Article: A new capitosaurid labyrinthodont from East Africa
Cranial and post-cranial amphibian remains from two localities in the Middle Triassic Manda Formation of the Ruhuhu area of Tanzania are described. A new species of Parotosaurus, P. promts is proposed.In the skull, the pterygoid canal is of particular interest and may have carried the VIIth nerve. The lower jaw has a well-developed pre-articular (hamate) process with behind it a pre-articular fossa.The neural arches, intercentra, and ribs show considerable regional variation. Ossified pleurocentra are described for the first time in a capitosaur.The dermal pectoral girdle is massive. Large trabeculae on the interclavicle and clavicles have been interpreted as a ridge system to resist a forward pull on the dorsal process of the clavicle by a cleidomastoideus muscle. Both fore and hind limbs are poorly ossified.The problem of jaw opening is discussed in capitosaurs and brachyopids. It is thought that in capitosaurs a cleidomastoideus muscle, attached to the tabular horn and to the clavicle, was used to raise the skull, while the depressor mandibulae muscle was used to lower the mandible. In brachyopids the first part of this system was probably an occipito-vertebral muscle.The retro-articular process and the stereospondylous vertebral column are considered.