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Hemistomia flexicolumella Ponder, 1982

Diagnostic features

The columella bulge distinguishes this snail from all other species on Lord Howe Island. However, P flexicolumella has a more prominent columellar bulge than H. beaumonti.

Like H. flexicolumella, the operculum has a rudimentary peg or is simple, and there is no white smear or spot. The shell is sculptured with growth lines only and the suture is simple or weakly channelled. The maximum length of the shell is about 2.6 mm.

The penis is simple in all Hemistomia species.

Classification

Hemistomia flexicolumella Ponder, 1982

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha 

Superfamily Truncatelloidea

Family Tateidae

Genus Hemistomia Crosse, 1872

Original name: Hemistomia flexicolumella Ponder, 1982. Ponder, W.F. (1982) Hydrobiidae of Lord Howe Island (Mollusca: Gastropoda: Prosobranchia). Australian Journal of Marine and Freshwater Research 33: 89-159.

Type locality: Southern tributary of creek in Erskine Valley on track to Mt. Gower, Lord Howe Island.

Biology and ecology

Found in streams, seepages and pools. It is assumed that like most tateids, the Lord Howe Island Tateidae feed on bacteria, microscopic algae, diatoms and possibly decaying vegetation. Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5B, p. 752-755.

Distribution

Restricted to the Erskine Valley, western slopes of Mt. Gower and Smoking Tree Ridge, Lord Howe Island.

Further reading

Ponder, W. F. (1982). Hydrobiidae of Lord Howe Island (Mollusca: Gastropoda: Prosobranchia). Australian Journal of Marine and Freshwater Research 33: 89-159.