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Austropyrgus dyerianus (Petterd, 1879)

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 dyerianus differs from the other species of this group in the following combination of characters: shell small, spire outline straight, whorls convex; pigmentation present on only medial section of penis; seminal receptacle at anterior edge of bursa copulatrix; anterior end of capsule gland tapering.

Classification

Austropyrgus dyerianus (Petterd, 1879)

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Original nameBithynia dyeriana Petterd, 1879. Petterd, W. F. (1879). List of the freshwater shells of Tasmania. Journal of Conchology 2: 81–88.

Type locality: Stream flowing into Long Bay, Tasman Peninsula, 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 known from a few small streams on the Tasman Peninsula, southeastern Tasmania.

Notes

Most species of Austropyrgus are geographically isolated and have restricted ranges, and this one has a rather small range.

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.