. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE DINOGEPHALIAN MANUS AND PES 25. Fig. 10. Micranteosaurus parvus. Type. SAM 4323 X Dorsal view of left pes as restored. Discussion The Dinocephalian feet are more primitive than those of the Sphenacodonts in that the first carpal is not elongated, but otherwise they are definitely more advanced. The digital formula in Sphenacodonts is 2, 3, 4, 5, 3—with a well-developed first digit, a great increase in length from second to fourth digit and a comparatively short fifth digit. In the Dinocephalia th
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE DINOGEPHALIAN MANUS AND PES 25. Fig. 10. Micranteosaurus parvus. Type. SAM 4323 X Dorsal view of left pes as restored. Discussion The Dinocephalian feet are more primitive than those of the Sphenacodonts in that the first carpal is not elongated, but otherwise they are definitely more advanced. The digital formula in Sphenacodonts is 2, 3, 4, 5, 3—with a well-developed first digit, a great increase in length from second to fourth digit and a comparatively short fifth digit. In the Dinocephalia the phalanges of the three middle toes are reduced in number, the first digit is weaker, the three middle digits are shortened and tend to become equal in length and the fifth digit becomes relatively stronger. Micranteosaurus, with a digital formula 2, 3, 4, 3, 3, has the most primitive feet; then comes Titanophoneus in which the fourth digit in the forefoot shows a fusion of two phalanges to produce the formula 2, 3, 3, 3, 3, which also obtains in the Titanosuchia and Tapinocephalia. Proximally the tarsus is still fairly primitive in the Anteosaurs and becomes more specialized in the Titanosuchians and Tapinocephalians. The distal phalanges in Anteosaurs still carried a claw as one would expect in carnivores, whereas in the Titanosuchians and Tapinocephalians, which were herbivores, the nails are flattened. The direction of development in the Dinocephalia seems to have been away from a crawling habit with sprawling feet to a more walking habit with the feet drawn in closer to the median line of the 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 South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
