Archaeotypotherium propheticus (new combination). Four specimens from central Chile, including three mandibular fragments and one partial upper dental series, are referred to the two existing species of Pseudhyrax. The upper dental series is one of the best examples known for the taxon, and is referred to Pseudhyrax cf. P. eutrachytheroides. Based on a metric study of Pseudhyrax specimens from Argentina, one of the Chilean mandibles is referred to Pseudhyrax eutrachytheroides, one to Pseudhyrax strangulatus, and a third to Pseudhyrax sp. indet. Analysis of a large sample of Archaeohyrax specimens from Salla, Bolivia, provides the basis for interpreting wear-related metric variation in archaeohyracid tooth dimensions. It demonstrates that most cheek teeth decrease in length and increase in width through increasing wear, although upper and lower third molars are exceptions. Owing to the dramatic metric and morphologic differences between worn and unworn archaeohyracid teeth, care should be taken when interpreting the systematic significance of metric differences among specimens of different wear states. A preliminary phylogenetic analysis suggests that taxa traditionally included in the Archaeohyracidae do not form a monophyletic group exclusive of Hegetotheriidae and that a comprehensive review of the names associated with major clades of typothere notoungulates is needed.