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Hemistomia pusillior (Iredale, 1944)

Diagnostic features

This species has a simple columella and an operculum with 4-8 short teeth on a white smear. The shell is sculptured with growth lines only and the suture impressed. Its maximum length is about 4.2 mm.

The penis is simple in all Hemistomia species.


Hemistomia pusillior (Iredale, 1944)

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha 

Superfamily Truncatelloidea

Family Tateidae

Genus Hemistomia Crosse, 1872

Original name: Fluviorissoina pusillior Iredale, 1944. Iredale, T. (1944) The land Mollusca of Lord Howe Island. Australian Zoologist 10: 299-334.

Type locality: 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.


Restricted to the summit of Mt. Gower, Lord Howe Island.


All the Hemistomia species are strongly clustered into distinct geographical locations on Lord Howe Island.

Further reading

Iredale, T. (1944). The land Mollusca of Lord Howe Island. Australian  Zoologist 10: 299-334, pls 17-20.

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