A New Species of the Genus <i>Diaphanosoma</i> Fischer (Crustacea: Cladocera: Sididae) from Claypans in Western Australia

Abstract

Diaphanosoma hamatum sp. nov. is described from material from claypans of a restricted area near Onslow in the north-west of Western Australia. It is characterized by some peculiar features, such as presence of well developed rostrum, small reduced eye, and large hooked spine on the apical end of upper twosegmented antennal branch, which distinguish it from other known species of the genus. The new species is probably closely related to the Australian D. unguiculatum and may be considered as the additional member of the Australian endemic fauna. The ecological signifi cance of morphological features of the species is discussed.