The shell is 1–5 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 16 (typically 3–4) pegs on the inner surface. Radula with 3–5 (typically 4) pairs of basal cusps on the central teeth. The penis is simple and tapering, and the prostate gland closed and somewhat kidney-shaped, with the pallial vas deferens emerging from middle of ventral side. The coiled oviduct ranges from a simple inverted U-shape to exhibiting several bends, loops or twists, and the pallial oviduct has a terminal to subterminal opening.
Austropyrgus is similar tothe tateid genus Fluvidona, although Fluvidona differs from Austropyrgus in a number of characters including the pupiform shell with a slightly reflected outer lip (Austropyrgus is typically conical with no lip reflection), in its red operculum (yellow in Austropyrgus), in lacking a gastric caecum (present in Austropyrgus) and in the oviduct joining the bursal duct dorsally rather than ventrally or ventro-laterally.
Austropyrgus Cotton, 1942
Class Gastropoda
Infraclass Caenogastropoda
Order Littorinida
Suborder Rissoidina
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 locality: Bacons Ceek, WSW. of Gordon, d’Entrecasteaux Channel, Tasmania, 43°16.70'S 147°11.50'E
Synonyms: Angrobia Iredale, 1943; Rivisessor, Iredale, 1943 (nom. nud. fide Köhler & Bouchet, 2020); Pupiphryx, Iredale, 1943; Revisessor Cotton, 1943 (see Köhler & Bouchet 2020).
We follow Clark et al. (2003).
Members of the genus can be found on all substrata 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.
Distributed throughout south-eastern Australia, with outliers in the Bunya Mountains, southern Queensland (Miller et al., 1999) and Dalhousie Springs (Ponder et al., 1996), northern South Australia.
Austropyrgus is the most speciose genus of all the Australian freshwater molluscs. Many species have very restricted geographical ranges.
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.
Köhler, F. & Bouchet, P. (2020). On unavailable genus-group names introduced by Tom Iredale for Australian non-marine gastropods: nomenclatural clarifications and descriptions of new genera. Molluscan Research 40: 150-159.
May, W. L. (1921). A revised census of the Tasmanian fluviatile Mollusca. Papers & Proceedings of the Royal Society of Tasmania 1920: 65-75.
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.
Perez, K. E., Ponder, W. F., Colgan, D. J., Clark, S. A. & Lydeard, C. (2005). Molecular phylogeny and biogeography of spring-associated hydrobiid snails of the Great Artesian Basin, Australia. Molecular Phylogenetics and Evolution 34: 545-556.
Petterd, W. F. (1889). Contributions for a systematic catalogue of the aquatic shells of Tasmania. Papers and Proceedings of the Royal Society of Tasmania 1888: 60-83.
Ponder, W. (2019). Tateidae Thiele, 1925. Pp. 134-138 in C. Lydeard & Cummings, K. S. Freshwater Mollusks of the World: a Distribution Atlas. Baltimore, John Hopkins University Press.
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.
