sculptured with uniform pitting; separation of protoconch from teleoconch distinct, with varix-like border. Teleoconch with spire much longer than length of aperture. Aperture ovate, slightly angled posteriorly, inner lip attached to parietal wall or partially to completely detached, although not markedly so, usually lower part not much separated from base; outer lip orthocline to opisthocline, weakly thickened, simple or with very slight reflection. Periphery rounded, base simple, imperforate in adults, rarely narrowly umbilicate in juveniles. All species are semi-opaque to opaque, white with a thin pale yellowish periostracum. Operculum, ovate, paucispiral, flat, yellowish; columellar edge slightly convex, outer edge strongly convex; outer surface simple, paucispiral, nucleus markedly eccentric; inner surface usually smooth with white smear or (in one species) large, broad peg.
The main differences between this genus and Beddomeia and Phrantela is that it lacks a pallial tentacle, has a slightly thickened edge to the outer apertural lip of the shell, an elongate-pupiform shell shape, long, S-shaped rectal coils, having the seminal receptacle on the middle of the left side of the bursa copulatrix and the wide, thick coiled oviduct which is smooth and firm in appearance (not soft and glandular) and is bound in very little connective tissue. It also differs from Phrantela in the anterior bursal duct, the swollen seminal receptacle and thick capsule and prostate glands (the latter perhaps in the type species only). Some species of Fluvidona have a somewhat similar pupiform shell shape to members of this genus, but differ in having a shell with a thickened peristome, opercular pegs, and multiple basal cusps on the central teeth of the radula.
Genus Nanocochlea Ponder & Clark, 1993
Original reference: Ponder, W.F., G.A. Clark, A.C. Miller & A. Toluzzi, (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: Large stream flowing from Lake Skinner, Snowy Range, Mt. Fields National Park, Tasmania.
Members of this genus commonly favour small seeps and very small streams, where they are often found buried in roots and gravel. They can also occur under boulders and in moss, under bark and leaves, and in pools and streams in limestone caves.
Known only from southern and south-western Tasmania.
Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.
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.
Ponder, W. F., Clark, S. A., Eberhard, S. & Studdert, J. B. (2005). A radiation of hydrobiid snails in the caves and streams at Precipitous Bluff, southwest Tasmania, Australia (Mollusca: Caenogastropoda: Rissooidea: Hydrobiidae s.l.). Zootaxa 1074: 1-66.