genome of the mudsnail Cipangopaludina cathayensis (Gastropoda: Viviparidae).

    PubMed

    Yang, Huirong; Zhang, Jia-En; Luo, Hao; Luo, Mingzhu; Guo, Jing; Deng, Zhixin; Zhao, Benliang

    2016-05-01

    We present the complete mitochondrial genome of Cipangopaludina cathayensis in this study. The mitochondrial genome is 17,157 bp in length, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes. All of them are encoded on the heavy strand except 7 tRNA genes on the light strand. Overall nucleotide compositions of the light strand are 44.51% of A, 26.74% of T, 20.48% of C and 8.28% of G. All the protein-coding genes start with ATG initiation codon except ATP6 with ATA and ND4 with TTG, and 2 types of termination codons are TAA (ATP6, ND2, COX1, COX2, ATP8, ND1, ND6, Cytb, COX3, ND4) and TAG (ND4L, ND5, ND3). There are 29 intergenic spacers and 5 gene overlaps. The tandem repeat sequences are observed in COX2, tRNA(Asp), ATP6, tRNA(Cys), S-rRNA, ND1, Cytb, ND4 and COX3 genes. Gene arrangement and distribution are different from the typical vertebrates. The absence of D-loop is consistent with the Gastropoda, but at least one lengthy non-coding region is essential regulatory element for the initiation of transcription and replication. PMID:25319293

  17. Nanoindentations on conch shells of Gastropoda and Bivalvia molluscs reveal anisotropic evolution against external attacks.

    PubMed

    Bignardi, Cristina; Petraroli, Michele; Pugno, Nicola M

    2010-10-01

    Nanoindentation method has been used to explore, at the nanoscale, the mechanical properties of four different representative types of conch shells belonging to the two biggest classes of molluscs, Gastropoda and Bivalvia, in order to compare nanohardness and Young's modulus with respect to the microstructural anisotropic architectures. For the experimental tests a Nano Indenter XP (MTS Nano Instruments, Oak Ridge TN) has been used. The mechanical tests have been carried out on the inner and outer surfaces of the shells, as well as on their cross-section, near to the inner/outer surfaces and in the middle layer. The results confirm the three layered anisotropic architecture of the investigated conchs. On each of these 5 surfaces, 2 x 5 indentations have been performed at different maximum depth: from 250 nm to 4 microm, with a step of 250 nm, for a total of 3200 tests. The numerous observations have been analysed applying an ad hoc modification of the Weibull Statistics, suggesting a natural evolution of the shells against external attacks. PMID:21137746

  18. Relationships within Cladobranchia (Gastropoda: Nudibranchia) based on RNA-Seq data: an initial investigation

    PubMed Central

    Goodheart, Jessica A.; Bazinet, Adam L.; Collins, Allen G.; Cummings, Michael P.

    2015-01-01

    Cladobranchia (Gastropoda: Nudibranchia) is a diverse (approx. 1000 species) but understudied group of sea slug molluscs. In order to fully comprehend the diversity of nudibranchs and the evolution of character traits within Cladobranchia, a solid understanding of evolutionary relationships is necessary. To date, only two direct attempts have been made to understand the evolutionary relationships within Cladobranchia, neither of which resulted in well-supported phylogenetic hypotheses. In addition to these studies, several others have addressed some of the relationships within this clade while investigating the evolutionary history of more inclusive groups (Nudibranchia and Euthyneura). However, all of the resulting phylogenetic hypotheses contain conflicting topologies within Cladobranchia. In this study, we address some of these long-standing issues regarding the evolutionary history of Cladobranchia using RNA-Seq data (transcriptomes). We sequenced 16 transcriptomes and combined these with four transcriptomes from the NCBI Sequence Read Archive. Transcript assembly using Trinity and orthology determination using HaMStR yielded 839 orthologous groups for analysis. These data provide a well-supported and almost fully resolved phylogenetic hypothesis for Cladobranchia. Our results support the monophyly of Cladobranchia and the sub-clade Aeolidida, but reject the monophyly of Dendronotida. PMID:26473045

  19. With a little help from DNA barcoding: investigating the diversity of Gastropoda from the Portuguese coast.

    PubMed

    Borges, Luísa M S; Hollatz, Claudia; Lobo, Jorge; Cunha, Ana M; Vilela, Ana P; Calado, Gonçalo; Coelho, Rita; Costa, Ana C; Ferreira, Maria S G; Costa, Maria H; Costa, Filipe O

    2016-01-01

    The Gastropoda is one of the best studied classes of marine invertebrates. Yet, most species have been delimited based on morphology only. The application of DNA barcodes has shown to be greatly useful to help delimiting species. Therefore, sequences of the cytochrome c oxidase I gene from 108 specimens of 34 morpho-species were used to investigate the molecular diversity within the gastropods from the Portuguese coast. To the above dataset, we added available COI-5P sequences of taxonomically close species, in a total of 58 morpho-species examined. There was a good match between ours and sequences from independent studies, in public repositories. We found 32 concordant (91.4%) out of the 35 Barcode Index Numbers (BINs) generated from our sequences. The application of a ranking system to the barcodes yield over 70% with top taxonomic congruence, while 14.2% of the species barcodes had insufficient data. In the majority of the cases, there was a good concordance between morphological identification and DNA barcodes. Nonetheless, the discordance between morphological and molecular data is a reminder that even the comparatively well-known European marine gastropods can benefit from being probed using the DNA barcode approach. Discordant cases should be reviewed with more integrative studies. PMID:26876495

  20. With a little help from DNA barcoding: investigating the diversity of Gastropoda from the Portuguese coast

    PubMed Central

    Borges, Luísa M. S.; Hollatz, Claudia; Lobo, Jorge; Cunha, Ana M.; Vilela, Ana P.; Calado, Gonçalo; Coelho, Rita; Costa, Ana C.; Ferreira, Maria S. G.; Costa, Maria H.; Costa, Filipe O.

    2016-01-01

    The Gastropoda is one of the best studied classes of marine invertebrates. Yet, most species have been delimited based on morphology only. The application of DNA barcodes has shown to be greatly useful to help delimiting species. Therefore, sequences of the cytochrome c oxidase I gene from 108 specimens of 34 morpho-species were used to investigate the molecular diversity within the gastropods from the Portuguese coast. To the above dataset, we added available COI-5P sequences of taxonomically close species, in a total of 58 morpho-species examined. There was a good match between ours and sequences from independent studies, in public repositories. We found 32 concordant (91.4%) out of the 35 Barcode Index Numbers (BINs) generated from our sequences. The application of a ranking system to the barcodes yield over 70% with top taxonomic congruence, while 14.2% of the species barcodes had insufficient data. In the majority of the cases, there was a good concordance between morphological identification and DNA barcodes. Nonetheless, the discordance between morphological and molecular data is a reminder that even the comparatively well-known European marine gastropods can benefit from being probed using the DNA barcode approach. Discordant cases should be reviewed with more integrative studies. PMID:26876495

  1. Feeding clusters and olfaction in the mangrove snail Terebralia palustris (Linnaeus) (Potamididae: Gastropoda).

    PubMed

    Fratini, S; Cannicci, S; Vannini, M

    2001-07-01

    Large numbers of the snail Terebralia palustris (Linnaeus) (Potamididae; Gastropoda) are frequently observed feeding in a cluster on a single fallen mangrove leaf, yet none are present on leaves nearby. Consequently, we investigated the food-finding ability of T. palustris in a Kenyan mangrove forest using field experiments. We estimated the attractive effect of different cues and analysed the paths (video-recorded) of snails when approaching a food-related odour. This intertidal snail can potentially use both air-borne and water-borne odours to locate food. T. palustris is attracted to conspecifics feeding on leaves, while intact leaves as well as non-feeding snails are not attractive. Moreover, the guiding stimulus appears to be compounds released when the leaves are damaged.T. palustris also seems able to discriminate between different food items; it is more strongly attracted to green mangrove leaves than senescent or fallen ones or mangrove propagules, probably because green leaves release a greater amount of attractive cues.Feeding snails thus recruit more snails to feed on the same leaf. The ecological implications of this behaviour are discussed: a large number of snails on the same leaf counteracts the ability of crabs to remove the leaf being eaten by the snails. PMID:11399273

  2. The long way to diversity--phylogeny and evolution of the Heterobranchia (Mollusca: Gastropoda).

    PubMed

    Dinapoli, Angela; Klussmann-Kolb, Annette

    2010-04-01

    Heterobranchia are one of the most species rich groups within Gastropoda, with poorly resolved phylogenetic relationships especially in basal taxa. In order to resolve phylogenetic relationships within the Heterobranchia, we pursued a molecular systematic approach by sequencing and analysing a variety of genetic markers (including nuclear 28S rDNA+18S rDNA and mitochondrial 16S rDNA+COI sequences). Maximum likelihood as well as Bayesian inference methods were used for phylogenetic reconstruction. Moreover, data quality was estimated for the purpose of proving the plausibility of the novel phylogenetic hypothesis using a variety of statistical tests as well as network analyses. Finally, a case study was conducted in order to estimate divergence ages using a "relaxed" molecular clock approach with fossils as minimum age constraints. All phylogenetic analyses revealed the Heterobranchia as monophyletic. Within the Heterobranchia, several well supported clades could be resolved. However, the traditional classification based on morphological data could not be confirmed due to paraphyletic Euthyneura as well as paraphyletic Pulmonata and polyphyletic Opisthobranchia. The estimation of data quality yielded a high degree of substitution saturation in many of the nucleotide positions while the Relative-Rate-Test revealed the highest evolution rates within the "Lower Heterobranchia". Although the dataset shows much conflict, many of the proposed hypotheses are supported by splits of the network analysis. The molecular clock approach was able to confirm some evolutionary hypotheses based on fossils such as the late occurrence of Pulmonata and Stylommatophora, respectively, during the Mesozoic. However, large 95% highest posterior density (HPD) intervals at some of the nodes made a precise dating of these nodes difficult. This molecular phylogenetic investigation provides the most comprehensive molecular study of relationships within the Heterobranchia to date. Due to the

  3. The complete mitochondrial genome of the nudibranch Roboastra europaea (Mollusca: Gastropoda) supports the monophyly of opisthobranchs.

    PubMed

    Grande, Cristina; Templado, José; Cervera, J Lucas; Zardoya, Rafael

    2002-10-01

    The complete nucleotide sequence (14,472 bp) of the mitochondrial genome of the nudibranch Roboastra europaea (Gastropoda: Opisthobranchia) was determined. This highly compact mitochondrial genome is nearly identical in gene organization to that found in opisthobranchs and pulmonates (Euthyneura) but not to that in prosobranchs (a paraphyletic group including the most basal lineages of gastropods). The newly determined mitochondrial genome differs only in the relative position of the trnC gene when compared with the mitochondrial genome of Pupa strigosa, the only opisthobranch mitochondrial genome sequenced so far. Pupa and Roboastra represent the most basal and derived lineages of opisthobranchs, respectively, and their mitochondrial genomes are more similar in sequence when compared with those of pulmonates. All phylogenetic analyses (maximum parsimony, minimum evolution, maximum likelihood, and Bayesian) based on the deduced amino acid sequences of all mitochondrial protein-coding genes supported the monophyly of opisthobranchs. These results are in agreement with the classical view that recognizes Opisthobranchia as a natural group and contradict recent phylogenetic studies of the group based on shorter sequence data sets. The monophyly of opisthobranchs was further confirmed when a fragment of 2,500 nucleotides including the mitochondrial cox1, rrnL, nad6, and nad5 genes was analyzed in several species representing five different orders of opisthobranchs with all common methods of phylogenetic inference. Within opisthobranchs, the polyphyly of cephalaspideans and the monophyly of nudibranchs were recovered. The evolution of mitochondrial tRNA rearrangements was analyzed using the cox1+rrnL+nad6+nad5 gene phylogeny. The relative position of the trnP gene between the trnA and nad6 genes was found to be a synapomorphy of opisthobranchs that supports their monophyly. PMID:12270894

  4. Homology and homoplasy of swimming behaviors and neural circuits in the Nudipleura (Mollusca, Gastropoda, Opisthobranchia).

    PubMed

    Newcomb, James M; Sakurai, Akira; Lillvis, Joshua L; Gunaratne, Charuni A; Katz, Paul S

    2012-06-26

    How neural circuit evolution relates to behavioral evolution is not well understood. Here the relationship between neural circuits and behavior is explored with respect to the swimming behaviors of the Nudipleura (Mollusca, Gastropoda, Opithobranchia). Nudipleura is a diverse monophyletic clade of sea slugs among which only a small percentage of species can swim. Swimming falls into a limited number of categories, the most prevalent of which are rhythmic left-right body flexions (LR) and rhythmic dorsal-ventral body flexions (DV). The phylogenetic distribution of these behaviors suggests a high degree of homoplasy. The central pattern generator (CPG) underlying DV swimming has been well characterized in Tritonia diomedea and in Pleurobranchaea californica. The CPG for LR swimming has been elucidated in Melibe leonina and Dendronotus iris, which are more closely related. The CPGs for the categorically distinct DV and LR swimming behaviors consist of nonoverlapping sets of homologous identified neurons, whereas the categorically similar behaviors share some homologous identified neurons, although the exact composition of neurons and synapses in the neural circuits differ. The roles played by homologous identified neurons in categorically distinct behaviors differ. However, homologous identified neurons also play different roles even in the swim CPGs of the two LR swimming species. Individual neurons can be multifunctional within a species. Some of those functions are shared across species, whereas others are not. The pattern of use and reuse of homologous neurons in various forms of swimming and other behaviors further demonstrates that the composition of neural circuits influences the evolution of behaviors. PMID:22723353

  5. Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia)

    NASA Astrophysics Data System (ADS)

    Kapan, Sevinç; Kabasakal, Sinem

    2016-04-01

    Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia) Sevinç KAPAN, Sinem KABASAKAL, Çanakkale Onsekiz Mart University, Engineering Faculty, Geological Engineering Department sevinckapan_yesilyurt@hotmail.com In this study, paleontology and stratigraphy of Neogene and Quaternary units around south of the Dardanelles have been examined using Gastropoda and Bivalvia fauna. In the investigation area, the base of the sediments that belongs to Neogene, consist of the volcanics which are formed with basalts, andesites and tuff. Neogene begins unconformity with basal conglomerate which are formed with basalt and tuff gravels. The measurable thickness of the Neogene sediments is approximately 200meters in total. First fossiliferius level which consist of Lymnocardium (Euxinicardium) nobile Sabba has showed similarities with the Pontian (Late Miocene) fauna of the Eastern Paratethys. The existence of Melanopsis and Psidium species indicate that the basin has been brackish water feeding by fresh water in the Early Pliocene. Theodoxus fluviatilis (Linne), Theodoxus (Calvertia) aff. imbricata Brusina, Theodoxus (Calvertia) licherdopoli scriptus (Stefanescu), Viviparus mammatus (Stefanescu), Valvata (Valavata) sulekiana Brusina, Valvata (Cincinna) crusitensis Fontannes, Hydrobia cf grandis Cobalcescu, Hydrobia ventrosa Monfort, Melanopsis (Melanopsis) cf. bergeroni Stefanescu, , Melanopsis (Melanopsis) sandbergeri rumana Tournouer, Melanopsis (Canthidomus) hybostoma anili Taner, Melanopsis (Canthidomus) hybostoma amaradica Fontannes, Melanopsis (Canthidomus) lanceolata Neumayr, Amphimelania fossariformis (Tournouer), Melanoides tuberculata monolithica (Bukowski), Radix (Radix) peregra (Müller), Planorbarius thiollierei (Michaud), Potamida (Potamida) craiovensis craiovensis (Tournouer), Potamida (Potamida) berbestiensis (Fontannes), Unio pristinus davilai Porumbaru, Unio subexquisitus Jatzko, Anadonta zmaji

  6. A new freshwater snail genus (Hydrobiidae, Gastropoda) from Montenegro, with a discussion on gastropod diversity and endemism in Skadar Lake

    PubMed Central

    Pešić, Vladimir; Glöer, Peter

    2013-01-01

    Abstract Karucia sublacustrina a new species of freshwater snails (Hydrobiidae, Gastropoda) is described based on material collected from Skadar Lake (Montenegro, Albania). The new species belongs to monotypic genus Karucia gen. n. The shell morphology and body shape of the new genus resembles Radomaniola Szarowska, 2006 and Grossuana Radoman, 1973, from which it differs in the larger shells with relatively slim and a slightly, but clearly shouldered body whorl. The number of gastropods from Skadar Lake basin tallies now 50 species. The adjusted rate of gastropod endemicity for Skadar Lake basin is estimated to be 38%. By compiling faunal and taxonomic data we also aim to provide information of relevance as to conservation efforts. PMID:23794834

  7. Comparison of broad band time series recorded parallel by FGI type interferometric water level and Lippmann type pendulum tilt meters at Conrad observatory, Austria

    NASA Astrophysics Data System (ADS)

    Ruotsalainen, Hannu; Papp, Gabor; Leonhardt, Roman; Ban, Dora; Szücs, Eszter; Benedek, Judith

    2016-04-01

    The Finnish Geodetic Institute (FGI) the progenitor of Finnish Geospatial Research Institute of NLS designed and built a 5.5m long prototype of interferometric water level tiltmeter (iWT) in early 2014. Geodetic and Geophysical Institute (GGI), Sopron, Hungary bought the instrument and started tilt measurement in August 2014 at the Conrad observatory (COBS), Austria to monitor geodynamical phenomena like microseisms, free oscillations of the Earth, earth tides, mass loading effects and crustal deformations in cooperation with Austrian Central Institute for Meteorology and Geodynamics (ZAMG) and the FGI. On the July 16 2015 a Lippmann-type 2D tilt sensor (LTS) was also installed by GGI on the 6 m long pier where iWT was set up previously. This situation opens a possibility to do broad band (from secular to seismic variations up to 15 Hz) geophysical signal analysis comparing the responses of long (several meters) and short (a few decimeters) base instruments implementing different physical principles (relative height change of a level surface and inclination change of the plumb line). The characteristics of the sensors are studied by the evaluation of the spectra of recorded signals dominated by microseisms. The iWT has internal interferometric calibration and it can be compared to Lippmanns tilt meter one. Both instruments show good long term ( > 1 day) stability when earth tides and ocean and air mass loading tilts are modelled.

  8. Phylogenetic relationships among Opisthobranchia (Mollusca: Gastropoda) based on mitochondrial cox 1, trnV, and rrnL genes.

    PubMed

    Grande, Cristina; Templado, Josè; Cervera, J Lucas; Zardoya, Rafael

    2004-11-01

    We reconstructed the phylogenetic relationships among 37 species representing seven main lineages within Opisthobranchia (Mollusca: Gastropoda) based on a mitochondrial fragment that included partial cox 1, complete trnV, and partial rrnL genes (about 2500 bp). Phylogenetic analyses confirmed tentatively that all studied main opisthobranch lineages conformed monophyletic groups except Nudibranchia. The sacoglossan Ascobulla was placed as the most basal lineage of opisthobranchs. The basommatophoran pulmonate Siphonaria was recovered within Opisthobranchia between Ascobulla and the remaining opisthobranchs. The latter were divided into two different lineages that await formal description: on one side, Cephalaspidea, Tylodinoidea, and Anaspidea (sharing features in the reproductive, digestive, and circulatory systems) were grouped together and, on the other Architectibranchia and Nudipleura (sharing similarities in the circulatory system) were recovered as sister group taxa. Two well-supported clades were recovered within Nudipleura: Pleuroanthobranchia (new taxon) and Cladobranchia. Pleuroanthobranchia (Pleurobranchoidea plus Anthobranchia) was defined by the presence of blood gland, the presence of calcareous spicules in the integument and the presence of a caecum with an opening directly into the stomach. The new molecular phylogeny provided a robust framework for comparative studies, and prompted a revision of the morphological synapomorphies diagnosing the main clades within opisthobranchs. PMID:15336672

  9. Assessing metal contamination from construction and demolition (C&D) waste used to infill wetlands: using Deroceras reticulatum (Mollusca: Gastropoda).

    PubMed

    Staunton, John A; Mc Donnell, Rory J; Gormally, Michael J; Williams, Chris D; Henry, Tiernan; Morrison, Liam

    2014-11-01

    Large quantities of construction and demolition waste (C&D) are produced globally every year, with little known about potential environmental impacts. In the present study, the slug, Deroceras reticulatum (Mollusca: Gastropoda) was used as the first biomonitor of metals (Ag, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Ti, Tl, V and Zn) on wetlands post infilling with construction and demolition (C&D) waste. The bioaccumulation of As, Ba, Cd, Co, Sb, Se and Tl were found to be significantly elevated in slugs collected on C&D waste when compared to unimproved pastures (control sites), while Mo, Se and Sr had significantly higher concentrations in slugs collected on C&D waste when compared to known contaminated sites (mining locations), indicating the potential hazardous nature of C&D waste to biota. Identifying exact sources for these metals within the waste can be problematic, due to its heterogenic nature. Biomonitors are a useful tool for future monitoring and impact studies, facilitating policy makers and regulations in other countries regarding C&D waste infill. In addition, improving separation of C&D waste to allow increased reuse and recycling is likely to be effective in reducing the volume of waste being used as infill, subsequently decreasing potential metal contamination. PMID:25298023

  10. Algivore or Phototroph? Plakobranchus ocellatus (Gastropoda) Continuously Acquires Kleptoplasts and Nutrition from Multiple Algal Species in Nature

    PubMed Central

    Maeda, Taro; Hirose, Euichi; Chikaraishi, Yoshito; Kawato, Masaru; Takishita, Kiyotaka; Yoshida, Takao; Verbruggen, Heroen; Tanaka, Jiro; Shimamura, Shigeru; Takaki, Yoshihiro; Tsuchiya, Masashi; Iwai, Kenji; Maruyama, Tadashi

    2012-01-01

    The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae. PMID:22848693

  11. Cm-p5: an antifungal hydrophilic peptide derived from the coastal mollusk Cenchritis muricatus (Gastropoda: Littorinidae)

    PubMed Central

    López-Abarrategui, Carlos; McBeth, Christine; Mandal, Santi M.; Sun, Zhenyu J.; Heffron, Gregory; Alba-Menéndez, Annia; Migliolo, Ludovico; Reyes-Acosta, Osvaldo; García-Villarino, Mónica; Nolasco, Diego O.; Falcão, Rosana; Cherobim, Mariana D.; Dias, Simoni C.; Brandt, Wolfgang; Wessjohann, Ludger; Starnbach, Michael; Franco, Octavio L.; Otero-González, Anselmo J.

    2015-01-01

    Antimicrobial peptides form part of the first line of defense against pathogens for many organisms. Current treatments for fungal infections are limited by drug toxicity and pathogen resistance. Cm-p5 (SRSELIVHQRLF), a peptide derived from the marine mollusk Cenchritis muricatus peptide Cm-p1, has a significantly increased fungistatic activity against pathogenic Candida albicans (minimal inhibitory concentration, 10 µg/ml; EC50, 1.146 µg/ml) while exhibiting low toxic effects against a cultured mammalian cell line. Cm-p5 as characterized by circular dichroism and nuclear magnetic resonance revealed an α-helical structure in membrane-mimetic conditions and a tendency to random coil folding in aqueous solutions. Additional studies modeling Cm-p5 binding to a phosphatidylserine bilayer in silico and isothermal titration calorimetry using lipid monophases demonstrated that Cm-p5 has a high affinity for the phospholipids of fungal membranes (phosphatidylserine and phosphatidylethanolamine), only moderate interactions with a mammalian membrane phospholipid, low interaction with ergosterol, and no interaction with chitin. Adhesion of Cm-p5 to living C. albicans cells was confirmed by fluorescence microscopy with FITC-labeled peptide. In a systemic candidiasis model in mice, intraperitoneal administration of Cm-p5 was unable to control the fungal kidney burden, although its low amphiphaticity could be modified to generate new derivatives with improved fungicidal activity and stability.—López-Abarrategui, C., McBeth, C., Mandal, S. M., Sun, Z. J., Heffron, G., Alba-Menéndez, A., Migliolo, L., Reyes-Acosta, O., García-Villarino, M., Nolasco, D. O., Falcão, R., Cherobim, M. D., Dias, S. C., Brandt, W., Wessjohann, L., Starnbach, M., Franco, O. L., Otero-González, A. J. Cm-p5: an antifungal hydrophilic peptide derived from the coastal mollusk Cenchritis muricatus (Gastropoda: Littorinidae). PMID:25921828

  12. Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species.

    PubMed

    Fallon, Phillip J Jr

    2016-01-01

    A review of the literature and examination of over 3,200 specimens of shallow water (<200 m) tropical western Atlantic (TWA) Drilliidae Olson, 1964 in museum and private collections has resulted in the recognition of numerous previously undescribed species, 100 of which are proposed here for the first time. A total of 65 names were found in the literature. Of these, 48 are considered valid, 16 synonyms, and one nomen dubium. In addition, characteristics that distinguish each genus currently in use for TWA shallow water species have indicated the need for reassignment (new combinations within Drilliidae) of 15 species. Some nomenclatural actions have come about from the literature review and include one taxon placed in junior synonymy (under an older name recently re-discovered) and one new name for a junior homonym. Two neotypes, five lectotype designations, and one new name are also proposed. Altogether, nomenclatural actions on 17% of valid previously described taxa are proposed. The 100 proposed names are placed in 12 available and one new genus: Agladrillia Woodring, 1928 (2), Bellaspira Conrad, 1868 (7), Calliclava McLean, 1971 (3), Cerodrillia Bartsch & Rehder, 1939 (11), Clathrodrillia Dall, 1918 (6), Decoradrillia, new genus (4), Douglassia Bartsch, 1934 (4), Fenimorea Bartsch, 1934 (15), Leptadrillia Woodring, 1928 (12), Lissodrillia Bartsch & Rehder, 1939 (8), Neodrillia Bartsch, 1943 (2), Splendrillia Hedley, 1922 (13), and Syntomodrillia Woodring, 1928 (13). These are the first reports of Calliclava in the western Atlantic, previously known only from the eastern Pacific. The new genus, Decoradrillia, is proposed to hold four new species and one existing that share a unique shell microsculpture and other morphological traits. One genus, Drillia Gray, 1838, is not currently believed to have TWA representatives. Three genera comprised exclusively of bathyal species are not treated in this work: Clavus Monfort, 1810 (=Eldridgea Bartsch, 1934), Globidrillia

  13. An integrative taxonomic investigation of the diversity of digenean parasites infecting the intertidal snail Austrolittorina unifasciata Gray, 1826 (Gastropoda: Littorinidae) in Australia.

    PubMed

    O'Dwyer, Katie; Faltýnková, Anna; Georgieva, Simona; Kostadinova, Aneta

    2015-06-01

    We investigated for the first time the digenean parasites of Austrolittorina unifasciata Gray (Gastropoda: Littorinidae), a periwinkle snail inhabiting the rocky shores of Australia. Here we present detailed morphological descriptions and molecular data (sequences for the mitochondrial cox1 and the nuclear 28S rRNA gene) for the cercariae and intramolluscan stages of the digenean parasites found. Five species, one each of the families Notocotylidae Lühe, 1909, Gorgocephalidae Manter, 1966 and Philophthalmidae Looss, 1899, and two of the family Renicolidae Dollfus, 1939, were recorded and characterised molecularly. Phylogenetic analyses at the superfamily level provided evidence for the familial and generic affiliation of the species and their relationships with congeners. This study is the first to provide data on the life cycle of a species of the family Gorgocephalidae, a parasite of kyphosid fish for which only adult stages had, thus far, been described. The relatively high prevalence of this species allowed mapping of the cox1 haplotype distribution of Gorgocephalus sp. Aus along the southern coast of New South Wales. PMID:25866083

  14. The Cylindrobulla/Ascobulla complex--unraveling problems in identification and adding to Cylindrobulla diversity (Gastropoda, Heterobranchia, Sacoglossa) by describing a new species.

    PubMed

    Laetz, Elise; Christa, Gregor; Händeler, Katharina; Wägele, Heike

    2014-01-01

    Sacoglossa (Gastropoda: Heterobranchia) are generally considered a monophyletic group, previously associated within the now defunct "Opisthobranchia", but now basally located within Panpulmonata. In the light of this new phylogenetic hypothesis, detailed knowledge of the most basal groups within Sacoglossa is of paramount importance. This study focuses on the genus Cylindrobulla, which is usually considered the most basal group within the Sacoglossa from a morphological point of view, because it does not share the typical elongate radula teeth of all other Sacoglossa. We describe a new species, Cylindrobulla schuppi sp. nov., and provide data on its food. We reexamined and clarify the radula of the type species C. beauii, review the genus with all other valid species, provide new characters to aid in the proper identification of species within this genus, compare it to the very similar genus Ascobulla, present a determination key using external characters to ensure proper identification of the two similar genera, and discuss phylogenetic relationships within the shelled sacoglossan, the Oxynoacea. PMID:25544526

  15. Incorporated nematocysts in Aeolidiella stephanieae (Gastropoda, Opisthobranchia, Aeolidoidea) mature by acidification shown by the pH sensitive fluorescing alkaloid Ageladine A.

    PubMed

    Obermann, Dana; Bickmeyer, Ulf; Wägele, Heike

    2012-11-01

    The sequestration of nematocysts (a special group of cnidocysts) from cnidarian prey with subsequent use in defence is described for few metazoan phyla. Members of the taxon Aeolidoidea (Nudibranchia, Gastropoda) are well-known for this. Questions regarding the reasons some nematocysts do not discharge when the gastropod feeds and how these same nematocysts can be transported along the digestive tract into specialized morphological structures called cnidosacs, remain unanswered. Within the cnidosac, nematocysts are incorporated in cells and finally be used for defence against predators. The most plausible explanation for this phenomenon suggests there are immature and therefore non-functional nematocysts in the food. A recent study by Berking and Herrmann (2005) on cnidarians suggested that the nematocysts mature by acidification via proton transfer into the nematocyst capsule. According to this hypothesis only immature nematocysts are transported into the cnidosac where they are then made functional through an accumulation of protons. In this study we present a fluorescence staining method that tests the hypothesis by Berking and Herrmann (2005) and detects changes in the pH values of incorporated nematocysts, interpreted as changes in maturation stages. This marker, the fluorescent dye Ageladine A, stains nematocyst capsules according to their pH values. With Ageladine A we were able to show that kleptocnides indeed change their pH value after incorporation into the aeolidoidean cnidosac. PMID:22910369

  16. A new approach to an old conundrum--DNA barcoding sheds new light on phenotypic plasticity and morphological stasis in microsnails (Gastropoda, Pulmonata, Carychiidae).

    PubMed

    Weigand, Alexander M; Jochum, Adrienne; Pfenninger, Markus; Steinke, Dirk; Klussmann-Kolb, Annette

    2011-03-01

    The identification of microsnail taxa based on morphological characters is often a time-consuming and inconclusive process. Aspects such as morphological stasis and phenotypic plasticity further complicate their taxonomic designation. In this study, we demonstrate that the application of DNA barcoding can alleviate these problems within the Carychiidae (Gastropoda, Pulmonata). These microsnails are a taxon of the pulmonate lineage and most likely migrated onto land independently of the Stylommatophora clade. Their taxonomical classification is currently based on conchological and anatomical characters only. Despite much confusion about historic species assignments, the Carychiidae can be unambiguously subdivided into two taxa: (i) Zospeum species, which are restricted to karst caves, and (ii) Carychium species, which occur in a broad range of environmental conditions. The implementation of discrete molecular data (COI marker) enabled us to correctly designate 90% of the carychiid microsnails. The remaining cases were probably cryptic Zospeum and Carychium taxa and incipient species, which require further investigation into their species status. Because conventional reliance upon mostly continuous (i.e. nondiscrete) conchological characters is subject to fallibility for many gastropod species assignments, we highly recommend the use of DNA barcoding as a taxonomic, cutting-edge method for delimiting microsnail taxa. PMID:21429131

  17. Behavioral thermoregulation and critical thermal limits of giant keyhole limpet Megathura crenulata(Sowerby 1825) (Mollusca; Vetigastropoda).

    PubMed

    Díaz, Fernando; Denisse Re, Ana; Salas, Alfredo; Galindo-Sanchez, Clara E; Gonzalez, Marco A; Sanchez, Adolfo; Rosas, Carlos

    2015-12-01

    The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a horizontal thermal gradient during the day at 18.9 °C and 18.3 °C for the night. The final preferendum determined for giant keyhole limpets was of 18.6±1.2 °C. Limpets' displacement velocity was 10.0±3.9 cm h(-1) during the light phase and 8.4±1.6 cm h(-1) during the dark phase. The thermotolerance (measured as CTMax at 50%) was determined in a keyhole limpet in three acclimation temperatures 17, 20, and 23 °C. Limpets were subjected to water increasing temperatures at a rate of 1 °C every 30 min, until they detached from the substrate. The critical thermal maximum at 50% was 27.2, 27.9 and 28.3 °C respectively. PMID:26615735

  18. An annotated catalogue and bibliography of the taxonomy, synonymy and distribution of the Recent Vetigastropoda of South Africa (Mollusca).

    PubMed

    Herbert, David G

    2015-01-01

    A complete inventory of the known Recent vetigastropod fauna of South Africa is provided. Bibliographic citations to works discussing the taxonomy, synonymy and distribution of the species in a southern African or south-western Indian Ocean context are provided. Additional explanatory notes are given where pertinent. New genus records for South Africa: Acremodontina B.A. Marshall, 1995; Choristella Bush, 1879; Cocculinella Thiele, 1909; Conjectura Finlay, 1926; Crosseola Iredale, 1924; Falsimargarita Powell, 1951; Lepetella Verrill, 1880; Profundisepta McLean & Geiger, 1998; Stomatella Lamarck, 1816; Stomatia Helbling, 1779; Stomatolina Iredale, 1937; Synaptocochlea Pilsbry, 1890; Tibatrochus Nomura, 1940; Visayaseguenzia Poppe, Tagaro & Dekker, 2006; Zetela Finlay, 1926. New species records for South Africa: Acremodontina aff. carinata Powell, 1940; Anatoma finlayi (Powell, 1937); Anatoma munieri (P. Fischer, 1862); Calliotropis acherontis B.A. Marshall, 1979; Calliotropis bucina Vilvens, 2006; Cocculinella minutissima (E.A. Smith, 1904); Diodora ruppellii (G.B. Sowerby (I), 1835); Emarginula costulata Deshayes, 1863; Emarginula decorata Deshayes, 1863; Jujubinus hubrechti Poppe, Tagaro & Dekker, 2006; Lepetella sp.; Seguenzia orientalis Thiele, 1925; Stomatella auricula Lamarck, 1816; Stomatia phymotis Helbling, 1779; Stomatolina angulata (A. Adams, 1850); Stomatolina cf. calliostoma (A. Adams, 1850); Stomatolina aff. danblumi Singer & Mienis, 1999; Stomatolina cf. rubra (Lamarck, 1822); Stomatolina sp.; Synaptocochlea concinna (Gould, 1845); Tectus mauritianus (Gmelin, 1791); Tibatrochus cf. incertus (Schepman, 1908); Turbo imperialis Gmelin, 1791; Turbo tursicus Reeve, 1848; Visayaseguenzia compsa (Melvill, 1904).New species: Spectamen martensi, replacement name for Spectamen semisculptum sensu Herbert (1987) (non Martens, 1904). New name: Oxystele antoni is proposed as a new name for Trochus (Turbo) variegatus (non Gmelin, 1791 =Heliacus) Anton, 1838. Revised taxonomy: Cyclostrema semisculptum Martens, 1904 is an earlier name for Solariella intermissa Thiele, 1925, and is referable to the genus Zetela Finlay, 1926; Margarita bicarinata A. Adams & Reeve, 1850 is considered to be a senior synonym of Solariella undata G.B. Sowerby (II), 1870, and is referable to the genus Ilanga Herbert, 1987. Validation of the name Trochus tigrinus Chemnitz, 1781 is credited to Dillwyn (1817) rather than Anton (1838). New synonyms: Clanculus exquisita Turton, 1932 =Calliostoma africanum Bartsch, 1915; Cyclostrema alfredensis Bartsch, 1915 =Parviturbo alfredensis (Bartsch, 1915); Cynisca gloriosa Bartsch, 1915 =Cinysca spuria (Gould, 1861); Herbertina hayesi Herbert, 1995 =Bruceina chenoderma (Barnard, 1963); Ilanga millardi Herbert, 1987 =Ilanga humillima (Thiele, 1925); Leptothyra africana Bartsch, 1915 =Cinysca spuria (Gould, 1861); Leptothyra albocincta Turton, 1932 =Tricolia striolata (Turton, 1932); Solariella undata G.B. Sowerby (II), 1870, S. gratiosa Thiele, 1925 and S. valdiviae Thiele, 1925 =Ilanga bicarinata bicarinata (A. Adams & Reeve, 1850); Solariella chuni Thiele, 1925, S. intermissa Thiele, 1925, S. gilchristi Barnard, 1963 and S. macleari Barnard, 1963 =Zetela semisculpta (Martens, 1904); Turbo (Collonia) armillatus G.B. Sowerby (III), 1886 =Cinysca spuria (Gould, 1861). New combinations: Basilissa (Ancistrobasis) compsa Melvill, 1904 is transferred to Visayaseguenzia; Calcar rhysopoma Barnard, 1964 is transferred to Bothropoma; Calliostoma glaucophaos Barnard, 1963 is transferred to Falsimargarita; Calliotropis chenoderma Barnard, 1963 is transferred to Bruceina; Collonia bicarinata Martens, 1902 is transferred to Cinysca; Crossea agulhasensis Thiele, 1925 is transferred to Conjectura; Cyclostrema semisculptum Martens, 1904 is transferred to Zetela; Cyclostremella farica Bartsch, 1915 is transferred to Dikoleps; Cynisca africana Bartsch, 1915 is transferred to Homalopoma; Leptogyra africana: Bartsch, 1915 is transferred to Cirsonella; Leptothyra agulhasensis Thiele, 1925 is transferred to Homalopoma; Leptothyra alfredensis Bartsch, 1915 is transferred to Parviturbo; Leptothyra sola Barnard, 1963 is transferred to a Parviturbo; Liotia (Cynisca) semiclausa Thiele, 1925 is transferred to Cinysca; Monilea spuria Gould, 1861 is transferred to Cinysca; Monodonta gibbula Thiele, 1925 is transferred to Cantrainea; Puncturella voraginosa Herbert & Kilburn, 1986 is transferred to Profundisepta; Solariella fuscomaculata G.B. Sowerby (III), 1892 is transferred to Skenea; Solariella turbynei Barnard, 1963 is transferred to Zetela; Turbo boswellae Barnard, 1969 is transferred to Cantrainea; Turbo foveolatus Barnard, 1963 is transferred to Crosseola; Turbo ponsonbyi G.B. Sowerby (III), 1897 is transferred to Bothropoma; Vitrinella agulhasensis Thiele, 1925 is transferred to Parviturbo; Vitrinella (Docomphala) arifca Bartsch, 1915 is transferred to Lodderena; Vitrinella inclinans Barnard, 1963 is transferred to Skenea. PMID:26624772

  19. CERT tribal internship program. Final intern report: David Conrad, 1993

    SciTech Connect

    1998-09-01

    The intern`s report contains a Master`s thesis entitled, ``An implementation analysis of the US Department of Energy`s American Indian policy as part of its environmental restoration and waste management mission.`` This thesis examines the implementation of a working relationship between the Nez Perce Tribe and the US Department of Energy`s Office of Environmental Restoration and Waste Management at the Hanford reservation. It examines the relationship using a qualitative methodology and three generations of policy analysis literature to gain a clear understanding of the potential for successful implementation.

  20. Components of mucus of terrestrial slugs (Gastropoda).

    PubMed

    Deyrup-Olsen, I; Luchtel, D L; Martin, A W

    1983-09-01

    Mucous secretion by the body wall of the terrestrial slugs (Ariolimax columbianus, Arionidae; and other species) was found to involve at least three distinct stages--release of vesicles, formation of granules, and organization of strands. Mucus is stored intracellularly in membrane-bound vesicles, and these are shed intact from the mucous cells. Disruption of the vesicle membrane, with release of contents, can be effected by endogenous lytic agent(s), as well as by exogenous surfactants, lipid solvents, or hypotonic media. Thereupon 1-micron granules are released. These may be stable, or they may change to material that is finely granular or in the form of strands; the transition to strands is facilitated by shear stress exerted through the fluid containing the mucous components. Lectins organize, or are organized with, the strands, as evidenced by agglutination of erythrocytes on them. Mucous formation, as seen in the living slug, differs markedly from the one-step process of exocytosis of fluid mucus inferred from studies of mucous membranes fixed for ultrastructural investigation. PMID:6614215

  1. FRESHWATER SNAILS (MOLLUSCA: GASTROPODA) OF NORTH AMERICA

    EPA Science Inventory

    Freshwater gastropod mollusks are represented in North America (north of Mexico) by 15 families, 78 genera and, as treated in this manual, 499 species. They are grouped into two large subclasses, the gill-breathing, operculated Prosobranchia and the lung-breathing, non-operculate...

  2. Molecular phylogeny of euthyneura (mollusca: gastropoda).

    PubMed

    Grande, Cristina; Templado, José; Cervera, J Lucas; Zardoya, Rafael

    2004-02-01

    A new phylogenetic hypothesis for Euthyneura is proposed based on the analysis of primary sequence data (mitochondrial cox1, trnV, rrnL, trnL(cun), trnA, trnP, nad6, and nad5 genes) and the phylogenetic utility of two rare genomic changes (the relative position of the mitochondrial trnP gene, and an insertion/deletion event in a conserved region of the mitochondrial Cox1 protein) is addressed. Both sources of phylogenetic information clearly rejected the monophyly of pulmonates, a group of gastropods well supported so far by morphological evidence. The marine basommatophoran pulmonate Siphonaria was placed within opisthobranchs and shared with them the insertion of a Glycine in the Cox 1 protein. The marine systellommatophoran pulmonate Onchidella was recovered at the base of the opisthobranch + Siphonaria clade. Opisthobranchs, Siphonaria, and Onchidella shared the relative position of the mitochondrial trnP gene between the mitochondrial trnA and nad6 genes. The land snails and slugs (stylommatophoran pulmonates) were recovered as an early split in the phylogeny of advanced gastropods. The monophyly of the Euthyneura (Opisthobranchia + Pulmonata) was rejected by the inclusion of the heterostrophan Pyramidella. PMID:14660702

  3. Taxonomical study on the mollusks collected in Marion-Dufresne (MD55) and other expeditions to SE Brazil: the Fissurellidae (Mollusca, Vetigastropoda).

    PubMed

    Simone, Luiz Ricardo L; Cunha, Carlo M

    2014-01-01

    The Fissurellidae collected by the Marion-Dufresne Expedition, as well as other regional expeditions to SE Brazil are examined taxonomically, treating 21 species, of which 20 are new. The following new species are described (order according to depth range; species marked with * are from expeditions other than MD55): Cornisepta uirapa (790-940 m), Cornisepta arrepiata (295-1,050 m), Cornisepta aninga (295-1,050 m), Cranopsis hycavis (637 m), Cranopsis nymphalis (295 m), Cranopsis enigmatica (790-940 m), Cranopsis cearensis* (250 m), Cranopsis apostrema (110-940 m), Cranopsis alaris (250-450 m), Cranopsis canopa* (250 m), Cranopsis columbaris* (250 m), Emarginula suspira (54-940 m), Emarginula icosisculpta (10-12 m), Manganesepta atiaia (950-1,570 m), Profundisepta denudata* (3,000 m), Puncturella volcano (607-620 m), Rimula leptarcis (85-105 m), Zeidora pussa (607-940 m), Zeidora crepidula (790-940 m), Hemimarginula hemitoma (1-105 m). Diodora mirifica Métivier, 1972 (10-12 m), common in Brazilian oceanic islands, is the only fissurellid species previously known from that area. The genera Cornisepta, Cranopsis, Manganesepta, Profundisepta, Zeidora, and Hemimarginula are reported for the first time from Brazil. Emarginula suspira is named for material that has been misidentified as E. tuberculosa, a Miocene Mediterranean fossil. PMID:25081465

  4. The Mitochondrial Genomes of the Nudibranch Mollusks, Melibe leonina and Tritonia diomedea, and Their Impact on Gastropod Phylogeny

    PubMed Central

    Sevigny, Joseph L.; Kirouac, Lauren E.; Thomas, William Kelley; Ramsdell, Jordan S.; Lawlor, Kayla E.; Sharifi, Osman; Grewal, Simarvir; Baysdorfer, Christopher; Curr, Kenneth; Naimie, Amanda A.; Okamoto, Kazufusa; Murray, James A.; Newcomb, James M.

    2015-01-01

    The phylogenetic relationships among certain groups of gastropods have remained unresolved in recent studies, especially in the diverse subclass Opisthobranchia, where nudibranchs have been poorly represented. Here we present the complete mitochondrial genomes of Melibe leonina and Tritonia diomedea (more recently named T. tetraquetra), two nudibranchs from the unrepresented Cladobranchia group, and report on the resulting phylogenetic analyses. Both genomes coded for the typical thirteen protein-coding genes, twenty-two transfer RNAs, and two ribosomal RNAs seen in other species. The twelve-nucleotide deletion previously reported for the cytochrome oxidase 1 gene in several other Melibe species was further clarified as three separate deletion events. These deletions were not present in any opisthobranchs examined in our study, including the newly sequenced M. leonina or T. diomedea, suggesting that these previously reported deletions may represent more recently divergent taxa. Analysis of the secondary structures for all twenty-two tRNAs of both M. leonina and T. diomedea indicated truncated d arms for the two serine tRNAs, as seen in some other heterobranchs. In addition, the serine 1 tRNA in T. diomedea contained an anticodon not yet reported in any other gastropod. For phylogenetic analysis, we used the thirteen protein-coding genes from the mitochondrial genomes of M. leonina, T. diomedea, and seventy-one other gastropods. Phylogenetic analyses were performed for both the class Gastropoda and the subclass Opisthobranchia. Both Bayesian and maximum likelihood analyses resulted in similar tree topologies. In the Opisthobranchia, the five orders represented in our study were monophyletic (Anaspidea, Cephalaspidea, Notaspidea, Nudibranchia, Sacoglossa). In Gastropoda, two of the three traditional subclasses, Opisthobranchia and Pulmonata, were not monophyletic. In contrast, four of the more recently named gastropod clades (Vetigastropoda, Neritimorpha

  5. The Mitochondrial Genomes of the Nudibranch Mollusks, Melibe leonina and Tritonia diomedea, and Their Impact on Gastropod Phylogeny.

    PubMed

    Sevigny, Joseph L; Kirouac, Lauren E; Thomas, William Kelley; Ramsdell, Jordan S; Lawlor, Kayla E; Sharifi, Osman; Grewal, Simarvir; Baysdorfer, Christopher; Curr, Kenneth; Naimie, Amanda A; Okamoto, Kazufusa; Murray, James A; Newcomb, James M

    2015-01-01

    The phylogenetic relationships among certain groups of gastropods have remained unresolved in recent studies, especially in the diverse subclass Opisthobranchia, where nudibranchs have been poorly represented. Here we present the complete mitochondrial genomes of Melibe leonina and Tritonia diomedea (more recently named T. tetraquetra), two nudibranchs from the unrepresented Cladobranchia group, and report on the resulting phylogenetic analyses. Both genomes coded for the typical thirteen protein-coding genes, twenty-two transfer RNAs, and two ribosomal RNAs seen in other species. The twelve-nucleotide deletion previously reported for the cytochrome oxidase 1 gene in several other Melibe species was further clarified as three separate deletion events. These deletions were not present in any opisthobranchs examined in our study, including the newly sequenced M. leonina or T. diomedea, suggesting that these previously reported deletions may represent more recently divergent taxa. Analysis of the secondary structures for all twenty-two tRNAs of both M. leonina and T. diomedea indicated truncated d arms for the two serine tRNAs, as seen in some other heterobranchs. In addition, the serine 1 tRNA in T. diomedea contained an anticodon not yet reported in any other gastropod. For phylogenetic analysis, we used the thirteen protein-coding genes from the mitochondrial genomes of M. leonina, T. diomedea, and seventy-one other gastropods. Phylogenetic analyses were performed for both the class Gastropoda and the subclass Opisthobranchia. Both Bayesian and maximum likelihood analyses resulted in similar tree topologies. In the Opisthobranchia, the five orders represented in our study were monophyletic (Anaspidea, Cephalaspidea, Notaspidea, Nudibranchia, Sacoglossa). In Gastropoda, two of the three traditional subclasses, Opisthobranchia and Pulmonata, were not monophyletic. In contrast, four of the more recently named gastropod clades (Vetigastropoda, Neritimorpha

  6. Details of gastropod phylogeny inferred from 18S rRNA sequences.

    PubMed

    Winnepenninckx, B; Steiner, G; Backeljau, T; De Wachter, R

    1998-02-01

    Some generally accepted viewpoints on the phylogenetic relationships within the molluscan class Gastropoda are reassessed by comparing complete 18S rRNA sequences. Phylogenetic analyses were performed using the neighbor-joining and maximum parsimony methods. The previously suggested basal position of Archaeogastropoda, including Neritimorpha and Vetigastropoda, in the gastropod clade is confirmed. The present study also provides new molecular evidence for the monophyly of both Caenogastropoda and Euthyneura (Pulmonata and Opisthobranchia), making Prosobranchia paraphyletic. The relationships within Caenogastropoda and Euthyneura data turn out to be very unstable on the basis of the present 18S rRNA sequences. The present 18S rRNA data question, but are insufficient to decide on, muricacean (Neogastropoda), neotaenioglossan, pulmonate, or stylommatophoran monophyly. The analyses also focus on two systellommatophoran families, namely, Veronicellidae and Onchidiidae. It is suggested that Systellommatophora are not a monophyletic unit but, due to the lack of stability in the euthyneuran clade, their affinity to either Opisthobranchia or Pulmonata could not be determined. PMID:9479694

  7. [Wilhelm Conrad Röntgen and the discovery of X-rays].

    PubMed

    Tubiana, M

    1996-01-01

    W.C. Röntgen reported the discovery of X-rays in December 1895 after seven weeks of assiduous work during which he had studied the properties of this new type of radiation able to go through screens of notable thickness. He named them X-rays to underline the fact that their nature was unknown. The news of this discovery immediately aroused an immense interest in the public and also initiated intense research in several directions. Physicians and physicists began as early as January 1896 to use X-rays on patients to investigate the skeleton and subsequently the lung and other organs. This was the birth or radiology. Rapidly they observed skin erythema, which led to the idea of using X-rays against a variety of lesions. In June 1896 the first patient was treated by radiotherapy. J.J. Thomson (Cambridge, U.K.) showed that X-rays were able to ionize gaz and the study of this phenomenon led to the discovery of electrons in 1897. In order to understand the emission of X-rays, H. Becquerel (Paris) investigated the role of the phosphorescence of the glass of the tube and while doing so discovered radioactivity in March 1896. X-rays and radioactivity were at the origin of the scientific revolution at the end of the 19th and the beginning of the 20th centuries. Research on radioactive materials demonstrated the existence of atoms which had been till then only a convenient hypothesis for explaining chemical reactions, but whose reality was considered as dubious by most physicists. Moreover, interaction of particles emitted by radionuclides and atoms enabled first the study of the structure of the atom and subsequently its nucleus. Matter, elements which were thought to be immutable were found to be transmutable, and eventually to disintegrate. The origin of the energy transferred to the radiation which was emitted appeared as a mystery and in order to explain it the physicist had to accept that matter could convert energy. In 1903 Einstein established the equivalence between matter and energy. Matter, energy, electricity, light which were formerly considered as continuous quantities were found to be discrete: there are particles of matter (elementary particles), energy (quanta, Planck 1905), electricity (electron), light (photons). Radioactive decay, particle interactions imposed a probabilistic physics which progressively replaced classic deterministic physics. Radioactivity can be used as a clock to measure time in the universe. Datations were made for fossils, art masterpieces and also for the earth, the solar system and universe. X-rays diffraction proved to be a powerful tool for studying crystals and molecules, in particular protein, and in 1953 enabled to demonstrate the DNA double helix. Hence X-rays and radioactivity originated a revolution in physics and science and in the vision of nature. The imperceptible and yet so powerful rays demonstrated the deficiencies of our senses. Mathematical entities and instrumentation must complement our sensations. The huge increment in our knowledge is accompanied by a divorce between the scientist and the layman who now often has great difficulties understanding new concepts not only in physics but also in biology. PMID:8696882

  8. A Study of Ideational Metafunction in Joseph Conrad's "Heart of Darkness": A Critical Discourse Analysis

    ERIC Educational Resources Information Center

    Alaei, Mahya; Ahangari, Saeideh

    2016-01-01

    The linguistic study of literature or critical analysis of literary discourse is no different from any other textual description; it is not a new branch or a new level or a new kind of linguistics but the application of existing theories and methods (Halliday, 2002). This study intends to determine how ideology or opinion is expressed in Joseph…

  9. VizieR Online Data Catalog: Galactic open clusters in RAVE (Conrad+, 2014)

    NASA Astrophysics Data System (ADS)

    Conrad, C.; Scholz, R.-D.; Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Roser, S.; Boeche, C.; Kordopatis, G.; Siebert, A.; Williams, M.; Munari, U.; Matijevic, G.; Grebel, E. K.; Zwitter, T.; de Jong, R. S.; Steinmetz, M.; Gilmore, G.; Seabroke, G.; Freeman, K.; Navarro, J. F.; Parker, Q.; Reid, W.; Watson, F.; Gibson, B. K.; Bienayme, O.; Wyse, R.; Bland-Hawthorn, J.; Siviero, A.

    2014-01-01

    The presented tables summarise new radial velocities and average metallicities for Galactic open clusters extracted from the Catalogue of Open Cluster Data (COCD; Kharchenko et al. 2005, Cat. J/A+A/438/1163, J/A+A/440/403). The data were obtained from the RAdial Velocity Experiment (RAVE; Kordopatis et al. 2013AJ....146..134K) through a cross match with the stellar catalogues related to the COCD. The RV and [M/H] values were computed as weighted means, considering the individual uncertainties of the included members and their cluster membership probability based on position, proper motion, and photometry. The three uncertainties listed originate from different calculations: "RVRAVE" and "MetRAVE" are the weighted mean values for RV and [M/H] "errRV" and "errMet" are equivalent to the uncertainty of the mean values "sigRV" and "sigMet" are the standard deviations of the mean values "eRV" and "eMet" weighted mean values of the individual uncertainties of the included open cluster (OC) members For the calculations we primarily considered most probable OC members (best members) with a membership probability of at least 61%. Only in cases where just one or no most probable members was available we also included possible members (good members) with membership probabilities above 14%. In the table we include the numbers for both types of members separately: best members -> "bmem" and good members -> "gmem". We included reference values for RVs from the second version of the Catalogue of Radial Velocities with Astrometric Data (CRVAD-2) and the Catalogue of Radial Velocities of Open Clusters and Associations (CRVOCA) provided by Kharchenko et al. 2007, Cat. III/254). The CRVAD-2 reference values were computed according to the RAVE values for identified OC members. The CRVOCA references were directly extracted from the catalogue and number of OC members used are given in column "nmem". The reference values for [M/H] were obtained from the online compilation provided by Dias et al. (2002, See B/ocl), hereafter referred to as DAML. These were obtained through different techniques and the literature references from DAML are also included in our table. In DAML actual [M/H] values are mixed with [Fe/H] values and we only considered the actual [M/H], based on information given in the references. (2 data files).

  10. Physella acuta: atypical mitochondrial gene order among panpulmonates (Gastropoda)

    PubMed Central

    Nolan, Journey R.; Bergthorsson, Ulfar; Adema, Coen M.

    2014-01-01

    Mitochondrial (mt) sequences are frequently used for phylogenetic reconstruction and for identification of species of molluscs. This study expands the phylogenetic range of Hygrophila (Panpulmonata) for which such sequence data are available by characterizing the full mt genome of the invasive freshwater snail Physella acuta (Physidae). The mt genome sequences of two P. acuta isolates from Stubblefield Lake, New Mexico, USA, differed in length (14,490 vs 14,314 bp) and showed 11.49% sequence divergence, whereas ITS1 and ITS2 sequences from the nuclear genome differed by 1.75%. The mt gene order of P. acuta (cox1, P, nad6, nad5, nad1, D, F, cox2, Y, W, nad4L, C, Q, atp6, R, E, rrnS, M, T, cox3, I, nad2, K, V, rrnL, L1, A, cytb, G, H, L2, atp8, N, nad2, S1, S2, nad4) differs considerably from the relatively conserved gene order within Panpulmonata. Phylogenetic trees show that the 13 protein-encoding mt gene sequences (equivalent codons) of P. acuta group according to gastropod phylogeny, yet branch lengths and dN/dS ratios for P. acuta indicate elevated amino acid substitutions relative to other gastropods. This study indicates that mt sequences of P. acuta are phylogenetically informative despite a considerable intraspecific divergence and the atypical gene order in its mt genome. PMID:25368439

  11. Morphological analysis of the Chinese Cipangopaludina species (Gastropoda; Caenogastropoda: Viviparidae)

    PubMed Central

    LU, Hong-Fa; DU, Li-Na; LI, Zhi-Qiang; CHEN, Xiao-Yong; YANG, Jun-Xing

    2014-01-01

    Viviparidae are widely distributed around the globe, but there are considerable gaps in the taxonomic record. To date, 18 species of the viviparid genus Cipangopaludina have been recorded in China, but there is substantial disagreement on the validity of this taxonomy. In this study, we described the shell and internal traits of these species to better discuss the validity of related species. We found that C. ampulliformis is synonym of C. lecythis, and C. wingatei is synonym of C. chinensis, while C. ampullacea and C. fluminalis are subspecies of C. lecythis and C. chinensis, respectively. C. dianchiensis should be paled in the genus Margarya, while C. menglaensis and C. yunnanensis belong to genus Mekongia. Totally, this leaves 11 species and 2 subspecies recorded in China. Based on whether these specimens’ spiral whorl depth was longer than aperture depth, these species or subspecies can be further divided into two groups, viz. chinensis group and cathayensis group, which can be determined from one another via the ratio of spiral depth and aperture depth, vas deferens and number of secondary branches of vas deferens. Additionally, Principal Component Analysis indicated that body whorl depth, shell width, aperture width and aperture length were main variables during species of Cipangopaludina. A key to all valid Chinese Cipangopaludina species were given. PMID:25465086

  12. The phylogeny and systematics of the Nassariidae revisited (Gastropoda, Buccinoidea).

    PubMed

    Galindo, Lee Ann; Puillandre, Nicolas; Utge, José; Lozouet, Pierre; Bouchet, Philippe

    2016-06-01

    Nassariidae are a group of scavenging, predominantly marine, snails that are diversified on soft bottoms as well as on rocky shores, and are the subject of numerous research papers in ecology, ecotoxicology or paleontology. A weak and/or apparently continuous variation in shell characters has resulted in an intimidating taxonomy, with complex synonymy lists. Over 1320 extant nominal species have been described, of which 442 are currently regarded as valid. Above species level, the state of the art is equally hazy, with four subfamilies and twelve genera currently accepted, and many other names in the graveyard of synonymy. A molecular analysis based on three mitochondrial (COI, 16S, 12S) and two nuclear (28S, H3) markers was conducted. Our dataset includes 218 putative nassariid species, comprising 9 of the 12 valid genera, and 25 nominal genera represented by their type species. The monophyly of the Nassariidae as classically construed is not confirmed. Species of Antillophos, Engoniophos, Phos, Nassaria, Tomlinia and Anentome (formerly considered Buccinidae) are included inside the Nassariidae clade. Within the Nassariinae, the tree unexpectedly demonstrates that species from the Atlantic and the Indo-Pacific form different clades which represent several independent diversification events. Through an integrative approach, the reconstruction of ancestral states was addressed for eight characters supposedly informative for taxonomy. Using numerous fossil calibration points, Nassariidae appear to have originated 120 MYA ago in Atlantic temperate waters during the Lower Cretaceous. Our results have a profound impact on nassariid taxonomy, especially with regard to the validity of subfamily- and genus-level names. PMID:27012605

  13. Untersuchungen zum Harnsäuremetabolismus von Littorina littorea (Gastropoda)

    NASA Astrophysics Data System (ADS)

    Heil, K. P.; Eichelberg, D.

    1983-12-01

    Periwinkles, as typical inhabitants of sea-shores, are subjected to extreme changes of environmental conditions, which affect their excretion. In Littorina littorea uric acid, urea and ammonium were detected particularly in the kidney, but the only metabolite excreted was ammonium. Only the concentration of uric acid was dependent on the availability of water; decreasing periods of submersion during low tide and raised salinities caused a higher concentration of uric acid, while increasing periods of submersion and lowered salinities effected the opposite. Transfer of periwinkles within their intertidal habitat and laboratory experiments to test the effect of salinity showed that the concentration of uric acid in the kidney is adaptable. The dependence of uric acid concentration in the kidney on environmental conditions and the ammoniotelic excretion of L. littorea are discussed with regard to its particular living conditions. It is suggested that uric acid serves as nitrogen depot and has a particular function in osmoregulation.

  14. A cladistic phylogeny of the family Patellidae (Mollusca: Gastropoda)

    PubMed Central

    Ridgway, S. A.

    1998-01-01

    A phylogenetic hypothesis for the patellid limpets is reconstructed by cladistic analysis of morphological characters from 37 species, representing all but one of the living members of the family. Characters included in the analysis are derived from shell shape and microstructure, headfoot and pallial complex, radula and sperm. The species fall into four clades, providing the basis for a new phylogenetic classification into four monophyletic genera: Helcion (four species; southern Africa), Cymbula (eight species; southern Africa, eastern Atlantic, southern Indian Ocean), Scutellastra (17 species; southern and southwestern Africa, Australia, Indo-West Pacific, Eastern Pacific) and Patella (nine species; northeastern Atlantic and Mediterranean). The analysis suggests sister-group relationships between Helcion and Cymbula, and between Scutellastra and Patella. In combination with present-day patterns of geographical distribution, this phylogenetic hypothesis is used to discuss the historical biogeography of the Patellidae. Scutellastra may have originated in southern Africa and dispersed across the Pacific, or alternatively may be a primitively Tethyan group. Both Helcion and Cymbula appear to have originated in southern Africa, but three Cymbula species have dispersed respectively to northwest Africa, St Helena and the southern Indian Ocean. The patellids of the northeastern Atlantic form a single clade, Patella (including P. pellucida), which may have arrived by northward dispersal of an ancestor from southern Africa, or possibly by vicariance of a widespread ancestral Tethyan distribution. The known fossil record of patellids is too fragmentary to permit choice between these alternatives.

  15. Rediscovery of Leptoxis compacta (Anthony, 1854) (Gastropoda: Cerithioidea: Pleuroceridae).

    PubMed

    Whelan, Nathan V; Johnson, Paul D; Harris, Phil M

    2012-01-01

    The Mobile River Basin is a hotspot of molluscan endemism, but anthropogenic activities have caused at least 47 molluscan extinctions, 37 of which were gastropods, in the last century. Nine of these suspected extinctions were in the freshwater gastropod genus Leptoxis (Cerithioidea: Pleuroceridae). Leptoxis compacta, a Cahaba River endemic, has not been collected for >70 years and was formally declared extinct in 2000. Such gastropod extinctions underscore the imperilment of freshwater resources and the current biodiversity crisis in the Mobile River Basin. During a May 2011 gastropod survey of the Cahaba River in central Alabama, USA, L. compacta was rediscovered. The identification of snails collected was confirmed through conchological comparisons to the L. compacta lectotype, museum records, and radulae morphology of historically collected L. compacta. Through observations of L. compacta in captivity, we document for the first time that the species lays eggs in short, single lines. Leptoxis compacta is restricted to a single location in the Cahaba River, and is highly susceptible to a single catastrophic extinction event. As such, the species deserves immediate conservation attention. Artificial propagation and reintroduction of L. compacta into its native range may be a viable recovery strategy to prevent extinction from a single perturbation event. PMID:22905139

  16. Acid phosphatase localization in neurons of Bulla gouldiana (Gastropoda: Opisthobranchia.

    PubMed

    Robles, L J; Fisher, S K

    1975-01-01

    The organization of the ganglia and the ultrastructure of the neurons of Bulla gouldiana are similar to those described for other molluscs. Acid phosphatase positive reactions were found in the large pigmented granules, small dense bodies, multivesicular bodies, and Golgi lamellae and associated vesicles. The small dense bodies and multivesicular bodies may be stages in the formation of the larger pigmented granules which are interpreted as lysosomes. Comparison is made between the pigmented granules in Bulla and the lipofuscin bodies of vertebrate neurons. The possible involvement of these pigmented granules in the hyperpolarization of Bulla and Aplysia neurons to light is discussed. PMID:1122539

  17. Spermiogenesis in the vermetid gastropod Dendropoma petraeum (Gastropoda, Prosobranchia).

    PubMed

    D'Ancona Lunetta, G; Damiani, F

    2002-01-01

    The structure and maturation of the male gonad of the Mediterranean vermetid gastropod Dendropoma petraeum are described. Histological sections of the gonads were made throughout development and gonad activity was monitored at regular monthly intervals. During the autumn months the gonad is very small and is surrounded by a large quantity of connective tissue; it becomes more voluminous from December to August, with the highest growth peak in springtime. The stages of spermatogenesis were also observed and described. PMID:12044050

  18. Redescription of Spirodentalium Walcott ( Gastropoda: Late Cambrian) from Wisconsin ( USA).

    USGS Publications Warehouse

    Yochelson, E.L.

    1987-01-01

    Spirodentalium Walcott, 1890, was originally described as a scaphopod. A reinterpretation of the type lot suggests that its overall shape is that of an open-coiled gastropod. If so, this is probably the earliest known open-coiled form and it is sinistral in coiling direction. -Author

  19. Redescription of Bellerophon bittneri (Gastropoda: Triassic) from Wyoming.

    USGS Publications Warehouse

    Yochelson, E.L.; Boyd, D.W.; Wardlaw, B.

    1985-01-01

    Bellerophon bittneri Newell and Kummel is an Early Triassic bellerophontacean from the Dinwoody Formation in the Wind River Mountains. The available type material consists of one fair, but incomplete, external mold, which resembles a Bellerophon but is actually a Retispira. After repeated search, additional specimens were found at one locality in the southern Wind River Range of Wyoming; Retispira bittneri is redescribed from this new material. Like other Triassic bellerophontaceans, there is nothing unusual about the species apart from occurrence in the Mesozoic; it is clearly congeneric with Permian Retispira from underlying rocks. -Authors

  20. Helicopsis persica n. sp. from northern Iran (Gastropoda: Geomitridae).

    PubMed

    Hausdorf, Bernhard; Bössneck, Ulrich

    2016-01-01

    Helicopsis Fitzinger, 1833 is a mainly eastern European genus of the xerophilous Helicellinae (Geomitridae, Helicoidea; for family systematics see Razkin et al. 2015) that is characterized by two symmetrical dart and accessory sacs. This is probably the plesiomorphous character state within the Geomitridae and Hygromiidae. Therefore, the delimitation and relationships of Helicopsis remained questionable (Hausdorf 1996). Most Helicopsis species are characterized by a lateral attachment of the outer layer of the penial papilla at the penis wall so that a cavity is separated in the proximal part of the penis (Schileyko 1978; Giusti et al. 1992; Hausdorf 1996). However, a similar cavity is present in some other Helicellinae (e.g., Pseudoxerophila, Xerolenta, Xeromunda). Giusti et al. (1992) considered these cavities artefacts, but it cannot be excluded that they are actually homologous to the cavity of Helicopsis. Therefore, it is doubtful whether such a cavity can be considered as an autapomorphy of Helicopsis. About ten species of Helicopsis are spread from Turkey and Bulgaria to the Ukraine with a centre of diversity on the Crimean peninsula. Only the type species, Helicopsis striata (Müller, 1774) is more widespread from Alsace in the west, the island Öland in the Baltic Sea in the north to Bulgaria and Turkey in the south and western Russia in the east. Furthermore, species from Morocco, Greece, Cyprus, Iran and the Kopetdag were classified as Helicopsis. The relationships between these species have to be examined in more detail. Here we describe a new Helicopsis species from Iran. PMID:27395547

  1. Loss of trematode parthenitae in Planorbella trivolvis (Mollusca: Gastropoda).

    PubMed

    Sears, B F; Rohr, J R

    2013-08-01

    Infection by trematode parthenitae (larval, asexual trematodes) has severe consequences for molluscan hosts, resulting in cessation of reproduction and early mortality. Here we present evidence that the freshwater snail Planorbella trivolvis can lose infections by trematode parthenitae. Of 8 P. trivolvis infected by reniferin parthenitae, 6 died within 2 wk, whereas the remaining 2 snails lost their infections within 82 days after initial examination. This phenomenon might suggest that molluscs can resist established trematode infections (i.e., "self-cure") or at least out-survive some trematode parthenitae. PMID:23387507

  2. The complete mitochondrial genome of Babylonia borneensis (Gastropoda: Neogastropoda: Buccinidae).

    PubMed

    Sung, Chia-Hsuan; Tseng, Chen-Te; Wang, Liang-Jong; Li, Yu-Chi; Lu, Jenn-Kan

    2016-09-01

    The complete mitochondrial genome sequence of the Babylonia borneensis is reported for the first time in this study. The length of genome was 15 556 bp, including 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. The nucleotide composition of the mitogenome showed AT-rich feature, with the AT content of 68.2%. Comparison of the identity of the B. borneensis mitogenome with B. areolata, B. lani and B. lutosa was 87.5%, 87.4% and 86.9%, respectively. The construction of phylogenetic tree showed high bootstrap support value. Babylonia borneensis grouped together with other Babylons and the lineages of Buccinidae was strongly supported. In this study, our results could provide a further understanding in the phylogenetic relationships of the Neogastropoda. PMID:27158871

  3. A phylogeny of the land snails (Gastropoda: Pulmonata).

    PubMed Central

    Wade, C. M.; Mordan, P. B.; Clarke, B.

    2001-01-01

    We have undertaken the first large-scale molecular phylogenetic analysis of the Stylommatophora. Sequences of the ribosomal RNA gene-cluster were examined in 104 species of snails and slugs from 50 families, encompassing all the currently recognized major groups. It allows an independent test of the present classification based on morphology. At the level of families our molecular phylogeny closely supports the current taxonomy, but the deep branches within the tree do not. Surprisingly, a single assemblage including the families Achatinidae, Subulinidae and Streptaxidae lies near the base of the tree, forming a sister group to all remaining stylommatophorans. This primary division into 'achatinoid' and 'non-achatinoid' taxa is unexpected, and demands a radical reinterpretation of early stylommatophoran evolution. In particular, the Orthurethra appear to be relatively advanced within the 'non-achatinoid clade', and broadly equivalent to other super-familial clusters. This indicates that supposedly primitive features such as the orthurethran kidney are derived. The molecular tree also suggests that the origin of the Stylommatophora is much earlier than the main period of their diversification. PMID:11270439

  4. Phylogenetic relationships among superfamilies of Neritimorpha (Mollusca: Gastropoda).

    PubMed

    Uribe, Juan E; Colgan, Don; Castro, Lyda R; Kano, Yasunori; Zardoya, Rafael

    2016-11-01

    Despite the extraordinary morphological and ecological diversity of Neritimorpha, few studies have focused on the phylogenetic relationships of this lineage of gastropods, which includes four extant superfamilies: Neritopsoidea, Hydrocenoidea, Helicinoidea, and Neritoidea. Here, the nucleotide sequences of the complete mitochondrial genomes of Georissa bangueyensis (Hydrocenoidea), Neritina usnea (Neritoidea), and Pleuropoma jana (Helicinoidea) and the nearly complete mt genomes of Titiscania sp. (Neritopsoidea) and Theodoxus fluviatilis (Neritoidea) were determined. Phylogenetic reconstructions using probabilistic methods were based on mitochondrial (13 protein coding genes and two ribosomal rRNA genes), nuclear (partial 28S rRNA, 18S rRNA, actin, and histone H3 genes) and combined sequence data sets. All phylogenetic analyses except one converged on a single, highly supported tree in which Neritopsoidea was recovered as the sister group of a clade including Helicinoidea as the sister group of Hydrocenoidea and Neritoidea. This topology agrees with the fossil record and supports at least three independent invasions of land by neritimorph snails. The mitochondrial genomes of Titiscania sp., G. bangueyensis, N. usnea, and T. fluviatilis share the same gene organization previously described for Nerita mt genomes whereas that of P. jana has undergone major rearrangements. We sequenced about half of the mitochondrial genome of another species of Helicinoidea, Viana regina, and confirmed that this species shares the highly derived gene order of P. jana. PMID:27456746

  5. Leiostyla beatae n. sp. from eastern Georgia (Gastropoda: Lauriidae).

    PubMed

    Walther, Frank; Hausdorf, Bernhard

    2015-01-01

    Leiostyla R.T. Lowe, 1852 is a disjunctly distributed pupilloid group of land snails known from the Macaronesian islands, Western Europe, Algeria, Bulgaria, Turkey, the Caucasus region and Iran (Pilsbry 1922-1923; Schileyko 1984; Gittenberger & Pieper 1988; Hausdorf 1990). In the Neogene the genus was more widespread in Central and Western Europe (Pilsbry 1922). Thus, the Caucasus region and the Macaronesian islands, where the highest recent diversity of Leiostyla species is found (Pilsbry 1922-1923), can be considered refugial areas. PMID:25947501

  6. The Genus Cerion (Gastropoda: Cerionidae) in the Florida Keys

    PubMed Central

    2015-01-01

    The systematic relationships and phylogeography of Cerion incanum, the only species of Cerion native to the Florida Keys, are reviewed based on partial sequences of the mitochondrial COI and 16S genes derived from 18 populations spanning the range of this species and including the type localities of all four described subspecies. Our samples included specimens of Cerion casablancae, a species introduced to Indian Key in 1912, and a population of C. incanum x C. casablancae hybrids descended from a population of C. casablancae introduced onto Bahia Honda Key in the same year. Molecular data did not support the partition of C. incanum into subspecies, nor could populations be apportioned reliably into subspecies based on morphological features used to define the subspecies. Phylogenetic analyses affirmed the derived relationship of C. incanum relative to other cerionids, and indicated a Bahamian origin for the Cerion fauna of southern Florida. Relationships among the populations throughout the Keys indicate that the northernmost populations, closest to the Tomeu paleoislands that had been inhabited by Cerion petuchi during the Calabrian Pleistocene, are the oldest. The range of Cerion incanum expanded as the archipelago that is the Florida Keys was formed since the lower Tarantian Pleistocene by extension from the northeast to the southwest, with new islands populated as they were formed. The faunas of the High Coral Keys in the northeast and the Oölite Keys in the southwest, both with large islands that host multiple discontinuous populations of Cerion, are each composed of well supported clades that are characterized by distinctive haplotypes. In contrast, the fauna of the intervening Low Coral Keys consist of a heterogeneous series of populations, some with haplotypes derived from the High Coral Keys, others from the Oölite Keys. Individuals from the C. incanum x C. casablancae hybrid population inhabiting the southeastern coast of Bahia Honda Key were readily segregated based on their mitogenome lineage, grouping either with C. incanum or with C. casablancae from Indian Key. Hybrids with C. casablancae mitogenomes had haplotypes that were more divergent from their parent mitogenome than were hybrids with C. incanum mitogenomes. PMID:26378443

  7. The phylogeography of Indoplanorbis exustus (Gastropoda: Planorbidae) in Asia

    PubMed Central

    2010-01-01

    Background The freshwater snail Indoplanorbis exustus is found across India, Southeast Asia, central Asia (Afghanistan), Arabia and Africa. Indoplanorbis is of economic importance in that it is responsible for the transmission of several species of the genus Schistosoma which infect cattle and cause reduced livestock productivity. The snail is also of medical importance as a source of cercarial dermatitis among rural workers, particularly in India. In spite of its long history and wide geographical range, it is thought that Indoplanorbis includes only a single species. The aims of the present study were to date the radiation of Indoplanorbis across Asia so that the factors involved in its dispersal in the region could be tested, to reveal potential historical biogeographical events shaping the phylogeny of the snail, and to look for signs that I. exustus might be polyphyletic. Results The results indicated a radiation beginning in the late Miocene with a divergence of an ancestral bulinine lineage into Assam and peninsular India clades. A Southeast Asian clade diverged from the peninsular India clade late-Pliocene; this clade then radiated at a much more rapid pace to colonize all of the sampled range of Indoplanorbis in the mid-Pleistocene. Conclusions The phylogenetic depth of divergences between the Indian clades and Southeast Asian clades, together with habitat and parasitological differences suggest that I. exustus may comprise more than one species. The timescale estimated for the radiation suggests that the dispersal to Arabia and to Southeast Asia was facilitated by palaeogeographical events and climate change, and did not require human involvement. Further samples from Afghanistan, Africa and western India are required to refine the phylogeographical hypothesis and to include the African Recent dispersal. PMID:20602771

  8. Lipoproteins of the egg perivitelline fluid of Pomacea canaliculata snails (Mollusca: Gastropoda).

    PubMed

    Garin, C F; Heras, H; Pollero, R J

    1996-12-01

    The lipid and protein composition of the perivitelline fluid of the eggs of Pomacea canaliculata was investigated. Two lipoproteins (PV 1 and PV 2) and one lipoprotein fraction (PV 3) were detected for the first time in gastropods. They represent 57.0, 7.5, and 35.5% of the egg total proteins, respectively. PV 1 is a glyco-carotene-protein complex with characteristics of a very high-density lipoprotein (VHDL). It has 0.33% lipids, mainly free sterols and phospholipids. The particle has a MW of 300 Kd and is composed of three subunits of 35, 32, and 28 Kd, respectively. PV 2 particle is a VHDL of 400 Kd and 3.75% lipids. The major lipid classes are free sterols and phospholipids and also have significant quantities of energy-providing triacylglycerides and free fatty acids. It is composed of two apoproteins of 67 and 31 Kd. PV 3 density corresponds to a high-density lipoprotein (HDL). It was fractionated into two subfractions "h" and "p". Fraction "h" contains 5.16% lipids, mainly free sterols, phospholipids, and free fatty acids, and two particles of 100 and 64 Kd. Dissociating electrophoresis showed two subunits of 34 and 29 Kd. Fraction "p" is composed of a single particle of 26 Kd that contains 9.5% lipids, which represents 30% of the total egg lipids. It has high levels of a carotenoid pigment. Besides it contains free fatty acids, hydrocarbons, sterified sterols, and triacylglycerides. These three fractions are probably the major supply of lipids and amino acids for the developing embryo. PMID:8972583

  9. Intraspecific and interspecific chemoattraction inBiomphalaria glabrata andHelisoma trivolvis (Gastropoda: Planorbidae).

    PubMed

    Marcopoulos, A A; Fried, B

    1994-10-01

    A Petri dish bioassay previously used to examine food preferences in planorbid snails was used to study intraspecific and interspecific chemoattraction inBiomphalaria glabrata (albino strain, M-line) andHelisoma trivolvis (Colorado strain) snails.B. glabrata snails showed significant intraspecific chemoattraction in the absence of visual cues and snail thigmotaxis.H. trivolvis snails also showed significant intraspecific chemoattraction. Interspecific chemoattraction between these species occurred in the bioassay, suggesting that the chemoattractants were not species specific. Artificial spring water conditioned by aqueous excretory-secretory products (snail-conditioned water) ofB. glabrata elicited significant intraspecific chemoattraction. However, lipophilic excretory-secretory products ofB. glabrata elicited significant chemorepulsion. Repellant factors in the lipophilic fraction were not characterized. PMID:24241838

  10. The Model Organism Hermissenda crassicornis (Gastropoda: Heterobranchia) Is a Species Complex

    PubMed Central

    Lindsay, Tabitha

    2016-01-01

    Hermissenda crassicornis is a model organism used in various fields of research including neurology, ecology, pharmacology, and toxicology. In order to investigate the systematics of this species and the presence of cryptic species in H. crassicornis, we conducted a comprehensive molecular and morphological analysis of this species covering its entire range across the North Pacific Ocean. We determined that H. crassicornis constitutes a species complex of three distinct species. The name Hermissensa crassicornis is retained for the northeast Pacific species, occurring from Alaska to Northern California. The name H. opalescens is reinstated for a species occurring from the Sea of Cortez to Northern California. Finally, the name H. emurai is maintained for the northwestern species, found in Japan and in the Russian Far East. These three species have consistent morphological and color pattern differences that can be used for identification in the field. PMID:27105319

  11. Molecular phylogeny of the Ellobiidae (Gastropoda: Panpulmonata) supports independent terrestrial invasions.

    PubMed

    Romero, Pedro E; Pfenninger, Markus; Kano, Yasunori; Klussmann-Kolb, Annette

    2016-04-01

    Gastropods of the family Ellobiidae are an interesting group in which to study transitions from intertidal to terrestrial realms. However, the phylogenetic relationships within this family still lack resolution. We present a phylogenetic hypothesis of the Ellobiidae based on Bayesian and maximum likelihood phylograms. We used nuclear (18S, 28S, H3) and mitochondrial (16S, 12S, COI) data, increasing the numbers of markers and data, and making this the most comprehensive phylogenetic study of the family to date. Our results support phylogenetic hypotheses derived from morphological data, and provide a supported framework to evaluate the internal relationships within Ellobiidae. The resulting phylogenetic trees support the previous hypothesis that the Ellobiidae are monophyletic only if the Trimusculinae (Otina, Smeagol and Trimusculus) are considered part of this family. In addition, we found that the Carychiinae, Ellobiinae and Pythiinae are reciprocally monophyletic and closely related, with the Carychiinae as sister group to Ellobiinae. Relationships within Melampodinae and Pedipedinae and their phylogenetic positions remain unresolved. Land invasion by the Ellobiidae occurred independently in Carychiinae and Pythia during different geological times (Mesozoic and Cenozoic, respectively). Diversification in the family does not appear to be related to past climate and biotic changes, neither the Cretaceous-Paleogene boundary nor the lowering of the sea level in the Oligocene. PMID:26724408

  12. Intracellular Immunohistochemical Detection of Tetrodotoxin in Pleurobranchaea maculata (Gastropoda) and Stylochoplana sp. (Turbellaria)

    PubMed Central

    Salvitti, Lauren R.; Wood, Susanna A.; Winsor, Leigh; Cary, Stephen Craig

    2015-01-01

    Tetrodotoxin (TTX), is a potent neurotoxin targeting sodium channels that has been identified in multiple marine and terrestrial organisms. It was recently detected in the Opisthobranch Pleurobranchaea maculata and a Platyhelminthes Stylochoplana sp. from New Zealand. Knowledge on the distribution of TTX within these organisms is important to assist in elucidating the origin and ecological role of this toxin. Intracellular micro-distribution of TTX was investigated using a monoclonal antibody-based immunoenzymatic technique. Tetrodotoxin was strongly localized in neutral mucin cells and the basement membrane of the mantle, the oocytes and follicles of the gonad tissue, and in the digestive tissue of P. maculata. The ova and pharynx were the only two structures to contain TTX in Stylochoplana sp. Using liquid chromatography-mass spectrometry, TTX was identified in the larvae and eggs, but not the gelatinous egg cases of P. maculata. Tetrodotoxin was present in egg masses of Stylochoplana sp. These data suggest that TTX has a defensive function in adult P. maculata, who then invest this in their progeny for protection. Localization in the digestive tissue of P. maculata potentially indicates a dietary source of TTX. Stylochoplana sp. may use TTX in prey capture and for the protection of offspring. PMID:25636158

  13. Progenesis in the evolution of the nudibranch mollusks genus Dendronotus (Gastropoda: Nudibranchia).

    PubMed

    Ekimova, I A; Malakhov, V V

    2016-03-01

    The morphology and postlarval ontogenesis of the radula in 11 species of the genus Dendronotus Alder et Hancock, 1845, has been studied. Four types of radula are recognized in adult mollusks. Proposed evidence suggests that small species of Dendronotus have evolved by progenesis. PMID:27193883

  14. Sphincterochilidae from Tunisia, with a note on the subgenus Rima Pallary, 1910 (Gastropoda, Pulmonata)

    PubMed Central

    Abbes, Intidhar; Nouira, Said; Neubert, Eike

    2011-01-01

    Abstract In order to establish an updated checklist of terrestrial gastropod from Tunisia, a revision of the species of Sphincterochilidae is presented, using bibliographic and museum records and the results of our own field work. As a result, only two species, Sphincterochila candidissima and Sphincterochila tunetana, are accepted to occur in Tunisia, and their type specimens are illustrated. The study of the morphological characters of the genital organs of both species clarified their subgeneric affiliation. Comparison of Sphincterochila tunetana with Sphincterochila cariosa from Lebanonshowed that the first has to be classified within the subgenus Albea, and the latter within Sphincterochila s. str.; the subgenus Rima Pallary, 1910 remains in the synonymy of Sphincterochila s. str. Bibliographic records of Sphincterochila baetica and Sphincterochila otthiana from Tunisia could not be confirmed, the latter probably lives close to the border with Algeria. PMID:22368450

  15. A Tale That Morphology Fails to Tell: A Molecular Phylogeny of Aeolidiidae (Aeolidida, Nudibranchia, Gastropoda)

    PubMed Central

    Carmona, Leila; Pola, Marta; Gosliner, Terrence M.; Cervera, Juan Lucas

    2013-01-01

    Aeolidida is one of the largest clades of nudibranchs with at least 560 known species. However, its systematics has not been studied in a comprehensive manner. Phylogenetic analyses of larger clades such as Nudibranchia or Cladobranchia have usually included a poor sample of aeolids. Furthermore, phylogenetic studies at the family or generic level in Aeolidida are a few and far between. The first molecular phylogeny of the aeolid family Aeolidiidae is presented here. This study, the most comprehensive for Aeolidida to date, uses new sequences of two mitochondrial (COI and 16S) genes and one nuclear gene (H3). 251 specimens from members of seven families of Aeolidida, including 39 species of Aeolidiidae were studied. Excluding Pleurolidia juliae, Aeolidiidae is monophyletic. Our results resolve the systematic relationships within the Aeolidiidae at a generic level, requiring changes in the systematics of this family. Spurilla, Anteaeolidiella, Limenandra and Aeolidia are well-supported and monophyletic clades. Aeolidiella stephanieae is transferred to Berghia and Aeolidiopsis ransoni and Spurilla salaamica to Baeolidia, to maintain the monophyletic lineages reflected in this study. The systematics of Cerberilla remains unclear. Some species earlier attributed to Aeolidiella are now grouped in a previously unnamed clade that we designate as Bulbaeolidia gen. nov. PMID:23658794

  16. Recognition of Macluritella ( Gastropoda) from the Upper Cambrian of Missouri and Nevada ( USA).

    USGS Publications Warehouse

    Yochelson, E.L.; Stinchcomb, B.L.

    1987-01-01

    Open-coiled euomphalacean gastropods have been identified for the first time in the Upper Cambrian Eminence Dolomite of Missouri. These gastropods have a triangular whorl profile and are conspecific with Hyolithes walcotti described from the Upper Cambrian of Nevada. That species is questionably reassigned to the gastropod genus Macluritella, hitherto known only from the Lower Ordovician of Colorado. -Authors Ordovician Colorado

  17. Late Paleozoic subulitacea (mollusca:gastropoda), mass extinctions and the replacement of evolutionary faunas

    SciTech Connect

    Erwin, D.H.

    1985-01-01

    Mesogastropod subulitaceans possess characteristics typical of active carnivores and occupied a trophic regime typical of the Mesozoic-Cenozoic evolutionary fauna. Despite occupying a vacant niche, subulitaceans are low in both diversity and abundance in late Paleozoic gastropod faunas. In addition, Paleozoic Archaeogastropoda and Mesogastropoda are taxonomically and functionally distinct from Mesozoic groups and display diversity dynamics typical of the Paleozoic evolutionary fauna, not the Mesozoic-Cenozoic fauna with which they were grouped by Sepkoski. Late Paleozoic gastropods are different from pre-Carboniferous taxa, but there is no preferential expansion of the major Mesozoic taxa, nor is there any pattern of exploitation of a major niche utilized by later groups but under-used by Paleozoic taxa. The high taxonomic level used Sepkoski's factor analysis neglects the finer scale of replacement and diversification. This distinct evolutionary behavior of Paleozoic gastropods may be typical of other taxa as well. It weakens the assertions of Kitchell and Carr and Sepkoksi and Miller that the replacement of evolutionary Fauna II by Fauna III began in the late Paleozoic and would have occurred even without the Guadelupian-Dzulfian mass extinction. Thus for gastropods at last, the Late Permian mass extinction did not merely speed up on ongoing process, but probably determined the evolutionary outcome.

  18. Histochemical research on metabolic pathways of glucose in some species of Mollusca Gastropoda.

    PubMed

    Bolognani Fantin, A M; Bolognani, L; Ottaviani, E; Franchini, A

    1987-01-01

    The metabolic pathways of glucose were studied by histochemical reactions in some species of gastropods living in different habitats. The glycolytic pathway is histochemically indicated by positive results for glucose-6-phosphate isomerase, fructose-1,6-biphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, and D-lactate dehydrogenase. The enzymes of the Krebs cycle gave different responses: isocitrate dehydrogenase and L-malate dehydrogenase were positive, whilst succinate dehydrogenase was constantly negative. Malate synthetase activity was also demonstrated. Despite L-glutamate dehydrogenase is undetectable, the presence of transaminase indicates the gluconeogenetic route. Phosphoglucomutase and glucose-6-phosphate phosphatase appear also positive. The metabolic meaning of our results were discussed. PMID:3111150

  19. Family matters: The first molecular phylogeny of the Onchidorididae Gray, 1827 (Mollusca, Gastropoda, Nudibranchia).

    PubMed

    Hallas, Joshua M; Gosliner, Terrence M

    2015-07-01

    Recent investigations into the evolution of the Onchidorididae using morphological based methods have resulted in low support for relationships among genera. This study aims to determine if molecular data corroborates recent morphological interpretations of the evolution of Onchidorididae. Five genetic markers: 16S, 18S, 28S, cytochrome c oxidase 1 (COI) and histone 3 (H3), were sequenced from 32 species comprising Onchidorididae and five other families, three from Phanerobranchia and two from Cryptobranchia. Phylogenies were estimated using maximum likelihood, and Bayesian inference analyses; with both yielding similar topologies. Molecular analyses resulted in high support for the monophyly of the suctorian clade and the placement of the genera within Onchidorididae. However, the Onchidorididae forms a paraphyletic grouping due to the recovery of the Goniodorididae and the Akiodorididae nested within family. In addition, the placement of Corambe as the most derived member of Onchidorididae is contradicted by the present study. Rather it is sister to a large clade that includes Acanthodoris and the species traditionally placed in Onchidoris and Adalaria, now defined as Onchidorididae. We have chosen to maintain Corambidae as a distinct taxon (including Corambe and Loy), sister to Onchidorididae. We also maintain Goniodorididae, Akiodorididae and Calycidoridae (including Calycidoris and Diaphorodoris), which along with the Onchidorididae and Corambidae comprise the suctorian superfamily Onchidoridoidea. Ancestral character reconstruction also suggests that the formation of a gill pocket, a character that currently defines the Cryptobranchia, may have evolved multiple times from an ancestor that lacked the ability to retract its gills into a fully formed gill pocket. The diversity of gill morphology displayed by the Onchidoridoidea will help give new insight into the evolution of this complex character within the Nudibranchia. PMID:25837732

  20. Molecular phylogenetic analysis of mudflat snails (Gastropoda: Euthyneura: Amphiboloidea) supports an Australasian centre of origin.

    PubMed

    Golding, Rosemary E

    2012-04-01

    Amphiboloidea is a small but widespread group of snails found exclusively, and often abundantly, in mudflat and associated salt marsh or mangrove habitat. This study uses molecular data from three loci (COI, 16S and 28S) to infer phylogenetic relationships in Amphiboloidea and examine its position in Euthyneura. All but two of the named extant species of Amphiboloidea and additional undescribed taxa from across Southeast Asia and the Arabian Gulf were sampled. In contrast to the current morphology-based classification dividing Amphiboloidea into three families, analysis of molecular data supports revision of the classification to comprise two families. Maningrididae is a monotypic family basal to Amphibolidae, which is revised to comprise three subfamilies: Amphibolinae, Phallomedusinae and Salinatorinae. Sequence divergence between Asian populations of Naranjia is relatively large and possibly indicative of species complexes divergent across the Strait of Malacca. Salinatorrosacea and Salinator burmana do not cluster with other Salinator species, and require generic reassignment. In addition, sequences were obtained from an undescribed species of Lactiforis from the Malay Peninsula. Reconstruction of ancestral distributions indicates a plesiomorphic distribution and centre of origin in Australasia, with two genera subsequently diversifying throughout Asia. Increasing the sampling density of amphiboloid taxa in a phylogenetic analysis of Euthyneura did not resolve the identity of the sister taxon to Amphibolidae, but confirmed its inclusion in Pulmonata/Panpulmonata. PMID:22210412

  1. TEMPERATURE TOLERANCE OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The red-rimmed melania Melanoides tuberculata is an exotic aquatic snail of the family Thiaridae that is spreading across the southern United States and in geothermal waters in several midwestern and northwestern states. In addition to its potential to displace native mollusks it is known to harbor...

  2. Population biology of the gastropod Olivella minuta (Gastropoda, Olividae) on two sheltered beaches in southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Petracco, Marcelo; Camargo, Rita Monteiro; Tardelli, Daniel Teixeira; Turra, Alexander

    2014-10-01

    The structure, dynamics and production of two populations of the olivid gastropod Olivella minuta were analyzed through monthly sampling from November 2009 through October 2011 on two sandy beaches, Pernambuco (very sheltered) and Barequeçaba (sheltered) in São Paulo state (23°48'S), southeastern Brazil. On both beaches, samples were taken along five transects established perpendicular to the waterline. Parameters of the von Bertalanffy growth function were estimated for both populations from monthly length-frequency distributions. The production and turnover ratios were determined using the mass-specific growth rate method. The population on the less-sheltered Barequeçaba Beach was less abundant (120.02 ± 22.60 ind m-1) than on Pernambuco Beach (3295.30 ± 504.86 ind m-1 (±SE)), which we attribute to the greater environmental stability of the latter. Conversely, the mean length, size of the largest individual, and body mass were higher at Barequeçaba than at Pernambuco. The significant differences in the growth of individuals and the mortality rate (Z) between the beaches suggest that density-dependent processes were operating at Pernambuco Beach. The production and P/B ratio at Pernambuco (12.12 g AFDM m-1 year-1 and 1.91 year-1) were higher than at Barequeçaba (0.82 g AFDM m-1 year-1 and 1.06 year-1). The difference in production can be attributed to the higher abundance on Pernambuco, while the higher P/B ratio resulted from the scarcity of smaller individuals in the intertidal zone of Barequeçaba. The P/B ratio estimated for the Pernambuco population is the highest found so far for sandy-beach gastropods. This study reinforces the theory that biological interactions are important regulators of sheltered sandy-beach populations. Future studies with multi-beach sampling are needed to better understand the life-history variations of O. minuta along gradients of degree of exposure of sandy beaches.

  3. Burnaia Miller, 2001 (Gastropoda, Heterobranchia, Nudibranchia): a facelinid genus with an Aeolidiidae's outward appearance

    NASA Astrophysics Data System (ADS)

    Carmona, Leila; Pola, Marta; Gosliner, Terrence M.; Cervera, Juan Lucas

    2015-09-01

    In recent years, several morphological and molecular analyses have been undertaken to study the phylogenetic systematics of Aeolidiidae members. The monospecific genus Burnaia could not be included in the previous analysis, due to the lack of material. This study includes two specimens of Burnaia helicochorda from Australia and places them in their systematic position using two mitochondrial and one nuclear genes (COI and 16S, and H3, respectively). A description of its anatomy is also included with colour pictures of the animal and scanning electron micrographs of radula and jaws. Based on our results, B. helicochorda does not belong to Aeolidiidae since it appears nested among some facelinids.

  4. Dynamics and ecology of an Indo-Pacific conch, Conomurex persicus (Mollusca: Gastropoda) in southeastern Turkey.

    PubMed

    Mutlu, Erhan; Ergev, Mehmet Betil

    2006-03-01

    Conomurex persicus, one of the tropical conchs, has been introduced to one of the subtropical regions, the northeastern Mediterranean Sea, and invaded sandy bottoms between 1 and 10 m deep. Population dynamics were studied from specimens collected with a standard dredge (60 x 15 cm mouth opening, 0.5 x 0.5 cm eye opening of net). Samples of C persicus were collected monthly along the 5 and 10 m depth contours off Erdemli, Mersin, Turkey, in February and May 2000. Intra-annual density depended on salinity levels, while inter-annual density was correlated with bottom water temperature. Specimens underwent spring emergences and winter burial and sheltering (disappearance). Emergence took place in March when temperatures rose and the disappearance occurred in October-November when temperatures dropped. Adults live at 10 m, juveniles are recruited at a 5 m depth. Recruitment began in April and continued for the next 6 months. In contrast to shell width or shell lip thickness, shell length was not a convenient index for estimation of growth parameters. Annual production and mortality were calculated to be 7.86 g m(-2) and 3.80 g m(-2), respectively, in April-November. PMID:18457181

  5. [Individual growth of Lymnaea stagnalis (Lymnaeidae, Gastropoda): II. Late postlarval ontogeny].

    PubMed

    Zotin, A A

    2009-01-01

    Our investigation on the growth of 14 individuals of the great pond snail Lymnaea stagnalis was performed in an aquatic culture at 18 degrees C beginning from the 10th week after hatching until death. It has been demonstrated that the increase in the mollusk mass follows an S-like curve during the whole studied period. Linear growth (conch height) follows a parabolic (convex) curve until the age of 39 weeks. Both weight and linear growth during studied period significantly approximate to the Bertalanffy equation, while the interrelation between mass and conch height corresponds to the allometric equation. The meanings of the coefficients of these equations do not differ significantly in different individuals. At the age of 38 to 39 weeks, all mollusks demonstrate breakage in the curve of linear growth, then followed with abrupt slowing of growth until stopping or even decreasing in size in some cases. Neither the Bertalanffy equation nor the allometric relation describe the linear growth of individuals with ages exceeding 39 weeks. PMID:20143629

  6. Granopupa in Iran, monophyly, and the fossil Granariinae (Gastropoda, Pulmonata, Chondrinidae).

    PubMed

    Gittenberger, Edmund; Kokshoorn, Bas; Bößneck, Ulrich; Reijnen, Bastian T; Groenenberg, Dirk S J

    2016-01-01

    Indisputable Chondrinidae, Granariinae species, characterized by shell shape and apertural dentition, are known from Eocene deposits to the Recent. The generic classification of the extant species is based on conchological, anatomical and molecular data that are available now for most of the known species, including 'Granaria' persica as a representative of the once problematic group of so-called eastern Granaria species. According to molecular and anatomical characters, these eastern species have to be classified with Granopupa granum in Granopupa. Graniberia gen. n. is introduced for Granaria braunii on the basis of molecular and conchological data. For the pre-Pleistocene species, two generic names are equally well available now, viz. Granopupa and Granaria. Shell characters only do not enable a decision here. For the sake of nomenclatorial stability we propose to use Granaria for these species. Because both molecular and anatomical data most likely will never be known for the fossils, it will remain unclear whether the combined extant and extinct Granaria species form a monophyletic group. PMID:27408543

  7. Synopsis of Central Andean Orthalicoid land snails (Gastropoda, Stylommatophora), excluding Bulimulidae

    PubMed Central

    Breure, Abraham S.H.; Avila, Valentín Mogollón

    2016-01-01

    Abstract A faunal overview is presented of the molluscan families Amphibulimidae, Megaspiridae, Odontostomidae, Orthalicidae, Simpulopsidae in Bolivia, Ecuador, and Peru. These Central Andean countries are known for their biodiverse malacofauna, of which the superfamily Orthalicoidea takes relatively a large share. In this paper the five families containing 103 (sub)species, for which systematic information (original publication, type locality, type depository, summarizing literature) and distributional records are presented. All species are illustrated by photographs of the type material or, if this could not be located, by a reproduction of the original figure. The following new taxon is introduced: Thaumastus (Thaumastus) sumaqwayqu sp. n. Junior subjective synonyms are established for: Plekocheilus (Sparnotion) Pilsbry, 1944 = Plekocheilus (Eudolichotis) Pilsbry, 1896; Scholvienia (Thomsenia) Strebel, 1910 = Scholvienia Strebel, 1910; Sultana (Trachyorthalicus) Strebel, 1909 = Sultana (Metorthalicus) Pilsbry, 1899; Plekocheilus (Eurytus) conspicuus Pilsbry, 1932 = Thaumastus (Thaumastus) hartwegi (Pfeiffer in Philippi, 1846); Zebra gruneri Strebel, 1909 = Orthalicus maracaibensis (Pfeiffer, 1856); Scholvienia jaspidea minor Strebel, 1910 = Scholvienia alutacea (Reeve, 1850); Bulimus bifasciatus unicolor Philippi, 1869 = Scholvienia brephoides (d’Orbigny, 1835). A new status is given to Plekocheilus mcgintyi ‘Pilsbry’ H.B. Baker, 1963 (subspecies of Bulinus piperitus Sowerby I, 1837); Strophocheilus superstriatus var. prodeflexus Pilsbry, 1895 (subspecies of Bulinus piperitus Sowerby I, 1837); Thaumastus (Quechua) salteri maximus Weyrauch, 1967 (subspecies of Thaumastus (Quechua) olmosensis Zilch, 1954); Pseudoglandina agitata Weyrauch, 1967 (nomen inquirendum). New combinations are: Clathrorthalicus corydon (Crosse, 1869), and Cyclodontina chuquisacana (Marshall, 1930). Lectotypes are now designated for Bulimus incisus Hupé, 1857 and Bulinus piperitus Sowerby I, 1837. PMID:27408531

  8. Review of the genus Endothyrella Zilch, 1960 with description of five new species (Gastropoda, Pulmonata, Plectopylidae)

    PubMed Central

    Páll-Gergely, Barna; Budha, Prem B.; Naggs, Fred; Backeljau, Thierry; Asami, Takahiro

    2015-01-01

    Abstract All known taxa of the genus Endothyrella Zilch, 1960 (family Plectopylidae) are reviewed. Altogether 23 Endothyrella species are recognized. All species are illustrated and whenever possible, photographs of the available type specimens are provided. Five new species are described: Endothyrella angulata Budha & Páll-Gergely, sp. n., Endothyrella dolakhaensis Budha & Páll-Gergely, sp. n. and Endothyrella nepalica Budha & Páll-Gergely, sp. n. from Nepal, Endothyrella robustistriata Páll-Gergely, sp. n. from the Naga Hills, India, and Endothyrella inexpectata Páll-Gergely, sp. n. from Sichuan, China. Helix (Plectopylis) munipurensis Godwin-Austen, 1875 is synonymized with Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) gregorsoni Gude, 1915 is synonymized with Helix (Plectopylis) macromphalus W. Blanford, 1870. Plectopylis plectostoma var. exerta Gude, 1901 is a synonym of Plectopylis plectostoma var. tricarinata Gude, 1896, which is a species in its own right. Five species of the genus Chersaecia viz. Plectopylis (Chersaecia) bedfordi Gude, 1915, Helix (Plectopylis) brahma Godwin-Austen, 1879, Helix (Plectopylis) Oglei Godwin-Austen, 1879, Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) williamsoni Gude, 1915 are moved to Endothyrella. The holotype of Plectopylis hanleyi Godwin-Austen, 1879 seems to be lost; therefore, Plectopylis hanleyi is considered to be a nomen dubium. PMID:26692792

  9. The Vermetidae of the Gulf of Kachchh, western coast of India (Mollusca, Gastropoda)

    PubMed Central

    Joshi, Devanshi MukundRay; Mankodi, Pradeep C.

    2016-01-01

    Abstract Coral reefs are often termed underwater wonderlands due to the presence of an incredible biodiversity including numerous invertebrates and vertebrates. Among the dense population of benthic and bottom-dwelling inhabitants of the reef, many significant species remain hidden or neglected by researchers. One such example is the vermetids, a unique group of marine gastropods. The present study attempts for the first time to assess the density and identify preferred reef substrates in the Gulf of Kachchh, state of Gujarat, on the western coast of India. A total of three species of the family Vermetidae were recorded during the study and their substrate preferences identified. PMID:26877684

  10. Identification of sequestered chloroplasts in photosynthetic and non-photosynthetic sacoglossan sea slugs (Mollusca, Gastropoda)

    PubMed Central

    2014-01-01

    Background Sacoglossan sea slugs are well known for their unique ability among metazoans to incorporate functional chloroplasts (kleptoplasty) in digestive glandular cells, enabling the slugs to use these as energy source when starved for weeks and months. However, members assigned to the shelled Oxynoacea and Limapontioidea (often with dorsal processes) are in general not able to keep the incorporated chloroplasts functional. Since obviously no algal genes are present within three (out of six known) species with chloroplast retention of several months, other factors enabling functional kleptoplasty have to be considered. Certainly, the origin of the chloroplasts is important, however, food source of most of the about 300 described species is not known so far. Therefore, a deduction of specific algal food source as a factor to perform functional kleptoplasty was still missing. Results We investigated the food sources of 26 sacoglossan species, freshly collected from the field, by applying the chloroplast marker genes tufA and rbcL and compared our results with literature data of species known for their retention capability. For the majority of the investigated species, especially for the genus Thuridilla, we were able to identify food sources for the first time. Furthermore, published data based on feeding observations were confirmed and enlarged by the molecular methods. We also found that certain chloroplasts are most likely essential for establishing functional kleptoplasty. Conclusions Applying DNA-Barcoding appeared to be very efficient and allowed a detailed insight into sacoglossan food sources. We favor rbcL for future analyses, but tufA might be used additionally in ambiguous cases. We narrowed down the algal species that seem to be essential for long-term-functional photosynthesis: Halimeda, Caulerpa, Penicillus, Avrainvillea, Acetabularia and Vaucheria. None of these were found in Thuridilla, the only plakobranchoidean genus without long-term retention forms. The chloroplast type, however, does not solely determine functional kleptoplasty; members of no-retention genera, such as Cylindrobulla or Volvatella, feed on the same algae as e.g., the long-term-retention forms Plakobranchus ocellatus or Elysia crispata, respectively. Evolutionary benefits of functional kleptoplasty are still questionable, since a polyphagous life style would render slugs more independent of specific food sources and their abundance. PMID:24555467

  11. [Inheritance of the background shell color in the snails Littorina obtusata (Gastropoda, Littorinidae)].

    PubMed

    Kozminsky, E V

    2014-10-01

    We investigated in a gastropod mollusk Littorina obtusata (L. obtusata) the inheritance of background shell coloration of the shell, which arises on the basis of three pigments: purple, orange, and yellow. We found that the hypothesis on polyallelic inheritance, as in the genus Cepaea, cannot explain the inheritance of shell color in periwinkles. We demonstrated that a separate genetic system is responsible for incorporation of each pigment into the shell. The composition of these genetic systems includes at least tw genes each in the case of the yellow and purple pigments. Our analysis shows that caution should be applied when extending the results obtained in the studies of the Cepaea genus to the other species of gastropods. PMID:25720250

  12. [Inheritance of longitudinal shell bands in the snails Littorina obtusata and Littorina saxatilis (Gastropoda, Prosobranchia)].

    PubMed

    Kozminskiĭ, E V

    2011-08-01

    The hypothesis of a monogenic inheritance of dark longitudinal bands on the shell in the gastropods Littorina obtusata and L. saxatilis was checked. One gene having two alleles proved to be responsible for the shell banding pattern in both of the species. The presence of bands was a dominant character in either case. PMID:21954620

  13. [Inheritance of white spots on the shell of Littorina obtusata (Gastropoda, Prosobranchia)].

    PubMed

    Kozminskiĭ, E V; Lezin, P A; Fokin, M V

    2010-12-01

    The hypothesis on monogenic inheritance of white spot pattern on the shell of the gastropod snail Littorina obtusata was tested. Although in most cases our results did not contradict this assumption, the hypothesis cannot explain the observed segregation in general. An alternative hypothesis was suggested, according to which the presence of spot pattern is controlled by two complementary biallelic genes. PMID:21434418

  14. [Morphobiochemical adaptations of Mediterranean Littorina punctata (Gmelin, 1790) (Mollusca, Gastropoda) to survival under supralittoral conditions].

    PubMed

    Aliakrinskaia, I O

    2014-01-01

    Behavioral and morphobiochemical adaptations of Littorina punctata to dwelling under supralittoral condi- tions are analyzed. A quantitative estimation of the hemoglobin content in the radular tissues of the mollusk is given. PMID:25735161

  15. Terrestrial slugs (Gastropoda, Pulmonata) in the NATURA 2000 areas of Cyprus island.

    PubMed

    Vardinoyannis, Katerina; Demetropoulos, Simon; Mylonas, Moissis; A Triantis, Kostas; Makris, Christodoulos; Georgiou, Gabriel; Wiktor, Andrzej; Demetropoulos, Andreas

    2012-01-01

    Terrestrial slugs of the Island of Cyprus were recently studied in the framework of a study of the whole terrestrial malacofauna of the island. The present work was carried out in the Natura 2000 conservation areas of the island in 155 sampling sites over three years (2004-2007). Museum collections as well as literature references were included. In total six species are present in the Natura 2000 areas of the island, belonging to three families: Limacidae, Agriolimacidae and Milacidae. One of the species, Milax riedeli, is a new record for the island. The distribution of the species across the island and in the surrounding areas is discussed. PMID:22451785

  16. Patterns of Diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean Region

    PubMed Central

    Ávila, Sérgio P.; Goud, Jeroen; de Frias Martins, António M.

    2012-01-01

    The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled and is up-to-date until July 2011. All species were classified according to their mode of larval development (planktotrophic and nonplanktotrophic), and bathymetrical zonation (shallow species—those living between the intertidal and 50 m depth, and deep species—those usually living below 50 m depth). 542 species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. The Mediterranean Sea is the most diverse site, followed by Canary Islands, Caribbean, Portugal, and Cape Verde. The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species, with predominance of Alvania spp. in the first site, and of Alvania and Schwartziella at Cape Verde. In spite of the large number of rissoids at Madeira archipelago, a large number of species are shared with Canaries, Selvagens, and the Azores, thus only about 8% are endemic to the Madeira archipelago. Most of the 542-rissoid species that live in the Atlantic and in the Mediterranean are shallow species (323), 110 are considered as deep species, and 23 species are reported in both shallow and deep waters. There is a predominance of nonplanktotrophs in islands, seamounts, and at high and medium latitudes. This pattern is particularly evident in the genera Crisilla, Manzonia, Onoba, Porosalvania, Schwartziella, and Setia. Planktotrophic species are more abundant in the eastern Atlantic and in the Mediterranean Sea. The results of the analysis of the probable directions of faunal flows support the patterns found by both the Parsimony Analysis of Endemicity and the geographical distribution. Four main source areas for rissoids emerge: Mediterranean, Caribbean, Canaries/Madeira archipelagos, and the Cape Verde archipelago. We must stress the high percentage of endemics that occurs in the isolated islands of Saint Helena, Tristan da Cunha, Cape Verde archipelago and also the Azores, thus reinforcing the legislative protective actions that the local governments have implemented in these islands during the recent years. PMID:22693430

  17. A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-eastern Western Australia

    PubMed Central

    Whisson, Corey S.; Breure, Abraham S.H.

    2016-01-01

    Abstract Bothriembryon sophiarum sp. n. is described, based on shell and anatomical morphology, from the coastal area of south-easternmost Western Australia. This is the first description of a new extant Australian bothriembryontid in 33 years. The shell of Bothriembryon sophiarum is slender with a unique teleoconch sculpture. It is found in low coastal scrub on cliff edges and escarpments and because of its restricted distribution, qualifies as a short range endemic. PMID:27199583

  18. Dutrochus, a new microdomatid (Gastropoda) genus from the Middle Devonian (Eifelian) of west-central Alaska

    USGS Publications Warehouse

    Blodgett, R.B.

    1993-01-01

    A new gastropod genus, Dutrochus, is established for members of the family Microdomatidae that are characterized by a reticulate ornament of spiral cords and intersecting, finer collabral threads, with all but one spiral cord being of nearly equal strength, and the single remaining cord being of stronger (nearly twice the order) magnitude and being situated at the periphery. It is represented by the type and only known species, Dutrochus alaskensis n. gen. and sp., from the upper part (lower Eifelian) of the Lower? and Middle Devonian Cheeneetnuk Limestone. The genus is very close and nearly homeomorphic to the Permian microdomatid genus Glyptospira. -from Author

  19. Reversal of density dependence of juvenile Littorina littorea (Gastropoda) growth in response to periphyton nutrient status

    NASA Astrophysics Data System (ADS)

    Sommer, Ulrich

    2001-05-01

    Experimental periphyton communities were grown in aquaria receiving media of differently enriched seawater (fully enriched, without Si enrichment, without N and P enrichment) and supplied differently with medium (batch and weekly replacement). Periphyton was subject to grazing by 1-6 individuals of juvenile Littorina littorea. Periphyton biomass was higher in the replacement aquaria than in the batch aquaria and higher in the full and the -Si medium than in the -NP medium. The N:C ratio of the periphyton increased with Littorina number in the batch aquaria and was unaffected by Littorina number in the replacement aquaria. Diatoms were most dominant in the -NP treatments and rarest in the -Si treatments. Chlorophytes were dominant in the -Si and the fully enriched treatments, but also Cyanobacteria contributed significantly to periphyton biomass in those treatments under nutrient replacement. Somatic growth of Littorina was negatively correlated to Littorina density in the replacement aquaria and positively density dependent in the batch aquaria. The latter is explained by improved food quality under stronger grazing pressure.

  20. Rediae of echinostomatid and heterophyid trematodes suppress phagocytosis of haemocytes in Littorina littorea (Gastropoda: Prosobranchia).

    PubMed

    Iakovleva, Nadya V; Shaposhnikova, Tania G; Gorbushin, Alexander M

    2006-05-01

    A modulation of the phagocytic activity of hemocytes from the common periwinkle Littorina littorea by secretory-excretory products (SEP) released by trematode rediae during axenic in vitro cultivation was studied. The SEP released by the parasites Himasthla elongata (Echinostomatidae) and Cryptocotyle lingua (Heterophyidae) were found to inhibit the phagocytosis of zymozan particles by periwinkle hemocytes. The specificity of SEP effects was assessed: SEP of Himasthla militaris and Cryptocotyle concavum, two trematodes belonging to the same genera but infecting another closely related prosobranch snail Hydrobia ulvae, were also shown to be able to suppress L. littorea hemocytes phagocytic activity. However, no decrease in phagocytosis rate was observed when SEP of H. elongata and C. lingua were applied to monolayers of hemocytes from the bivalve mollusc Mytilus edulis. SEP from H. elongata was fractionated; only those fractions containing proteins of molecular weight more than 50 kDa were shown to possess inhibitory activity. Different H. elongata SEP concentrations were tested in for their ability to suppress phagocytosis by L. littorea hemocytes. Even very low SEP concentrations were shown to retain their ability to decrease phagocytosis rate, the inhibitory effect being dose-dependent. Hemocytes derived from snails naturally infected with H. elongata were also found to have lower phagocytic ability as compared to healthy individuals. PMID:16438967

  1. Complete mitochondrial genome of the giant ramshorn snail Marisa cornuarietis (Gastropoda: Ampullariidae).

    PubMed

    Wang, Mingling; Qiu, Jian-Wen

    2016-05-01

    We report the complete mitochondrial genome (mitogenome) of the giant ramshorn snail Marisa cornuarietis, a biocontrol agent of freshwater weeds and snail vectors of schistosomes. The mitogenome is 15,923 bp in length, encoding 13 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs. The mitogenome is A+T biased (70.0%), with 28.9% A, 41.1% T, 16.7% G, and 13.3% C. A comparison with Pomacea canaliculata, the other member in the same family (Ampullariidae) with a sequenced mitogenome, shows that the two species have an identical gene order, but their intergenic regions vary substantially in sequence length. The mitogenome data can be used to understand the population genetics of M. cornuarietis, and resolve the phylogenetic relationship of various genera in Ampullariidae. PMID:25259454

  2. Macroevolution of venom apparatus innovations in auger snails (Gastropoda; Conoidea; Terebridae)

    PubMed Central

    Castelin, M.; Puillandre, N.; Kantor, Yu. I.; Modica, M.V.; Terryn, Y.; Cruaud, C.; Bouchet, P.; Holford, M.

    2012-01-01

    The Terebridae are a diverse family of tropical and subtropical marine gastropods that use a complex and modular venom apparatus to produce toxins that capture polychaete and enteropneust preys. The complexity of the terebrid venom apparatus suggests that venom apparatus development in the Terebridae could be linked to the diversification of the group and can be analyzed within a molecular phylogenetic scaffold to better understand terebrid evolution. Presented here is a molecular phylogeny of 89 terebrid species belonging to 12 of the 15 currently accepted genera, based on Bayesian inference and Maximum Likelihood analyses of amplicons of 3 mitochondrial (COI, 16S and 12S) and one nuclear (28S) genes. The evolution of the anatomy of the terebrid venom apparatus was assessed by mapping traits of six related characters: proboscis, venom gland, odontophore, accessory proboscis structure, radula, and salivary glands. A novel result concerning terebrid phylogeny was the discovery of a previously unrecognized lineage, which includes species of Euterebra and Duplicaria. The non- monophyly of most terebrid genera analyzed indicates that the current genus-level classification of the group is plagued with homoplasy and requires further taxonomic investigations. Foregut anatomy in the family Terebridae reveals an inordinate diversity of features that covers the range of variability within the entire superfamily Conoidea, and that hypodermic radulae have likely evolved independently on at least three occasions. These findings illustrate that terebrid venom apparatus evolution is not perfunctory, and involves independent and numerous changes of central features in the foregut anatomy. The multiple emergence of hypodermic marginal radular teeth in terebrids are presumably associated with variable functionalities, suggesting that terebrids have adapted to dietary changes that may have resulted from predator-prey relationships. The anatomical and phylogenetic results presented serve as a starting point to advance investigations about the role of predator-prey interactions in the diversification of the Terebridae and the impact on their peptide toxins, which are promising bioactive compounds for biomedical research and therapeutic drug development. PMID:22440724

  3. A nomenclator of extant and fossil taxa of the Valvatidae (Gastropoda, Ectobranchia)

    PubMed Central

    Haszprunar, Gerhard

    2014-01-01

    Abstract A compilation of all supra- and (infra-) specific taxa of extant and fossil Valvatidae, a group of freshwater operculate snails, is provided, including taxa initially described in this family and subsequently classified in other families, as well as names containing errors or misspellings. The extensive reference list is directly linked to the available electronic source (digital view or pdf-download) of the respective papers. PMID:24578604

  4. Caribbean Bulimulus revisited: physical moves and molecular traces (Mollusca, Gastropoda, Bulimulidae)

    PubMed Central

    2016-01-01

    Twenty-five samples of Bulimulus species are studied, partly from localities within their known distribution range, partly based on interceptions where the material originates from localities where the species seem to be recently introduced and non-native. Molecular study of cytochrome oxidase 1 (CO1) reveals the origin of some of these introductions, but is less conclusive for others. Four different methods for species delimitation were applied, which did not result in unambiguous species hypotheses. For a rapid identification of morphologically indistinct species, a more comprehensive database of sequences is needed. PMID:27069787

  5. A new species of Lienardia (Gastropoda: Conoidea) from the Philippines and the Spratly Islands

    PubMed Central

    Rosenberg, Gary; Stahlschmidt, Peter

    2013-01-01

    A new species of Lienardia (Conoidea: Clathurellidae) is described from the Philippines and Spratly Islands and compared to L. giliberti Souverbie, 1874, with which it has been confused. The species is routinely found in lumun-lumun nets in the southern Philippines, particularly in the Panglao area, in depths of 50 and 110 m. Correlations between radular morphology and shell coloration support maintaining Lienardia and Clathurella as distinct genera. PMID:23913992

  6. Not so sluggish: the success of the Felimare picta complex (Gastropoda, Nudibranchia) crossing Atlantic biogeographic barriers

    PubMed Central

    Levy, André

    2016-01-01

    The molecular phylogeny of the Atlanto-Mediterranean species of the genus Felimare, particularly those attributed to the species F. picta, was inferred using two mitochondrial markers (16S and COI). A recent revision of the Chromodorididae clarified the taxonomic relationships at the family level redefining the genus Felimare. However, conflicting taxonomic classifications have been proposed for a restrict group of taxa with overlapping morphological characteristics and geographical distributions designated here as the Felimare picta complex. Three major groups were identified: one Mediterranean and amphi-Atlantic group; a western Atlantic group and a tropical eastern Atlantic group. F. picta forms a paraphyletic group since some subspecies are more closely related with taxa traditionaly classified as independent species (e.g. F. zebra) than with other subspecies with allopatric distributions (e.g. F. picta picta and F. picta tema). Usually, nudibranchs have adhesive demersal eggs, short planktonic larval phases and low mobility as adults unless rafting on floating materials occurs. Surprisingly however, the phylogeny of the F. picta complex suggests that they successfully cross main Atlantic biogeographic barriers including the mid-Atlantic barrier. This ability to cross different biogeographic barriers may be related to F. picta’s distinct life history and ecological traits. Compared to other Chromodorididae F. picta has larger eggs and planktotrophic larvae which could be related to a longer planktonic phase. PMID:26823995

  7. Bayerotrochus delicatus, a new species of pleurotomariid from Yap Seamount, near Palau, Western Pacific (Gastropoda: Pleurotomariidae).

    PubMed

    Zhang, Suping; Zhang, Shuqian; Wei, Peng

    2016-01-01

    A new pleurotomariid species, Bayerotrochus delicatus sp. nov., collected from the Yap Seamount, near Palau, Western Pacific (8°51'N, 137°47'E), is described and illustrated. The generic assignment is based on morphology and molecular evidence. The new species is characterized by a small, depressed trochoid shell sculptured with delicate spiral threads and axial riblets; the shell surface is lustrous orange mottled with iridescence. The radula has a formula of R + 3 + 23 + (ca. 30) + (ca. 65) + 9. These features can separate Bayerotrochus delicatus sp. nov. from its congeners. To determine the relationships of Bayerotrochus delicatus sp. nov. with other pleurotomariids, a neighbor-joining (NJ) tree was established using available sequences of cytochrome c oxidase I gene (COI) from this study and GenBank. PMID:27615927

  8. Synopsis of valid species-group taxa for freshwater Gastropoda recorded from the European Neogene

    PubMed Central

    Neubauer, Thomas A.; Kroh, Andreas; Harzhauser, Mathias; Georgopoulou, Elisavet; Mandic, Oleg

    2014-01-01

    Abstract Here we present a complete list of all valid species-group taxa of freshwater gastropods reported from Miocene and Pliocene deposits in Europe. The last comparable work dates back to the 1920s and covered about 1,600 names. The extensive literature research underlying the present work revealed considerable changes in the taxonomic and systematic frameworks of Neogene freshwater gastropods and yielded a total number of 2,156 accepted taxa. Each taxon is accompanied by a full citation of its first description; where the information is available, page number and illustration reference are provided. First descriptions available as open-access full-text sources on the web were linked via hyperlink to the first page of the publication. PMID:25152683

  9. Larval trematode infections in Galba truncatula (Gastropoda, Lymnaeidae) from the Brenne Regional Natural Park, central France.

    PubMed

    Rondelaud, D; Vignoles, P; Dreyfuss, G

    2016-05-01

    Adult Galba truncatula ( ≥ 4 mm in shell height) were collected from 135 habitats for 3 years (2012-2014) to identify parasite species via the study of cercariae, and to determine the prevalence of each digenean infection in relation to the type of snail habitat (six types). A total of 323 infected snails and ten digenean species were noted in the bodies of 11,025 G. truncatula after their dissection. Snails with Calicophoron daubneyi and/or Fasciola hepatica were found in 20.7% and 12.5% of the habitats, respectively, and most of these infected snails were collected from rainwater-draining furrows and pools in meadows. The percentages were lower for snails with Echinostoma revolutum (9.6% of habitats) and Haplometra cylindracea (7.4%), and were less than 5% for those parasitized by any of the other five species of digenean. The highest prevalence of all digenean infections was noted in pools (9.4%), followed by furrows located in meadows (8.3%) and ponds (5.1%). The prevalence noted for each digenean infection varied with the type of habitat. In furrows located in meadows, the infection rate of C. daubneyi in snails (3.5%) was significantly higher than that of F. hepatica (2.2%). In pools, values greater than 1.5% were noted for C. daubneyi, H. cylindracea and Opistoglyphe ranae. In ponds, E. revolutum was the dominant species (prevalence, 2.5%). Parasite species richness in G. truncatula was greater in the Brenne Natural Regional Park than in the nearby region of Limousin (ten instead of eight). The distribution and prevalence of each parasite species were dependent on the type and location of each snail habitat. PMID:25804319

  10. New taxa of terrestrial molluscs from Turkey (Gastropoda, Pristilomatidae, Enidae, Hygromiidae, Helicidae)

    PubMed Central

    Gümüş, Burçin Aşkım; Neubert, Eike

    2012-01-01

    Abstract This paper reports on results of several collecting trips of the authors in Turkey. In the course of this research, a long-lasting question was addressed. It could be proven that the nominal species Bulimus frivaldskyi L. Pfeiffer, 1847 is closely related to Meijeriella canaliculata Bank, 1985, and thus this species is shifted from the genus Ena Turton, 1831, to the genus Meijeriella Bank, 1985. Meijeriella canaliculata Bank, 1985, could be recorded from Turkey for the first time. The nomenclatural situation of the species Euchondrus septemdentatus (Roth, 1839) vs. its replacement name Euchondrus borealis (Mousson, 1874) is discussed. A new arrangement of the species formely comprised in the genus Zebrina Held, 1837 is presented, and the genera Rhabdoena Kobelt & Moellendorff, 1902, and Leucomastus A. Wagner, 1927 are re-established. The following species and subspecies new to science could be described: Vitrea gostelii sp. n. (Pristilomatidae), Turanena demirsoyi sp. n., Euchondrus paucidentatus sp. n., Rhabdoena gostelii sp. n. (all Enidae), Metafruticicola kizildagensis sp. n. (Hygromiidae), and Assyriella thospitis menkhorsti ssp. n. (Helicidae). For several other species, new distribution records are listed. PMID:22423194

  11. Mitochondrial genome sequences of landsnails Aegista diversifamilia and Dolicheulota formosensis (Gastropoda: Pulmonata: Stylommatophora).

    PubMed

    Huang, Chih-Wei; Lin, Si-Min; Wu, Wen-Lung

    2016-07-01

    The first mitochondrial genome sequences of Aegista and Dolicheulota belonging to Bradybaenidae are described in this report. Mitogenomic sequences were generated from Illumina paired-end sequencing. The complete mitogenome of Aegista diversifamilia was 14,039 bp in length and nearly complete mitogenome of Dolicheulota formosensis was 14,237 bp. Both mitogenomes consisted of 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes. Most genes were overlapped with neighboring genes that the overlapping regions ranged from 2 to 64 bp in A. diversifamilia and from 1 to 45 bp in D. formosensis. Novel gene arrangement, tRNA-Tyr-ND3-tRNA-Trp, was identified in A. diversifamilia, whereas D. formosensis showed identical gene order to other Bradybaenidae mitogenomes. Maximum likelihood phylogenetic tree suggested Aegista as a sister clade to Euhadra and Dolicheulota. Bradybaenidae is monophyly sister clade to Camaenidae. PMID:26094989

  12. A new species of hydrobiid snails (Mollusca, Gastropoda, Hydrobiidae) from central Greece

    PubMed Central

    Radea, Canella

    2011-01-01

    Abstract Anew minute valvatiform species belonging to the genus Daphniola Radoman, 1973, Daphniola eptalophos sp. n., from mountain Parnassos, Greece is described. The new species has a transparent valvatiform-planispiral shell, wide and open umbilicus, grey-black pigmented soft body and head and a black penis with a small colorless outgrowth on the left side near its base. A comparative table of shell dimensions and a key to the species known for this endemic genus for Greece are provided. PMID:22144853

  13. Terrestrial slugs (Gastropoda, Pulmonata) in the NATURA 2000 areas of Cyprus island

    PubMed Central

    Vardinoyannis, Katerina; Demetropoulos, Simon; Mylonas, Moissis; A.Triantis, Kostas; Makris, Christodoulos; Georgiou, Gabriel; Wiktor, Andrzej; Demetropoulos, Andreas

    2012-01-01

    Abstract Terrestrial slugs of the Island of Cyprus were recently studied in the framework of a study of the whole terrestrial malacofauna of the island. The present work was carried out in the Natura 2000 conservation areas of the island in 155 sampling sites over three years (2004–2007). Museum collections as well as literature references were included. In total six species are present in the Natura 2000 areas of the island, belonging to three families: Limacidae, Agriolimacidae and Milacidae. One of the species, Milax riedeli, is a new record for the island. The distribution of the species across the island and in the surrounding areas is discussed. PMID:22451785

  14. Patterns of diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean region.

    PubMed

    Ávila, Sérgio P; Goud, Jeroen; de Frias Martins, António M

    2012-01-01

    The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled and is up-to-date until July 2011. All species were classified according to their mode of larval development (planktotrophic and nonplanktotrophic), and bathymetrical zonation (shallow species--those living between the intertidal and 50 m depth, and deep species--those usually living below 50 m depth). 542 species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. The Mediterranean Sea is the most diverse site, followed by Canary Islands, Caribbean, Portugal, and Cape Verde. The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species, with predominance of Alvania spp. in the first site, and of Alvania and Schwartziella at Cape Verde. In spite of the large number of rissoids at Madeira archipelago, a large number of species are shared with Canaries, Selvagens, and the Azores, thus only about 8% are endemic to the Madeira archipelago. Most of the 542-rissoid species that live in the Atlantic and in the Mediterranean are shallow species (323), 110 are considered as deep species, and 23 species are reported in both shallow and deep waters. There is a predominance of nonplanktotrophs in islands, seamounts, and at high and medium latitudes. This pattern is particularly evident in the genera Crisilla, Manzonia, Onoba, Porosalvania, Schwartziella, and Setia. Planktotrophic species are more abundant in the eastern Atlantic and in the Mediterranean Sea. The results of the analysis of the probable directions of faunal flows support the patterns found by both the Parsimony Analysis of Endemicity and the geographical distribution. Four main source areas for rissoids emerge: Mediterranean, Caribbean, Canaries/Madeira archipelagos, and the Cape Verde archipelago. We must stress the high percentage of endemics that occurs in the isolated islands of Saint Helena, Tristan da Cunha, Cape Verde archipelago and also the Azores, thus reinforcing the legislative protective actions that the local governments have implemented in these islands during the recent years. PMID:22693430

  15. Systematics of the family Plectopylidae in Vietnam with additional information on Chinese taxa (Gastropoda, Pulmonata, Stylommatophora)

    PubMed Central

    Páll-Gergely, Barna; Hunyadi, András; Ablett, Jonathan; Lương, Hào Văn; Fred Naggs; Asami, Takahiro

    2015-01-01

    Abstract Vietnamese species from the family Plectopylidae are revised based on the type specimens of all known taxa, more than 600 historical non-type museum lots, and almost 200 newly-collected samples. Altogether more than 7000 specimens were investigated. The revision has revealed that species diversity of the Vietnamese Plectopylidae was previously overestimated. Overall, thirteen species names (anterides Gude, 1909, bavayi Gude, 1901, congesta Gude, 1898, fallax Gude, 1909, gouldingi Gude, 1909, hirsuta Möllendorff, 1901, jovia Mabille, 1887, moellendorffi Gude, 1901, persimilis Gude, 1901, pilsbryana Gude, 1901, soror Gude, 1908, tenuis Gude, 1901, verecunda Gude, 1909) were synonymised with other species. In addition to these, Gudeodiscus hemmeni sp. n. and Gudeodiscus messageri raheemi ssp. n. are described from north-western Vietnam. Sixteen species and two subspecies are recognized from Vietnam. The reproductive anatomy of eight taxa is described. Based on anatomical information, Halongella gen. n. is erected to include Plectopylis schlumbergeri and Plectopylis fruhstorferi. Additionally, the genus Gudeodiscus is subdivided into two subgenera (Gudeodiscus and Veludiscus subgen. n.) on the basis of the morphology of the reproductive anatomy and the radula. The Chinese Gudeodiscus phlyarius werneri Páll-Gergely, 2013 is moved to synonymy of Gudeodiscus phlyarius. A spermatophore was found in the organ situated next to the gametolytic sac in one specimen. This suggests that this organ in the Plectopylidae is a diverticulum. Statistically significant evidence is presented for the presence of calcareous hook-like granules inside the penis being associated with the absence of embryos in the uterus in four genera. This suggests that these probably play a role in mating periods before disappearing when embryos develop. Sicradiscus mansuyi is reported from China for the first time. PMID:25632253

  16. Annotated type catalogue of the Amphibulimidae (Mollusca, Gastropoda, Orthalicoidea) in the Natural History Museum, London

    PubMed Central

    Breure, Abraham S.H.; Ablett, Jonathan D.

    2011-01-01

    Abstract The type status is described of 39 taxa classified within the family Amphibulimidae (superfamily Orthalicoidea) and kept in the London museum. One taxon, Bulimus elaeodes Pfeiffer, 1853, is removed to the Strophocheilidae. Lectotypes are designated for Bulimus adoptus Reeve, 1849; Bulimus (Eurytus) eros Angas, 1878; Helix onca d'Orbigny, 1835; Amphibulima pardalina Guppy, 1868. The type status of the following taxon is changed to lectotype in accordance with Art. 74.6 ICZN: Strophocheilus (Dryptus) jubeus Fulton, 1908. As general introduction to this and following papers on Orthalicoid types in the Natural History Museum, a brief history of the London collection is given and several examples of handwriting from different authors are presented. PMID:22144852

  17. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda)

    PubMed Central

    Ito, S.; Wakamatsu, K.; Goral, T.; Edwards, N. P.; Wogelius, R. A.; Henkel, T.; de Oliveira, L. F. C.; Maia, L. F.; Strekopytov, S.; Speiser, D. I.; Marsden, J. T.

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments. PMID:27367426

  18. DNA barcoding reveals neritid diversity (Mollusca: Gastropoda) diversity in Malaysian waters.

    PubMed

    Chee, S Y; Mohd Nor, Siti Azizah

    2016-05-01

    This is the first study to identify and determine the phylogenetics of neritids found in Malaysia. In total, twelve species from the family Neritidae were recorded. Ten species were from the genus Nerita and two species were from the genus Neritina. DNA barcodes were successfully assigned to each species. Although some of these species were previously reported in the region, three are only presently reported in this study. The dendrogram showed Nerita and Neritina strongly supported in their respective monophyletic clades. Phylogenetic positions of some species appeared unstable in the trees. This could be due to the differences in a small number of nucleotides, thus minimizing genetic variation between each specimen and species. PMID:25471442

  19. Neuromuscular development of Aeolidiella stephanieae Valdéz, 2005 (Mollusca, Gastropoda, Nudibranchia)

    PubMed Central

    2010-01-01

    Background Studies on the development of the nervous system and the musculature of invertebrates have become more sophisticated and numerous within the last decade and have proven to provide new insights into the evolutionary history of organisms. In order to provide new morphogenetic data on opisthobranch gastropods we investigated the neuromuscular development in the nudibranch Aeolidiella stephanieae Valdéz, 2005 using immunocytochemistry as well as F-actin labelling in conjunction with confocal laser scanning microscopy (cLSM). Results The ontogenetic development of Aeolidiella stephanieae can be subdivided into 8 stages, each recognisable by characteristic morphological and behavioural features as well as specific characters of the nervous system and the muscular system, respectively. The larval nervous system of A. stephanieae includes an apical organ, developing central ganglia, and peripheral neurons associated with the velum, foot and posterior, visceral part of the larva. The first serotonergic and FMRFamidergic neural structures appear in the apical organ that exhibits an array of three sensory, flask-shaped and two non-sensory, round neurons, which altogether disappear prior to metamorphosis. The postmetamorphic central nervous system (CNS) becomes concentrated, and the rhinophoral ganglia develop together with the anlage of the future rhinophores whereas oral tentacle ganglia are not found. The myogenesis in A. stephanieae begins with the larval retractor muscle followed by the accessory larval retractor muscle, the velar or prototroch muscles and the pedal retractors that all together degenerate during metamorphosis, and the adult muscle complex forms de novo. Conclusions Aeolidiella stephanieae comprises features of the larval and postmetamorphic nervous as well as muscular system that represent the ground plan of the Mollusca or even the Trochozoa (e. g. presence of the prototrochal or velar muscle ring). On the one hand, A. stephanieae shows some features shared by all nudibranchs like the postmetamorphic condensation of the CNS, the possession of rhinophoral ganglia and the lack of oral tentacle ganglia as well as the de novo formation of the adult muscle complex. On the other hand, the structure and arrangement of the serotonergic apical organ is similar to other caenogastropod and opisthobranch gastropods supporting their sister group relationship. PMID:20205753

  20. Mitochondrial genome of the endangered marine gastropod Strombus gigas Linnaeus, 1758 (Mollusca: Gastropoda).

    PubMed

    Márquez, Edna J; Castro, Erick R; Alzate, Juan F

    2016-01-01

    The queen conch Strombus gigas is an endangered marine gastropod of significant economic importance across the Greater Caribbean region. This work reports for the first time the complete mitochondrial genome of S. gigas, obtained by FLX 454 pyrosequencing. The mtDNA genome encodes for 13 proteins, 22 tRNAs and 2 ribosomal RNAs. In addition, the coding sequences and gene synteny were similar to other previously reported mitogenomes of gastropods. PMID:25186797

  1. [Growth of Strombus gigas (Gastropoda: Strombidae) snail in 4 environments of Quintana Roo, Mexico].

    PubMed

    Navarrete, A J

    2001-03-01

    The growth rate of queen conch cultured in pens was studied from October 1993 to March 1994. Sixteen pens (50 m2 each, four pens per environment), were set in four environments: Thalassia, Thalassia-sand, Sand and Coral within a reef lagoon on Punta Gavilan and Banco Chinchorro. Twenty conchs were introduced in each pen (sizes: 100-120, 120-140, 140-160 and 160-180 mm shell length) and measured monthly to the nearest mm. Growth rate was assessed by two methods: a) shell marginal mean increase and b) the Gulland-Holt method considering all conch within pens. In the first method, the environment Sand had the highest growth (3.21 +/- 0.26 mm/month) at Punta Gavilan, whereas at Banco Chinchorro, highest growth was recorded in Coral (2.31 +/- 0.44 mm/month). Considering the second method, highest asymptotic length conch in Punta Gavilan occurred in Thalassia-sand (287.5 mm), whereas in Banco Chinchorro the highest asymptotic length was measured in Sand (318.1 mm). There were significant differences in growth between sites; juvenile growth is related with habitat quality mainly food availability. PMID:11795173

  2. Pharyngeal movements during feeding sequences of Navanax inermis (Gastropoda: Opisthobranchia) in successive stages of dissection.

    PubMed

    Susswein, A J; Achituv, Y; Cappell, M S; Bennett, M V

    1987-03-01

    Feeding in Navanax inermis Cooper was filmed and analysed after various dissections. In preparations with a cut through the body wall exposing the pharynx and buccal ganglia, completely normal feeding was observed. In addition to seven motor acts previously described in intact animals, an eighth act, peristalsis, was observed. In preparations with the pharynx excised from the animal but attached to the buccal ganglia, four motor acts were observed: flaring, expansion, contraction and peristalsis. In addition to increasing information about the nature of feeding movements in Navanax, these data indicate that preparations suitable for neurophysiological studies are capable of producing a variety of feeding acts. PMID:3559467

  3. Catecholamines and dihydroxyphenylalanine in metamorphosing larvae of the nudibranch Phestilla sibogae Bergh (Gastropoda: Opisthobranchia).

    PubMed

    Pires, A; Coon, S L; Hadfield, M G

    1997-09-01

    The content of catecholamines and dihydroxyphenylalanine in larvae of the nudibranch Phestilla sibogae was analyzed by high-performance liquid chromatography with electrochemical detection. Dihydroxyphenylalanine, norepinephrine and dopamine were identified in larvae of all ages examined (5 through 12 days post-fertilization). Dihydroxyphenylalanine could be accurately quantified only in larvae of ages 8 through 12 days, when its average concentration increased from 0.62 to 6.71 x 10(-2) pmol micrograms protein-1. Between ages 5 and 12 days dopamine rose from 0.081 to 0.616 pmol microgram protein-1, and norepinephrine from 0.45 to 2.17 x 10(-2) pmol micrograms protein-1. Dihydroxyphenylalanine, dopamine and norepinephrine were also measured at different stages of metamorphic progress in 10- to 12-day larvae. Dihydroxyphenylalanine increased by a factor of 2.4 between the onset and completion of metamorphosis, but levels of dopamine and norepinephrine remained stable. One millimolar alpha-methyl-DL-m-tyrosine, an inhibitor of catecholamine synthesis, inhibited natural metamorphosis and depleted endogenous norepinephrine and especially dopamine, respectively, to 75% and 35% of control values. The existence of unexpectedly high levels of catecholamines in metamorphically competent larvae, and the association of catecholamine depletion with inhibition of metamorphosis, indicate that these compounds may participate in the control of gastropod development. PMID:9309865

  4. New ultrastructural aspects of the spermatozoon of Aplysia depilans (Gastropoda, Opisthobranchia).

    PubMed

    Vita, P; Corral, L; Azevedo, C

    2001-01-01

    The spermatozoon of the sea hare Aplysia depilans was studied under scanning (SEM) and transmission electron microscopy (TEM). Previous descriptions of this sperm and related species, both from light and electron microscopy, were inconsistent with each other. These descriptions include A. depilans, A. punctata, A. fasciata, A. kurodai and Bursatella leachiplei. Several detailed micrographs provide a new ultrastructural model and reveal new aspects such as the presence of acrosome and the absence of a glycogen piece, therefore the modified dense ring is the terminal structure. Results also show that previous models are incorrect in many aspects. The spermatozoon is a long slender uniflagellated cell with a complex helical structure and a length of approximately 165 microm. Observed in SEM the spermatozoon has an undifferentiated head and tail. The nucleus is cord-shaped and helically intertwined with the axoneme/mitochondrial derivative complex. The mitochondrial derivative has only one glycogen helix. Glycogen presence was demonstrated by Thiéry's method. Typical heterobranchia spermatozoa features are recognised. From bibliographic analysis, a high degree of similarity was found with the sperm of Pleurobranchea maculata (Notaspidea). PMID:11686398

  5. A comparative ultrastructural investigation of the cephalic sensory organs in Opisthobranchia (Mollusca, Gastropoda).

    PubMed

    Göbbeler, K; Klussmann-Kolb, A

    2007-12-01

    Cephalic sensory organs (CSOs) are specialised structures in the head region of adult Opisthobranchia involved in perception of different stimuli. The gross morphology of these organs differs considerably among taxa. The current study aims at describing the cellular morphology of the CSOs in order to reveal cellular patterns, especially of sensory epithelia, common for opisthobranchs. Transmission electron microscopy was used to characterise the fine structure of the organs and to compare the CSOs of four different opisthobranch species. The cellular composition of the sensory system is conserved among taxa. The epidermal cells in sensory regions are always columnar and ciliated cells are frequently apparent. The sensory cells are primary receptors arranged in subepidermal cell clusters. They extend dendrites which penetrate the epithelium and reach the surface. Some of the dendrites bear cilia, whereas others only build a small protuberance. Processing of sensory information takes place in the peripheral glomeruli of all species. Moreover, few taxa possess additional peripheral ganglia at the base of their CSOs. The results of the present study might support other investigations indicating that the posterior CSOs are primarily involved in distance chemoreception, whereas the anterior CSOs might be used for contact chemoreception and mechanoreception. PMID:17881026

  6. Sperm tail differentiation in the nudibranch mollusc Hypselodoris tricolor (Gastropoda, Opisthobranchia).

    PubMed

    Medina, A; Moreno, F J; García-Herdugo, G

    1988-06-01

    The sperm axoneme of Hypselodoris tricolor forms from a single centriole that is located initially beneath the plasma membrane and then migrates to the nuclear surface. A conspicuous centriolar adjunct-like formation is present in the neck of midspermatids, but it becomes very reduced at the end of spermiogenesis. In spermatocyte and spermatid mitochondria, intracristal bodies originate from the accumulation of a dense material in some cristae. From our observations and foregoing reports, it may be concluded that the process of sperm tail differentiation in opisthobranchs resembles that in pulmonates, whereas it differs in many respects from that occurring in prosobranchs. The appearance of intracristal bodies in modified mitochondria seems to be a special feature of spermatogenesis in the opisthobranchs that does not occur in the two other groups of gastropod molluscs. PMID:3235038

  7. Reexamination of the gill withdrawal reflex of Aplysia californica Cooper (Gastropoda; Opisthobranchia).

    PubMed

    Leonard, J L; Edstrom, J; Lukowiak, K

    1989-06-01

    The gill withdrawal reflex (GWR), an important model system for neural mechanisms of learning, varies in form and amplitude within as well as between preparations and is therefore a heterogeneous collection of action patterns, not a reflex. At least 4 action patterns occur in response to mechanical stimulation of the siphon. It is often impossible to categorize a particular movement unambiguously. All may occur spontaneously. Gill movements may be described as combinations of 10 actions; 4 involving vein movements are described here. All actions and action patterns can occur in preparations lacking the central nervous system. Some vein movements may generate considerable force without markedly altering gill area. It is suggested that this explains why some early studies failed to identify the important role of the peripheral nervous system in the GWR. Studies based on the assumption that the GWR involves a single type of movement controlled by cells of the parietovisceral ganglion require reevaluation. PMID:2544202

  8. Accumulation and identification of lipofuscin-like pigment in the neurons of Bulla gouldiana (Gastropoda: Opisthobranchia).

    PubMed

    Robles, L J

    1978-01-01

    A few reports suggest that pigmented granules found in molluscan neurons accumulate with age as do lipofuscin granules in vertebrate cells; however, no reports on molluscan neurons include detailed descriptions of granule accumulation or histochemical tests to identify the pigment as lipofuscin-like. In this study light microscope observations of living ganglia from 1.7, 2.7, and 3.0 cm and larger (shell length) sized Bulla gouldiana showed an increasing accumulation of orange-red pigment in the perikaryon corresponding to increasing shell size (i.e. age). With the electron microscope similar results were obtained, and lipofuscin-like granules were seen in the nerve cell cytoplasm of veliger larvae and in all adult sized Bulla. Staining with Sudan black B, Nile blue, chrome alum hematoxylin, PAS reagents, and exposure of the neurons to u.v. light to observe subsequent autofluorescence, yielded positive results in the areas of pigmented granule accumulation. Thus, the brillant orange-red granules that accumulate with age in the peripheral cytoplasm of adult Bulla neurons, and which are probably also present in larval stages, chemically resemble the lipofuscin granules of vertebrates. Similarities and differences between molluscan pigmented granules and vertebrate lipofuscin granules, in relation to structure and mechanisms of development and accumulation, are discussed. PMID:625150

  9. Larval rearing, metamorphosis, growth and reproduction of the eolid nudibranch hermissenda crassicornis (eschscholtz, 1831) (gastropoda: opisthobranchia).

    PubMed

    Harrigan, J F; Alkon, D L

    1978-06-01

    1. Hermissenda crassicornis is a subannual nudibranch species that reproduces year-round. 2. There is a significant positive relationship between adult weight, diameter of the egg mass, estimated number of eggs per egg mass, and average number of eggs per capsule. 3. There is a planktonic veliger stage of 34 days minimum at 13 degrees -15 degrees C. 4. Larvae metamorphose on at least three species of hydroids. 5. To develop in reasonable numbers to a state competent to metamorphose veligers require a diet that includes phytoplankton of larger cell size (10-11 microm) than the commonly used Isochrysis and Monochrysis (5 microm). 6. Although Hermissenda feeds on a wide variety of sessile invertebrate species in the ocean, a diet of tunicate alone (Ciona intestinalis) promotes good growth and survival in the laboratory. 7. Egg mass deposition is initiated only after first copulation, except in the last month of life, and continues from about one-month post-metamorphosis to death, at about four months post-metamorphosis. Generation time (egg-to-egg) may be as short as 2.5 months. 8. A laboratory strain of Hermissenda is being established to provide animals of known history for research on the neural correlates of behavior. Animals, at least initially, are being selected for fast growth rate. PMID:20693369

  10. Microanatomy and ultrastructure of the excretory system of two pelagic opisthobranch species (Gastropoda: Gymnosomata and Thecosomata).

    PubMed

    Fahrner, A; Haszprunar, G

    2000-04-01

    The microanatomy and ultrastructure of the excretory system of Pneumoderma sp. (Gymnosomata) and Creseis virgula Rang, 1828 (Thecosomata) have been investigated by means of semithin serial sections, reconstructions and transmission electron microscopy. The studies revealed a functional metanephridial system consisting of a heart with a single ventricle and auricle in a pericardial cavity and a single kidney in both species. Podocytes in the atrial wall of the pericardial epithelium are the site of ultrafiltration, whereas the flat epithelium of the kidney with numerous basal infoldings and a dense microvillous border on the luminal surface suggests modification of the ultrafiltrate. In Pneumoderma sp., additional loci of ultrafiltration with identical fine structure (meandering slits with diaphragms covered by extracellular matrix) occur in the solitary rhogocytes (pore cells). The presence of podocytes situated on the atrial wall in representatives of two higher opisthobranch taxa contradicts former ideas on the loss of the primary site of ultrafiltration in the ancestors of the Opisthobranchia. PMID:11085207

  11. Slugs' last meals: molecular identification of sequestered chloroplasts from different algal origins in Sacoglossa (Opisthobranchia, Gastropoda).

    PubMed

    Händeler, Katharina; Wägele, Heike; Wahrmund, Ute; Rüdinger, Mareike; Knoop, Volker

    2010-11-01

    Some sacoglossan sea slugs have become famous for their unique capability to extract and incorporate functional chloroplasts from algal food organisms (mainly Ulvophyceae) into their gut cells. The functional incorporation of the so-called kleptoplasts allows the slugs to rely on photosynthetic products for weeks to months, enabling them to survive long periods of food shortage over most of their life-span. The algal food spectrum providing kleptoplasts as temporary, non-inherited endosymbionts appears to vary among sacoglossan slugs, but detailed knowledge is sketchy or unavailable. Accurate identification of algal donor species, which provide the chloroplasts for long-term retention is of primary importance to elucidate the biochemical mechanisms allowing long-term functionality of the captured chloroplast in the foreign animal cell environment. Whereas some sacoglossans forage on a variety of algal species, (e.g. Elysia crispata and E. viridis) others are more selective. Hence, characterizing the range of functional sacoglossan-chloroplast associations in nature is a prerequisite to understand the basis of this enigmatic endosymbiosis. Here, we present a suitable chloroplast gene (tufA) as a marker, which allows identification of the respective algal kleptoplast donor taxa by analysing DNA from whole animals. This novel approach allows identification of donor algae on genus or even species level, thus providing evidence for the taxonomic range of food organisms. We report molecular evidence that chloroplasts from different algal sources are simultaneously incorporated in some species of Elysia. NeigborNet analyses for species assignments are preferred over tree reconstruction methods because the former allow more reliable statements on species identification via barcoding, or rather visualize alternative allocations not to be seen in the latter. PMID:21565106

  12. COMPARATIVE SPERM ULTRASTRUCTURE IN FIVE GENERA OF THE NUDIBRANCH FAMILY CHROMODORIDIDAE (GASTROPODA: OPISTHOBRANCHIA).

    PubMed

    Wilson, NERIDA G.; Healy, JOHN M.

    2002-05-01

    Sperm ultrastructure is examined in representatives of five genera of the nudibranch gastropod family Chromodorididae: (Chromodoris, Hypselodoris, Glossodoris, Risbecia and Pectenodoris) and the results compared with previous work on other gastropods, especially other nudibranchs. As chromodoridid phylogeny is still incompletely understood, this study partly focuses on the search for new and as yet untapped sources of informative characters. Like spermatozoa of most other heterobranch gastropods, those of the Chromodorididae are elongate, complex cells composed of an acrosomal complex (small, rounded acrosomal vesicle, and columnar acrosomal pedestal), a condensed nucleus, sub-nuclear ring, a highly modified mid-piece (axoneme + coarse fibres surrounded by a glycogen-containing, helically-coiled mitochondrial derivative) and terminally a glycogen piece (or homologue thereof). The finely striated acrosomal pedestal is a synapomorphy of all genera examined here, but interestingly also occurs in at least one dorid (Rostanga arbutus). Substantial and potentially taxonomically informative differences were also observed between genera in the morphology of the nucleus, the neck region of the mid-piece, and also the terminal glycogen piece. The subnuclear ring is shown for the first time to be a segmented, rather than a continuous structure; similarly, the annular complex is shown to consist of two structures, the annulus proper and the herein-termed annular accessory body. PMID:12011239

  13. A new phylogeny of the Cephalaspidea (Gastropoda: Heterobranchia) based on expanded taxon sampling and gene markers.

    PubMed

    Oskars, Trond R; Bouchet, Philippe; Malaquias, Manuel António E

    2015-08-01

    The Cephalaspidea is a diverse marine clade of euthyneuran gastropods with many groups still known largely from shells or scant anatomical data. The definition of the group and the relationships between members has been hampered by the difficulty of establishing sound synapomorphies, but the advent of molecular phylogenetics is helping to change significantly this situation. Yet, because of limited taxon sampling and few genetic markers employed in previous studies, many questions about the sister relationships and monophyletic status of several families remained open. In this study 109 species of Cephalaspidea were included covering 100% of traditional family-level diversity (12 families) and 50% of all genera (33 genera). Bayesian and maximum likelihood phylogenetics analyses based on two mitochondrial (COI, 16S rRNA) and two nuclear gene markers (28S rRNA and Histone-3) were used to infer the relationships of Cephalaspidea. The monophyly of the Cephalaspidea was confirmed. The families Cylichnidae, Diaphanidae, Haminoeidae, Philinidae, and Retusidae were found non-monophyletic. This result suggests that the family level taxonomy of the Cephalaspidea warrants a profound revision and several new family and genus names are required to reflect the new phylogenetic hypothesis presented here. We propose a new classification of the Cephalaspidea including five new families (Alacuppidae, Colinatydidae, Colpodaspididae, Mnestiidae, Philinorbidae) and one new genus (Alacuppa). Two family names (Acteocinidae, Laonidae) and two genera (Laona, Philinorbis) are reinstated as valid. An additional lineage with family rank (Philinidae "Clade 4") was unravelled, but no genus and species names are available to reflect the phylogeny and formal description will take place elsewhere. PMID:25916189

  14. New Indo-Pacific species of the genus Teretia Norman, 1888 (Gastropoda: Raphitomidae).

    PubMed

    Morassi, Mauro; Bonfitto, Antonio

    2015-01-01

    Four new species are assigned to the genus Teretia Norman, 1888 in the family Raphitomidae Bellardi, 1875 and herein described: Teretia neocaledonica sp. nov., T. sysoevi sp. nov., T. tongaensis sp. nov. from the southeastern Pacific and Teretia tavianii sp. nov. from the Gulf of Aden. The new species represent the first Indo-Pacific record of a genus previously known in the recent molluscan fauna by only two species from the Atlantic Ocean-Mediterranean Sea and Southern Africa. A possible Tethyan origin for the genus Teretia is suggested.  PMID:25661630

  15. Update on the distribution and phylogenetics of Biomphalaria (Gastropoda: Planorbidae) populations in Guangdong Province, China.

    PubMed

    Attwood, Stephen W; Huo, Guan-Nan; Qiu, Jian-Wen

    2015-01-01

    In 1973 planorbid snails then identified as Biomphalaria straminea were discovered in Hong Kong, China. It was assumed that these snails had been introduced to Hong Kong via the import of tropical fish by air from South America. In 2012 Biomphalaria were found for the first time in Guangdong Province, China. In view of the renewed interest in these invasive snails, a morphological and DNA-sequence based phylogenetic study was undertaken for seven populations of Biomphalaria snails collected in Guangdong. Morphologically and phylogenetically, five of the populations clustered more closely with Biomphalaria kuhniana than with B. straminea. Levels of genetic diversity among the populations were about half those of autochthonous populations in Brazil, the phylogenetic relationships did not correlate with a radiation from any one international port in China, and different lineages appeared associated with different ports. Consequently in explaining the current distribution of the snails, multiple colonization events, each establishing a new local snail population near to maritime international container ports, were considered more likely than the spread of snails from Hong Kong to China. The displacement of B. straminea by B. kuhniana in Guangdong is considered as an explanation for the habitat changes observed among the snails between Hong Kong in the 1980s and the present. The conclusions of the study are that any risk of Schistosoma mansoni transmission in China is more likely to come from parasite importation in the intramolluscan stage, than from transmission by migrant workers from South America or Africa. In addition, although likely to be rare, sporadic outbreaks of imported schistosomiasis (caused by invading infected snails) could be a threat to public health in the vicinity of International container ports (not only in Guangdong Province). Further work is called for to investigate further the presence of B. kuhniana and its potential interactions with B. straminea (the former is thought to be incompatible with S. mansoni), and the responses of Chinese Biomphalaria to potential competitors such as Thiaridae. The current expansion of container ports in Brazil and Venezuela, and the increase in trade with China, is likely to accentuate any current risk of imported schistosomiasis, and surveillance around ports in China, together with further research, are necessary. PMID:24811366

  16. The shallow-water New Caledonia Drilliidae of genus Clavus Montfort, 1810 (Mollusca: Gastropoda: Conoidea).

    PubMed

    Kilburn, Richard N; Fedosov, Alexander; Kantor, Yuri

    2014-01-01

    Species of the genus Clavus of the conoidean family Drilliidae that occur in the littoral and shallow waters of New Caledonia are here revised. This study is based primarily on recent expedition material from the Institut de Recherche pour le Développement (New Caledonia) and Muséum National d'Histoire Naturelle (France). A total of 22 species is recorded, of which eight are described as new. New species: Clavus boucheti, Clavus delphineae, Clavus virginieae, Clavus picoides, Clavus squamiferus, Clavus devexistriatus, Clavus hylikos, Clavus maestratii; New synonyms: Tylotiella Habe, 1958 = Clavus; Clavus leforestieri Hervier, 1896 = Pleurotoma obliquicostata Reeve, 1845; Pleurotoma mariei Crosse, 1869 = Pleurotoma lamberti Montrouzier, 1860; Clavus mighelsi Kay, 1979, new name for Pleurotoma acuminata Mighels, 1845, non J. Sowerby, 1816, was misidentified by Kay 1979; the lectotype of P. acuminata Mighels, 1845, is mangeliine. Clavus mighelsi sensu Kay 1979, is a synonym of Pleurotoma humilis E. A. Smith, 1879. It is suggested that Pleurotoma pulchella Reeve, 1845, sometimes treated as an Indo-Pacific species, may be a senior synonym of Fenimorea halidorema Schwengel, 1940, from the tropical western Atlantic. Nomen dubium: Pleurotoma mediocris Deshayes, 1863. PMID:24943803

  17. Iron-encrusted diatoms and bacteria epibiotic on Hydrobia ulvae (Gastropoda: Prosobranchia)

    NASA Astrophysics Data System (ADS)

    Gillan, D. C.; Cadée, G. C.

    2000-02-01

    Rust-coloured shells of the gastropod Hydrobia ulvae collected in the Wadden Sea near Texel and in the Jade Busen were analysed under the scanning electron microscope. Most of the shells were found to be covered with a microbial community encrusted with an iron-rich mineral containing traces of Mn, Mg, Ca and Si (EDAX analysis). The community formed a biofilm including two morphotypes of diatoms identified as Cocconeis placentula and Achnanthes lemmermanni, two morphotypes of slender filamentous bacteria resembling Leucothrix and Flexibacter, aggregates of coccoid cells and large trichomes resembling members of the cyanobacterial orders Pleurocapsales and Stigonematales, respectively. The most frequent microorganisms of the biofilm were diatoms and filamentous bacteria.

  18. Taxonomic revision of the rock-dwelling door snail genus Montenegrina Boettger, 1877 (Mollusca, Gastropoda, Clausiliidae)

    PubMed Central

    Fehér, Zoltán; Szekeres, Miklós

    2016-01-01

    Abstract The genus Montenegrina is revised on the basis of material available at the Hungarian Natural History Museum (Budapest), Naturhistorisches Museum Wien (Vienna), and the Naturmuseum Senckenberg (Frankfurt am Main), as well as newly discovered populations. The following new taxa are described: Montenegrina haringae sp. n., Montenegrina lillae sp. n., Montenegrina prokletiana sp. n., Montenegrina sturanyana sp. n., Montenegrina grammica erosszoltani ssp. n., Montenegrina grammica improvisa ssp. n., Montenegrina hiltrudae desaretica ssp. n., Montenegrina hiltrudae selcensis ssp. n., Montenegrina laxa delii ssp. n., Montenegrina nana barinai ssp. n., Montenegrina prokletiana kovacsorum ssp. n., Montenegrina rugilabris golikutensis ssp. n., Montenegrina rugilabris gregoi ssp. n., Montenegrina skipetarica danyii ssp. n., Montenegrina skipetarica gurelurensis ssp. n., Montenegrina skipetarica pifkoi ssp. n., Montenegrina skipetarica puskasi ssp. n., Montenegrina sporadica tropojana ssp. n., Montenegrina sturanyana gropana ssp. n., Montenegrina sturanyana ostrovicensis ssp. n., and Montenegrina tomorosi hunyadii ssp. n. A neotype is designated for Montenegrina helvola (Küster, 1860), and Montenegrina cattaroensis antivaricostata nom. n. was introduced to replace the junior homonym Clausilia umbilicata costata Boettger, 1907 (non Pfeiffer, 1928). Of each taxon types or specimens from the type localities are figured, and distribution maps are provided. PMID:27408595

  19. Redescription of Bellerophon asiaticus Wirth (Early Triassic: Gastropoda) from China, and a survey of Triassic Bellerophontacea.

    USGS Publications Warehouse

    Yochelson, E.Y.; Yin, Hongfu

    1985-01-01

    The bilaterally symmetrical gastropod Bellerophon asiaticus Wirth is redescribed from specimens collected in Guizhou Province, PRC. The species is reassigned to Retispira, a common late Paleozoic taxon. Retispira is another example of a Paleozoic gastropod genus that crossed the era boundary. Associated pelecypods that date these Guizhou occurrences as Early Triassic are well known species in PRC and are illustrated. Both Bellerophon and Euphemites probably occur in the Early Triassic, though the quality of illustrations leaves some uncertainty; the existence of Stachella in the Triassic is more problematic. There was no dramatic reduction of the Bellerophontacea from their abundance and diversity in the Permian. It may be a general phenomenon that most late Paleozoic family-level and many generic-level taxa of gastropods were unaffected by the late Permian 'crisis'. from Authors

  20. The phylogeny and taxonomy of austral monodontine topshells (Mollusca: Gastropoda: Trochidae), inferred from DNA sequences.

    PubMed

    Donald, Kirsten M; Kennedy, Martyn; Spencer, Hamish G

    2005-11-01

    The systematics of topshells (family Trochidae) is currently unresolved: at present even the generic boundaries within this group are poorly defined. In this study, we used sequence data of two mitochondrial genes (16S and cytochrome oxidase 1, COI) and one nuclear gene (actin) to resolve the phylogeny of a closely related subgroup of the Trochidae, 30 species of largely Southern Hemisphere monodontine topshells. The phylogenies constructed revealed five well-supported generic clades: a South African clade (genus Oxystele Philippi, 1847), which lay basally to four internal Pacific clades (genera Chlorodiloma Pilsbry, 1889; Monodonta Lamarck, 1799; Austrocochlea Fischer, 1885; and Diloma Philippi, 1845). The molecular phylogenies constructed in this study shed light on previously unresolved relationships between different groups of topshells, allowing for the first time assignation (based on DNA sequence) of clearly defined, well-supported taxonomic and nomenclatural classification of monodontine topshells species. Austrocochlea crinita (Philippi, 1849), A. odontis (Wood, 1828), A. adelaidae (Philippi, 1849), and A. millelineata (Bonnet, 1864) are placed in the genus Chlorodiloma, which we resurrect from synonymy with Austrocochlea. The Japanese M. confusa Tapparone-Canefri, 1874 is treated as a separate species from M. labio (Linné, 1758). Melagraphia Gray, 1847 is synonymised with Diloma and its sole member, M. aethiops (Gmelin, 1791), along with A. concamerata (Wood, 1828), is transferred to that genus. The Juan Fernandez endemic D. crusoeana (Pilsbry, 1889) is synonymised with D. nigerrima (Gmelin, 1791). We find that morphologically cryptic species are not necessarily close genetically. PMID:15936215

  1. Molecular phylogeny reveals the polyphyly of the snail genus Cepaea (Gastropoda: Helicidae).

    PubMed

    Neiber, Marco T; Hausdorf, Bernhard

    2015-12-01

    Snails in the genus Cepaea are important model organisms in ecogenetic studies because of their colour and banding polymorphism. The monophyly of this group has been almost unanimously assumed based on superficial similarities in shell form and colouration. However, molecular phylogenetic analyses based on mitochondrial and nuclear sequences of 20 genera of Helicidae unequivocally demonstrated that Cepaea as currently understood is a polyphyletic assemblage. Only C. nemoralis and C. hortensis are retained in Cepaea, whereas C. vindobonensis is referred to Caucasotachea and C. sylvatica to Macularia based on our molecular phylogeny. Cepaea and Macularia belong to the western clade of the Helicinae, whereas Caucasotachea is nested in the eastern clade which probably diverged in the late Eocene. Because of the large phylogenetic distances between Cepaea, Macularia and Caucasotachea, it has to be shown whether the genetic mechanism underlying the simpler banding polymorphism in C. vindobonensis and M. sylvatica is a simpler version of the supergene that determines the polymorphism in Cepaea in the strict sense. This case illustrates the importance of sound phylogenetic analyses as a basis for any predictions in comparative biology. PMID:26256642

  2. A nomenclator of extant and fossil taxa of the Melanopsidae (Gastropoda, Cerithioidea)

    PubMed Central

    Neubauer, Thomas A.

    2016-01-01

    Abstract This nomenclator provides details on all published names in the family-, genus-, and species-group, as well as for a few infrasubspecific names introduced for, or attributed to, the family Melanopsidae. It includes nomenclaturally valid names, as well as junior homonyms, junior objective synonyms, nomina nuda, common incorrect subsequent spellings, and as far as possible discussion on the current status in taxonomy. The catalogue encompasses three family-group names, 79 genus-group names, and 1381 species-group names. All of them are given in their original combination and spelling (except mandatory corrections requested by the Code), along with their original source. For each family- and genus-group name, the original classification and the type genus and type species, respectively, are given. Data provided for species-group taxa are type locality, type horizon (for fossil taxa), and type specimens, as far as available. PMID:27551193

  3. Bisphenol A Induces Superfeminization in the Ramshorn Snail (Gastropoda: Prosobranchia) at Environmentally Relevant Concentrations

    PubMed Central

    Oehlmann, Jörg; Schulte-Oehlmann, Ulrike; Bachmann, Jean; Oetken, Matthias; Lutz, Ilka; Kloas, Werner; Ternes, Thomas A.

    2006-01-01

    Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions. PMID:16818258

  4. A new species of Cerithium (Gastropoda: Cerithiidae) from the South China Sea

    NASA Astrophysics Data System (ADS)

    Sun, Qimeng; Zhang, Suping

    2014-09-01

    Specimens of a new species of Cerithiidae, Cerithium mangrovum n. sp., were collected during two surveys along the coasts of Hainan and Guangdong Province, China. Usually associated with potamidid snails, this species often occurs in large populations between the mid-high tidal zones in a range of habitats, including mangroves, grass beds, silt, mud, and coral reefs. C. mangrovum n. sp. has a slender and tapering shell and the straight-sided whorl bears three aligned beaded spiral cords. The thick outer lip has a wide posterior sinus. It morphologically resembles C. coralium Kiener, 1841. The shell of C. coralium is usually larger and wider and the spiral cords are not as beaded as in C. mangrovum n. sp. Its radula has a rachidian tooth with a shallow, wide, median basal projection while the rachidian tooth of C. mangrovum n. sp. has a moderately long, median basal projection.

  5. A new species of Lataxiena Jousseaume, 1883 (Gastropoda: Muricidae) from the East and South China Seas

    NASA Astrophysics Data System (ADS)

    Zhang, Suping; Zhang, Shuqian

    2015-03-01

    A new muricid gastropod species, Lataxiena lutescena sp. nov., is described and illustrated. The new species was recognized during reidentification of the Muricidae collection in the Marine Biological Museum, Chinese Academy of Sciences, Qingdao. The specimens of the new species were collected from the East and South China Seas off Fujian, Guangdong, and Hainan Provinces. Lataxiena lutescena sp. nov. is similar to Lataxiena blosvillei (Deshayes, 1832) in general shape, but can be distinguished from the latter by the shell sculpture and radular characteristics. Lataxiena lutescena sp. nov. also resembles Lataxiena bombayana (Melvill, 1893), but differs from that species in the shell shape and anal notches and in lacking short spines on the shell.

  6. New species of the genus Elachisina (Gastropoda: Elachisinidae) from northeastern Brazil.

    PubMed

    Cunha, Carlo M; Santos, Franklin N; Lima, Silvio F B

    2016-01-01

    The family Elachisinidae Ponder, 1985 includes minute marine gastropods that live predominantly in the sublittoral zone (Ponder & Keyzer 1998; Rolán & Rubio 2001; Rolán & Gofas 2003). Most elachisinids have been included in the genus Elachisina Dall, 1918 based on their shell morphology (Warén 1996; Rolán & Rubio 2001; Rolán & Gofas 2003), consequently, very little is known about the habitat and ecological niche of the species (Ponder & Keyzer 1998; Rolán & Gofas 2003). Elachisina floridana (Rehder, 1943) is the only Atlantic congener collected alive, and is known to live beneath rocks and in rocky crevices in the intertidal zone to about 1 m depth in the Bahamas and Caribbean Sea (Ponder 1985; Ponder & Keyzer 1998; Rolán & Gofas 2003; Redfern 2013). Eastern Atlantic E. canarica (Nordsieck & García-Talavera, 1979) was also collected alive from the Canary Islands, but with no information on the habitat (Rolán & Gofas 2003). The islands of the northeastern Atlantic and West Africa are the regions with the greatest Elachisina richness known, totaling nine species (Rolán & Rubio 2001; Rolán & Gofas 2003). Only E. floridana has been recognized so far to be widely distributed throughout the Western Atlantic (Rolán & Gofas 2003; Rios 2009; Redfern 2013). PMID:27470791

  7. Review of the genus Endothyrella Zilch, 1960 with description of five new species (Gastropoda, Pulmonata, Plectopylidae).

    PubMed

    Páll-Gergely, Barna; Budha, Prem B; Naggs, Fred; Backeljau, Thierry; Asami, Takahiro

    2015-01-01

    All known taxa of the genus Endothyrella Zilch, 1960 (family Plectopylidae) are reviewed. Altogether 23 Endothyrella species are recognized. All species are illustrated and whenever possible, photographs of the available type specimens are provided. Five new species are described: Endothyrella angulata Budha & Páll-Gergely, sp. n., Endothyrella dolakhaensis Budha & Páll-Gergely, sp. n. and Endothyrella nepalica Budha & Páll-Gergely, sp. n. from Nepal, Endothyrella robustistriata Páll-Gergely, sp. n. from the Naga Hills, India, and Endothyrella inexpectata Páll-Gergely, sp. n. from Sichuan, China. Helix (Plectopylis) munipurensis Godwin-Austen, 1875 is synonymized with Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) gregorsoni Gude, 1915 is synonymized with Helix (Plectopylis) macromphalus W. Blanford, 1870. Plectopylis plectostoma var. exerta Gude, 1901 is a synonym of Plectopylis plectostoma var. tricarinata Gude, 1896, which is a species in its own right. Five species of the genus Chersaecia viz. Plectopylis (Chersaecia) bedfordi Gude, 1915, Helix (Plectopylis) brahma Godwin-Austen, 1879, Helix (Plectopylis) Oglei Godwin-Austen, 1879, Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) williamsoni Gude, 1915 are moved to Endothyrella. The holotype of Plectopylis hanleyi Godwin-Austen, 1879 seems to be lost; therefore, Plectopylis hanleyi is considered to be a nomen dubium. PMID:26692792

  8. Atlanta ariejansseni, a new species of shelled heteropod from the Southern Subtropical Convergence Zone (Gastropoda, Pterotracheoidea).

    PubMed

    Wall-Palmer, Deborah; Burridge, Alice K; Peijnenburg, Katja T C A

    2016-01-01

    The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to ocean acidification and ocean warming, and atlantids are likely to be useful indicators of these changes. However, we still lack fundamental information on their taxonomy and biogeography, which is essential for monitoring the effects of a changing ocean. Integrated morphological and molecular approaches to taxonomy have been employed to improve the assessment of species boundaries, which give a more accurate picture of species distributions. Here a new species of atlantid heteropod is described based on shell morphology, DNA barcoding of the Cytochrome Oxidase I gene, and biogeography. All specimens of Atlanta ariejansseni sp. n. were collected from the Southern Subtropical Convergence Zone of the Atlantic and Indo-Pacific oceans suggesting that this species has a very narrow latitudinal distribution (37-48°S). Atlanta ariejansseni sp. n. was found to be relatively abundant (up to 2.3 specimens per 1000 m(3) water) within this narrow latitudinal range, implying that this species has adapted to the specific conditions of the Southern Subtropical Convergence Zone and has a high tolerance to the varying ocean parameters in this region. PMID:27551204

  9. Venomous mollusks: the risks of human accidents by conus snails (gastropoda: conidae) in Brazil.

    PubMed

    Haddad, Vidal; de Paula Neto, João Batista; Cobo, Válter José

    2006-01-01

    Mollusks of the genus Conus present a venomous apparatus composed of radulae, a chitin structure linked to glands, which injects potent neurotoxic peptides, causing serious human envenomation and even death, associated with the blockage of certain receptors and muscular paralysis. No reported envenomation has occurred in Brazil, but certain populations are at risk of accidents. PMID:17160331

  10. Report of a human accident caused by Conus regius (Gastropoda, Conidae).

    PubMed

    Haddad, Vidal; Coltro, Marcus; Simone, Luiz Ricardo L

    2009-01-01

    Conus regius is a venomous mollusc in the Conidae family, which includes species responsible for severe or even fatal accidents affecting human beings. This is the first report on a clinical case involving this species. It consisted a puncture in the right hand of a diver who presented paresthesia and movement difficulty in the whole limb. The manifestations disappeared after around twelve hours, without sequelae. PMID:19802483

  11. [Occurrence of Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) in Brazil: intermediate snail host of angiostrongyliasis].

    PubMed

    Teles, H M; Vaz, J F; Fontes, L R; Domingos, M de F

    1997-06-01

    Achatina fulica, the intermediate snail host of angiostrongyliasis and also an agricultural pest, is being bred in Brazil for human consumption as "escargot". The snail has escaped from its artificial breeding sites and its dispersal in Itariri country, State of S. Paulo, is reported here for the first time. A. fulica is a transmitter of the rat lungworm Angiostrongylus cantonensis, nematode which causes meningoencephalic angiostrongyliasis; the risks of human contamination are commented on. PMID:9515269

  12. Sequential colonization and diversification of Galapágos endemic land snail genus Bulimulus (Gastropoda, Stylommatophora).

    PubMed

    Parent, Christine E; Crespi, Bernard J

    2006-11-01

    Species richness on island or islandlike systems is a function of colonization, within-island speciation, and extinction. Here we evaluate the relative importance of the first two of these processes as a function of the biogeographical and ecological attributes of islands using the Galápagos endemic land snails of the genus Bulimulus, the most species-rich radiation of these islands. Species in this clade have colonized almost all major islands and are found in five of the six described vegetation zones. We use molecular phylogenetics (based on COI and ITS 1 sequence data) to infer the diversification patterns of extant species of Bulimulus, and multiple regression to investigate the causes of variation among islands in species richness. Maximum-likelihood, Bayesian, and maximum-parsimony analyses yield well-resolved trees with similar topologies. The phylogeny obtained supports the progression rule hypothesis, with species found on older emerged islands connecting at deeper nodes. For all but two island species assemblages we find support for only one or two colonization events, indicating that within-island speciation has an important role in the formation of species on these islands. Even though speciation through colonization is not common, island insularity (distance to nearest major island) is a significant predictor of species richness resulting from interisland colonization alone. However, island insularity has no effect on the overall bulimulid species richness per island. Habitat diversity (measured as plant species diversity), island elevation, and island area, all of which are indirect measures of niche space, are strong predictors of overall bulimulid land snail species richness. Island age is also an important independent predictor of overall species richness, with older islands harboring more species than younger islands. Taken together, our results demonstrate that the diversification of Galápagos bulimulid land snails has been driven by a combination of geographic factors (island age, size, and location), which affect colonization patterns, and ecological factors, such as plant species diversity, that foster within-island speciation. PMID:17236423

  13. The Vermetidae of the Gulf of Kachchh, western coast of India (Mollusca, Gastropoda).

    PubMed

    Joshi, Devanshi MukundRay; Mankodi, Pradeep C

    2016-01-01

    Coral reefs are often termed underwater wonderlands due to the presence of an incredible biodiversity including numerous invertebrates and vertebrates. Among the dense population of benthic and bottom-dwelling inhabitants of the reef, many significant species remain hidden or neglected by researchers. One such example is the vermetids, a unique group of marine gastropods. The present study attempts for the first time to assess the density and identify preferred reef substrates in the Gulf of Kachchh, state of Gujarat, on the western coast of India. A total of three species of the family Vermetidae were recorded during the study and their substrate preferences identified. PMID:26877684

  14. Granopupa in Iran, monophyly, and the fossil Granariinae (Gastropoda, Pulmonata, Chondrinidae)

    PubMed Central

    Gittenberger, Edmund; Kokshoorn, Bas; Bößneck, Ulrich; Reijnen, Bastian T.; Groenenberg, Dirk S. J.

    2016-01-01

    Abstract Indisputable Chondrinidae, Granariinae species, characterized by shell shape and apertural dentition, are known from Eocene deposits to the Recent. The generic classification of the extant species is based on conchological, anatomical and molecular data that are available now for most of the known species, including ‘Granaria’ persica as a representative of the once problematic group of so-called eastern Granaria species. According to molecular and anatomical characters, these eastern species have to be classified with Granopupa granum in Granopupa. Graniberia gen. n. is introduced for Granaria braunii on the basis of molecular and conchological data. For the pre-Pleistocene species, two generic names are equally well available now, viz. Granopupa and Granaria. Shell characters only do not enable a decision here. For the sake of nomenclatorial stability we propose to use Granaria for these species. Because both molecular and anatomical data most likely will never be known for the fossils, it will remain unclear whether the combined extant and extinct Granaria species form a monophyletic group. PMID:27408543

  15. Synopsis of Central Andean Orthalicoid land snails (Gastropoda, Stylommatophora), excluding Bulimulidae.

    PubMed

    Breure, Abraham S H; Avila, Valentín Mogollón

    2016-01-01

    A faunal overview is presented of the molluscan families Amphibulimidae, Megaspiridae, Odontostomidae, Orthalicidae, Simpulopsidae in Bolivia, Ecuador, and Peru. These Central Andean countries are known for their biodiverse malacofauna, of which the superfamily Orthalicoidea takes relatively a large share. In this paper the five families containing 103 (sub)species, for which systematic information (original publication, type locality, type depository, summarizing literature) and distributional records are presented. All species are illustrated by photographs of the type material or, if this could not be located, by a reproduction of the original figure. The following new taxon is introduced: Thaumastus (Thaumastus) sumaqwayqu sp. n. Junior subjective synonyms are established for: Plekocheilus (Sparnotion) Pilsbry, 1944 = Plekocheilus (Eudolichotis) Pilsbry, 1896; Scholvienia (Thomsenia) Strebel, 1910 = Scholvienia Strebel, 1910; Sultana (Trachyorthalicus) Strebel, 1909 = Sultana (Metorthalicus) Pilsbry, 1899; Plekocheilus (Eurytus) conspicuus Pilsbry, 1932 = Thaumastus (Thaumastus) hartwegi (Pfeiffer in Philippi, 1846); Zebra gruneri Strebel, 1909 = Orthalicus maracaibensis (Pfeiffer, 1856); Scholvienia jaspidea minor Strebel, 1910 = Scholvienia alutacea (Reeve, 1850); Bulimus bifasciatus unicolor Philippi, 1869 = Scholvienia brephoides (d'Orbigny, 1835). A new status is given to Plekocheilus mcgintyi 'Pilsbry' H.B. Baker, 1963 (subspecies of Bulinus piperitus Sowerby I, 1837); Strophocheilus superstriatus var. prodeflexus Pilsbry, 1895 (subspecies of Bulinus piperitus Sowerby I, 1837); Thaumastus (Quechua) salteri maximus Weyrauch, 1967 (subspecies of Thaumastus (Quechua) olmosensis Zilch, 1954); Pseudoglandina agitata Weyrauch, 1967 (nomen inquirendum). New combinations are: Clathrorthalicus corydon (Crosse, 1869), and Cyclodontina chuquisacana (Marshall, 1930). Lectotypes are now designated for Bulimus incisus Hupé, 1857 and Bulinus piperitus Sowerby I, 1837. PMID:27408531

  16. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

    PubMed

    Williams, S T; Ito, S; Wakamatsu, K; Goral, T; Edwards, N P; Wogelius, R A; Henkel, T; de Oliveira, L F C; Maia, L F; Strekopytov, S; Jeffries, T; Speiser, D I; Marsden, J T

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments. PMID:27367426

  17. Prestonellinae-validation of the name as a new subfamily of Bothriembryontidae (Mollusca, Gastropoda, Orthalicoidea).

    PubMed

    Bruggen, A C Van; Herbert, David G; Breure, Abraham S H

    2016-01-01

    The affinities of the enigmatic South African land snail genus Prestonella Connolly, 1929 were discussed by Herbert (2007) and Herbert & Mitchell (2009), who showed, on the basis of morphological and molecular data, that the genus is referable to the superfamily Orthalicoidea. Currently, the three described species of Prestonella are the only known African representatives of this diverse superfamily. Earlier, van Bruggen (1978) had recognized that these species formed a distinct group and had placed them in the (new) family Prestonellidae. However, as noted by Bouchet & Rocroi (2005: 140), no diagnosis was provided by van Bruggen; the name Prestonellidae thus does not meet the requirements of ICZN Art. 13.1, and is not an available name. In this paper we will redress this issue, also taking into account more recent research which has shed light on the systematic position of this genus within the Orthalicoidea. PMID:27394284

  18. A new Middle Miocene Niveria Jousseaume, 1884 (Mollusca: Gastropoda: Trivioidea) from Hungary

    NASA Astrophysics Data System (ADS)

    Fehse, Dirk

    2011-02-01

    A new species of Niveria from the Middle Miocene (Badenian) of the Paratethys of Borsodbóta, Hungary is described. This species is characterized by its callused dorsum and dorsal depression. Niveria jozefgregoi sp. nov. is discussed with comparative species from the Badenian of Hungary, the Pliocene of the Mediterranean region, Florida and Recent species from Madeira and the Islas Galápagos.

  19. Severnsia strombeulima n. gen. & sp. from Hawaii (Mollusca, Gastropoda: Caenogastropoda: Eulimidae).

    PubMed

    Geiger, Daniel L

    2016-01-01

    The malacofauna of Hawaii is rather well-known, owing to Kay (1979) and Severns (2011). Both works stand out because they include a large number of the generally under-represented micromollusks (<5 mm). Here a striking new genus and species of a microsnail is reported from that region. PMID:27394283

  20. A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-eastern Western Australia.

    PubMed

    Whisson, Corey S; Breure, Abraham S H

    2016-01-01

    Bothriembryon sophiarum sp. n. is described, based on shell and anatomical morphology, from the coastal area of south-easternmost Western Australia. This is the first description of a new extant Australian bothriembryontid in 33 years. The shell of Bothriembryon sophiarum is slender with a unique teleoconch sculpture. It is found in low coastal scrub on cliff edges and escarpments and because of its restricted distribution, qualifies as a short range endemic. PMID:27199583

  1. Rich and rare—First insights into species diversity and abundance of Antarctic abyssal Gastropoda (Mollusca)

    NASA Astrophysics Data System (ADS)

    Schwabe, Enrico; Michael Bohn, Jens; Engl, Winfried; Linse, Katrin; Schrödl, Michael

    2007-08-01

    The abyssal depths of the polar oceans are thought to be low in diversity compared with the shallower polar shelves and temperate and tropical deep-sea basins. Our recent study on the gastropod fauna of the deep Southern Ocean gives evidence of the existence of a rich gastropod assemblage at abyssal depths. During the ANDEEP I and II expeditions to the southern Drake Passage, Northwestern Weddell Sea, and South Sandwich Trench, gastropods were collected by bottom and Agassiz trawls, epibenthic sledge, and multicorer, at 40 stations in depths between 127 and 5194 m. On the whole, 473 specimens, corresponding to 93 species of 36 families, were obtained. Of those, 414 specimens were caught below 750 m depth and refer to 84 (90%) benthic species of 32 (89%) families. Most families were represented by a single species only. The numerically dominant families were Skeneidae and Buccinidae (with 10 and 11 species, respectively), Eulimidae and Trochidae (with 9 species each), and Turridae (6 species). Thirty-Seven benthic deep-sea species (44%) were represented by a single specimen, and another 20 species (24%) were found at a single station, suggesting that more than two thirds of Antarctic deep-sea gastropod species are very rare or have a very scattered distribution. Of the 27 species occurring at two or more deep-sea stations, 14 were collected with different gear. Approximately half of the deep-water species are new to science or have been recently described. The present investigation increases the total number of recorded benthic Antarctic deep-sea gastropods (below 750 m) from 115 to 177. The previously known depth ranges have been extended, often considerably, for 31 species. The collected deep-sea gastropods comprise both eurybathic shelf species (29%) and apparently true deep-sea species (58%); some of the latter may belong to a so far unknown Antarctic abyssal fauna. Geographical ranges of the collected Antarctic benthic deep-sea gastropod species appear limited, and all these 84 species seem endemic to Antarctica south of the Polar Front. Comparing diversity and abundances based on epibenthic sledge samples, there is no clear relationship between Antarctic deep-sea gastropod abundance and species richness with depth. However, both Antarctic and adjacent deep-sea areas are still far from being adequately sampled to allow more comprehensive conclusions.

  2. Quantification of midkine gene expression in Patella caerulea (Mollusca, Gastropoda) exposed to cadmium

    NASA Astrophysics Data System (ADS)

    Stillitano, Francesca; Mugelli, Alessandro; Cerbai, Elisabetta; Vanucci, Silvana

    2007-10-01

    The release of cadmium into many coastal areas represents a threat to ecosystems and human health; cadmium is carcinogenic in mammals and in both marine invertebrates and vertebrates. The use of molluscs to assess the ecologic risk associated with contaminants is strongly recommended on account of their ecological role and on their highly conserved control and regulatory pathways that are often homologous to vertebrate systems. We previously identified a midkine family protein in the limpet Patella caerulea; the midkine is a recently discovered cytokines family with unequivocal informative value on repairing injury and neoplastic processes in mammals. Here we report on midkine ( mdk) and α-tubulin ( α-tub) gene expression patterns in P. caerulea exposed to cadmium. Limpets, collected on two occasions from a breakwater at a marina (Tyrrhenian Sea) were exposed to sublethal cadmium concentrations (0.5 and 1 mg l -1 Cd) over a 10-day exposure period. RNA was extracted from the viscera of unexposed and exposed specimens. Real time TaqMan RT-PCR was performed to measure the relative mdk and α-tub gene expression levels. A remarkable mdk over-expression was observed in all exposed animals with respect to unexposed ones; mdk over-expression was significantly higher in both treatments when compared with un-treatment (mean expression levels: 23- and 38-fold, for 0.5 and 1 mg l -1 Cd treatment, respectively; ANOVA, for both P < 0.01). The study also indicates that the mdk up-regulation was significantly Cd-concentration dependent ( P < 0.05). A significant up-regulation of the constitutive α-tub gene was also observed in 1 mg l -1 Cd-treated animals (mean expression level: 4-fold; ANOVA, P < 0.05). In conclusion, these data provide the first evidence paving the way for the use of the midkine as a promising new biomarker of effect in the environment risk assessment policy.

  3. Atlanta ariejansseni, a new species of shelled heteropod from the Southern Subtropical Convergence Zone (Gastropoda, Pterotracheoidea)

    PubMed Central

    Wall-Palmer, Deborah; Burridge, Alice K.; Peijnenburg, Katja T.C.A.

    2016-01-01

    Abstract The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to ocean acidification and ocean warming, and atlantids are likely to be useful indicators of these changes. However, we still lack fundamental information on their taxonomy and biogeography, which is essential for monitoring the effects of a changing ocean. Integrated morphological and molecular approaches to taxonomy have been employed to improve the assessment of species boundaries, which give a more accurate picture of species distributions. Here a new species of atlantid heteropod is described based on shell morphology, DNA barcoding of the Cytochrome Oxidase I gene, and biogeography. All specimens of Atlanta ariejansseni sp. n. were collected from the Southern Subtropical Convergence Zone of the Atlantic and Indo-Pacific oceans suggesting that this species has a very narrow latitudinal distribution (37–48°S). Atlanta ariejansseni sp. n. was found to be relatively abundant (up to 2.3 specimens per 1000 m3 water) within this narrow latitudinal range, implying that this species has adapted to the specific conditions of the Southern Subtropical Convergence Zone and has a high tolerance to the varying ocean parameters in this region. PMID:27551204

  4. Taxonomic revision of the rock-dwelling door snail genus Montenegrina Boettger, 1877 (Mollusca, Gastropoda, Clausiliidae).

    PubMed

    Fehér, Zoltán; Szekeres, Miklós

    2016-01-01

    The genus Montenegrina is revised on the basis of material available at the Hungarian Natural History Museum (Budapest), Naturhistorisches Museum Wien (Vienna), and the Naturmuseum Senckenberg (Frankfurt am Main), as well as newly discovered populations. The following new taxa are described: Montenegrina haringae sp. n., Montenegrina lillae sp. n., Montenegrina prokletiana sp. n., Montenegrina sturanyana sp. n., Montenegrina grammica erosszoltani ssp. n., Montenegrina grammica improvisa ssp. n., Montenegrina hiltrudae desaretica ssp. n., Montenegrina hiltrudae selcensis ssp. n., Montenegrina laxa delii ssp. n., Montenegrina nana barinai ssp. n., Montenegrina prokletiana kovacsorum ssp. n., Montenegrina rugilabris golikutensis ssp. n., Montenegrina rugilabris gregoi ssp. n., Montenegrina skipetarica danyii ssp. n., Montenegrina skipetarica gurelurensis ssp. n., Montenegrina skipetarica pifkoi ssp. n., Montenegrina skipetarica puskasi ssp. n., Montenegrina sporadica tropojana ssp. n., Montenegrina sturanyana gropana ssp. n., Montenegrina sturanyana ostrovicensis ssp. n., and Montenegrina tomorosi hunyadii ssp. n. A neotype is designated for Montenegrina helvola (Küster, 1860), and Montenegrina cattaroensis antivaricostata nom. n. was introduced to replace the junior homonym Clausilia umbilicata costata Boettger, 1907 (non Pfeiffer, 1928). Of each taxon types or specimens from the type localities are figured, and distribution maps are provided. PMID:27408595

  5. Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus)

    PubMed Central

    Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

    2016-01-01

    Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. PMID:27324580

  6. A phylogeny for the pomatiopsidae (Gastropoda: Rissooidea): a resource for taxonomic, parasitological and biodiversity studies

    PubMed Central

    2014-01-01

    Background The Pomatiopsidae are reported from northern India into southern China and Southeast Asia, with two sub-families, the Pomatiopsinae (which include freshwater, amphibious, terrestrial and marine species) and the freshwater Triculinae. Both include species acting as intermediate host for species of the blood-fluke Schistosoma which cause a public health problem in East Asia. Also, with around 120 species, triculine biodiversity exceeds that of any other endemic freshwater molluscan fauna. Nevertheless, the origins of the Pomatiopsidae, the factors driving such a diverse radiation and aspects of their co-evolution with Schistosoma are not fully understood. Many taxonomic questions remain; there are problems identifying medically relevant species. The predicted range is mostly unsurveyed and the true biodiversity of the family is underestimated. Consequently, the aim of the study was to collect DNA-sequence data for as many pomatiopsid taxa as possible, as a first step in providing a resource for identification of epidemiologically significant species (by non-malacologists), for use in resolving taxonomic confusion and for testing phylogeographical hypotheses. Results The evolutionary radiation of the Triculinae was shown to have been rapid and mostly post late Miocene. Molecular dating indicated that the radiation of these snails was driven first by the uplift of the Himalaya and onset of a monsoon system, and then by late-Pliocene global warming. The status of Erhaia as Anmicolidae is supported. The genera Tricula and Neotricula are shown to be non-monophyletic and the tribe Jullieniini may be polyphyletic (based on convergent characters). Triculinae from northern Vietnam could be derived from Gammatricula of Fujian/Yunnan, China. Conclusions The molecular dates and phylogenetic estimates in this study are consistent with an Australasian origin for the Pomatiopsidae and an East to West radiation via Oligocene Borneo-Philippines island hopping to Japan and then China (Triculinae arising mid-Miocene in Southeast China), and less so with a triculine origin in Tibet. The lack of monophyly in the medically important genera and indications of taxonomic inaccuracies, call for further work to identify epidemiologically significant taxa (e.g., Halewisia may be potential hosts for Schistosoma mekongi) and highlight the need for surveys to determine the true biodiversity of the Triculinae. PMID:24548800

  7. Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus).

    PubMed

    Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

    2016-01-01

    Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. PMID:27324580

  8. Odontomariinae, a new middle paleozoic subfamily of slit-bearing euophaloidean gastropods (Euophalomorpha, Gastropoda)

    USGS Publications Warehouse

    Fryda, J.; Heidelberger, D.; Blodgett, R.B.

    2006-01-01

    A new subfamily, the Odontomariinae subfam. nov., is established herein for a distinctive group of uncoiled, slit-bearing Middle Devonian euomphalid gastropods. Its taxonomic position is based on the recent discovery of open coiled protoconchs and it is placed within the Euomphalomorpha. The genera Odontomaria Odontomaria C. F. Roemer and Tubiconcha n. gen. belonging to this new subfamily are enlarged based on studies on new material of the following species: Odontomaria semiplicata (Sandberger & Sandberger), Odontomaria gracilis n. sp., Odontomaria jankei n. sp., Odontomaria cheeneetnukensis n. sp., Odontomaria cindiprellerae n. sp. and Tubiconcha leunissi (Heidelberger, 2001). Members of the Odontomariinae were mainly sedentary organisms in high-energy, moderately shallow water. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

  9. The complete mitochondrial genome of Chinese land snail Aegista aubryana (Gastropoda: Pulmonata: Bradybaenidae).

    PubMed

    Yang, Xue; Xie, Guang-Long; Wu, Xiao-Ping; Ouyang, Shan

    2016-09-01

    Aegista aubryana is an endemic land snail in China. The complete mitochondrial genome of A. aubryana was first determined using long PCR reactions and primer walking method (accession number KT192071). The genome has a length of 14 238 bp, containing 37 typical mitochondrial genes (13 protein-coding genes, 22 tRNA genes and 2 rRNA genes). The base composition of the whole heavy strand is A 31.32%, T 37.86%, C 14.46% and G 16.36%. The results of phylogenetic analyses showed that the A. aubryana is most closely related to Mastigeulota kiangsinensis. This new complete mitochondrial genome can be the basic data for further studies on mitogenome comparison, molecular taxonomy and phylogenetic analyses in bradybaenid snails and Molluscs at large. PMID:26260173

  10. Bridging gaps in the molecular phylogeny of the Lymnaeidae (Gastropoda: Pulmonata), vectors of Fascioliasis

    PubMed Central

    2010-01-01

    Background Lymnaeidae snails play a prominent role in the transmission of helminths, mainly trematodes of medical and veterinary importance (e.g., Fasciola liver flukes). As this family exhibits a great diversity in shell morphology but extremely homogeneous anatomical traits, the systematics of Lymnaeidae has long been controversial. Using the most complete dataset to date, we examined phylogenetic relationships among 50 taxa of this family using a supermatrix approach (concatenation of the 16 S, ITS-1 and ITS-2 genes, representing 5054 base pairs) involving both Maximum Likelihood and Bayesian Inference. Results Our phylogenetic analysis demonstrates the existence of three deep clades of Lymnaeidae representing the main geographic origin of species (America, Eurasia and the Indo-Pacific region). This phylogeny allowed us to discuss on potential biological invasions and map important characters, such as, the susceptibility to infection by Fasciola hepatica and F. gigantica, and the haploid number of chromosomes (n). We found that intermediate hosts of F. gigantica cluster within one deep clade, while intermediate hosts of F. hepatica are widely spread across the phylogeny. In addition, chromosome number seems to have evolved from n = 18 to n = 17 and n = 16. Conclusion Our study contributes to deepen our understanding of Lymnaeidae phylogeny by both sampling at worldwide scale and combining information from various genes (supermatrix approach). This phylogeny provides insights into the evolutionary relationships among genera and species and demonstrates that the nomenclature of most genera in the Lymnaeidae does not reflect evolutionary relationships. This study highlights the importance of performing basic studies in systematics to guide epidemiological control programs. PMID:21143890

  11. Caribbean Bulimulus revisited: physical moves and molecular traces (Mollusca, Gastropoda, Bulimulidae).

    PubMed

    Breure, Abraham S H

    2016-01-01

    Twenty-five samples of Bulimulus species are studied, partly from localities within their known distribution range, partly based on interceptions where the material originates from localities where the species seem to be recently introduced and non-native. Molecular study of cytochrome oxidase 1 (CO1) reveals the origin of some of these introductions, but is less conclusive for others. Four different methods for species delimitation were applied, which did not result in unambiguous species hypotheses. For a rapid identification of morphologically indistinct species, a more comprehensive database of sequences is needed. PMID:27069787

  12. Dating and biogeographical patterns in the sea slug genus Acanthodoris Gray, 1850 (Mollusca, Gastropoda, Nudibranchia).

    PubMed

    Hallas, Joshua M; Simison, W Brian; Gosliner, Terrence M

    2016-04-01

    Recent studies investigating vicariance and dispersal have been focused on correlating major geological events with instances of taxonomic expansion by incorporating the fossil record with molecular clock analyses. However, this approach becomes problematic for soft-bodied organisms that are poorly represented in the fossil record. Here, we estimate the phylogenetic relationships of the nudibranch genus Acanthodoris Gray, 1850 using three molecular markers (16S, COI, H3), and then test two alternative geologically calibrated molecular clock scenarios in BEAST and their effect on ancestral area reconstruction (AAR) estimates employed in LAGRANGE. The global temperate distribution of Acanthodoris spans multiple geological barriers, including the Bering Strait (∼5.32 Mya) and the Baja Peninsula (∼5.5 Mya), both of which are used in our dating estimates. The expansion of the Atlantic Ocean (∼95-105 Mya) is also used to calibrate the relationship between A. falklandica Eliot, 1905 and A. planca Fahey and Valdés, 2005, which are distributed in southern Chile and South Africa respectively. Phylogenetic analyses recovered strong biogeographical signal and recovered two major clades representing northern and southern hemispheric distributions of Acanthodoris. When all three geological events are applied to the calibration analyses, the age for Acanthodoris is estimated to be mid-Cretaceous. When the expansion of the Atlantic Ocean is excluded from our analyses, however, Acanthodoris is estimated to be much younger, with a divergence time estimate during the Miocene. Regardless of divergence estimates, our AAR suggests that Acanthodoris may have origins in the Atlantic Ocean with the Atlantic acting as a dispersal point to the northeastern Pacific. These results suggest that Acanthodoris exhibits a rare instance of western trans-arctic expansion. This study also shows that northeast Pacific specimens of A. pilosa should be regarded as A. atrogriseata and that A. serpentinotus should be regarded as a synonym of A. pina. PMID:26752594

  13. Annotated type catalogue of the Bulimulidae (Mollusca, Gastropoda, Orthalicoidea) in the Natural History Museum, London

    PubMed Central

    Breure, Abraham S.H.; Ablett, Jonathan D.

    2014-01-01

    Abstract The type status is described of 404 taxa classified within the family Bulimulidae (superfamily Orthalicoidea) and kept in the London museum. Lectotypes are designated for Bulimus aurifluus Pfeiffer, 1857; Otostomus bartletti H. Adams, 1867; Helix cactorum d’Orbigny, 1835; Bulimus caliginosus Reeve, 1849; Bulimus chemnitzioides Forbes, 1850; Bulimus cinereus Reeve, 1849; Helix cora d’Orbigny, 1835; Bulimus fallax Pfeiffer, 1853; Bulimus felix Pfeiffer, 1862; Bulimus fontainii d’Orbigny, 1838; Bulimus fourmiersi d’Orbigny, 1837; Bulimus (Mesembrinus) gealei H. Adams, 1867; Bulimus gruneri Pfeiffer, 1846; Bulimus humboldtii Reeve, 1849; Helix hygrohylaea d’Orbigny, 1835; Bulimus jussieui Pfeiffer, 1846; Bulimulus (Drymaeus) binominis lascellianus E.A. Smith, 1895; Helix lichnorum d’Orbigny, 1835; Bulimulus (Drymaeus) lucidus da Costa, 1898; Bulimus luridus Pfeiffer, 1863; Bulimus meleagris Pfeiffer, 1853; Bulimus monachus Pfeiffer, 1857; Bulimus montagnei d’Orbigny, 1837; Helix montivaga d’Orbigny, 1835; Bulimus muliebris Reeve, 1849; Bulimus nigrofasciatus Pfeiffer in Philippi 1846; Bulimus nitelinus Reeve, 1849; Helix oreades d’Orbigny, 1835; Helix polymorpha d’Orbigny, 1835; Bulimus praetextus Reeve, 1849; Bulinus proteus Broderip, 1832; Bulimus rusticellus Morelet, 1860; Helix sporadica d’Orbigny, 1835; Bulimus sulphureus Pfeiffer, 1857; Helix thamnoica var. marmorata d’Orbigny, 1835; Bulinus translucens Broderip in Broderip and Sowerby I 1832; Helix trichoda d’Orbigny, 1835; Bulinus ustulatus Sowerby I, 1833; Bulimus voithianus Pfeiffer, 1847; Bulimus yungasensis d’Orbigny, 1837. The type status of the following taxa is changed to lectotype in accordance with Art. 74.6 ICZN: Bulimulus (Drymaeus) caucaensis da Costa, 1898; Drymaeus exoticus da Costa, 1901; Bulimulus (Drymaeus) hidalgoi da Costa, 1898; Bulimulus (Drymaeus) interruptus Preston, 1909; Bulimulus (Drymaeus) inusitatus Fulton, 1900; Bulimulus latecolumellaris Preston, 1909; Bulimus (Otostomus) napo Angas, 1878; Drymaeus notabilis da Costa, 1906; Drymaeus notatus da Costa, 1906; Bulimulus (Drymaeus) nubilus Preston, 1903; Drymaeus obliquistriatus da Costa, 1901; Bulimus (Drymaeus) ochrocheilus E.A. Smith, 1877; Bulimus (Drymaeus) orthostoma E.A. Smith, 1877; Drymaeus expansus perenensis da Costa, 1901; Bulimulus pergracilis Rolle, 1904; Bulimulus (Drymaeus) plicatoliratus da Costa, 1898; Drymaeus prestoni da Costa, 1906; Drymaeus punctatus da Costa, 1907; Bulimus (Leptomerus) sanctaeluciae E.A. Smith, 1889; Bulimulus (Drymaeus) selli Preston, 1909; Drymaeus subventricosus da Costa, 1901; Bulimulus (Drymaeus) tigrinus da Costa, 1898; Drymaeus volsus Fulton, 1907; Drymaeus wintlei Finch, 1929; Bulimus zhorquinensis Angas, 1879; Bulimulus (Drymaeus) ziczac da Costa, 1898. The following junior subjective synonyms are established: Bulimus antioquensis Pfeiffer, 1855 = Bulimus baranguillanus Pfeiffer, 1853; Drymaeus bellus da Costa, 1906 = Drymaeus blandi Pilsbry, 1897; Bulimus hachensis Reeve 1850 = Bulimus gruneri Pfeiffer, 1846 = Bulimus columbianus Lea, 1838; Bulimus (Otostomus) lamas Higgins 1868 = Bulimus trujillensis Philippi, 1867; Bulimulus (Drymaeus) binominis lascellianus E.A. Smith, 1895 = Bulimulus (Drymaeus) binominis E.A. Smith, 1895; Drymaeus multispira da Costa, 1904 = Helix torallyi d’Orbigny, 1835; Bulimulus (Drymaeus) plicatoliratus Da Costa, 1898 = Bulimus convexus Pfeiffer, 1855; Bulimus sugillatus Pfeiffer, 1857 = Bulimus rivasii d’Orbigny, 1837; Bulimus meridionalis Reeve 1848 [June] = Bulimus voithianus Pfeiffer, 1847. New combinations are: Bostryx montagnei (d’Orbigny, 1837); Bostryx obliquiportus (da Costa, 1901); Bulimulus heloicus (d’Orbigny, 1835); Drymaeus (Drymaeus) lusorius (Pfeiffer, 1855); Drymaeus (Drymaeus) trigonostomus (Jonas, 1844); Drymaeus (Drymaeus) wintlei Finch, 1929; Drymaeus (Mesembrinus) conicus da Costa, 1907; Kuschelenia (Kuschelenia) culminea culminea (d’Orbigny, 1835); Kusche

  14. Impact of mercury contamination on the population dynamics of Peringia ulvae (Gastropoda): Implications on metal transfer through the trophic web

    NASA Astrophysics Data System (ADS)

    Cardoso, P. G.; Sousa, E.; Matos, P.; Henriques, B.; Pereira, E.; Duarte, A. C.; Pardal, M. A.

    2013-09-01

    The effects of mercury contamination on the population structure and dynamics of the gastropod Peringia ulvae (also known as Hydrobia ulvae) and its impact on the trophic web were assessed along a mercury gradient in Ria de Aveiro (Portugal). The gastropod was revealed to be a tolerant species to the contaminant, since the highest densities, biomasses and growth productivity values were recorded at the intermediate contaminated area followed by the most contaminated one and finally the least contaminated area. P. ulvae was however negatively affected by mercury in terms of growth and life span. So, in the most contaminated area the population was characterised mainly by the presence of juveniles and young individuals. The intermediate contaminated area showed a greater equilibrium in terms of groups' proportion, being the adults the dominant set. The least contaminated area presented intermediate values. P. ulvae life spans were shortest in the most contaminated area (7-8 mo), followed by the least contaminated area (10-11 mo) and finally, the intermediate one (11-14 mo). P. ulvae revealed to be an important vehicle of mercury transfer from sediments to the trophic web, incorporating approximately 15 g of Hg, annually, in the inner area of the Laranjo Bay (0.6 Km2). Therefore, despite P. ulvae being revealed to be not a good bio-indicator of mercury contamination, since it did not suffer profound modifications in its structure and functioning, it is a crucial element in the mercury biomagnification processes throughout the food web.

  15. Food-induced esterase electromorphs in Carinarion spp. and their effects on taxonomic data analysis (Gastropoda, Pulmonata, Arionidae).

    PubMed

    Jordaens, K; Van Riel, P; Verhagen, R; Backeljau, T

    1999-03-01

    Nonspecific esterases (EST) are often used to measure genetic variation, yet they may be influenced by environmental factors such as food, climate and age. This may produce misleading similarity indices and genetic diversity estimates (i.e., clone or strain diversities in uniparental organisms). Therefore, polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (IEF) were used to investigate environmental effects on the EST variation in natural Carinarion populations, as well as in 45 individuals that were raised individually on carrots to produce offspring by selfing. Food effects on EST profiles in these progenies were examined by raising them on different food items (lettuce, nettle, or paper). Our results indicated that: (i) Arion (Carinarion) fasciatus and A. (C.) silvaticus show species-specific EST profiles, (ii) A. fasciatus-like outcrossers most probably are conspecific with A. fasciatus s.s., (iii) not all EST variation has a Mendelian basis since lettuce and nettle altered EST profiles, and (iv) food effects on EST profiles differed strongly between individuals. Although food-induced EST profiles did not affect taxonomic interpretations, they did inflate genetic diversity estimates and thus provided misleading population-genetic data. PMID:10217156

  16. DNA barcodes and phylogenetic affinities of the terrestrial slugs Arion gilvus and A. ponsi (Gastropoda, Pulmonata, Arionidae).

    PubMed

    Breugelmans, Karin; Jordaens, Kurt; Adriaens, Els; Remon, Jean Paul; Cardona, Josep Quintana; Backeljau, Thierry

    2013-12-30

    The Iberian Peninsula is a region with a high endemicity of species of the terrestrial slug subgenus Mesarion. Many of these species have been described mainly on subtle differences in their proximal genitalia. It therefore remains to be investigated 1) whether these locally diverged taxa also represent different species under a phylogenetic species concept as has been shown for other Mesarion species outside the Iberian Peninsula, and 2) how these taxa are phylogenetically related. Here, we analysed DNA sequence data of two mitochondrial (COI and 16S) genes, and of the nuclear ITS1 region, to explore the phylogenetic affinities of two of these endemic taxa, viz. Arion gilvus Torres Mínguez, 1925 and A. ponsi Quintana Cardona, 2007. We also evaluated the use of these DNA sequence data as DNA barcodes for both species. Our results showed that ITS did not allow to differentiate among most of the Mesarion molecular operational taxonomic units (MOTUs) / morphospecies in Mesarion. Yet, the overall mean p-distance among the Mesarion MOTUs / morphospecies for both mtDNA fragments (16.7% for COI, 13% for 16S) was comparable to that between A. ponsi and its closest relative A. molinae (COI: 14.2%; 16S: 16.2%) and to that between A. gilvus and its closest relative A. urbiae (COI: 14.4%; 16S: 13.4%). Hence, with respect to mtDNA divergence, both A. ponsi and A. gilvus, behave as other Mesarion species or putative species-level MOTUs and thus are confirmed as distinct 'species'. PMID:24453553

  17. Extreme mtDNA divergences in a terrestrial slug (Gastropoda, Pulmonata, Arionidae): accelerated evolution, allopatric divergence and secondary contact.

    PubMed

    Pinceel, J; Jordaens, K; Backeljau, T

    2005-09-01

    Extremely high levels of intraspecific mtDNA differences in pulmonate gastropods have been reported repeatedly and several hypotheses to explain them have been postulated. We studied the phylogeny and phylogeography of 51 populations (n = 843) of the highly polymorphic terrestrial slug Arion subfuscus (Draparnaud, 1805) across its native distribution range in Western Europe. By combining the analysis of single stranded conformation polymorphisms (SSCP) and nucleotide sequencing, we obtained individual sequence data for a fragment of the mitochondrial 16S rDNA and a fragment of the nuclear ITS1. Additionally, five polymorphic allozyme loci were scored. Based on the 16S rDNA phylogeny, five monophyletic haplotype groups with sequence divergences of 9-21% were found. Despite this deep mitochondrial divergence, the haplotype groups were not monophyletic for the nuclear ITS1 fragment and haplotype group-specific allozyme alleles were not found. Although there is evidence for an accelerated mtDNA clock, the divergence among the haplotype groups is older than the Pleistocene and their current allopatric ranges probably reflect allopatric divergence and glacial survival in separate refugia from which different post-glacial colonization routes were established. A range-overlap of two mtDNA groups (S1 and S2, 21% sequence divergence) stretched from Central France and Belgium up to the North of the British Isles. The nuclear data suggest that this secondary contact resulted in hybridization between the allopatrically diverged groups. Therefore, it seems that, at least for two of the groups, the deep mtDNA divergence was only partially accompanied by the formation of reproductive isolation. PMID:16135122

  18. Opisthobranchia (Mollusca, Gastropoda) – more than just slimy slugs. Shell reduction and its implications on defence and foraging

    PubMed Central

    Wägele, Heike; Klussmann-Kolb, Annette

    2005-01-01

    Background In general shell-less slugs are considered to be slimy animals with a rather dull appearance and a pest to garden plants. But marine slugs usually are beautifully coloured animals belonging to the less-known Opisthobranchia. They are characterized by a large array of interesting biological phenomena, usually related to foraging and/or defence. In this paper our knowledge of shell reduction, correlated with the evolution of different defensive and foraging strategies is reviewed, and new results on histology of different glandular systems are included. Results Based on a phylogeny obtained by morphological and histological data, the parallel reduction of the shell within the different groups is outlined. Major food sources are given and glandular structures are described as possible defensive structures in the external epithelia, and as internal glands. Conclusion According to phylogenetic analyses, the reduction of the shell correlates with the evolution of defensive strategies. Many different kinds of defence structures, like cleptocnides, mantle dermal formations (MDFs), and acid glands, are only present in shell-less slugs. In several cases, it is not clear whether the defensive devices were a prerequisite for the reduction of the shell, or reduction occurred before. Reduction of the shell and acquisition of different defensive structures had an implication on exploration of new food sources and therefore likely enhanced adaptive radiation of several groups. PMID:15715915

  19. A review of the microgastropod genus Systenostoma Bavay & Dautzenberg, 1908 and a new subterranean species from China (Gastropoda, Pulmonata, Hypselostomatidae).

    PubMed

    Jochum, Adrienne; Slapnik, Rajko; Kampschulte, Marian; Martels, Gunhild; Heneka, Markus; Páll-Gergely, Barna

    2014-01-01

    A review of the microgastropod genus Systenostoma is provided. Thai and Malaysian species are transferred to a new genus, Angustopila (type species: Systenostoma tamlod Panha & Burch, 1999). A new subterranean Angustopila species is described here. Conchologically, the new species is most similar to the cave-dwelling, Thai A. tamlod (Panha & Burch, 1999). One Thai species (Systenostoma edentata) is transferred to the genus Hypselostoma. Vietnamese members remain in the genus Tonkinospira (nomen novum) for Systenostoma Bavay & Dautzenberg, 1908 (non Systenostoma Marsson, 1887). A comprehensive map of former Systenostoma species is presented. SEM and NanoCT images, including a video of A. huoyani sp. n. internal shell morphology, provide novel perspectives of the shells of Angustopila and of the scarcely known Vietnamese Tonkinospira species. The biology of these snails is not yet known but collection localities suggest a troglophilic ecology. PMID:24899848

  20. Surviving the Messinian Salinity Crisis? Divergence patterns in the genus Dendropoma (Gastropoda: Vermetidae) in the Mediterranean Sea.

    PubMed

    Calvo, Marta; Alda, Fernando; Oliverio, Marco; Templado, José; Machordom, Annie

    2015-10-01

    Four genetically distinct clades were recently described under the name Dendropoma petraeum, a Mediterranean endemic vermetid gastropod. The aim of this work is to date the processes that drove to the diversification within this taxon and to relate them to the corresponding historical events occurred in the Mediterranean Sea. Sequences from mitochondrial and nuclear markers were obtained from specimens collected in 29 localities spanning over 4000km across the entire distribution range of D. petraeum species complex. The phylogenetic and coalescent-based analyses confirmed the four well-supported and largely differentiated lineages of D. petraeum, clearly delimited geographically along a west-east axis within the Mediterranean Sea: Western, Tyrrhenian-Sicilian, Ionian-Aegean and Levantine lineages. Divergence time estimates, obtained using a range of known substitution rates for other marine gastropods, indicated two main stages of diversification. In the first period (between 9.5 and 4.5mya), the ancestral D. petraeum diverged into the current four lineages. The most recent period occurred between 3.72 and 0.66mya in the late Pliocene-early Pleistocene, and included the main within-lineage diversification events. Therefore, if the divergence time between the major lineages of Dendropoma in the Mediterranean actually predated or coincided with the Messinian Salinity Crisis, then they should have survived to this dramatic period within the Mediterranean, as supported by Bayes Factors model comparison. Conversely, if the divergence started after the crisis, congruent with the idea that no true marine organism survived the Messinian Salinity Crisis, then our results indicate substitution rates of Dendropoma much higher than usual (5.16% per million years for COI, 3.04% for 16S). More recent climate changes seem to have conditioned the demographic history of each lineage differently. While Western and Tyrrhenian-Sicilian lineages both underwent an increase in their effective population sizes from 1.5 to 0.6mya coinciding with a long interglacial period, the Ionian-Aegean and Levantine lineages showed constant effective population sizes since 2-2.5mya, suggesting that these eastern lineages might represent small and relict populations surviving the subsequent Quaternary glaciations in isolated refugia. PMID:26002830

  1. mtDNA ribosomal gene phylogeny of sea hares in the genus Aplysia (Gastropoda, Opisthobranchia, Anaspidea): Implications for comparative neurobiology

    SciTech Connect

    Medina, Monica; Collins, Timothy M.; Walsh, Patrick J.

    2000-08-10

    Sea hares within the genus Aplysia are important neurobiological model organisms, and as studies based on different Aplysia species appear in the literature, a phylogenetic framework has become essential. We present a phylogenetic hypothesis for this genus, based on portions of two mitochondrial genes (12S and 16S). In addition, we reconstruct the evolution of several behavioral characters of interest to neurobiologists in order to illustrate the potential benefits of a phylogeny for the genus Aplysia. These benefits include the determination of ancestral traits, the direction and timing of evolution of characters, prediction of the distribution of traits, and identification of cases of independent acquisition of traits within lineages. This last benefit may prove especially useful in understanding the linkage between behaviors and their underlying neurological basis.

  2. Antimicrobial activities of the tissue extracts of Babylonia spirata Linnaeus, 1758 (Mollusca: Gastropoda) from Thazhanguda, southeast coast of India

    PubMed Central

    Periyasamy, N; Srinivasan, M; Balakrishnan, S

    2012-01-01

    Objective To investigate the antimicrobial activity of the tissue extracts of Babylonia spirata (B. spirata) against nine bacterial and three fungal pathogens. Methods Crude extract of gastropod was tested for inhibition of bacterial and fungal growth. Antibacterial assay was carried out by disc diffusion method and in vitro antifungal activity was determined against Czapex Dox agar. The antimicrobial activity was measured accordingly based on the inhibition zone around the disc impregnated with gastropod extract. Molecular size of muscle protein was determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). And fourier transform infrared spectroscopy (FTIR) spectro photometry analysis was also studied. Results The maximum inhibition zone (12 mm) was observed against Pseudomonas aeruginosa in the crude ethanol extract of B. spirata and the minimum inhibition zone (2 mm) was noticed against Staphylococcus aureus in the crude methanol extract of B. spirata. Water extract of B. spirata showed the highest activity against Vibrio parahaemolyticus, Staphylococcus aureus and Candida albicans. Ethanol, acetone, methanol, chloroform and water extracts showed antimicrobial activity against almost all the bacteria and fungus. Compared with water extracts, ethanol and methanol extracts showed higher activity against all pathogens. The molecular weight of protein of the gastropod sample ranged from 2-110 kDa on SDS-PAGE. FTIR analysis revealed the presence of bioactive compounds signals at different ranges. Conclusions The research shows that the great medicinal value of the gastropod muscle of B. spirata may be due to high quality of antimicrobial compounds. PMID:23569831

  3. Developmental toxicity of metaldehyde in the embryos of Lymnaea stagnalis (Gastropoda: Pulmonata) co-exposed to the synergist piperonyl butoxide.

    PubMed

    Hallett, Katrina C; Atfield, Andrew; Comber, Sean; Hutchinson, Thomas H

    2016-02-01

    Metaldehyde is a widely used molluscicide in countries where damage to crops from slugs and snails is a major problem associated with warm and wet winters. In the UK it is estimated that over 8% of the area covered by arable crops is treated with formulated granular bait pellets containing metaldehyde as the main active ingredient. Metaldehyde is hydrophilic (log Kow=0.12), water soluble (200 mg·L(-1) at 17 °C) and has been detected in UK surface waters in the concentration range of typically 0.2-0.6 μg·L(-1) (maximum 2.7 μg·L(-1)) during 2008-2011. In the absence of chronic data on potential hazards to non-target freshwater molluscs, a laboratory study was conducted to investigate the impact of metaldehyde on embryo development in the gastropod Lymnaea stagnalis (RENILYS strain) and using zinc as a positive control. L. stagnalis embryos were exposed to metaldehyde under semi-static conditions at 20±1 °C and hatching success and growth (measured as shell height and intraocular distance) examined after 21 d. Exposure concentrations were verified using HPLC and gave 21 d (hatching)NOEC and (hatching)LOEC mean measured values of 36 and 116 mg MET·L(-1), respectively (equal to the 21 d (shell height)NOEC and (shell height)LOEC values). For basic research purposes, a second group of L. stagnalis embryos was co-exposed to metaldehyde and the pesticide synergist piperonyl butoxide (PBO). Co-exposure to the PBO (measured concentrations between 0.47-0.56 mg·L(-1)) reduced hatching success from 100% to 47% and resulted in a 30% reduction in embryo growth (shell height) in snail embryos co-exposed to metaldehyde at 34-36 mg·L(-1) over 21 d. In conclusion, these data suggest mollusc embryos may have some metabolic detoxication capacity for metaldehyde and further work is warranted to explore this aspect in order to support the recent initiative to include molluscs in the OECD test guideline programme. PMID:26575636

  4. Shallow water heterobranch sea slugs (Gastropoda: Heterobranchia) from the Región de Atacama, northern Chile

    PubMed Central

    Valdés, Ángel

    2016-01-01

    The coast of northern Chile has been sparsely studied in regards to its invertebrate fauna, with just a few works reviewing the distribution of local mollusks. This work presents a survey of the shallow water heterobranch sea slugs currently occurring around the port of Caldera (27 °S), in the Región de Atacama, northern Chile. Eight species of sea slugs were found in this study: Aplysiopsis cf. brattstroemi (Marcus, 1959), Baptodoris peruviana (d’Orbigny, 1837), Diaulula variolata (d’Orbigny, 1837), Doris fontainii d’Orbigny, 1837, Onchidella marginata (Couthouy in Gould, 1852), Phidiana lottini (Lesson, 1831), Tyrinna delicata (Abraham, 1877) and the new species Berthella schroedli sp. nov., described herein. All of the species found in the area are endemic to South America, having distributions in the southeastern Pacific and South Atlantic Oceans, from Ancash, Perú to Peninsula Valdés, Argentina, and two of them represent species which are endemic to the Chilean coasts (Aplysiopsis cf. brattstroemi and Berthella schroedli). The finding of a previously undescribed species emphasizes the need of further surveys, particularly in subtidal and deeper waters, in order to improve the knowledge on this neglected fauna in Atacama. PMID:27168975

  5. Standardization of a Patella spp. (Mollusca, Gastropoda) embryo-larval bioassay and advantages of its use in marine ecotoxicology.

    PubMed

    Pérez, Sara; Fernández, Nuria; Ribeiro, Pedro A

    2016-05-01

    The use of three limpet species, Patella vulgata Linnaeus, 1758, Patella depressa Pennant, 1777 and Patella ulyssiponensis Gmelin, 1791 as model organisms in marine ecotoxicology has been evaluated. Initial laboratory experiments were aimed to standardize a biological test with embryos and larvae of Patella spp, establishing the percentage of normal trochophore larvae as endpoint. Before conducting in vitro fertilization, oocytes must be maturated artificially by incubation in an alkaline solution; therefore, alkalinizing agent, pH and time of eggs alkalinization were evaluated. Moreover, time of sperm activation, optimum sperm and oocytes concentration during fertilization, gamete contact time, use of stirring during the fertilization, egg concentration and incubation temperature were examined. Minimum sample size per treatment was also estimated. Exposure of oocytes for 10min to FSW alkalinized with NH4OH at pH 9.0, the use of undiluted sperm pre-activated during 45min and a concentration of 200 oocytesmL(-1), a gamete-contact time of 180min and egg incubation at 18°C during 24h at a concentration of 80 eggsmL(-1) were the conditions allowing maximal embryo-larval development success. With an error of 0.05, a sampling size ≥320 allows a 95% confidence in the estimate. This Patella spp. acute bioassay fulfills a number of important a priori requirements to be used in ecotoxicological studies. Nevertheless, in vitro fertilization requires considerable handling, which may lead to failure in fecundation. Such difficulties are also addressed, in order to facilitate the routine use of this protocol by other laboratories. PMID:26845705

  6. DNA barcodes and phylogenetic affinities of the terrestrial slugs Arion gilvus and A. ponsi (Gastropoda, Pulmonata, Arionidae)

    PubMed Central

    Breugelmans, Karin; Jordaens, Kurt; Adriaens, Els; Remon, Jean Paul; Cardona, Josep Quintana; Backeljau, Thierry

    2013-01-01

    Abstract The Iberian Peninsula is a region with a high endemicity of species of the terrestrial slug subgenus Mesarion. Many of these species have been described mainly on subtle differences in their proximal genitalia. It therefore remains to be investigated 1) whether these locally diverged taxa also represent different species under a phylogenetic species concept as has been shown for other Mesarion species outside the Iberian Peninsula, and 2) how these taxa are phylogenetically related. Here, we analysed DNA sequence data of two mitochondrial (COI and 16S) genes, and of the nuclear ITS1 region, to explore the phylogenetic affinities of two of these endemic taxa, viz. Arion gilvus Torres Mínguez, 1925 and A. ponsi Quintana Cardona, 2007. We also evaluated the use of these DNA sequence data as DNA barcodes for both species. Our results showed that ITS did not allow to differentiate among most of the Mesarion molecular operational taxonomic units (MOTUs) / morphospecies in Mesarion. Yet, the overall mean p-distance among the Mesarion MOTUs / morphospecies for both mtDNA fragments (16.7% for COI, 13% for 16S) was comparable to that between A. ponsi and its closest relative A. molinae (COI: 14.2%; 16S: 16.2%) and to that between A. gilvus and its closest relative A. urbiae (COI: 14.4%; 16S: 13.4%). Hence, with respect to mtDNA divergence, both A. ponsi and A. gilvus, behave as other Mesarion species or putative species-level MOTUs and thus are confirmed as distinct ‘species’. PMID:24453553

  7. New insight in lymnaeid snails (Mollusca, Gastropoda) as intermediate hosts of Fasciola hepatica (Trematoda, Digenea) in Belgium and Luxembourg

    PubMed Central

    2014-01-01

    Background The present study aims to assess the epidemiological role of different lymnaeid snails as intermediate hosts of the liver fluke Fasciola hepatica in Belgium and Luxembourg. Methods During summer 2008, 7103 lymnaeid snails were collected from 125 ponds distributed in 5 clusters each including 25 ponds. Each cluster was located in a different biogeographic area of Belgium and Luxembourg. In addition, snails were also collected in sixteen other biotopes considered as temporary wet areas. These snails were identified as Galba truncatula (n = 2474) (the main intermediate host of F. hepatica in Europe) and Radix sp. (n = 4629). Moreover, several biological and non-biological variables were also recorded from the different biotopes. DNA was extracted from each snail collected using Chelex® technique. DNA samples were screened through a multiplex PCR that amplifies lymnaeid internal transcribed spacer 2 gene sequences (500–600 bp) (acting as an internal control) and a 124 bp fragment of repetitive DNA from Fasciola sp. Results Lymnaeid snails were found in 75 biotopes (53.2%). Thirty individuals of G. truncatula (1.31%) and 7 of Radix sp. (0.16%) were found to be positive for Fasciola sp. The seven positive Radix sp. snails all belonged to the species R. balthica (Linnaeus, 1758). Classification and regression tree analysis were performed in order to better understand links and relative importance of the different recorded factors. One of the best explanatory variables for the presence/absence of the different snail species seems to be the geographic location, whereas for the infection status of the snails no obvious relationship was linked to the presence of cattle. Conclusions Epidemiological implications of these findings and particularly the role of R. balthica as an alternative intermediate host in Belgium and Luxembourg were discussed. PMID:24524623

  8. Mitochondrial and nuclear DNA analysis revealed a cryptic species and genetic introgression in Littorina sitkana (Mollusca, Gastropoda).

    PubMed

    Azuma, Noriko; Yamazaki, Tomoyasu; Chiba, Susumu

    2011-12-01

    We investigated mitochondrial and nuclear DNA genotypes in nominal Littorina sitkana samples from 2 localities in Eastern Hokkaido, northern Japan. Our results indicated the existence of cryptic species. In the analysis of partial mitochondrial Cytchrome b gene sequences, haplotypes of L. sitkana samples were monophyletic in a phylogenetic tree with orthologous sequences from other Littorina species, but were apparently separated in 2 clades. One included typical L. sitkana (CBa clade) samples, which formed a clade with an allopatric species, L. horikawai. The other, CBb, was independent from CBa and L. horikawai. Haplotypes of the mitochondrial 16S rRNA gene also separated into 2 clades. We additionally examined intron sequence of the heat shock cognate 70 (HSC70) nuclear gene and identified 17 haplotypes. These were also separated into 2 clades, HSCa and HSCb. Among the examined Hokkaido samples, 60% of individuals were heterozygotes. However, each heterozygote consisted of haplotypes from the same clade, HSCa or HSCb, and no admixture of HSCa and HSCb haplotypes was observed. These results indicate reproductive isolation between the 2 clades. Among the genotyped Hokkaido samples, 93% of individuals had CBa + HSCa or CBb + HSCb genotypes, and 7% had CBb + HSCa genotypes. The discrepancy between the mtDNA and nuclear DNA haplotypes in a few individuals may have been caused by genetic introgression due to past hybridization. PMID:22374127

  9. Heat production in Littorina saxatilis Olivi and Littorina neritoides L. (gastropoda: Prosobranchia) during an experimental exposure to air

    NASA Astrophysics Data System (ADS)

    Kronberg, Inge

    1990-06-01

    The adaptation of littorinid molluscs to prolonged aerial exposure was investigated by the determination of heat production. Littorina saxatilis, inhabiting the upper eulittoral, reached a maximum metabolic activity during submersion (heat production: 3.26×10-3J s-1 (gadw)-1. On the first three days of desiccation, the heat production was continuously reduced to 40% of the submersed value. A prolonged aerial exposure was lethal for this species. In the supralittoral L. neritoides, three stages of energy metabolism could be observed: An intermediate heat production during submersion (1.97×10-3Js-1 (gadw)-1), an increased metabolism during the first hour of aerial exposure (heat production 204% of submersed value), and a minimal metabolism (39% of the submersed value and 19% of maximum value) during the following days and weeks of desiccation. Recovery depended on water salinity; L. saxatilis proved to be less euryhaline than L. neritoides. Thus, the metabolic adaptations correlate with the level of littoral habitat; inactivity combined with a drastically reduced energy consumption is a metabolically economic way to survive in periodically dry environments.

  10. Annotated type catalogue of the Megaspiridae, Orthalicidae, and Simpulopsidae (Mollusca, Gastropoda, Orthalicoidea) in the Natural History Museum, London

    PubMed Central

    Breure, Abraham S. H.; Ablett, Jonathan D.

    2015-01-01

    Abstract The type status is described for 65 taxa of the Orthalicoidea, classified within the families Megaspiridae (14), Orthalicidae (30), and Simpulopsidae (20); one taxon is considered a nomen inquirendum. Lectotypes are designated for the following taxa: Helix brephoides d’Orbigny, 1835; Simpulopsis cumingi Pfeiffer, 1861; Bulimulus (Protoglyptus) dejectus Fulton, 1907; Bulimus iris Pfeiffer, 1853. The type status of Bulimus salteri Sowerby III, 1890, and Strophocheilus (Eurytus) subirroratus da Costa, 1898 is now changed to lectotype according Art. 74.6 ICZN. The taxa Bulimus loxostomus Pfeiffer, 1853, Bulimus marmatensis Pfeiffer, 1855, Bulimus meobambensis Pfeiffer, 1855, and Orthalicus powissianus var. niveus Preston 1909 are now figured for the first time. The following taxa are now considered junior subjective synonyms: Bulimus marmatensis Pfeiffer, 1855 = Helix (Cochlogena) citrinovitrea Moricand, 1836; Vermiculatus Breure, 1978 = Bocourtia Rochebrune, 1882. New combinations are: Kuschelenia (Bocourtia) Rochebrune, 1882; Kuschelenia (Bocourtia) aequatoria (Pfeiffer, 1853); Kuschelenia (Bocourtia) anthisanensis (Pfeiffer, 1853); Kuschelenia (Bocourtia) aquila (Reeve, 1848); Kuschelenia (Bocourtia) badia (Sowerby I, 1835); Kuschelenia (Bocourtia) bicolor (Sowerby I, 1835); Kuschelenia (Bocourtia) caliginosa (Reeve, 1849); Kuschelenia (Bocourtia) coagulata (Reeve, 1849); Kuschelenia (Bocourtia) cotopaxiensis (Pfeiffer, 1853); Kuschelenia (Bocourtia) filaris (Pfeiffer, 1853); Kara indentata (da Costa, 1901); Clathrorthalicus magnificus (Pfeiffer, 1848); Simpulopsis (Eudioptus) marmartensis (Pfeiffer, 1855); Kuschelenia (Bocourtia) nucina (Reeve, 1850); Kuschelenia (Bocourtia) ochracea (Morelet, 1863); Kuschelenia (Bocourtia) peaki (Breure, 1978); Kuschelenia (Bocourtia) petiti (Pfeiffer, 1846); Clathrorthalicus phoebus (Pfeiffer, 1863); Kuschelenia (Bocourtia) polymorpha (d’Orbigny, 1835); Scholvienia porphyria (Pfeiffer, 1847); Kuschelenia (Bocourtia) purpurata (Reeve, 1849); Kuschelenia (Bocourtia) quechuarum Crawford, 1939; Quechua salteri (Sowerby III, 1890); Kuschelenia (Bocourtia) subfasciata Pfeiffer, 1853; Clathrorthalicus victor (Pfeiffer, 1854). In an addedum a lectotype is being designated for Bulimulus (Drymaeus) interruptus var. pallidus Preston, 1909. An index is included to all taxa mentioned in this paper and the preceding ones in this series (Breure and Ablett 2011, 2012, 2014). PMID:25632243

  11. Replacement names and nomenclatural comments for problematic species-group names in Europe's Neogene freshwater Gastropoda. Part 2.

    PubMed

    Neubauer, Thomas A; Harzhauser, Mathias; Kroh, Andreas; Elisavet, Georgopoulou; Mandic, Oleg

    2014-01-01

    In the course of a new database project on Miocene to Recent freshwater gastropods of Europe, a great many of primary and secondary homonyms were revealed. Such nomenclatural issues need clarification in order to avoid misunderstandings and wrong statements about geographical distributions and temporal ranges. The following 16 new names are introduced to replace existing homonyms: Theodoxus militaris jurisicpolsakae nom. n., Viviparus stevanovici nom. n., Melanopsis haueri ripanjensis nom. n., Melanopsis wolfgangfischeri nom. n., Micromelania ramacanensis nom. n., Pseudamnicola welterschultesi nom. n., Muellerpalia haszprunari nom. n., Muellerpalia pseudovalvatoides nom. n., Lithoglyphus gozhiki nom. n., Valvata heidemariae willmanni nom. n., Radix macaleti nom. n., Gyraulus okrugljakensis nom. n., Gyraulus rasseri nom. n., Gyraulus vrapceanus nom. n., Planorbarius halavatsi nom. n., and Segmentina mosbachensis nom. n. Additionally, six cases of homonyms are discussed that are not replaced by new names, because they are considered junior synonyms. PMID:25147468

  12. The nudibranch names mentioned as n.sp. in Bergh (1861) are almost all nomina nuda (Gastropoda: Heterobranchia: Nudibranchia).

    PubMed

    Jensen, Kathe; Nielsen, Claus

    2014-01-01

    In a publication in Danish from 1861, Bergh described the nematocysts found in a number of nudibranch species. Many of the species had been described previously, but a number were new and given names, but without a description. These species are nomina nuda. We have translated the "descriptions", including the foot-notes, and reproduced the original plate to show that only the nematocysts (real or assumed) were described. The only species given a short description fulfilling the requirements of the ICZN is Pleurophyllidia quadrilateralis, which was described as the only species in the new genus Sancara. This in turn was shown to be a junior synonym of Linguella de Blainville, 1823. All the species were subsequently described anatomically in detail and made valid in a number of papers, and most of the type material is located in the Zoological Museum, Copenhagen (Natural History Museum of Denmark). The names in current use have been given. PMID:24872286

  13. Cryptic Species in Tropic Sands - Interactive 3D Anatomy, Molecular Phylogeny and Evolution of Meiofaunal Pseudunelidae (Gastropoda, Acochlidia)

    PubMed Central

    Neusser, Timea P.; Jörger, Katharina M.; Schrödl, Michael

    2011-01-01

    Background Towards realistic estimations of the diversity of marine animals, tiny meiofaunal species usually are underrepresented. Since the biological species concept is hardly applicable on exotic and elusive animals, it is even more important to apply a morphospecies concept on the best level of information possible, using accurate and efficient methodology such as 3D modelling from histological sections. Molecular approaches such as sequence analyses may reveal further, cryptic species. This is the first case study on meiofaunal gastropods to test diversity estimations from traditional taxonomy against results from modern microanatomical methodology and molecular systematics. Results The examined meiofaunal Pseudunela specimens from several Indo-Pacific islands cannot be distinguished by external features. Their 3D microanatomy shows differences in the organ systems and allows for taxonomic separation in some cases. Additional molecular analyses based on partial mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA markers revealed considerable genetic structure that is largely congruent with anatomical or geographical patterns. Two new species (Pseudunela viatoris and P. marteli spp. nov.) are formally described integrating morphological and genetic analyses. Phylogenetic analysis using partial 16S rRNA, COI and the nuclear 18S rRNA markers shows a clade of Pseudunelidae species as the sister group to limnic Acochlidiidae. Within Pseudunela, two subtypes of complex excretory systems occur. A complex kidney already evolved in the ancestor of Hedylopsacea. Several habitat shifts occurred during hedylopsacean evolution. Conclusions Cryptic species occur in tropical meiofaunal Pseudunela gastropods, and likely in other meiofaunal groups with poor dispersal abilities, boosting current diversity estimations. Only a combined 3D microanatomical and molecular approach revealed actual species diversity within Pseudunela reliably. Such integrative methods are recommended for all taxonomic approaches and biodiversity surveys on soft-bodied and small-sized invertebrates. With increasing taxon sampling and details studied, the evolution of acochlidian panpulmonates is even more complex than expected. PMID:21912592

  14. Seven new hypselostomatid species from China, including some of the world’s smallest land snails (Gastropoda, Pulmonata, Orthurethra)

    PubMed Central

    Páll-Gergely, Barna; Hunyadi, András; Jochum, Adrienne; Asami, Takahiro

    2015-01-01

    Abstract Seven new species of Hypselostomatidae are described from the Chinese province Guangxi: Angustopila dominikae Páll-Gergely & Hunyadi, sp. n., Angustopila fabella Páll-Gergely & Hunyadi, sp. n., Angustopila subelevata Páll-Gergely & Hunyadi, sp. n., Angustopila szekeresi Páll-Gergely & Hunyadi, sp. n., Hypselostoma socialis Páll-Gergely & Hunyadi, sp. n., Hypselostoma lacrima Páll-Gergely & Hunyadi, sp. n. and Krobylos sinensis Páll-Gergely & Hunyadi, sp. n. The latter species is reported from three localities. All other new species are known only from the type locality. Specimens nearly identical to the type specimens of Angustopila huoyani Jochum, Slapnik & Páll-Gergely, 2014 were found in a cave in northern Guangxi, 500 km from the type locality. Adult individuals of Angustopila subelevata sp. n. (shell height = 0.83–0.91 mm, mean = 0.87 mm) and Angustopila dominikae sp. n. (shell height of the holotype = 0.86 mm) represent the smallest known members of the Hypselostomatidae, and thus are amongst the smallest land snails ever reported. We note that Pyramidula laosensis Saurin, 1953 might also belong to Krobylos. Paraboysidia neglecta van Benthem Jutting, 1961, which was previously included in Angustopila, is classified in Hypselostoma. PMID:26478698

  15. A new member of troglobitic Carychiidae, Koreozospeum nodongense gen. et sp. n. (Gastropoda, Eupulmonata, Ellobioidea) is described from Korea.

    PubMed

    Jochum, Adrienne; Prozorova, Larisa; Sharyi-Ool, Mariana; Páll-Gergely, Barna

    2015-01-01

    A new genus of troglobitic Carychiidae Jeffreys, 1830 is designated from Nodong Cave, North Chungcheong Province, Danyang, South Korea. This remarkable find represents a great range extension and thus, a highly distant distribution of troglobitic Carychiidae in Asia. The Zospeum-like, carychiid snails were recently included, without a formal description, in records documenting Korean malacofauna. The present paper describes Koreozospeum Jochum & Prozorova, gen. n. and illustrates the type species, Koreozospeum nodongense Lee, Prozorova & Jochum, sp. n. using novel Nano-CT images, including a video, internal shell morphology, SEM and SEM-EDX elemental compositional analysis of the shell. PMID:26312456

  16. The Application of Electric Shock as a Novel Pest Control Method for Apple Snail, Pomacea canaliculata (Gastropoda: Ampullariidae)

    NASA Astrophysics Data System (ADS)

    Yagyu, Yoshihito; Tsuji, Satoshi; Satoh, Saburoh; Yamabe, Chobei

    The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be applied intermittently to reduce the amount of energy that is wasted when the snail is in its shell made of one of the insulator. The minimum electric shock required for controlling snails and the time required for movement after application of electric shock to determine the frequency of each electric shock were investigated using two methods; vertical and horizontal application of the electrical stimulation. The results showed that there is a strong correlation between the strength of electric shock and the reaction of the snails, and electric shock made snails inactive when it was applied 0.35 A/m2 in the horizontal direction and 0.45 A/m2 in the vertical direction with water of 11 mS/m. A positive correlation was also found between electric shock and the reaction of the snails and shell height. In comparison with larger snails, the smaller snails had higher threshold levels against electric current density because their shorter feet tended to have lower voltage dorp. Moreover, the frequency of electric shock should be chosen the minimum duration for the inactive condition, and it was approximately 10 seconds. Consequently the direction of electric current should be in the horizontal direction above 0.35 A/m2 and the frequency of electric shock should be less than 10 seconds for practical use. However, electric shock would have to be maintained at greater than 0.35 A/m2 because snails might become habituated to electric shock and water in paddy field would have high electric conductivity.

  17. Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda) in the Museum für Naturkunde, Berlin.

    PubMed

    Breure, Abraham S H

    2013-01-01

    The type status is described of 96 taxa classified within the superfamily Orthalicoidea and present in the Mollusca collection of the Museum für Naturkunde der Humboldt-Universität zu Berlin. Lectotypes are designated for the following taxa: Orthalicus elegans Rolle, 1895; Bulimus maranhonensis Albers, 1854; Orthalicus nobilis Rolle, 1895; Orthalichus tricinctus Martens, 1893. Orthalicus sphinx tresmariae is introduced as new name for Zebra sphinx turrita Strebel, 1909, not Zebra quagga turrita Strebel, 1909. The following synonyms are established: Zebra crosseifischeri Strebel, 1909 = Orthalicus princeps fischeri Martens, 1893; Orthalicus isabellinus Martens, 1873 = Orthalicus bensoni (Reeve, 1849); Zebra zoniferus naesiotes Strebel, 1909 = Orthalicus undatus (Bruguière, 1789); Porphyrobaphe (Myiorthalicus) dennisoni pallida Strebel, 1909 = Hemibulimus dennisoni (Reeve, 1848); Zebra delphinus pumilio Strebel, 1909 = Orthalicus delphinus (Strebel, 1909); Orthalicus (Laeorthalicus) reginaeformis Strebel, 1909 = Corona perversa (Swainson, 1821); Bulimus (Eurytus) corticosus Sowerby III, 1895 = Plekocheilus (Eurytus) stuebeli Martens, 1885. The taxon Bulimus (Eudioptus) psidii Martens, 1877 is now placed within the family Sagdidae, tentatively in the genus Platysuccinea. Appendices are included with an index to all the types of Orthalicoidea extant (including those listed by Köhler 2007) and a partial list of letters present in the correspondence archives. PMID:23794831

  18. Revision of the genus Turris Batsch, 1789 (Gastropoda: Conoidea: Turridae) with the description of six new species

    PubMed Central

    Kilburn, Richard N.; Fedosov, Alexander E.; Olivera, Baldomero M.

    2012-01-01

    The taxonomy of the genus Turris Batsch, 1789, type genus of the family Turridae, widespread in shallow-water habitats of tropic Indo-Pacific, is revised. A total of 31 species of Turris, are here recognized as valid. New species described: Turris chaldaea, Turris clausifossata, Turris guidopoppei, Turris intercancellata, Turris kantori, T. kathiewayae. Homonym renamed: Turris bipartita nom. nov. for Pleurotoma variegata Kiener, 1839 (non Philippi, 1836). New synonymies: Turris ankaramanyensis Bozzetti, 2006 = Turris tanyspira Kilburn, 1975; Turris imperfecti, T. nobilis, T. pulchra and T. tornatum Röding, 1798, and Turris assyria Olivera, Seronay & Fedosov, 2010 = T. babylonia; Turris dollyi Olivera, 2000 = Pleurotoma crispa Lamarck, 1816; Turris totiphyllis Olivera, 2000 = Turris hidalgoi Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000; Turris kilburni Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000 = Turris pagasa Olivera, 2000; Turris (Annulaturris) munizi Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000 = Gemmula lululimi Olivera, 2000. Revised status: Turris intricata Powell, 1964, Pleurotoma variegata Kiener, 1839 (non Philippi, 1836) and Pleurotoma yeddoensis Jousseaume, 1883, are regarded as full species (not subspecies of Turris crispa). Neotype designated: For Pleurotoma garnonsii Reeve, 1843, to distinguish it from Turris garnonsii of recent authors, type locality emended to Zanzibar. New combination: Turris orthopleura Kilburn, 1983, is transferred to genus Makiyamaia, family Clavatulidae. PMID:23847408

  19. [Predation of Lymnaea (Galba) truncatula Müller by Zonitoides nitidus Müller (Mollusca Gastropoda Pulmonata) (author's transl)].

    PubMed

    Rondelaud, D

    1975-01-01

    Zonitoides nitidus is omnivorous with carnivorous tendancies: the presence of food coming from snails is required for growth of this predator. This snail is not selective for the choice of its preys. Zonitoides cannot be taken for an absolute predator for all growing periods of Lymnaea truncatula: eggs and large snails are not eaten. This species can be cannibal. PMID:1211765

  20. A new species of Haplosporidium Caullery & Mesnil, 1899 in the marine false limpet Siphonaria lessonii (Gastropoda: Siphonariidae) from Patagonia.

    PubMed

    Ituarte, Cristián; Bagnato, Estefanía; Siddall, Mark; Cremonte, Florencia

    2014-05-01

    A new species of Haplosporidium Caullery & Mesnil, 1899 parasitising the pulmonate gastropod Siphonaria lessonii Blainville in Patagonia, Argentina, is described based on morphological (scanning and transmission electron microscopy) and sequence (small subunit ribosomal RNA gene) data. Different stages of sporulation were observed as infections disseminated in the digestive gland. Haplosporidium patagon n. sp. is characterised by oval or slightly subquadrate spores with an operculum that is ornamented with numerous short digitiform projections of regular height, perpendicular to and covering its outer surface. The operculum diameter is slightly larger than the apical diameter of the spore. Neither the immature nor mature spores showed any kind of projections of the exosporoplasm or of the spore wall. Regarding phylogenetic affinities, the new species was recovered as sister to an undescribed species of Haplosporidium Caullery & Mesnil, 1899 from the polychaete family Syllidae Grube from Japanese waters. The morphological characters (ornamentation of the operculum, spore wall structure, shape and size of spores, and the lack of spore wall projections) corroborate it as an as yet undescribed species of Haplosporidium and the first for the phylum in marine gastropods of South America. Siphonaria lessonii is the only known host to date. PMID:24711113

  1. Recent expansion and relic survival: Phylogeography of the land snail genus Helix (Mollusca, Gastropoda) from south to north Europe.

    PubMed

    Fiorentino, V; Manganelli, G; Giusti, F; Ketmaier, V

    2016-05-01

    Little is known about the evolutionary history of Helix, despite the fact that it includes the largest land snails in the western Palaearctic, some of which (e.g. H. pomatia Linnaeus, 1758) are valuable human food. We compared two groups of Helix with apparently contrasting evolutionary histories: the widespread species H. pomatia and the group distributed along the Italian Apennine chain, a relatively unknown set of species with a restricted distribution over a range of altitudes. To reconstruct the evolutionary trajectories of these two groups, we analysed morphological (shell and genitalia) and molecular characters (mitochondrial and nuclear markers) in a total of 59 populations from northern and central Europe (H. pomatia) and along the Apennine chain (various species). We also reconstructed the phylogeny and the evolutionary history of the genus by combining our data with that currently available in the literature. We found that spatial changes did not merely imply fragmentation of populations, but also implied environmental changes (woodlands vs. grasslands) that may have triggered the observed phenotypic diversification. We also found that Anatolia is the ancestral range of Helix and is therefore an important area for the Palaearctic diversity. The results provide insights into the evolutionary history of species richness and more generally into the processes that may have shaped the distribution and diversification of these organisms across Europe and the peri-Mediterranean area. PMID:26926944

  2. Population genetic structure of Bellamya aeruginosa (Mollusca: Gastropoda: Viviparidae) in China: weak divergence across large geographic distances.

    PubMed

    Gu, Qian H; Husemann, Martin; Ding, Baoqing; Luo, Zhi; Xiong, Bang X

    2015-11-01

    Bellamya aeruginosa is a widely distributed Chinese freshwater snail that is heavily harvested, and its natural habitats are under severe threat due to fragmentation and loss. We were interested whether the large geographic distances between populations and habitat fragmentation have led to population differentiation and reduced genetic diversity in the species. To estimate the genetic diversity and population structure of B. aeruginosa, 277 individuals from 12 populations throughout its distribution range across China were sampled: two populations were sampled from the Yellow River system, eight populations from the Yangtze River system, and two populations from isolated plateau lakes. We used seven microsatellite loci and mitochondrial cytochrome oxidase I sequences to estimate population genetic parameters and test for demographic fluctuations. Our results showed that (1) the genetic diversity of B. aeruginosa was high for both markers in most of the studied populations and effective population sizes appear to be large, (2) only very low and mostly nonsignificant levels of genetic differentiation existed among the 12 populations, gene flow was generally high, and (3) relatively weak geographic structure was detected despite large geographic distances between populations. Further, no isolation by linear or stream distance was found among populations within the Yangtze River system and no signs of population bottlenecks were detected. Gene flow occurred even between far distant populations, possibly as a result of passive dispersal during flooding events, zoochoric dispersal, and/or anthropogenic translocations explaining the lack of stronger differentiation across large geographic distances. The high genetic diversity of B. aeruginosa and the weak population differentiation are likely the results of strong gene flow facilitated by passive dispersal and large population sizes suggesting that the species currently is not of conservation concern. PMID:26640670

  3. Oxidative stress responses and toxin accumulation in the freshwater snail Radix swinhoei (Gastropoda, Pulmonata) exposed to microcystin-LR.

    PubMed

    Zhang, Junqian; Xie, Zhicai; Wang, Zhi

    2016-01-01

    Microcystin-LR (MCLR) is one of the most common toxins in eutrophic freshwater ecosystems. The ecotoxicological effects of MCLR in freshwater ecosystems have been widely documented; however, the physiological effects of MCLR on freshwater snails and the underlying toxicity/detoxification mechanisms have not been well investigated. In this laboratory study, antioxidant system responses in the hepatopancreas and the digestive tract of Radix swinhoei, a typical freshwater snail, exposed to 0.01 mg/L to 2 mg/L MCLR were explored. Antioxidant enzymes, particularly superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), in the digestive tracts were effectively generated at 0.2 and 2 mg/L MCLR. However, SOD and CAT activities in the hepatopancreas were activated only at 0.2 mg/L MCLR. Glutathione (GSH) concentrations in the digestive tracts significantly increased at 0.01 to 0.2 mg/L MCLR; by comparison, GSH concentrations in the hepatopancreas remained stable. No oxidative damage (lipid peroxidations) occurred in the digestive tracts and the hepatopancreas when the snail was exposed to ≤0.2 mg/L MCLR. MCLR accumulation in different snail tissues was also examined. MCLR accumulated in different tissues and showed the following pattern: hepatopancreas > gonads > digestive tracts > muscles. Bioaccumulated concentrations in these four tissues increased as MCLR exposure concentrations increased; by contrast, bioaccumulation factors decreased as MCLR exposure concentrations increased. Our results indicated that R. swinhoei is sensitively responsive to MCLR by changing antioxidant system status to cope with the toxicity. Snails may be vectors of MCs that transfer MCs in eutrophic lakes via food chains or food web. PMID:26362638

  4. [Genetic diversity in two populations of the snail Strombus gigas (Gastropoda: Strombidae) from Yucatan, Mexico, using microsatellite].

    PubMed

    Zamora-Bustillos, Roberto; Rodríguez-Canul, Rossanna; García de León, Francisco J; Tello Cetina, Jorge

    2011-09-01

    The pink conch Strombus gigas is an important fisheries resource in the Caribbean region, including the Yucatán Peninsula. We analyzed the genetic diversity and genetic structure of two populations (Alacranes Reef and Chinchorro Bank) with the use of five microsatellite molecular markers. The results indicate that the two populations are in the same rank of genetic diversity (He), from 0.613 to 0.692. Significant deviation from H-WE was observed in the both populations due to deficit to heterozygotes, this was attributed to inbreeding as a consequence of over-fishing; nevertheless, other possible causes considered are mixing of individuals from two or more populations, and the existence of null alleles. Levels of genetic differentiation indicated the existence of a single homogenous population in the Yucatan Peninsula (F(ST) de 0.003, p = 0.49), which fits with highest levels of gene flow is significant (2.3 individuals) between both populations. Results from this study support the hypothesis that S. gigas is part of a single panmictic population in the Yucatan Peninsula; therefore, this fishery resource should be regulated the same way for both areas. PMID:22017119

  5. Analysis of nitric oxide-cyclic guanosine monophosphate signaling during metamorphosis of the nudibranch Phestilla sibogae Bergh (Gastropoda: Opisthobranchia)

    PubMed Central

    Bishop, Cory D.; Pires, Anthony; Norby, Shong-Wan; Boudko, Dmitri; Moroz, Leonid L.; Hadfield, Michael G.

    2014-01-01

    SUMMARY The gas nitric oxide (NO), and in some cases its downstream second messenger, cyclic guanosine monophosphate (cGMP) function in different taxa to regulate the timing of life-history transitions. Increased taxonomic sampling is required to foster conclusions about the evolution and function of NO/cGMP signaling during life-history transitions. We report on the function and localization of NO and cGMP signaling during metamorphosis of the nudibranch Phestilla sibogae. Pharmacological manipulation of NO or cGMP production in larvae modulated responses to a natural settlement cue from the coral Porites compressa in a manner that suggest inhibitory function for NO/cGMP signaling. However, these treatments were not sufficient to induce metamorphosis in the absence of cue, a result unique to this animal. We show that induction of metamorphosis in response to the settlement cue is associated with a reduction in NO production. We documented the expression of putative NO synthase (NOS) and the production of cGMP during larval development and observed no larval cells in which NOS and cGMP were both detected. The production of cGMP in a bilaterally symmetrical group of cells fated to occupy the distal tip of rhinophores is correlated with competence to respond to the coral settlement cue. These results suggest that endogenous NO and cGMP are involved in modulating responses of P. sibogae to a natural settlement cue. We discuss these results with respect to habitat selection and larval ecology. PMID:18460091

  6. Description and evaluation of imposex in Strombus canarium Linnaeus, 1758 (Gastropoda, Strombidae): a potential bio-indicator of tributyltin pollution.

    PubMed

    Cob, Zaidi Che; Arshad, Aziz; Bujang, Japar Sidik; Abd Ghaffar, Mazlan

    2011-07-01

    Strombus canarium Linnaeus, 1758 is an important gastropod species within the study area and was traditionally collected for food by the locals. The objective of the present study is to assess the incidence of imposex and its severity in this species. Adult conchs were sampled during their main reproductive period, from October 2005 to January 2006, at Sungai Pulai estuary, Johor Straits, Malaysia. A total of 32.81% of adult females showed imposex characteristics, with varying degrees of severity though. The relative penis size (RPS) index ranged from 1.74 to 33.29 (mean = 13.40 ± 2.27, n = 21), while the relative penis length (RPL) index ranged from 6.28 to 55.19 (mean = 25.83 ± 3.33, n = 21). The use of vas deferens sequence (VDS) index was however cannot be applied as the presence of egg groove obscured any vas deferens development in affected females. Sequence of imposex (male penis) development in female conch, from merely a small stump to an advance male penis homologous was therefore carefully analyzed and described, and an alternative imposex classification scheme was proposed. S. canarium can be a good indicator for monitoring of organotin pollution within the study area. However, more studies are needed in order to further develop and test its validity and application, such as its correlation with levels of pollutant within the tissues and the environment, as well as its application on other Strombus species. PMID:20824325

  7. No evidence for a culturable bacterial tetrodotoxin producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida).

    PubMed

    Salvitti, Lauren R; Wood, Susanna A; McNabb, Paul; Cary, Stephen Craig

    2015-02-01

    Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography-mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464

  8. Opisthobranchia (Mollusca, Gastropoda) - more than just slimy slugs. Shell reduction and its implications on defence and foraging.

    PubMed

    Wägele, Heike; Klussmann-Kolb, Annette

    2005-02-16

    BACKGROUND: In general shell-less slugs are considered to be slimy animals with a rather dull appearance and a pest to garden plants. But marine slugs usually are beautifully coloured animals belonging to the less-known Opisthobranchia. They are characterized by a large array of interesting biological phenomena, usually related to foraging and/or defence. In this paper our knowledge of shell reduction, correlated with the evolution of different defensive and foraging strategies is reviewed, and new results on histology of different glandular systems are included. RESULTS: Based on a phylogeny obtained by morphological and histological data, the parallel reduction of the shell within the different groups is outlined. Major food sources are given and glandular structures are described as possible defensive structures in the external epithelia, and as internal glands. CONCLUSION: According to phylogenetic analyses, the reduction of the shell correlates with the evolution of defensive strategies. Many different kinds of defence structures, like cleptocnides, mantle dermal formations (MDFs), and acid glands, are only present in shell-less slugs. In several cases, it is not clear whether the defensive devices were a prerequisite for the reduction of the shell, or reduction occurred before. Reduction of the shell and acquisition of different defensive structures had an implication on exploration of new food sources and therefore likely enhanced adaptive radiation of several groups. PMID:15715915

  9. mtDNA ribosomal gene phylogeny of sea hares in the genus Aplysia (Gastropoda, Opisthobranchia, Anaspidea): implications for comparative neurobiology.

    PubMed

    Medina, M; Collins, T M; Walsh, P J

    2001-01-01

    Sea hares within the genus Aplysia are important neurobiological model organisms; as more studies based on different Aplysia species are appearing in the literature, a phylogenetic framework has become essential. We present a phylogenetic hypothesis for this genus, based on portions of two mitochondrial genes (12S and 16S). In addition, we reconstruct the evolution of several behavioral characters of interest to neurobiologists to illustrate the potential benefits of a phylogeny for the genus Aplysia. These benefits include determination of ancestral traits, direction and timing of evolution of characters, prediction of the distribution of traits, and identification of cases of independent acquisition of traits within lineages. This last benefit may prove especially useful in understanding the linkage between behaviors and their underlying neurological bases. PMID:12116938

  10. Digestive system of the sacoglossan Plakobranchus ocellatus (Gastropoda: Opisthobranchia): light- and electron-microscopic observations with remarks on chloroplast retention.

    PubMed

    Hirose, Euichi

    2005-08-01

    The sacoglossan Plakobranchus ocellatus feeds by sucking the cytoplasmic contents from algae and retains intact algal chloroplasts within the cells of the digestive gland. Morphology of the entire digestive system of this species was firstly described by means of a combination of histology and electron microscopy (both SEM and TEM). The short alimentary canal is confined to the head, and the anus opens at the anterior right corner of the pericardial swelling, as is the case in many non-shelled sacoglossans. The alimentary canal of the specimens examined rarely contained ingesta, suggesting that the retained chloroplasts provide sufficient nourishment to the sacoglossan hosts and that sea slugs with empty stomachs survive well in the field. The digestive gland, with the retained chloroplasts, branches from the stomach and is sparsely distributed throughout the body, including the head region, but is aggregated mainly in the dorsal lamellae. Chloroplasts were occasionally found in the epithelial cells in the transitional region from the stomach wall to the digestive gland, which may be a site at which chloroplasts are incorporated into the animal cells by endocytosis. Numerous microvilli filling the lumen of the digestive gland suggest that molecules are actively transferred within the gland. The sea slug thus apparently provides a favorable environment to support the long-term retention and function of chloroplasts. PMID:16141704