DOCSLIB.ORG

Prey Capture in Ly Onsiella Form Osa (Bivalvia: Anomalodesmata

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Prey Capture in Ly Onsiella Form Osa (Bivalvia: Anomalodesmata Pacific Science (1984), vol. 38, no. 4 © 1985 by the University of Hawaii Press. All rights reserved Prey Capture in Lyonsiella formosa (Bivalvia: Anomalodesmata: Verticordiacea) 1 BRIAN MORTON2 ABSTRACT: A specimen of the bathyal verticordiid Lyonsiella formosa has been obtained from Hawaii at 460 m depth. Assignment of this specimen to L. formosa suggests that this species has a much wider range than hitherto believed. Dissection and subsequent histological examination ofthe specimen suggests a mechanism of prey capture completely different from that previously described for this species and resembling that attributed to Poromya granulata. Sensory papillae on the siphonal tentacles probably detect the prey. Prey capture is by eversion of an enormous hoodlike cowl of the inhalant siphon. Inversion brings the prey into the mantle cavity. Further distension of the siphon within the mantle cavity is believed to push the prey into the buccal apparatus comprising medially fused labial palps . The unfused tips of the palps or the foot may assist in this. A model of the hydraulic changes that may occur in Lyonsiellaformosa to effect prey capture is described. The similar modes offeeding exhibited by L.formosa (Verticordiidae) and Poromya granulata (Poromyidae) suggest a close affinity. ON TH E DEEP OCEANFLOOR two bivalve taxa the mechanism of prey capture. Feeding in have adopted a predatory mode of life. Pos- . Poromya was explained by Morton (1981a) sibly all species of the Propeamussiidae are who showed that the inhalant siphon com­ carnivores (Knudsen 1970, 1979), though the prised a huge raptorial cowl beneath which mechanism of prey capture is unknown. prey were trapped before being withdrawn Con versely, the Parilimyidae, Verticordiidae, into the mantle cavity. Morton (1981b) also Poromyidae, and Cuspidariidae of the ancient explained prey capture in Parilimya , the rap­ and peculiar subclass Anomalodesmata have torial inhalant siphon this time being with­ well-known predatory habits. Each species drawn by elongate siphonal (taenioid) retrac­ has particular morphological adaptations to tor muscles. Allen and Turner (1974) investi­ its predatory life style, but the single most im­ gated the Verticordiidae in great detail but did portant feature of them all is the active mus­ not come to any firm conclusions with regard cular pumping of fluids in and out of the to how prey is captured, stating that (p. 513) mantle cavity, to facilitate prey capture, in­ "the tentacles in L. abyssicola and probably in stead of the ciliary movement of fine sus­ all other species, extend across the surface pended material. The prey is digested by pro­ layer of the abyssal sediment in life and pas­ teolytic enzymes (Reid 1977) within a highly sively wait for organisms to brush against them modified gut (Purchon 1956). Yonge (1928) and adhere to them"; and later (also p. 513) investigated Poromya and Cuspidaria but " the tentacles with adhering food contract Reid and Reid (1974) were the first to demon­ and move inwards into the inhalant aperture strate the mechanism of prey capture in Cuspi­ where they are wiped clean by the constriction daria. This was subsequently confirmed by of the inhalant aperture and valve-when the Allen and Morgan (1981) who also investi­ latter is present. " This view was later re­ gated poromyids but could not elaborate on iterated by Allen (1983). Allen and Turner (1974) describe a variety of siphonal types for the verticordiids they in­ 1 Manu script accepted II April 1984. 2 The University of Hong Kong, Depart ment of Zoo­ vestigated, suggesting a greater diversity of logy, Hong Kong. feeding strategies than sticky tentacles. Ac- 283 284 PACIFIC SCIENCE, Volume 38, October 1984 cordingly, Lyonsiella formosa is here investi­ a box dredge operating at a depth of 460 m gated in greater detail, special attention being and with a sea temperature of 9° C. No ob­ paid to the possible mechanism of prey servations on the living animal were possible, capture. as it was dead by the time the dredge reached the surface. It was preserved in 5 percent neu­ tral formalin. Following dissection, the speci­ men was transversely sectioned at 6 Jlm and TAXONOMY alternate sections stained in either Ehrlichs' Lyonsiellaformosa (Jeffreys, 1881)has been haematoxylin and eosin or Masson's tri­ further described by Allen and Turner (1974) chrome. The broken shell has been deposited who also illustrated the structure of the body in the collections of the Bernice P. Bishop as well as the shell. The species has only been Museum (Reg. no. 207491). recorded from the Atlantic (i.e., the Canaries, Azores, Bay of Biscay, and GulfofMexico) at depths ranging between 366 and 3783m (Allen and Turner 1974, Knudsen 1979). I have also FUNCTIONAL MORPHOLOGY examined the type specimen (AMNH Reg. no. The Shell 61238). Lyonsiella elegans (Thiele and Jaeckel, 1931) The shell (Figure lA) is exceedingly fragile, has only been recorded from the type locality , equivalve, and markedly inequilateral. The Station 242 (404 m) of the Valdivia Expedition anterior face is rounded and somewhat re­ (1898- 1899) (6° 34.8' S, 39° 35.5' E) at Dar es duced relative to the posterior which is in­ Salaam. I have not seen the type specimen of flated. The posterior margin is ventrally this species, there being an excellent illus­ angular and has a corrugated outline. tration of it (Thiele and Jaeckel 1931). Whereas the anterior face is smooth, the pos­ Thiele and Jaeckel acknowledge that Lyon ­ terior is radially ridged and concentrically siella elegans resembles the Atlantic L. for­ ringed. From each umbone arises a single rib mosa, and Allen and Turner (1974) have that extends to the ventral margin just pos­ shown that the shells of different -sized speci­ terior to the mid line. Seven or eight further mens ofthe latter species vary considerably in rays extend to the posterior and posterodorsal overall form and in details of the sculpture. margin of the shell. The specimen here under consideration was At the junction of each ray with a con­ obtained from a depth of 460 m off Hawaii centric ring a sharp spine is produced, though and bears a very strong resemblance to L. in this specimen most have been broken off. elegans. Bearing in mind the great variability Spines in different positions adorn the shells in shell form of L.formosa, however, and as­ ofLyonsiellaformosa illustrated by Allen and suming that L. elegans is possibly equally vari­ Turner (1974), but a series of spines on the able, it seems very probable that L. elegans is dorsal part of the shell appear more resistant but ajunior synonym of L.formosa. As will be and characterize all individuals, including the seen later, the specimen is morphologically type of L. elegans (Thiele and Jaeckel , 1931). indistinguishable from L. formosa. It accord­ The shell between the posterior rays and the ingly seems likely that L. formosa is not re­ single more median rib is concave. Allen and stricted to the Atlantic, but is a widely dis­ Turner (1974) illustrate exceedingly fine rays tributed bathyal species. on the anterior face, these are barely discern ­ ible in this specimen . The surface of the shell is finely grained. From the dorsal aspect (Fig­ ure 1B) the great expansion of the posterior MATERIALS AND METHODS region of the shell is more clearly seen. This re­ The specimen of Lyonsiellaformosa here in­ sults from , as will be seen later, the location of vestigated was obtained during a short re­ the prey-capturing organs posteriorly. The search visit to Hawaii in December 1981 with shell is widely emarginate posteriorly and less Prey Capture in Lyonsiella-MoRToN 285 L 2·5mm c lmm F IGURE I. LyonsiellaJormosa. The shell as seen from A, the right side, and B, the dorsal aspect; C, an enlarged view of the hinge plate of the left valve. FP, fused pcriostracum; ILL, inner ligament layer; L, lithodesma. so anteriorly. The umbones point slightly tiny pedal retractor muscles-anterior (APR) forward. and posterior (PPR). Other muscles are con­ Hinge structure has similarly been described cerned with pallial retraction (Figure 7A, by Allen and Turner (1974) (Figure IC). PRM). From the exhalant siphon extends a There are no hinge teeth. The primary liga­ thin array of muscles (Figure 2, ESR) which ment is small and internal, comprising inner posteriorly attach to the shell approximately ligament layer (ILL) only, this being calcified where the dorsal margin ofthe ascending lam­ mid-ventrally into an inconspicuous litho­ ella of the outer demibranch unites with the desma (L). The dorsal borders of the shell are mantle. united by a thin layer of fused periostracum The inhalant siphon is retracted by a pair of (FP) forming a " secondary" ligament whose muscles within the fused ventral mantle mar­ main function is to assist in the alignment of gin and which have their origins posterior to the valves. the pedal gape. The muscles are attached at the single near-median rib on each valve and extend posteriorly into the inhalant siphon, The Musculature radiating as they do. The two adductor muscles (Figure 2, AA; Since the muscles are probably derived PA) are of approximately equal size (iso­ from the more typical bivalve siphonal retrac­ myarian) and are bordered internally by very tor system, these are called taenioid muscles 286 PACIFIC SCIENCE, Volume 38, October 1984 PPR PA 00 ES ESR APR H-- - AA FLP J....'...'.'..'. Zmrn TM < FO PPG BG T BYG FIGURE 2. Ly onsiellafo rmosa. The organs of the mantle cavity after removal of the right shell valve and mantle lobe. AA , anterior adductor muscle; APR, anterior pedal retractor muscle; BG, byssal gland ; BYG, byssal groove; DD, digestive diverticula; ES, exhalan t siphon; ES R, exhalant siphonal retractor muscle; FLP, fused labial palps; FO, foot; HE, heart; ID, inner demibranch; K, kidney; LS, lacunal system; 0 , ovary; OD, out er demibranch; P, periostracum; PA, posterior adductor muscle; PE, pericard ium; PPG, posterior limit of pedal gape; PPR, posterior pedal retractor muscle; SC , siphonal cowl; T, testis; TM, taenioid muscle.
Load more

Recommended publications
  • Long-Duration Anesthetization of Squid (Doryteuthis Pealeii) T
    Marine and Freshwater Behaviour and Physiology Vol. 43, No. 4, July 2010, 297–303 Long-duration anesthetization of squid (Doryteuthis pealeii) T. Aran Mooneya,b*, Wu-Jung Leeb and Roger T. Hanlona aMarine Resources Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA; bWoods Hole Oceanographic Institution, Woods Hole, MA 02543, USA (Received 4 May 2010; final version received 15 June 2010) Cephalopods, and particularly squid, play a central role in marine ecosystems and are a prime model animal in neuroscience. Yet, the capability to investigate these animals in vivo has been hampered by the inability to sedate them beyond several minutes. Here, we describe methods to anesthetize Doryteuthis pealeii, the longfin squid, noninvasively for up to 5 h using a 0.15 mol magnesium chloride (MgCl2) seawater solution. Sedation was mild, rapid (54 min), and the duration could be easily controlled by repeating anesthetic inductions. The sedation had no apparent effect on physiological evoked potentials recorded from nerve bundles within the statocyst system, suggesting the suitability of this solution as a sedating agent. This simple, long-duration anesthetic technique opens the possibility for longer in vivo investigations on this and related cephalopods, thus expanding potential neuroethological and ecophysiology research for a key marine invertebrate group. Keywords: anesthesia; sedation; squid; Loligo; neurophysiology; giant axon Introduction Although cephalopods are key oceanic organisms used extensively as experimental animals in a variety of research fields (Gilbert et al. 1990), there is a relative paucity of information on maintaining them under anesthesia for prolonged durations. Lack of established protocols for sedation beyond several minutes constrains Downloaded By: [Hanlon, Roger T.] At: 12:46 19 August 2010 experimental conditions for many neurobiological and physiological preparations.
    [Show full text]
  • Microchemistry of Juvenile Mercenaria Mercenaria Shell: Implications for Modeling Larval Dispersal
    Vol. 465: 155–168, 2012 MARINE ECOLOGY PROGRESS SERIES Published September 28 doi: 10.3354/meps09895 Mar Ecol Prog Ser Microchemistry of juvenile Mercenaria mercenaria shell: implications for modeling larval dispersal A. M. Cathey1,*, N. R. Miller2, D. G. Kimmel3 1Department of Biology, East Carolina University, Greenville, North Carolina 27858, USA 2Department of Geological Sciences, The University of Texas at Austin, Austin, Texas 78712, USA 3Department of Biology, Institute for Coastal Science and Policy, East Carolina University, Greenville, North Carolina 27858, USA ABSTRACT: The elemental signature of trace and minor elements within biominerals has been used to investigate the larval dispersal of bivalves. We investigated the potential of this technique by examining elemental signals in juvenile shells of the hard clam Mercenaria mercenaria within an estuarine−lagoonal system near Cape Lookout, North Carolina, USA. We assessed the spatial distinction (~12 to 40 km) and temporal stability (fall versus spring) of elemental concentrations using inductively coupled plasma mass spectrometry (ICP-MS). Twelve minor and trace elements were present at detectable levels in all shell samples: calcium (Ca), manganese (Mn), aluminum (Al), titanium (Ti), cobalt (Co), copper (Cu), barium (Ba), magnesium (Mg), zinc (Zn), lead (Pb), nickel (Ni), and strontium (Sr). Discriminant function analyses (DFA) using metal to Ca ratios as independent variables correctly assigned hard clams to their site of collection with 100% success from both fall and spring sampling events. Mn:Ca ratio proved to be the most effective discrimi- nator explaining 91.2 and 71.9% of our among-group variance, respectively. Elemental concentra- tions within juvenile shell differed temporally.
    [Show full text]
  • Growth and Seasonal Energetics of the Antarctic Bivalve Laternula Elliptica from King George Island, Antarctica
    MARINE ECOLOGY PROGRESS SERIES Vol. 257: 99–110, 2003 Published August 7 Mar Ecol Prog Ser Growth and seasonal energetics of the Antarctic bivalve Laternula elliptica from King George Island, Antarctica In-Young Ahn1,*, Jeonghee Surh2, You-Gyoung Park2, Hoonjeong Kwon2, Kwang-Sik Choi3, Sung-Ho Kang1, Heeseon J. Choi1, Ko-Woon Kim1, Hosung Chung1 1Polar Sciences Laboratory, Korea Ocean Research & Development Institute (KORDI), Ansan, PO Box 29, Seoul 425-600, Republic of Korea 2Department of Food and Nutrition, Seoul National University, Sillim-dong, Kwanak-ku, Seoul 151-742, Republic of Korea 3Department of Aquaculture, Cheju National University, Ara-1-dong, Cheju 690-756, Republic of Korea ABSTRACT: The Antarctic marine environment is characterized by extreme seasonality in primary production, and herbivores must cope with a prolonged winter period of food shortage. In this study, tissue mass and biochemical composition were determined for various tissues of the bivalve Later- nula elliptica (King & Broderip) over a 2 yr period, and its storage and use of energy reserves were investigated with respect to seasonal changes in food level and water temperature. Total ash-free dry mass (AFDM) accumulated rapidly following phytoplankton blooms (with peak values immediately before and after spawning) and was depleted considerably during the spawning and winter periods. Most of the variation was in the muscle, gonads and digestive gland. Spawning peaked in January and February and caused considerable protein and lipid losses in the muscle, gonads and digestive gland. In winter (March to August), the muscle and digestive gland lost considerable mass, while gonad mass increased; this suggests that the muscle tissue and digestive gland serve as major energy depots for both maintenance metabolism and gonad development in winter.
    [Show full text]
  • The Recent Molluscan Marine Fauna of the Islas Galápagos
    THE FESTIVUS ISSN 0738-9388 A publication of the San Diego Shell Club Volume XXIX December 4, 1997 Supplement The Recent Molluscan Marine Fauna of the Islas Galapagos Kirstie L. Kaiser Vol. XXIX: Supplement THE FESTIVUS Page i THE RECENT MOLLUSCAN MARINE FAUNA OF THE ISLAS GALApAGOS KIRSTIE L. KAISER Museum Associate, Los Angeles County Museum of Natural History, Los Angeles, California 90007, USA 4 December 1997 SiL jo Cover: Adapted from a painting by John Chancellor - H.M.S. Beagle in the Galapagos. “This reproduction is gifi from a Fine Art Limited Edition published by Alexander Gallery Publications Limited, Bristol, England.” Anon, QU Lf a - ‘S” / ^ ^ 1 Vol. XXIX Supplement THE FESTIVUS Page iii TABLE OF CONTENTS INTRODUCTION 1 MATERIALS AND METHODS 1 DISCUSSION 2 RESULTS 2 Table 1: Deep-Water Species 3 Table 2: Additions to the verified species list of Finet (1994b) 4 Table 3: Species listed as endemic by Finet (1994b) which are no longer restricted to the Galapagos .... 6 Table 4: Summary of annotated checklist of Galapagan mollusks 6 ACKNOWLEDGMENTS 6 LITERATURE CITED 7 APPENDIX 1: ANNOTATED CHECKLIST OF GALAPAGAN MOLLUSKS 17 APPENDIX 2: REJECTED SPECIES 47 INDEX TO TAXA 57 Vol. XXIX: Supplement THE FESTIVUS Page 1 THE RECENT MOLLUSCAN MARINE EAUNA OE THE ISLAS GALAPAGOS KIRSTIE L. KAISER' Museum Associate, Los Angeles County Museum of Natural History, Los Angeles, California 90007, USA Introduction marine mollusks (Appendix 2). The first list includes The marine mollusks of the Galapagos are of additional earlier citations, recent reported citings, interest to those who study eastern Pacific mollusks, taxonomic changes and confirmations of 31 species particularly because the Archipelago is far enough from previously listed as doubtful.
    [Show full text]
  • Octopus Consciousness: the Role of Perceptual Richness
    Review Octopus Consciousness: The Role of Perceptual Richness Jennifer Mather Department of Psychology, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; [email protected] Abstract: It is always difficult to even advance possible dimensions of consciousness, but Birch et al., 2020 have suggested four possible dimensions and this review discusses the first, perceptual richness, with relation to octopuses. They advance acuity, bandwidth, and categorization power as possible components. It is first necessary to realize that sensory richness does not automatically lead to perceptual richness and this capacity may not be accessed by consciousness. Octopuses do not discriminate light wavelength frequency (color) but rather its plane of polarization, a dimension that we do not understand. Their eyes are laterally placed on the head, leading to monocular vision and head movements that give a sequential rather than simultaneous view of items, possibly consciously planned. Details of control of the rich sensorimotor system of the arms, with 3/5 of the neurons of the nervous system, may normally not be accessed to the brain and thus to consciousness. The chromatophore-based skin appearance system is likely open loop, and not available to the octopus’ vision. Conversely, in a laboratory situation that is not ecologically valid for the octopus, learning about shapes and extents of visual figures was extensive and flexible, likely consciously planned. Similarly, octopuses’ local place in and navigation around space can be guided by light polarization plane and visual landmark location and is learned and monitored. The complex array of chemical cues delivered by water and on surfaces does not fit neatly into the components above and has barely been tested but might easily be described as perceptually rich.
    [Show full text]
  • The Lower Bathyal and Abyssal Seafloor Fauna of Eastern Australia T
    O’Hara et al. Marine Biodiversity Records (2020) 13:11 https://doi.org/10.1186/s41200-020-00194-1 RESEARCH Open Access The lower bathyal and abyssal seafloor fauna of eastern Australia T. D. O’Hara1* , A. Williams2, S. T. Ahyong3, P. Alderslade2, T. Alvestad4, D. Bray1, I. Burghardt3, N. Budaeva4, F. Criscione3, A. L. Crowther5, M. Ekins6, M. Eléaume7, C. A. Farrelly1, J. K. Finn1, M. N. Georgieva8, A. Graham9, M. Gomon1, K. Gowlett-Holmes2, L. M. Gunton3, A. Hallan3, A. M. Hosie10, P. Hutchings3,11, H. Kise12, F. Köhler3, J. A. Konsgrud4, E. Kupriyanova3,11,C.C.Lu1, M. Mackenzie1, C. Mah13, H. MacIntosh1, K. L. Merrin1, A. Miskelly3, M. L. Mitchell1, K. Moore14, A. Murray3,P.M.O’Loughlin1, H. Paxton3,11, J. J. Pogonoski9, D. Staples1, J. E. Watson1, R. S. Wilson1, J. Zhang3,15 and N. J. Bax2,16 Abstract Background: Our knowledge of the benthic fauna at lower bathyal to abyssal (LBA, > 2000 m) depths off Eastern Australia was very limited with only a few samples having been collected from these habitats over the last 150 years. In May–June 2017, the IN2017_V03 expedition of the RV Investigator sampled LBA benthic communities along the lower slope and abyss of Australia’s eastern margin from off mid-Tasmania (42°S) to the Coral Sea (23°S), with particular emphasis on describing and analysing patterns of biodiversity that occur within a newly declared network of offshore marine parks. Methods: The study design was to deploy a 4 m (metal) beam trawl and Brenke sled to collect samples on soft sediment substrata at the target seafloor depths of 2500 and 4000 m at every 1.5 degrees of latitude along the western boundary of the Tasman Sea from 42° to 23°S, traversing seven Australian Marine Parks.
    [Show full text]
  • Thyasira Succisa, Lyonsia Norwegica and Poromya Granulata in The
    Marine Biodiversity Records, page 1 of 4. # Marine Biological Association of the United Kingdom, 2015 doi:10.1017/S1755267215000287; Vol. 8; e47; 2015 Published online First record of three Bivalvia species: Thyasira succisa, Lyonsia norwegica and Poromya granulata in the Adriatic Sea (Central Mediterranean) pierluigi strafella, luca montagnini, elisa punzo, angela santelli, clara cuicchi, vera salvalaggio and gianna fabi Istituto di Scienze Marine (ISMAR), Consiglio Nazionale delle Ricerche (CNR), Largo Fiera della Pesca, 2, 60125 Ancona, Italy Three species of bivalves, Thyasira succisa, Lyonsia norwegica and Poromya granulate, were recorded for the first time in the Adriatic Sea during surveys conducted from 2010 to 2012 on offshore relict sand bottoms at a depth range of 45–80 m. Keywords: Thyasira succisa, Lyonsia norwegica, Poromia granulata, Adriatic Sea, bivalvia Submitted 12 December 2014; accepted 8 March 2015 INTRODUCTION yet been formerly reported in the official checklist for the Italian marine faunal species for the Adriatic Sea Although species distribution changes over time, sudden (Schiaparelli, 2008). range extensions are often prompted by anthropic and The family Thyasiridea (Dall, 1900) includes 14 genera. natural causes. This may be direct, by the introduction of a The species belonging to this family have a small, mostly new species for a defined purpose (e.g. aquaculture) or indir- thin, light shell, with more or less marked plicae on the pos- ect (e.g. ballast water). Natural changes (e.g. global warming) terior end. The anterior margin is often flattened and the could also provide opportunities for species to colonize areas hinge is almost without teeth (Jeffreys, 1876; Pope & Goto, where, until recently, they were not able to survive (Kolar & 1991).
    [Show full text]
  • Patterns of Bathymetric Zonation of Bivalves in the Porcupine Seabight and Adjacent Abyssal Plain, NE Atlantic
    ARTICLE IN PRESS Deep-Sea Research I 52 (2005) 15–31 www.elsevier.com/locate/dsr Patterns of bathymetric zonation of bivalves in the Porcupine Seabight and adjacent Abyssal plain, NE Atlantic Celia Olabarriaà Southampton Oceanography Centre, DEEPSEAS Benthic Biology Group, Empress Dock, Southampton SO14 3ZH, UK Received 23 April2004; received in revised form 21 September 2004; accepted 21 September 2004 Abstract Although the organization patterns of fauna in the deep sea have been broadly documented, most studies have focused on the megafauna. Bivalves represent about 10% of the deep-sea macrobenthic fauna, being the third taxon in abundance after polychaetes and peracarid crustaceans. This study, based on a large data set, examined the bathymetric distribution, patterns of zonation and diversity–depth trends of bivalves from the Porcupine Seabight and adjacent Abyssal Plain (NE Atlantic). A total of 131,334 individuals belonging to 76 species were collected between 500 and 4866 m. Most of the species showed broad depth ranges with some ranges extending over more than 3000 m. Furthermore, many species overlapped in their depth distributions. Patterns of zonation were not very strong and faunal change was gradual. Nevertheless, four bathymetric discontinuities, more or less clearly delimited, occurred at about 750, 1900, 2900 and 4100 m. These boundaries indicated five faunistic zones: (1) a zone above 750 m marking the change from shelf species to bathyal species; (2) a zone from 750 to 1900 m that corresponds to the upper and mid- bathyalzones taken together; (3) a lowerbathyalzone from 1900 to 2900 m; (4) a transition zone from 2900 to 4100 m where the bathyal fauna meets and overlaps with the abyssal fauna and (5) a truly abyssal zone from approximately 4100–4900 m (the lower depth limit of this study), characterized by the presence of abyssal species with restricted depth ranges and a few specimens of some bathyalspecies with very broad distributions.
    [Show full text]
  • Redalyc.New Geographic and Depth Records for Deep-Water Mollusks In
    Revista Mexicana de Biodiversidad ISSN: 1870-3453 [email protected] Universidad Nacional Autónoma de México México Zamorano, Pablo; Hendrickx, Michel E.; Toledano Granados, Arturo New geographic and depth records for deep-water mollusks in the Gulf of California, Mexico Revista Mexicana de Biodiversidad, vol. 78, núm. 2, 2007, pp. 311-318 Universidad Nacional Autónoma de México Distrito Federal, México Available in: http://www.redalyc.org/articulo.oa?id=42578208 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Revista Mexicana de Biodiversidad 78: 311- 318, 2007 New geographic and depth records for deep-water mollusks in the Gulf of California, Mexico Nuevos registros geográfi cos y batimétricos para moluscos de mar profundo en el golfo de California, México Pablo Zamorano1, Michel E. Hendrickx1* and Arturo Toledano-Granados2 1Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Sinaloa 8200, México. 2Unidad Académica Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México. *Correspondent: [email protected] Abstract. Six oceanographic cruises (Talud IV-IX) were made in the southern Gulf of California aboard the R/V El Puma of the Universidad Nacional Autónoma de México. A total of 56 species of deep-sea mollusks were identifi ed, of which 16 (13 Bivalvia, 2 Gastropoda, 1 Scaphopoda) represent either a new geographic or bathymetric record, or both.
    [Show full text]
  • THE LISTING of PHILIPPINE MARINE MOLLUSKS Guido T
    August 2017 Guido T. Poppe A LISTING OF PHILIPPINE MARINE MOLLUSKS - V1.00 THE LISTING OF PHILIPPINE MARINE MOLLUSKS Guido T. Poppe INTRODUCTION The publication of Philippine Marine Mollusks, Volumes 1 to 4 has been a revelation to the conchological community. Apart from being the delight of collectors, the PMM started a new way of layout and publishing - followed today by many authors. Internet technology has allowed more than 50 experts worldwide to work on the collection that forms the base of the 4 PMM books. This expertise, together with modern means of identification has allowed a quality in determinations which is unique in books covering a geographical area. Our Volume 1 was published only 9 years ago: in 2008. Since that time “a lot” has changed. Finally, after almost two decades, the digital world has been embraced by the scientific community, and a new generation of young scientists appeared, well acquainted with text processors, internet communication and digital photographic skills. Museums all over the planet start putting the holotypes online – a still ongoing process – which saves taxonomists from huge confusion and “guessing” about how animals look like. Initiatives as Biodiversity Heritage Library made accessible huge libraries to many thousands of biologists who, without that, were not able to publish properly. The process of all these technological revolutions is ongoing and improves taxonomy and nomenclature in a way which is unprecedented. All this caused an acceleration in the nomenclatural field: both in quantity and in quality of expertise and fieldwork. The above changes are not without huge problematics. Many studies are carried out on the wide diversity of these problems and even books are written on the subject.
    [Show full text]
  • Constructional Morphology of the Shell/Ligament System in Opisthogyrate Rostrate Bivalves J
    Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 106, 221–227, 2017 Constructional morphology of the shell/ligament system in opisthogyrate rostrate bivalves J. Echevarrı´a, S. E. Damborenea and M. O. Mancen˜ido CONICET – Museo de La Plata, Paseo del Bosque s/n, (1900) La Plata, Buenos Aires province, Argentina. Email: [email protected] ABSTRACT: The bivalve ligament provides the thrust for shell opening, acting as the resistance in a lever system against which adductor muscle effort is applied. Usually, its outer lamellar layer is subjected to tensile stress, while the inner fibrous layer is compressed, with the pivotal axis located between them. However, opisthogyrate rostrate bivalves display a concave dorsal margin, and both the umbo and the postero-dorsal angle of the shell project dorsally to the ligament, which then fails to act as pivotal axis. Three opisthogyrate rostrate genera of unrelated lineages show somewhat dif- ferent solutions to this morpho-functional challenge. In Cuspidaria (Anomalodesmata), the ligament is internal, subjected only to compression and ventral to the pivotal axis, a thickened periostracum develops, forcing the dorsal margins of the valves to act as pivotal axis, and the posterior parts of the shell’s dorsal margins gape dorsally. In Nuculana (Palaeotaxodonta), the inner layer of the ligament is internal, the outer layer is external but reduced, and some species develop a dorsal ridge parallel to the commissural plane, on a level with the rostrum and acting as pivotal axis. In Pterotrigonia (Palaeoheterodonta) and other rostrate trigoniides, the ligament is external opisthodetic, but is allometrically reduced.
    [Show full text]
  • Entodesma Navicula Class: Bivalvia, Heterodonta Order: Pholadomyoida/ Anomalodesmata the Rock-Dwelling Entodesma Family: Lyonsiidae
    Phylum: Mollusca Entodesma navicula Class: Bivalvia, Heterodonta Order: Pholadomyoida/ Anomalodesmata The rock-dwelling entodesma Family: Lyonsiidae Taxonomy: The Anomalodesmata is a well surround a mantle, head, foot and viscera supported monophyletic group of bivalves that (see Plate 393B, Coan and Valentich-Scott has previously been regarded as a subclass 2007). The Pholadomyoida are characterized (e.g., Coan and Scoot 1997; Dreyer et al. by a shell that has nacreous interior and 2003), however, recently authors suggest it inconspicuous hinge teeth (if present at all). should no longer be designated as such and, The Lyonsiidae are unique among the, instead, be included as a basal lineage of the exclusively marine, group Anomalodesmata Heterodonta (Harper et al. 2006; Healy et al. due to their attachment to hard surfaces with 2008). The generic designations within the byssal threads (Dreyer et al. 2003; Harper et Lyonsiidae have also been unclear al. 2005). Entodesma species are distinct historically, including as few as one and as within the Lyonsiidae in their habit to attach to many as twelve genera (Prezant rocks and nestle into crevices. This behavior 1980,1981b). Lyonsiid subgeneric and renders their shells thick and of variable specific designations are often based on shape, and their byssus strong (Prezant variable characters (e.g., periostracal color, 1981b, 1981c). shell shape and sculpture) leading to several Body: Broadly rounded externally, and with synonyms and subgenera that were thick shell and variable morphology. The left abandoned altogether by Prezant (1980, valve often larger and extending longer than 1981b). Entodesma navicula has been right (Lyonsiidae, Prezant 1981b). (See Fig.
    [Show full text]