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Austropyrgus Cotton, 1942

Diagnostic features

The shell is more than 1 mm to less than 5 mm in length, conical, elongate conical or pupiform, with evenly convex (one species with angulation) to flattened whorls, smooth.

Operculum flat, paucispiral, yellowish, with a white smear and 1–6 (typically 3–4) pegs on the inner surface. Radula with 3–5 (typically 4) pairs of basal cusps on the central teeth. The penis simple and tapering and the prostate gland closed and more-or-less kidney-shaped with pallial vas deferens emerging from middle of ventral side. The coiled oviduct ranges from a simple inverted U-shape to having several bends, loops or twists and the pallial oviduct has a terminal to subterminal opening.

Austropyrgus is similar to the tateid genus Fluvidonaalthough Fluvidona differs from Austropyrgus in a number of characters including the pupiform shell with a slightly reflected outer lip (Austropyrgus typically conical with no lip reflection), in possessing a red operculum (yellow in Austropyrgus), lacking a gastric caecum (present in Austropyrgus) and the oviduct joining the bursal duct dorsally rather than ventrally or ventro-laterally.

Classification

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Austropyrgus Cotton, 1942

Type species: Paludina nigra Quoy & Gaimard, 1834 (= Austropyrgus niger (Quoy & Gaimard, 1834))

Original reference: Cotton, B.C. (1942). Australian Gastropoda of the families Hydrobiidae, Assimineidae and Acmeidae. Transactions of the Royal Society of South Australia 66: 124–129.

Type locality: Small stream flowing into the d’Entrecasteaux Channel, Tasmania. Neotype localityBacons Ceek, WSW. of Gordon, d’Entrecasteaux Channel, Tasmania.

Synonyms: Angrobia Iredale, 1943; Rivisessor, Iredale, 1943; Pupiphryx, Iredale, 1943

State of taxonomy

We follow Clark et al. (2003) in this resource.

Biology and ecology

Members of the genus can be found on all substrates but are most often found amongst leaves, weeds and roots and on and under stones and wood. A few taxa crawl on sediment in the open, such as those from various small springs in Victoria and Tasmania.

All species of Austropyrgus appear to lay solitary egg capsules that contain a single egg and development is direct.

Distribution

Distributed throughout southeastern Australia, with outliers in the Bunya Mountains, southern Queensland (Miller et al., 1999) and Dalhousie Springs (Ponder et al., 1996), northern South Australia.

Notes

Austropyrgus is the most speciose genus of Australian freshwater molluscs. Many species have very restricted geographical ranges.

Further reading

Beesley, P. L., Ross, G. J. B. and Wells, A. (Eds). (1998). Mollusca: The Southern Synthesis. Fauna of Australia. Vol. 5. CSIRO Publishing, Melbourne. Part A. Pp. i-xvi,1-563, Part B i-viii, 565-1234.

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.

Miller, A. C., Ponder, W. F. & Clark, S. A. (1999). Freshwater snails of the genera Fluvidona and Austropyrgus (Gastropoda, Hydrobiidae) from northern New South Wales and southern Queensland, Australia. Invertebrate Taxonomy 13: 461-493. 

Ponder, W. F., Colgan, D. J., Terzis, T., Clark, S. A. & Miller, A. C. (1996). Three new morphologically and genetically determined species of hydrobiid gastropods from Dalhousie Springs, northern South Australia, with the description of a new genus. Molluscan Research 17: 49-109.

Ponder, W. F. & Colgan, D. J. (2002). What makes a narrow range taxon? Insights from Australian freshwater snails. Invertebrate Systematics 16: 571-582.

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.

Iredale, T. (1943). A basic list of the fresh water Mollusca of Australia. Australian Zoologist 10: 188-230. 

Smith, B. J. (1992). Non-marine Mollusca. Pp. i-xii, 1-408 in W. W. K. Houston. Zoological Catalogue of Australia, 8. Canberra, Australian Government Publishing Service.

Smith, B. J. & Kershaw, R. C. (1979). Field guide to the non-marine Molluscs of South-eastern Australia. Canberra, A.N.U. Press.

Smith, B. J. & Kershaw, R. C. (1981). Tasmanian Land and Freshwater Molluscs. Hobart, University of Tasmania.