. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 248 ANNALS OF THE SOUTH AFRICAN MUSEUM corresponds to the Meckelian foramen which, in living crocodilians, lies between the angular and splenial. Prearticular This element is not normally found in crocodilians, but it occurs in early mesosuchians such as Pelagosaurus and Metriorhynchus. In Orthosuchus it is a slender, elongate element which forms the ventral margin of the adductor fossa. Anteriorly it is overlapped by the coronoid, and may have extended forward medially to this element to contribute
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 248 ANNALS OF THE SOUTH AFRICAN MUSEUM corresponds to the Meckelian foramen which, in living crocodilians, lies between the angular and splenial. Prearticular This element is not normally found in crocodilians, but it occurs in early mesosuchians such as Pelagosaurus and Metriorhynchus. In Orthosuchus it is a slender, elongate element which forms the ventral margin of the adductor fossa. Anteriorly it is overlapped by the coronoid, and may have extended forward medially to this element to contribute to the inner wall of the Meckelian canal. The foramen which transmits the chorda tympani branch of the facial nerve, and which is almost universally present on the inner surface of the prearticular, cannot be discerned. However, there is a groove running along its inner surface. Posteriorly the prearticular lies over the anterior edge of the articular. Articular On the right side this element is fused by matrix to the condylar surface of the quadrate, while only fragments of the left articular are preserved. The glenoid fossa cannot be seen, although from the contour of the articular area it appears to consist of a large internal and smaller external articular surfaces. THE VERTEBRAL COLUMN AND RIBS General features The presacral series is complete but for a gap which corresponds to three mid-dorsal vertebrae, giving a presacral count of 24. Of these, probably eight may be regarded as cervicals. Two sacral vertebrae are in articulation with the most anterior caudal vertebra. Seven other caudal vertebrae are known, of which only one is in a reasonable state of preservation. The vertebral column shows regional differentiation both in the progressive. Fig. 8. Orthosuchus stormbergi. Anterior (upper row), and posterior (lower row) views of vertebrae (natural size). A. Cervical six. B. Cervical five. C & D. Dorsal seventeen. E & F. Dorsal twenty- four. G & H. Caudal four
Size: 2085px × 1198px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
