Notes on reproductive behaviour and ontogeny in two species of Hypseleotris (= Carassiops ) (Gobiidae: Teleostei)

Hypseleotris klunzingeri and H. galii are morphologically similar species both endemic to Australia, with allopatric distribution. Sexual dimorphism in both species is marked, and they spawn during the warmer months of the year when water temperatures exceed 20°C. Both species show similar prespawning behaviour, but H. klunzingeri lays very small ovoid eggs which adhere to grass and twigs at the water's edge, whereas H. galii lays larger eggs which are attached to the "roof" of hard objects on the bottom. Attachment in both instances is by means of adhesive discs. The eggs of H. galii are about twice the size of those of H. klunzingeri, and hatching takes about twice as long. Some of these differences may be adaptations to the different habitats of the two species.