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Austropyrgus pisinnus Clark, Miller & Ponder 2003

Diagnostic features

This species belongs to the Austropyrgus cooma group, whose members are characterised by generally pupiform to conical, small to medium sized shells, where the last whorl and base are evenly convex. A. pisinnus differs from other members of the group in the following combination of characters: shell small, with straight spire outline and convex whorls; ctenidium abutting anterior end or separated by short efferent branchial blood vessel; penis pigmented on the medial section only; capsule gland with indistinct glandular zones.

This species is not found together with any other species of Austropyrgus. However, A. salvus is found nearby and can be distinguished from A. pisinnus by its larger, broader shell.

Classification

Austropyrgus pisinnus Clark, Miller & Ponder 2003

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Original name: Austropyrgus pisinnus 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: Tributary of Dismal Creek, tributary of Hardwood River, 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 currently only known from the type locality in southwest Tasmania.

Notes

Most species of Austropyrgus are geographically isolated and have restricted ranges, and this one does not appear to be an exception.

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.