Fig. 1.
 MACN A52-617, holotype oi Archaeohyrax patagonicus, left side of skull, viewed as right (adapted from
 Ameghino, 1897…
       
          
        typotheres) were members of the endemic South
 American group Notoungulata. George Gaylord
 Simpson's views on the…
       
          
        Oldfieldthomasia
 Acropithecus
 Eohyrax
 Pseudhyrax
 Archaeotypotherium
 Protarchaeohyrax
 Archaeohyrax
 Hegetotherium
 Fig. 18…
       
          
        nation of the members (e.g., Archaeohegetotheria,
 Hegetoarchaeohyracoidea) could also be used.
 Some combination of these…
       
          
        mostly late Oligocene Deseadan SALMA. Filling
 a niche that presumably was similar to that of the
 hypsodont archaeohyracids,…