A primitive amphibian from the Late Devonian of New South Wales

A locality in the Late Devonian Cloghnan Shale (Nangar Subgroup) near Forbes, N.S.W., has yielded a rich vertebrate fauna including the antiarchs Bothriolepis and Remigolepis, the phyllolepid Phyllolepis, the dipnoan Soederberghia, and the jaw of a new ichthyostegaliid amphibian Metaxygnathus denticulus gen. et sp. nov. The amphibian is the oldest known member of the group with the possible exception of Elpistostege Westoll, and it retains characters previously associated with the rhipidistian fishes. The musculatures of rhipidistian and amphibian jaws are analysed and are shown to be functionally related to distinctive morphologies of the articulatory region in each group, Metaxygnathus being of amphibian type. Comparison is made with the Greenland ichthyostegids, and rhipidistians such as Eusthenodon.