New Leontiniids (Class Mammalia, Order Notoungulata, Family Leontiniidae) from the Salla Beds of Bolivia (Deseadan, Late Oligocene)

Abstract

A revised diagnosis of the Leontiniidae (Class Mammalia, Order Notoungulata) is provided and leontiniids of the Deseadan South American Land Mammal "age" (SALMA; late Oligocene) are summarized. Two new species of leontinids from the Deseadan Salla Beds of Bolivia are described and placed within the new genus, Anayatherium; the smaller A. ekecoa and a much larger A. fortis. A phylogenetic analysis suggests that these species are closely related to the derived Patagonian genera Ancylocoelus and Colpodon, with the loss of the canine serving as a putative synapomorphy uniting these taxa. Although leontiniids are the most frequently encountered taxa at many other Deseadan localities, they are exceedingly rare at Salla. This scarcity, the scarcity of other ungulates with low crowned cheek teeth and the heavy tooth wear of a relatively young individual of A. ekecoa suggest that ungulates with low crowned teeth were at a selective disadvantage at Salla.