. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 33. Dorsoventral cross-sections of Lange- baanweg Agriotherium hemimandibles with arrows indicating premasseteric fossae. A. L45114. B. L45062. The teeth of Indarctos and Agriotherium provide much evidence in support of the theory that they are directly related. As is often the case with carnivore incisors and canines, little of signifi- cance emerged from a study of these teeth in Indarctos and Agriotherium, except that they are essentially similar morphologically The I1 and I2 are perhaps the
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 33. Dorsoventral cross-sections of Lange- baanweg Agriotherium hemimandibles with arrows indicating premasseteric fossae. A. L45114. B. L45062. The teeth of Indarctos and Agriotherium provide much evidence in support of the theory that they are directly related. As is often the case with carnivore incisors and canines, little of signifi- cance emerged from a study of these teeth in Indarctos and Agriotherium, except that they are essentially similar morphologically The I1 and I2 are perhaps the most distinctive of the anterior teeth in A. africanum, and they are closely matched by those of the /. atticus specimen from Samos described by Helbing (1932, fig. 2) (NMB-Sam31). The anterior teeth of Agriotherium are distinguished from those of Indarctos principally by their larger size, this being a reflection of the overall size differences between the two genera. It is worth noting in this connection that since the Agriotheriinae, like other ursids, exhibit appreciable sexual dimorphism, it is possible that large males of advanced Indarctos were of similar size to, and perhaps even slightly larger than, small Agriotherium females. For example, in terms of overall size the maxillary fragment of a small A. insigne specimen from Montpellier (NMB- MP549) is virtually identical in size to corresponding parts of the Vienna /. atticus specimen (NMW-Samos 1912, 29) (Fig. 34). Similarly, the Florida Indarctos skull is in some respects as large as that of the Langebaanweg Agrio- therium, which belongs to a male, and would therefore have been larger than those of A. africanum females. Thus size alone may not necessarily be a reliable criterion for distinguishing the two genera. One of the general trends in ursid evolution has been the emphasis on the development of the posterior cheek teeth, and the reduction in size or even loss of the anterior premolars (Pj-Pg). More reduced premo
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
