Austropyrgus rectus (Ponder, Colgan, Clark, Miller & Terzis, 1994)

Diagnostic features

This species belongs to the Austropyrgus rectus group, with members characterised by small to medium-sized, narrow to broad shells, with spires of average length to very elongate, a straight outline and typically flattened to slightly convex whorls. The coiled oviduct has one or more bends, loops or twists.

Austropyrgus rectus differs from the other members of this group in the following combination of characters: shell medium in size, with slightly convex whorls; pallial vas deferens with several coils at prostate gland; female genital opening of medium length.

This species is found in sympatry with A. turbatus from which its shell differs in its very slightly convex (almost flattened) whorls.

Classification

Austropyrgus rectus  (Ponder, Colgan, Clark, Miller & Terzis, 1994)

Class Gastropoda

Infraclass Caenogastropoda

Order Littorinida

Suborder Rissoidina

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Original nameFluvidona recta Ponder, Colgan, Clark, Miller & Terzis, 1994. In Ponder, W.F., Colgan, D. J., Clark, G. A., Miller, A. C. & Terzis, T.  (1994). Microgeographic, genetic and morphological differentiation of freshwater snails—the Hydrobiidae of Wilsons Promontory, Victoria, south-eastern Australia. Australian Journal of Zoology 42: 557–678.

Type locality: Squeaky Beach Creek, about 60m above road, Wilsons Promontory, Victoria.

Biology and ecology

In streams on water weeds, hard substrata (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.

Distribution

This species is only known from a few small coastal streams on Wilsons Promontory, Victoria.

Notes

Most species of Austropyrgus are geographically isolated and have restricted ranges, and this one is no 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.

Ponder, W. F., Colgan, D. J., Clark, G. A., Miller, A. C. & Terzis, T. (1994). Microgeographic, genetic and morphological differentiation of freshwater snails - the Hydrobiidae of Wilson's Promontory, Victoria, south-eastern Australia. Australian Journal of Zoology 42: 557-678.