Idoteidae of Australia and New Zealand (Crustacea : Isopoda : Valvifera)

Abstract

The isopod family Idoteidae is diagnosed to distinguish it from other valviferan families. It is represented in Australia by 23 species and in New Zealand by four species. Except for the pelagic cosmopolitan species, Idotea metallica, all species occur only in shallow macroalgae and sea-grass habitats and are mostly confined to temperate waters. In Australia, the species have more or less limited ranges along the southern coast between Sydney (33°S.) and just north of Perth (29°S.) with the exception of three species which occur in subtropical Western Australia. In New Zealand, no species is found north of Wellington (41°S.).

The valviferan family-groups are briefly reviewed and the Idoteidae rediagnosed. The Australian species Lyidotea nodata Hale, 1929 is removed to the arcturid complex, but its family placement is uncertain. Some species from New Zealand, 'Austridotea (Austridotea)' annectans Nicholls, 1937, 'A. (A.)' benhami Nicholls, 1937, 'Notidotea' lacustris (Thomson, 1879), and Idotea festiva Chilton, 1885, are regarded as chaetiliids and are also excluded.

A new genus, Batedotea, is erected for Crabyzos elongata Miers. A neotype is selected for Zdotea stricta Dana and the species' position in Euidotea is confirmed. All genera and species are diagnosed and illustrated and complete synonymies are given. A key for their identification is presented.

The Australian species are: Batedotea elongata (Miers), Crabyzos longicaudatus Bate, Engidotea cristata, sp. nov., Euidotea bakeri (Collinge), E. caeruleotincta Hale, E. danai, sp. nov., Euidotea halei, sp. nov., E. peronii (Milne Edwards), E. stricta (Dana), I. brevicorna Milne Edwards, I. metallica Bosc, Paridotea aquarii, sp. nov., P. collingei, sp. nov., P. miersi, sp, nov., P. munda Hale, P. simplex, sp. nov., P. ungulata (Pallas), Pentidotea australis Hale, Synidotea grisea, sp. nov., S. keablei, sp. nov., S. watsonae, sp. nov., Synidotea sp. and Synischia levidensis Hale.

The New Zealand species are: Batedotea elongata (Miers), Euidotea durvillei, sp. nov., I. metallica Bosc and Paridotea ungulata (Pallas).

A more restrictive definition of the Idotea implies that many of its Northern Hemisphere species may need to be included in other genera. Idotea hectica (Pallas) is placed in Synischia Hale.