. Annals of the South African Museum. Annale van die Suid-Afrikaanse Museum. 408 ANNALS OF THE SOUTH AFRICAN MUSEUM SPHENETHMOID PARIETAL. EPIPTERYGOID PTERYGOID Fig. 7. Palaeogyrinus. Lateral view of suspensorial region as though sectioned through a plane parallel to the quadrate ramus. (After Panchen, 1964.) interpreted as a primitive condition and that a progressive reduction of the epipterygoid ossification is to be seen in later labyrinthodonts. Although Triassic labyrinthodonts are not on the phylogenetic line leading to reptiles, the structure of the palatoquadrate is nevertheless of in
. Annals of the South African Museum. Annale van die Suid-Afrikaanse Museum. 408 ANNALS OF THE SOUTH AFRICAN MUSEUM SPHENETHMOID PARIETAL. EPIPTERYGOID PTERYGOID Fig. 7. Palaeogyrinus. Lateral view of suspensorial region as though sectioned through a plane parallel to the quadrate ramus. (After Panchen, 1964.) interpreted as a primitive condition and that a progressive reduction of the epipterygoid ossification is to be seen in later labyrinthodonts. Although Triassic labyrinthodonts are not on the phylogenetic line leading to reptiles, the structure of the palatoquadrate is nevertheless of interest. It consists of two parts, a horizontal cartilaginous anterior part and a mainly vertical ossified posterior part (Sushkin, 1899; Watson, 1919 and 1926, and Save-Soderbergh, 1936). The vertical part had, at least in Lyrocephalus, basal, ascending and otic processes. Save-Soderbergh maintains that all these processes were embodied in the epipterygoid in the most completely ossified individuals, but that in Aphaneramma and Platystega the ascending process only was included in the epipterygoid. The epipterygoid was joined to the quadrate ossification by means of a cartilaginous link which rested in a groove of the ramus of the pterygoid. We may therefore assume that the palatoquadrate survived in laby- rinthodonts complete from the quadrate to at least the front end of the epipterygoid. COTYLOSAURIA Whether or not the seymouriamorphs are considered amphibians or reptiles, the skull of primitive forms such as Seymouria and Kollassia show that they are not far removed from the anthracosaurian amphibians from which the seymouriamorphs and more advanced reptiles have been derived (Romer, 1956). The epipterygoid, which is not well known and seems to be slow to. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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