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Amerianna compar Iredale, 1943


This genus is in need of revision, and the species concepts we have used have not been rigorously tested. This situation can only be resolved by additional molecular and morphological studies involving comprehensive sampling.

Diagnostic features

This rather small species has a stepped spire due to the last whorl not being on the same plane as the other whorls. The periphery is sharply angled, usually with a weak to moderate carina as in the larger A. reevei.


Amerianna compar Iredale, 1943

Class Gastropoda

Subclass Heterobranchia

Order Hygrophila

Superfamily Planorboidea

Family Planorbidae

Genus Amerianna Strand, 1928

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

Type locality: Lennard River, Western Australia.

State of taxonomy

The species of Amerianna require taxonomic revision - the classification presented here is modified but is based on shells alone.

Biology and ecology

On water weeds, wood etc., in ponds and billabongs. Feeds on algae and detritus. Egg mass a jelly strip containing many small eggs. Development direct.

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 from the Indian Ocean Division, northern Western Australia, across the coastal tropical north of Northern Territory and Queensland, to north-eastern New South Wales.

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.

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

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