The lower jaw of an aegialodontid mammal from the Early Cretaceous of Mongolia

Abstract

A partial lower jaw is described of an aegialodontid mammal, Kielantherium gobiensis Dashzeveg, 1975, from the Guchin Us beds of Mongolia (?Aptian or ?Albian). The jaw has four molars and four or five premolar loci. A count of P5 M4 is argued to be primitive for the Tribosphenida. McKcnna's interpretation of the postcanine dentition of Peramus as P5 M3 is accepted. It follows that the Peramura could not lead to the Tribosphenida, which apparently arose from unknown ‘pantotheres’ with not less than nine postcanine teeth.