. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE POSTCRANIAL SKELETON OF HETERODONTOSAURUS TUCKI 193 of the ilio-fibularis. Three other ridges can be made out clearly: a vertical ridge on the posterior surface of the fibula, 16 mm below the fibular head and about 12 mm long; a smaller ridge on the lateral fibular surface just below and anterior to the former; another vertical ridge continuous with the second on the edge of the lateral buttress described above. The first may be associated with a head of the digital flexors and the others with th
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE POSTCRANIAL SKELETON OF HETERODONTOSAURUS TUCKI 193 of the ilio-fibularis. Three other ridges can be made out clearly: a vertical ridge on the posterior surface of the fibula, 16 mm below the fibular head and about 12 mm long; a smaller ridge on the lateral fibular surface just below and anterior to the former; another vertical ridge continuous with the second on the edge of the lateral buttress described above. The first may be associated with a head of the digital flexors and the others with the peroneal muscles. Pes {Tigs 1, IOC, 20B, 21-22) The right pes is complete and well preserved save for a transverse fracture proximally and some displacement near the metatarsal bases. The left pes is virtually incomplete except for the phalanges and part of the distal tarsals. The following description, therefore, depends only on the right pes. The distal tarsals of H. tucki differ considerably from those preserved in other ornithischians. In the latter, they are usually flat, disc-shaped bones not ankylosed with the metatarsals. Fabrosaurus is similar to other ornithischians in this respect and in no way resembles H. tucki. The three distal tarsals of H. tucki are fused with each other and with the four metatarsals; the latter are also fused with each other. So just as the tibia-fibula is a structural tibiotarsus, the foot is a structural tarsometatarsus. The fifth digit is only a small splint of bone on the proximoventral surface of digit 4. Though fused, the individual tarsals are still distinguishable: distal tarsal 1 caps metatarsals 1 and 2, distal tarsal 2 caps metatarsal 3, and distal tarsal 3 caps metatarsal 4. A ridge rises along the medial and posterior margins of distal tarsal 1; the anterior margin is rounded and the articular surface permitted ^^-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for read
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
