Australichthys longidorsalis was named by Gardiner (1969). Its type specimen is Geological Survey of South Africa, Pretoria, a partial skeleton (tolerably complete fish wanting tail and paired fins), and it is a 3D body fossil. Its type locality is Schiethoogte 279, which is in a Tournaisian lacustrine - large mudstone/marl in the Waaiport Formation of South Africa.