Abstract

Halaphritis platycephala, a new genus and species of the perciform suborder Notothenioidei, is described from coastal reef habitats of temperate Australia. It is a rarely seen, cryptic, nocturnal species that lives deeply concealed in crevices and caves during the day. In external appearance, Halaphritis superficially resembles the parapatric, monotypic pseudaphritid, Pseudaphritis urvillii (Valenciennes), an estuarine and freshwater species that is among the most primitive extant notothenioid fishes. Based on osteology, dentition, and fin and sensory canal structures, Halaphritis is provisionally included in the temperate marine family Bovichtidae. In addition to its unique character mix, Halaphritis can be distinguished from confamilial genera by having a rounded caudal fin, unbranched pectoral fin rays and strongly protruding, dorsally directed eyes. The endemic coexistence of possibly the two most primitive icefish genera in cool temperate Australian seas is supportive of a Gondwanan linkage, specifically an Australian/eastern Antarctic origin of the suborder. Current inclusion of the primitive family Bovichtidae in the suborder has been challenged on molecular grounds but a search for fresh tissue of Halaphritis to confirm its position within the basal notothenioids has so far proven unsuccessful.