Bradysaurus
Bradysaurus is a genus of large, primitive and widespread pareiasaur. They possessed a covering of armoured scutes, likely serving as defense against their main predators, the gorgonopsians.
Fossils of Bradysaurus are known from the Tapinocephalus Tapinocephalus [Assemblage Zone|Assemblage Zone] of the South African Karoo. Along with the similarly large dinocephalia, the bradysaurs constituted the herbivorous megafauna of the late Middle Permian Period.
Description
Bradysaurus was in length and half a tonne to a tonne in weight. The skull was large, broad and rounded at the front. It was coarsely sculptured and knobby, with the sutures between the bones not clearly visible.The marginal teeth were high-crowned, with only a few cusps, which is a primitive characteristic. The feet were short and broad, the phalangeal count being 2,3,3,3,2 on the fore-foot and 2,3,3,4,3 on the hind. The whole body is protected by dermal scutes, although these are not as thick or heavy as in more advanced forms.
Classification and species
Bradysaurus is the only member of the subfamily Bradysaurinae. It is the most primitive known pareiasaur and can be considered a good ancestral type from which the others developed. Its large dimensions show that, even very early in their evolutionary history, these strange animals had already attained an optimal size. Even later, more advanced forms, like Scutosaurus, were no larger. The advantage of large size was to provide defense against predators and to maintain a stable body temperature.Kuhn 1969 lists no fewer than nine species for this genus, but this is certainly an excessive number. Boonstra 1969 distinguishes only four species on the basis of tooth structure, two of which Kuhn places in the genus Embrithosaurus. The genera Brachypareia, Bradysuchus, Koalemasaurus, and Platyoropha are synonyms of Bradysaurus.