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Austropyrgus pagodoides Clark, Miller & Ponder 2003

Diagnostic features

This species belongs to the Austropyrgus sparsus group, whose members are characterised by the following shell features: small to medium sized shells, conical, with convex to slightly convex whorls. Furthermore, in females, the coiled oviduct is of an inverted U-shape or with two or more bends, loops or twists.

Austropyrgus pagodoides differs from other members of the group in the following combination of characters: shell medium in size, with last whorl and base either evenly convex (females) or strongly angled to keeled (males) (see line drawings of shells); seminal receptacle located at anterior edge of bursa copulatrix and the  coiled oviduct and bursal duct join just behind pallial wall.

This species is among the more unusual members of the genus and indeed of the Australian tateid fauna, in that there is marked sexual dimorphism - males possess a prominent keel on the whorls, whereas females lack this keel.

Classification

Austropyrgus pagodoides Clark, Miller & Ponder 2003

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Original name: Austropyrgus pagodoides Clark, Miller & Ponder 2003. Clark, S. A., Miller, A. C. and Ponder, W. F. (2003). Revision of the snail genus Austropyrgus (Gastropoda: Hydrobiidae): A morphostatic radiation of freshwater gastropods in southeastern Australia.  Records of the Australian Museum Supplement 28: 1–109.

Type locality: Lake Sorell, Tasmania.

Biology and ecology

In streams on water weeds, hard substrate (rocks etc.) and crawling on litter and sediment. Can be locally abundant. Assumed to feed by scraping bacteria and microalgae. Lay solitary capsules containing a single egg. Direct development.

Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5B, p. 752-755.

Distribution

This species is restricted to Lake Sorell, central Tasmania.

Notes

Most members of Austropyrgus, including this species, are geographically isolated and have restricted ranges.

Further reading

Clark, S. A., Miller, A. C. & Ponder, W. F. (2003). Revision of the snail genus Austropyrgus (Gastropoda: Hydrobiidae): a morphostatic radiation of freshwater gastropods in southeastern Australia. Records of the Australian Museum 28: 1–109.