Arctostylopida

Reappraisal of arctostylopid mammal Kazachostylops occidentalis from the late Paleocene of Kazakhstan and phylogenetic relationships within Arctostylopida

“…Asiostylops is the sister taxon to the clade uniting the two lineages. This cladogram was repeated by Cifelli and Schaff (1998, fig. 21.3).…”

The origin and evolution of mammals

“…Length of restored skull approx. 4 cm (Cifelli and Schaff 1998). are molarised and the cheek teeth have a welldeveloped and characteristic bilophodont form.…”

“…They were, perhaps, comparable in feeding habits to the modern day hyraxes. Several authors had placed arctostylopidans as a basal group of the South American ungulate order Notoungulata, but Cifelli et al (1989;Cifelli and Schaff 1998) have argued that the dental similarities are superficial and probably convergent. Thus their affinities are at present unclear.…”

“…At one time, it was believed that there were Palaeocene notoungulates in China and North America, which were placed in a primitive family Arctostylopidae (page 242). However, the dental similarities on which the proposed relationship was based are evidently convergent and the arctostylopids are properly placed in an entirely unrelated placental order of their own (Cifelli et al 1989;Cifelli and Schaff 1998). This leaves notoungulates as exclusively South American, with the single exception of the Pleistocene Mixotoxodon, which briefly extended its range into central America.…”