Beddomeia angulata Ponder & Clark, 1993

Diagnostic features

Species of the B. hullii group are found in the northern half of Tasmania. Their shells are small (1.7-3.7 mm in length; most less than 3.5 mm), simple, ovate-conic to broadly conic, with a thin inner lip and no columellar bulge. The periphery of the last whorl of the shell is rounded, subangled or angled and the penis simple.

The angled periphery of the last whorl of this taxon gives this conical shell a very distinctive shape. In general size and shape it is similar to B. lodderae but differs from that taxon in the shape of the bursa copulatrix and the position of its duct.

Classification

Beddomeia angulata Ponder & Clark, 1993

Class Gastropoda

Infraclass Caenogastropoda

Order Littorinida

Suborder Rissoidina

Superfamily Truncatelloidea

Family Beddomeiidae

Genus Beddomeia Petterd, 1889

Original name: Beddomeia angulata Ponder & Clark, 1993. In Ponder, W.F., Clark, G.A., Miller, A. & 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.

Type locality: Tributary of Rapid River, 18.2 km south of Holden Road, along Pipeline Road, Tasmania.

Biology and ecology

On and under rocks and on vegetation in streams.Egg capsules typical of Beddomeia (dome-shaped, with broad attachment base, covered with minute, mainly white sand grains and other fragments; contain a single egg) were found at the type locality but B. cf. bellii is also common in that locality so it is uncertain as to which species (or both) the capsules belong. Development is direct.

Distribution

This species occurs in a tributary of Rapid River, Tasmania.

Notes

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

This species is on the Tasmanian Threatened Species Protection Act 1995 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.