Mollusca Three Classes

Total Page：16

File Type：pdf, Size：1020Kb

Mollusca Three Classes 1. Gastropoda (gastropods)~ slugs and snails 2. Bivalvia (bivalves) ~ clams and other two- shelled shellfish 3. Cephalopoda (cephalopods) ~ squids, octopuses and cuttlefish 1 Bodies of Mollusks • A mollusk has a soft body which is usually covered by a hard outer shell. • Exceptions: – Slugs and octopuses have lost their shells through evolution – Squids have very reduced shells Anatomy of a Mollusk • All mollusks have: – Foot ~ the muscular foot helps it move – Visceral mass ~ contains the gills, gut, and other organs – Mantle ~ covers the visceral mass to protect the mollusks without shells • Most mollusks have: – Shell ~ protects the mollusk from predators and keeps land mollusks from drying out. 2 Symmetry of Mollusks • Mollusks have bilateral symmetry. – The two halves of the body mirror each other. Anatomy of a Snail (gastropod) 3 Anatomy of a Clam (bivalve) Anatomy of a Squid (cephalopod) 4 Eating Behaviors • Bivalves (clams) ~ filter tiny plant and bacteria from the water • Gastropods (snails) ~ eat with a radula (tiny tongue covered with teeth. – The radula is used to scrape algae off rocks and pieces of leaves and seaweed • Cephalopods (squid) ~use tentacles to grab their prey and put it in their powerful jaws. Blue-ringed octopus 5 Market Squid Moon Snail chasing its food 6 Achatina fulica Giant African Land Snail The largest land snail known is the Giant African Land Snail. It can weigh up to 2 pounds and be 15 inches long. Commonly Eaten Mollusks cockles conch oysters clams scallops abalone whelks Mussels Pen shells 7.

Copy Link

Recommended publications

INTRODUCTION the Peruvian "Lead Snail"
RADIATION DECONTAMINATION OF PERUVIAN MARINE "LEAD SNAIL" (THAIS CHOCOLATA) INOCULATED WITH VIBRIO CHOLERAE Ol EL TOR Z. TORRES Instituto Peruano de Energia Nuclear XA0100965 F. ARIAS Universidad Nacional del Centro del Peru Peru Abstract In vivo studies were conducted using marine snails (Thais chocolatd) artificially contaminated in a tank containing sea water inoculated with a pure culture of Vibrio cholerae, such that 105 colony forming units per gram (CFU/g) were uptaken by the mollusks in 1.5 h. A radiation Di0 value of 0.12 kGy was determined for V. cholerae upon subsequent irradiation of the live snails at doses in the range 0.0-4.0 kGy. A second series of tests were conducted using naturally contaminated, non-inoculated snails, shelled and packaged simulating commercial procedures, irradiated at 0.0-3.0 kGy, and stored at 2-4°C. These tests indicated that a dose of 2.0 kGy was optimal to extend the microbiological shelf- life of the snails to 21 days without inducing significant adverse sensory or chemical effects. Non- irradiated snails similarly treated and stored spoiled after only seven days. INTRODUCTION The Peruvian "lead snail" (Thais chocolatd) is a mollusk having a single, heavy, large and wide valve, uniformly brown in color, from which an orange internal columnella and bluish interior can be observed. Its average size is 88-mm long by 35-mm dia. (Rosales, 1988). This snail is typically found in marine rocky beds, where it forms banks at a depth of some 30 m, affixing itself to rocks in temperate waters (15-17°C).
[Show full text]
Zhang Et Al., 2015
Estuarine, Coastal and Shelf Science 153 (2015) 38e53 Contents lists available at ScienceDirect Estuarine, Coastal and Shelf Science journal homepage: www.elsevier.com/locate/ecss Modeling larval connectivity of the Atlantic surfclams within the Middle Atlantic Bight: Model development, larval dispersal and metapopulation connectivity * Xinzhong Zhang a, , Dale Haidvogel a, Daphne Munroe b, Eric N. Powell c, John Klinck d, Roger Mann e, Frederic S. Castruccio a, 1 a Institute of Marine and Coastal Science, Rutgers University, New Brunswick, NJ 08901, USA b Haskin Shellﬁsh Research Laboratory, Rutgers University, Port Norris, NJ 08349, USA c Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39564, USA d Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, VA 23529, USA e Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA article info abstract Article history: To study the primary larval transport pathways and inter-population connectivity patterns of the Atlantic Received 19 February 2014 surfclam, Spisula solidissima, a coupled modeling system combining a physical circulation model of the Accepted 30 November 2014 Middle Atlantic Bight (MAB), Georges Bank (GBK) and the Gulf of Maine (GoM), and an individual-based Available online 10 December 2014 surfclam larval model was implemented, validated and applied. Model validation shows that the model can reproduce the observed physical circulation patterns and surface and bottom water temperature, and Keywords: recreates the observed distributions of surfclam larvae during upwelling and downwelling events. The surfclam (Spisula solidissima) model results show a typical along-shore connectivity pattern from the northeast to the southwest individual-based model larval transport among the surfclam populations distributed from Georges Bank west and south along the MAB shelf.
[Show full text]
Life in the Fast Lane – from Hunted to Hunter Middle School Version
Life in the Fast Lane: From Hunted to Hunter Lab Activity: Dissection of a Squid-A Cephalopod Middle School Version Lesson by Kevin Goff Squid and octopi are cephalopods [say “SEFF-uh-luh-pods”]. The name means “head-foot,” because these animals have VIDEOS TO WATCH gripping, grasping arms that emerge straight from their heads. Watch this short clip on the Shape of Life At first glance, they seem totally different from every other website to become familiar with basic mollusc anatomy: creature on Earth. But in fact, they are molluscs, closely related • “Mollusc Animation: Abalone Body to snails, slugs, clams, oysters, mussels, and scallops. Like all Plan” (under Animation; 1.5 min) modern day molluscs, cephalopods descended from simple, Note the abalone’s foot, radula, and shell- snail-like ancestors. These ancient snails crept sluggishly on making mantle. These were present in the seafloor over 500 million years ago. Their shells resembled the snail-like ancestor of all molluscs an umbrella, probably to shield them from the sun’s intense ultraviolet radiation. When all sorts of new predators appeared on the scene, with powerful jaws or crushing claws, a thin shell was no match for such weapons. Over time, some snails evolved thicker shells, often coiled and spiky. These heavy shells did a better job of fending off predators, but they came with a price: They were costly to build and a burden to lug around. These snails sacrificed speed for safety. This lifestyle worked fine for many molluscs. And, still today, nearly 90% of all molluscs are heavily armored gastropods that crawl around at a snail’s pace.
[Show full text]
Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny
Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades einer Doktorin der Naturwissenschaften genehmigte Dissertation vorgelegt von Diplom-Biologin Simone Faller aus Frankfurt am Main Berichter: Privatdozent Dr. Rudolf Loesel Universitätsprofessor Dr. Peter Bräunig Tag der mündlichen Prüfung: 09. März 2012 Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar. Contents 1 General Introduction 1 Deep Metazoan Phylogeny 1 Neurophylogeny 2 Mollusca 5 Nemertea 6 Aim of the thesis 7 2 Neuroanatomy of Minor Mollusca 9 Introduction 9 Material and Methods 10 Results 12 Caudofoveata 12 Scutopus ventrolineatus 12 Falcidens crossotus 16 Solenogastres 16 Dorymenia sarsii 16 Polyplacophora 20 Lepidochitona cinerea 20 Acanthochitona crinita 20 Scaphopoda 22 Antalis entalis 22 Entalina quinquangularis 24 Discussion 25 Structure of the brain and nerve cords 25 Caudofoveata 25 Solenogastres 26 Polyplacophora 27 Scaphopoda 27 i CONTENTS Evolutionary considerations 28 Relationship among non-conchiferan molluscan taxa 28 Position of the Scaphopoda within Conchifera 29 Position of Mollusca within Protostomia 30 3 Neuroanatomy of Nemertea 33 Introduction 33 Material and Methods 34 Results 35 Brain 35 Cerebral organ 38 Nerve cords and peripheral nervous system 38 Discussion 38 Peripheral nervous system 40 Central nervous system 40 In search for the urbilaterian brain 42 4 General Discussion 45 Evolution of higher brain centers 46 Neuroanatomical glossary and data matrix – Essential steps toward a cladistic analysis of neuroanatomical data 49 5 Summary 53 6 Zusammenfassung 57 7 References 61 Danksagung 75 Lebenslauf 79 ii iii 1 General Introduction Deep Metazoan Phylogeny The concept of phylogeny follows directly from the theory of evolution as published by Charles Darwin in The origin of species (1859).
[Show full text]
A Phylum-Wide Survey Reveals Multiple Independent Gains of Head Regeneration Ability in Nemertea
bioRxiv preprint doi: https://doi.org/10.1101/439497; this version posted October 11, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea Eduardo E. Zattara1,2,5, Fernando A. Fernández-Álvarez3, Terra C. Hiebert4, Alexandra E. Bely2 and Jon L. Norenburg1 1 Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA 2 Department of Biology, University of Maryland, College Park, MD, USA 3 Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain 4 Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 5 INIBIOMA, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Bariloche, RN, Argentina Corresponding author: E.E. Zattara, [email protected] Abstract Animals vary widely in their ability to regenerate, suggesting that regenerative abilities have a rich evolutionary history. However, our understanding of this history remains limited because regeneration ability has only been evaluated in a tiny fraction of species. Available comparative regeneration studies have identified losses of regenerative ability, yet clear documentation of gains is lacking. We surveyed regenerative ability in 34 species spanning the phylum Nemertea, assessing the ability to regenerate heads and tails either through our own experiments or from literature reports. Our sampling included representatives of the 10 most diverse families and all three orders comprising this phylum.
[Show full text]
Biology and Description of Antisabia Juliae Sp. Nov., New Hipponicid Gastropod Commensal on Turbo Spp
SCI. MAR., 61 (Supl. 2): 5-14 SCIENTIA MARINA 1997 ECOLOGY OF MARINE MOLLUSCS. J.D. ROS and A. GUERRA (eds.) Biology and description of Antisabia juliae sp. nov., new Hipponicid gastropod commensal on Turbo spp. in Laing Island (Papua New Guinea)* MATHIEU POULICEK1, JEAN-CLAUDE BUSSERS1 and PIERRE VANDEWALLE2 1Animal Ecology Laboratory and 2Functional Morphology Laboratory, Zoological Institute, Liège University. 22, Quai Van Beneden, B-4020 Liège. Belgium. SUMMARY: The gastropod family Hipponicidae comprises widely distributed but poorly known sedentary species. On the beach-rock of the coral reefs of Laing Island (Papua New Guinea) live rich populations of several gastropod Turbo species of which many specimens have attached to their shell a hipponicid gastropod attributed to a new species, Antisabia juliae. This new species, described in this paper, appears to have adapted its mode of life on live turbinids in several ways result- ing in morphological changes (thin basal plate loosely adherent to the supporting shell, functional eyes, very long snout, functional radula, small osphradium) and ethological changes (foraging behaviour: it appears to feed on the epiphytic com- munity growing on the host, in the vicinity of the “host” shell). Except for these characteristics, the mode of life appears quite similar to that of other hipponicid species with few big females surrounded by several much smaller males. Development occurs within the egg mass inside the female shell and a few young snails escape at the crawling stage. Key words: Mollusca, Gastropoda, ecology, Hipponicidae, Papua New Guinea, Indopacific. RESUMEN: BIOLOGÍA Y DESCRIPCIÓN DE ANTISABIA JULIAE SP. NOV., UN NUEVO GASTERÓPODO HIPONÍCIDO COMENSAL DE TURBO SPP.
[Show full text]
Husbandry of the Carnivorous Land Snail, Powelliphanta Augusta (Gastropoda: Pulmonata: Rhytdidae)
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ResearchArchive at Victoria University of Wellington Husbandry of the Carnivorous Land Snail, Powelliphanta augusta (Gastropoda: Pulmonata: Rhytdidae) By Thomas Edward Allan A thesis submitted to the Victoria University of Wellington in fulfillment of the requirements for the degree of Master of Science in Ecological Restoration Victoria University of Wellington 2010 1 Abstract Key aspects of the captive husbandry of Powelliphanta augusta, a newly-described New Zealand land snail are investigated: how they should be managed and fed to provide individuals for release, and how a long-term captive population can be maintained as an insurance against extinction in the wild. This project arises from almost all members of this species having been brought into captivity due to their displacement in the wild by an opencast coalmine. Powelliphanta (F: Rhytididae) is a genus of endemic carnivorous snails, which includes 10 species, 27 subspecies and numerous undescribed taxa. As well as its diversity, Powelliphanta is renowned for the large size of its members (up to 90mm diameter) and their attractively-patterned shells. Most taxa are threatened due to habitat loss and predation by introduced mammalian predators. The study commences with a literature review to refine husbandry methods and to assess requirements for captive breeding of snails. From this review investigations are made into stocking densities, substrate, reproductive biology, body condition and growth of the P. augusta captive population. To determine an appropriate stocking density for P. augusta groups of six snails were kept at two densities; with either 720cm2, or 1440cm2 per group.
[Show full text]
Annelids, Arthropods, Molluscs 2. Very Diverse, Mostly Marine B. Characteristics 1
Molluscs A. Introduction 1. Three big Protostome Phyla - Annelids, Arthropods, Molluscs 2. Very diverse, mostly marine B. Characteristics 1. Bilateral symmetrical, unsegmented with definite head 2. Muscular foot 3. Mantle - mantle cavity a. Secretes shell - Calcium carbonate 4. Ciliated epithelium 5. Coelom reduced - around heart 6. Open circulatory system 7. Gaseous exchange by gills, lung, or just body surface 8. Metanephridia - empty into mantle cavity C. Body Plan 1. Generalized mollusc a. Mantle - secreted shell b. Mantle - cavity has gills - posterior - location important 2. Head-foot a. Head - 1. Radula - rasping tongue a. Mostly for scraping - snails b. Some (Cone shells) modified to a dart and poison b. Foot - Variously modified 1. Ventral sole-like structure - movement 2. May be shaped for burrowing 3. Shell 1. Made of Calcium Carbonate Molluscs 2. Three layers a. Periostracum - organic layer - not always visible b. Prismatic layer - prim-shaped crystals of calcium carbonate 1. Secreted by gladular margin of mantle 2. Grows as animal grows c. Nacreous layer 1. Continuously secreted by mantle on interior of shell 2. Pearls 4. Reproduction a. Larval stages 1. Trochophore - first stage to hatch from egg 2. Veliger - planktonic larva of most marine snails and bivalves a. Beginnings of foot, shell and mantle D. Classes - problem of segmentation - is it the original body plan - have molluscs lost segementation? 1. Monoplacophora - genus Neopilina a. Serial repetition in body form b. Single shell c. Interesting story of discovery 2. Polyplacophora - chitons a. Segmented shell - plates b. Multiple gills down side of body - not like generalized plan c. Rock dwellers that use radula to scrape algae off rocks 3.
[Show full text]
Brief Glossary and Bibliography of Mollusks
A Brief Glossary of Molluscan Terms Compiled by Bruce Neville Bivalve. A member of the second most speciose class of Mollusca, generally bearing a shell of two valves, left and right, and lacking a radula. Commonly called clams, mussels, oysters, scallops, cockles, shipworms, etc. Formerly called pelecypods (class Pelecypoda). Cephalopoda. The third dominant class of Mollusca, generally without a true shell, though various internal hard structures may be present, highly specialized anatomically for mobility. Commonly called octopuses, squids, cuttles, nautiluses. Columella. The axis, real or imaginary, around and along which a gastropod shell grows. Dextral. Right-handed, with the aperture on the right when the spire is at the top. Most gastropods are dextral. Gastropod. A member of the largest class of Mollusca, often bearing a shell of one valve and an operculum. Commonly called snails, slugs, limpets, conchs, whelks, sea hares, nudibranchs, etc. Mantle. The organ that secretes the shell. Mollusk (or mollusc). A member of the second largest phylum of animals, generally with a non-segmented body divided into head, foot, and visceral regions; often bearing a shell secreted by a mantle; and having a radula. Operculum. A horny or calcareous pad that partially or completely closes the aperture of some gastropodsl. Periostracum. The proteinaceous layer covering the exterior of some mollusk shells. Protoconch. The larval shell of the veliger, often remains as the tip of the adult shell. Also called prodissoconch in bivlavles. Radula. A ribbon of teeth, unique to mollusks, used to procure food. Sinistral. Left-handed, with the aperture on the left when the spire is at the top.
[Show full text]
Photoperiod and Temperature Interaction in the Helix Pomatia
Photoperiod and temperature interaction in the determination of reproduction of the edible snail, Helix pomatia Annette Gomot Laboratoire de Zoologie et Embryologie, UA CNRS 687, Faculté des Sciences et Techniques et Centre Universitaire d'Héliciculture, Université de Franche-Comté, 25030 Besançon Cedex, France Summary. Snails were kept in self-cleaning housing chambers in an artificially con- trolled environment. Mating was frequent under long days (18 h light) and rare under short days (8 h light) regardless of whether the snails were kept at 15\s=deg\Cor 20\s=deg\C.An interaction between photoperiod and temperature was observed for egg laying. The number of eggs laid (45\p=n-\50/snail)and the frequency of egg laying (90\p=n-\130%)were greater in long than in short days (16\p=n-\35/snailand 27\p=n-\77%)but a temperature of 20\s=deg\C redressed, to some extent, the inhibitory effect of short days. At both temperatures only long photoperiods brought about cyclic reproduction over a period of 16 weeks, con- firming the synchronizing role of photoperiod on the neuroendocrine control of egg laying in this species of snail. Keywords: edible snail; mating; egg laying; photoperiod; temperature Introduction The effects of photoperiod and temperature, which influence most reproductive cycles of animals of temperate regions, have given rise to a certain number of observations for pulmonate gastropods. In basommatophorans, the influence of photoperiod and temperature on reproduction has been shown in four species of lymnaeids and planorbids (Imhof, 1973), in Melampus (Price, 1979), in Lymnaea stagnalis (Bohlken & Joosse, 1982; Dogterom et ai, 1984; Joosse, 1984) and in Bulinus truncatus (Bayomy & Joosse, 1987).
[Show full text]
Chemoreception in Spider Conch, Lambis Lambis (Mollusca: Gastropoda)
Sm all er Re s e ar ch Cont r ib utions 111 Chemoreception in spider conch, Lambis lambis (Mollusca: Gastropoda) V. Deepak Samuel & |amila Patterson Samuel, V.D. & J. Patterson. 2001. Chemoreception in spider conch, Lambis lambis (Mollusca: Gastropoda) - Phuket Marine Biological Center Special Publication 25(1,): 111,-11,2. Extracts of sea weed, clam, fish, crab, acid, base and commercial agar were used in chemoreception tests of Lambislambis. This species exhibited a faster response towards extracts of red algae (Hypnea muscifurmis, Hypenea aalentise and Gracilnria corticatn) than towards other extracts. V. Deepak Samuel and I amila P ntterson. Suganthi Deuadason Marine Research lnstitute 44, Beach Road, Tuticorin - 528 001,India. E-mail : s dmar i@m d4.u snl. ne t. in the laboratory. They were starved for 7 days INTRODUCTION before the olfactory tests. A11 the animals Gastropods possess a sensory organ referred measured about 13.5 cm in length. Tests were to as the osphradium. It consists of patches of performed in rectangular tanks containing epithelium located on the posterior margin of filtered sea water. each afferent gill membrane and they function Extracts were made of plants and animals: as chemoreceptors. The osphradium can also red algae Graciloria corticata, Hypnea detect the amount of sediment in the inhalant musciformls and H. aalentine, greer. algae Ulaa current (Barnes 1987). The gastropods receive lactuca, brown algae Sargassum ruightii, the stimuli through the respiratory current. The clams Meretrix meretrix and Donax cuneAtus, time needed for olfactory detection may vary cuttlefish Sepiabreaimana, crab Cancer Sp., and between species. fish Sillago sihama were selected and about 50 Four types of reaction to stimuli have been g were homogenized (1:1; v l*).
[Show full text]
Endemic Land Snail Fauna (Mollusca) on a Remote Peninsula in the Ogasawara Archipelago, Northwestern Pacific1
Endemic Land Snail Fauna (Mollusca) on a Remote Peninsula in the Ogasawara Archipelago, Northwestern Pacific1 Satoshi Chiba2,3, Angus Davison,4 and Hideaki Mori3 Abstract: Historically, the Ogasawara Archipelago harbored more than 90 na- tive land snail species, 90% of which were endemic. Unfortunately, about 40% of the species have already gone extinct across the entire archipelago. On Haha- jima, the second-largest island and the one on which the greatest number of species was recorded, more than 50% of species are thought to have been lost. We report here the results of a recent survey of the snails of a remote peninsula, Higashizaki, on the eastern coast of Hahajima. Although the peninsula is small (@0.3 km2) and only part is covered by forest (<0.1 km2), we found 12 land snail species, all of which are endemic to Ogasawara. Among these species, five had been thought to already be extinct on Hahajima, including Ogasawarana yoshi- warana and Hirasea acutissima. Of the former, there has been no record since its original description in 1902. Except for the much larger island of Anijima and the main part of Hahajima, no single region on the Ogasawara Archipelago maintains as great a number of native land snail species. It is probable that the land snail fauna of the Higashizaki Peninsula is exceptionally well preserved be- cause of a lack of anthropogenic disturbance and introduced species. In some circumstances, even an extremely small area can be an important and effective refuge for threatened land snail faunas. The native land snail fauna of the Pacific one such example: of 95 recorded species, islands is one of the most seriously endan- more than 90% are endemic (Kuroda 1930, gered faunas in the world (e.g., Murray et al.
[Show full text]