A new Eocene anagalid (Mammalia: Euarchontoglires) from Mongolia and its implications for the group’s phylogeny and dispersal

Abstract

Anagalidae are extinct primitive Euarchontoglires from Asia, regarded as relatively closely related to basal Glires. So far, the group has been reported only from China and stratigraphically spans from the early Paleocene to the latest Eocene/earliest Oligocene. Anagalids are characterized by a relatively full dental formula featuring slightly enlarged semi-procumbent incisors, prominent canines, and tall cheek teeth with usually heavily worn crowns, indicative of an abrasive diet. Here we report a new genus and species from the late Eocene Ergilin Dzo Formation in southern Mongolia. The first non-Chinese anagalid is also the northernmost record of the family. Zofiagale ergilinensis gen. and sp.nov. is remarkable for its relatively small size (comparable only to the Paleocene genera Huaiyangale and Stenanagale), lack of P1, and molariform teeth showing almost no wear, suggesting a different diet than most Anagalidae. Furthermore, its molars display a strong buccal cingulum, a character in anagalids shared only with Wanogale. Our phylogenetic analysis of representatives of all anagalid genera based on 82 dental characters places Anagale and Anaptogale as the most basal lineages and clusters Zofiagale gen. nov. together with Qipania and Hsiuannania. These results suggest three independent northward dispersal events within the family in the late Eocene.