Morphology and ontogeny of the humerus of the Triassic temnospondyl amphibian Metoposaurus diagnosticus

摘要

A morphology of 22 humeri of Metoposaurus diagnosticus from Late Triassic assemblage of Krasiejow (Poland) reveals general metoposauroid conditions, being well-ossified with well-developed processes and wide, flattened ends. These characteristics do not occur in the humerus referred to as M, diagnosticus by FRAAS, proving the improper identification of this specimen. In contrast to other metoposauroid species' humeri, they exhibit a smaller degree of torsion of the ends, unrelated to absolute size. Together with the unscrewed head shape, oblique position of the condylus radialis, less prominent processus supinatorhts and crista deltopectoralis, these indicate a paddle function of the forelimbs and therefore imply a fully aquatic mode of life for M. diagnosticus.