Gobiopterusin New Zealand (Teleostei: Gobiidae), with observations on sexual dimorphism

The small, transparent gobioid Gobiopterus semivestitus is recorded for the first time from New Zealand, from a tributary of Ngunguru River, near Whangarei, Northland. Distinctive features of its sexual dimorphism are reported, in particular enlarged fins and greatly enlarged jaw dentition in the male. The origins of this species in New Zealand waters are uncertain: it could have been here for some time, unobserved; it could have dispersed recently to New Zealand across the Tasman Sea from Australia; or it could have arrived in ships’ ballast water.