. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE DINOCEPHALIAN MANUS AND PES 21 The single centrale is a fairly large rounded bone lying between the astragalus and the second and third distalia. There are five distal tarsals of which the fourth is the largest. The first three metatarsals are very short, but the fourth and especially the fifth are larger and look more like normal metacarpals. The first phalanges are small bones roughly triangular in shape with the apices distally articulated with the second phalanges. The second phalanges are so
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE DINOCEPHALIAN MANUS AND PES 21 The single centrale is a fairly large rounded bone lying between the astragalus and the second and third distalia. There are five distal tarsals of which the fourth is the largest. The first three metatarsals are very short, but the fourth and especially the fifth are larger and look more like normal metacarpals. The first phalanges are small bones roughly triangular in shape with the apices distally articulated with the second phalanges. The second phalanges are somewhat larger and have expanded ends and a waist. The terminal phalanges are broad, slightly curving bones carrying a flat nail. The digital formula is 2, 3, 3, 3, 3, with the toes of nearly equal length, but the first is the shortest with the fourth only slightly longer than the other three. In figure 5 the system of grooves in both astragalus and calcaneum are well shown in ventral view. These grooves probably housed tendons associated with the tarsal joint which apparently functioned in a most peculiar manner and difficult to understand. I have attempted in figure 6 to show the peculiar action of the ankle joint. In a. the leg is shown at the completion of the swing forwards with the toes just about to make contact with the ground. In this position it is evident that the fibula has its bipartite distal facet in contact with the facet on the astragalus. Fig. 6. Tapinocephalid lower hind-limb showing ankle joint in three positions. a—at completion of the forward swing c—at completion of the stride b—standing and carrying body weight. 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
