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Family  Gryphaeidae

Honeycomb Oysters

This is a numerically small family, with only about 11 species, that resembles the true oysters but have honeycomb-like shell microstructure. They are mainly tropical, being common in the Indo-West Pacific, including northern Australia. They live cemented to hard substrates intertidally but may fall off when they reach a large size. There are only two species known in NSW, both extending from the tropics southwards into northern NSW.

Family Reference

Huber’s Compendium of Bivalves provides illustrations of the species worldwide.

Coverage

Al the species known from NSW are treated here.

Identification Notes

The largest of the NSW species, Hyotissa hyotis, grows up to 300 mm in length, but has a corroded, featureless appearance at that size. When small, it is more recognisable, with the usual zigzag oyster profile. The other species, Hyotissa numista, always has an eroded irregular shell, even when small.