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Planorbarius corneus (Linnaeus, 1758)

Diagnostic features

Large sinistral, biconcave shell, whorls rounded and spire sunken. Umbilicus very wide. Animal brown or red with thin tentacles.It differs from the similar Planorbella duryi in having more rounded whorls and lacking the distinct mantle mottling of that species.

Classification

Planorbarius corneus (Linnaeus, 1758)

Common name: Ram's Horn Snail.

Class Gastropoda

Subclass Heterobranchia

Superfamily Planorboidea

Family Planorbidae

Genus Planorbarius Duméril, 1806 (Type species: Helix corneus, Linnaeus, 1758) (=Coretus, Gray, 1847).

Original name: Helix corneus Linnaeus, 1758

Original reference: Linnaeus, C. (1758). Systema Naturae, per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Editio decima, reformata.  Holmiae : Laurentii Salvii Tom. 1-824 pp.

Type locality: Northern Europe.

Synonyms: Planorbis adelosius Bourguignat, 1859

Biology and ecology

On water weeds etc. in ponds. Feed on algae and detritus. Egg mass an elongate capsule containing 12-40 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.

Distribution

Introduced from Europe, common in aquariums but not established (to our knowledge) in the wild in mainland Australia but in ponds in urban areas in Tasmania (Launceston).

Native distribution Western Europe to Siberia and the Middle East.

Notes

This large, red-coloured species is sometimes encountered in the aquarium trade. It has gone by the name of Planorbis corneus for many years.

Further reading

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

Kershaw, R. C. (1991). Snail and Slug Pests of Tasmania, Queen Victoria Museum and Art Gallery.

Ng, T.H., Tan, S.K., Wong, W.H., Meier, R., Chan, S-Y., Tan, H.H. and Yeo, D.C.J. 2016. Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade. PLOS One. DOI:10.1371/journal.pone.0161130.

Smith, B. J. and Kershaw, R. C. (1979). Field guide to the non-marine molluscs of south eastern Australia. Australian National University Press, Canberra, Australia.

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