The columella bulge distinguishes this snail from all other species on Lord Howe Island. However, H. 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.
Hemistomia flexicolumella Ponder, 1982
Class Gastropoda
Infraclass Caenogastropoda
Order Littorinida
Suborder Rissoidina
Superfamily Truncatelloidea
Family Tateidae
Genus Hemistomia Crosse, 1872
Original name: Hemistomia flexicolumella Ponder, 1982. In 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.
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.
Restricted to the Erskine Valley, western slopes of Mt Gower and Smoking Tree Ridge, Lord Howe Island.
Ponder, W. F. (1982). Hydrobiidae of Lord Howe Island (Mollusca: Gastropoda: Prosobranchia). Australian Journal of Marine and Freshwater Research 33: 89-159.
