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.
This species differs from other members of the group with regards to its radula with sharply pointed median cusps on central and lateral teeth (blunter in other taxa); male genital system with prostate gland extending only 1/3 of length into pallial roof (1/2 or more in other taxa); female genital system with coiled oviduct extending beyond posterior edge of bursa copulatrix (not beyond posterior edge in other taxa) and albumen gland extending into pallial wall about 1/3 of length (more in other taxa).
Beddomeia fallax Ponder & Clark, 1993
Class Gastropoda
Infraclass Caenogastropoda
Order Littorinida
Suborder Rissoidina
Superfamily Truncatelloidea
Family Tateidae
Original name: Beddomeia fallax Ponder & Clark, 1993. In 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.
Type locality: Heathcote Creek, on Castra Road, Upper Castra, Tasmania.
This species lives under stones in a small stream. Egg capsules presumably 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.
Only known from Heathcote Creek, Upper Castra and a few nearby locations in mid-north Tasmania.
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).
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.
