Systematics of gastropod snail

Systematics of gastropod snail

1. Systematics of Gastropod Snail

2. Gastropoda The  Gastropoda  or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to large  There are many thousands of species of sea snails and sea slugs, as well as freshwater snails, freshwater limpets, land snails and land slugs

3. Classification of Gastropoda There three divisions of the gastropods regarded by various authors as subclasses Subclass- Prosobranchiata Gills are located anterior to the heart The shell aperture is usually with a calcareous or horny operculum There respiration is through gills and the sexes are separate This sub class contains majority of the gastropods-marine, fresh water and land snails

4. Classification of Gastropoda The subclass is divided into three orders Order- Archaeogastropoda Each snail has two auricles, two internal gills and two kidneys The gonads discharge through the right kidney directly into water 2. Order- Mesogastropoda One auricle, one gill and one kidney The gonad open independently through a separate genital tract The shell is sometimes provided with a siphonal canal

5. Classification of Gastropoda 3. Order- Neogastropoda The snail belonging to this order are same as the mesogastropods except that a more or less elongated siphonal canal of the shell Families under Prosobranchiata are divided into three categories-

6. Hydrobiidae ( Amnicola ) Assimineidae ( Assiminea grayana ) Thiaridae ( Thiara ) Pilidae ( Pila ) Viviparidae (Viviparous) Pleuroceridae ( Pleurocera ) 1. Freshwater Snail

7. Neritidae ( Neritina ) Potamidae ( Pirenella ) Littorinidae ( Littorina ) Muricidae ( Urosalpinx ) Nassariidae ( Nassarius ) Conidae ( Conus ) 2. Brackish water and Marine Snail

8. Helicinidae ( Helicina ) Truncatellidae ( Truncatella ) Pomatiasidae ( Opisthosiphon ) 3. Terrestrial Snail

9. Classification of Gastropoda Subclass- Opisthobranchiata The gill when present is posterior to the heart The shell is reduced or absent and calcareous spicules are present in naked forms The opisthobranchs are hermaphrodite and live among seaweeds and under rocks

10. Classification of Gastropoda Subclass- Pulmonata They have no gills The shell when present , is usually in the form of a simple , regular spire, which may be only rudimentary The Pulmonates are hermaphrodites There are three subdivision of pulmonates that are regarded as orders- Order- Basommatophora They possess one pair of contractile tentacles with eyes at the bases The shell is conical, discoidal or patelliform

11. Classification of Gastropoda Male and female genital tract open separately to the exterior

12. Planorbidae ( Biomphalaria ) Lymnaeidae ( Lymnaea ) Physidae ( Physa ) Ancylidae ( Ferrissia ) 1. Freshwater Snail

13. Carychiidae ( Carychium ) Ellobiidae ( Melampus ) Gadiniidae ( Gadinia ) Siphonaridae ( Siphonaria ) 2. Terrestrial Snail 3. Brackish Water and Marine Snail

14. Classification of Gastropoda 2. Order- Stylommatophora The member of this order are land snails and slugs Each specimen possess two pairs of tentacles, with eyes at the tips of the posterior tentacles The land snail possess well developed and conspicuous shells while the slug possess rudimentary concealed shells or have no shells The head-foot region of the land snails is covered with scales

15. Helicidae (Helix) Helicellidae ( Hygromia ) Bradybaenidae ( Bradybaena ) Succineidae ( Succinea ) Endodontidae ( Anguispira ) Polygyridae ( Polygyra ) 1. Terrestrial Snail

16. Bulimulidae ( Bulimulus ) Cionellidae ( Cionella ) Zonitidae ( Zonitoides ) Helminthoglyptidae ( Cepolis ) 1. Terrestrial Snail ( Cont …..)

17. Limacidae ( Limax ) Philomycidae ( Philomycus ) Arionidae ( Arion ) 2. slugs

18. Classification of Gastropoda 3. Order- Systellommatophora This order includes those species of slugs that are mostly tropical The members of this order possess two pairs of contractile tentacles, with eyes at the tip of the posterior pair These slugs have neither an external nor an internal shell Veronicellidae ( Veronicella )

19. Refference : https :// en.wikipedia.org/wiki/Snail Geerat Vermeij , The Geography of Evolutionary Opportunity: Hypothesis and Two Cases in Gastropods; Integrative and Comparative Biology 42(5):935-40 • November 2002 http :// bioweb.uwlax.edu/bio210/2011/allsop_dani/classification.htm http :// animaldiversity.org/accounts/Gastropoda/ https :// images.search.yahoo.com/yhs/search?hspart=iba&hsimp=yhs-1&type=sdnt_5344_CRW_BD&p=pila+snail