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Austropyrgus rectoides Clark, Miller & Ponder 2003

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 rectoides differs from the other members of this group in the following combination of characters: shell of medium size, broad, with flattened whorls; penis not pigmented; pallial vas deferens straight or slightly undulating at prostate gland.

This species is found in sympatry with five other species of Austropyrgus (A. conicus, A. procerus, A. juliae, A. lochi and A. mersus) throughout its currently recognized range, with up to three in any one location. It can be separated from all these species by its larger, broader shell.

Classification

Austropyrgus rectoides Clark, Miller & Ponder 2003

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Original name: Austropyrgus rectoides 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 Fixters Creek, at northern end of Brittons Swamp, 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 known from a number of small coastal streams and rivers of northern and western Tasmania, including Hunter Island.

Notes

Although most species of Austropyrgus are geographically isolated and have restricted ranges, a few - such as A. rectoides - have wider 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.