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Bayardella cosmeta (Iredale, 1943)

Diagnostic features

Only Glyptophysa aliciae and Bayardella johni have similar heavy periostracal spiral ridges. B. cosmeta has a narrower spire and a less distinct shoulder and tends to be smaller than G. aliciae. B. cosmeta is also more spindle-shaped (elongate) compared to B. johni.


Bayardella cosmeta (Iredale, 1943)

Class Gastropoda

Subclass Heterobranchia

Order Hygrophila

Superfamily Planorboidea

Family Planorbidae

Genus Bayardella Burch, 1977

Original name: Glyptamoda cosmeta Iredale, 1943. Iredale, T. (1943). A basic list of the freshwater Mollusca of Australia. Australian Zoologist 10: 188-230.

Type locality: Calala Lagoon, near Tamworth, New South Wales.

Biology and ecology

Under wood and stones, in streams. Capable of aestivation (Smith and Burn, 1976), biology otherwise unstudied.

Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5B, p. 1072-1074.


This species occurs in Queensland, New South Wales and Victoria (Murray-Darling Division), and isolated pockets of Central Australia (Northern Territory).


This distinctive species is rather rare.

Further reading

Baker, F. C. (1945). The molluscan family Planorbidae. Urbana USA, University of Illinois Press.

Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing. 

Burch, J. B. (1977). A new freshwater snail (Basommatophora : Planorbidae) from Australia, Plesiophysa (Bayardella) johni. Malacological Review 10: 79-80.

Hubendick, B. (1955). Phylogeny of the Planorbidae. Transactions of the Zoological Society of London 28: 453-542.

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

Iredale, T. (1944a). Guide to the freshwater shells of New South Wales. Part 2. Australian Naturalist 11: 113–127.

Smith, J. B. & Burn, R. (1976). Glyptophysa cosmeta (Iredale, 1943) in Victoria (Lymnaeoidea: Planorbidae), with notes on aestivation. Journal of the Malacological Society of Australia 3: 175-176.

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

Walker, J. C. (1988). Classification of Australian buliniform planorbids (Mollusca: Pulmonata). Records of the Australian Museum 40: 61-89.