Two new species of roughy (Trachichthyidae: Optivus) from coastal waters of southern Australia
Abstract
Names are provided for two allopatric species of Optivus occurring in shelf waters of southeastern and southwestern Australia that have been treated in recent Australian literature. Optivus agastos n.sp., distributed from southern Queensland to central Victoria and northeastern Tasmania, and at Lord Howe Island, differs from the very similar O. elongatus, which is limited to New Zealand, in having fewer gill rakers (22-24, rarely 25, versus 25-27, rarely 24), slightly smaller eye, longer snout, and enlarged teeth along the inner margin of the premaxilla. Optivus agrammus n.sp., distributed from western South Australia to southwestern Western Australia, can be distinguished from congeners most readily by the lack of stripes on its caudal-fin lobes, curved dorsal outline of its nape and head in lateral profile, relatively deeper and shorter caudal peduncle, and lower dorsal and anal fins.
