AFRICAN AMPHIBIOUS FISHES AND THE INVASION OF THE LAND BY THE TETRAPODS

Many species of amphibious fishes (fishes that live both in and out of water as normal parts of their life histories), belonging to a divers e array of families, occur in both freshwater and marine habitats in m any parts of Africa. Some of the best studied forms are common in wide ly occurring intertidal habitats along much of the African seacoast. S everal species of mudskippers (family Gobiidae, subfamily Oxudercinae) occur in mangrove areas and in other protected muddy or sandy habitat s. A larger and more diverse group of blennies (family Blenniidae), so me of which are called rockskippers, occur in mainly rocky habitats. T he primary focus of this paper is on both the mud- and rockskippers. N one of the living amphibious fishes are directly related to or descend ed from the ancient sarcopterygian fishes that appear to have been the ancestors of all tetrapods. However, studies of the biochemical, ecop hysiological, functional morphological, and behavioural adaptations sh own by the living forms for amphibious modes of life provide us with d iverse examples of evolutionarily successful, functional suites of ada ptations that might also have been used, in varying combinations, by a ncestral forms that could have occupied similar habitats.