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Family  Haminoeidae

Haminoeid bubble shells

The species of Haminoeidae are some of the few plentiful and predictably abundant sea slugs in tropical and temperate seas. They occur on reefs and on mud and sand flats, around all of the Australian coastline. There are several hundred species worldwide, distributed among about 15 genera.

In this family the shells are always external, and lightly or moderately calcified. They vary in form from elongate with a narrow aperture, as in Cylichnatys, to globose with a wider aperture, as in Haminoea. The inner whorls are resorbed, allowing more space for the animal, which can fully retract into its shell. Haminoeids have both a radula and gizzard plates to masticate their food.

Species live intertidally and in the shallow subtidal. They are herbivorous, grazing on green algae, and are most commonly infaunally with a few being epifaunal. The infaunal species burrow through the top layer of fine sediment and are usually drab in colour, while the epifaunal species craw upon their host alga, and are often brightly coloured.

Family Reference

Burn (2015) described and illustrated the Victorian species and some of the NSW species.

Coverage

In addition to the species treated in detail, the following are recorded from NSW:

Ventomnestia colorata Iredale, 1936.

This species was named from a single shell taken by the dredge Triton in Sydney Harbour. The Triton specimens were dredged from below the surface of the Harbour bottom, and may be fossils, often of tropical species not presently found in the Harbour. The species is probably the same as Mnestia girardi (Audouin, 1826).

Atys naucum (Linnaeus, 1758)

This was listed by Iredale & McMichael (1962, species 1847) as occurring in NSW. It is only known from NSW as fossils, taken by the dredge Triton. Presently the southernmost authentic record for this species is Hervey Bay in southern Queensland.

The following were reported as living in NSW by Nimbs & Smith (2017):

Haminoea crocata Pease, 1860. Port Stephens, Sydney.

Haminoea cymbalum (Quoy & Gaimard, 1832). Solitary Islands, Port Macquarie, Port Stephens.

Haminoea ovalis Pease, 1868. Port Stephens.

Identification Notes

Some haminoeid shells are elongate, thus impossible to distinguish solely on shell characters from those of the Cylichnidae. More often, as in Haminoea, the shells are globose, with a fairly wide aperture.