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Beddomeia tasmanica (T. Woods, 1876)

Diagnostic features

Species in the B. tasmanica group have small shells (length 1.2-2.8 mm) with a depressed spire and open umbilicus. The penis is simple. 

This species differs from other members of the group in its small shell (< 2 mm in length and width), about equal in length and width, with a prominent umbilicus; the pallial cavity has an arched rectum on the roof and the radula has the dorsal edge of the central teeth with a shallow indentation.

Classification

Beddomeia tasmanica (T. Woods, 1876)

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Beddomeia Petterd, 1889

Original name: Valvata tasmanica T. Woods, 1876. Woods, J. E. Tenison (1876). On the freshwater shells of Tasmania. Papers and Proceedings of the Royal Society of Tasmania 1875: 66-82.

Type locality: ‘Small trickling stream in Gould's Country’ (Woods 1876).

Biology and ecology

Under stones and rocks in deeper streams. The white egg capsules are laid on the undersides of rocks and are like those of other species of Beddomeia - dome-shaped, with broad attachment base, covered with minute, mainly white sand grains and other fragments and containing a single egg. Development direct..

Distribution

This species is known from a small number of streams (Groom River catchment) in Gould’s Country and its surroundings, north-eastern Tasmania.

Notes

All species of Beddomeia are geographically isolated and have restricted ranges.

This species is on the Tasmanian Threatened species list of Invertebrate Animals as Rare (small population at risk).

Further reading

Ponder, W. F., Clark, G. A., Miller, A. C. & Toluzzi, A. (1993). On a major radiation of freshwater snails in Tasmania and eastern Victoria: a preliminary overview of the Beddomeia group (Mollusca: Gastropoda: Hydrobiidae). Invertebrate Taxonomy 7: 501-750.