BOREAMERYX, AN UNUSUAL NEW ARTIODACTYL (MAMMALIA) FROM THE PLIOCENE OF ARCTIC CANADA AND ENDEMISM IN ARCTIC FOSSIL MAMMALS

Abstract

Boreameryx braskerudi, gen. et sp. nov., from Early Pliocene (about 5-4 Ma) deposits of Ellesmere Island, Nunavut, is represented by the posterior portion of a dentary with three molars, a partial calcaneum, unciform, and fragments of long bones and ribs. The incompletely known structure of Boreameryx must leave open the questions of its relationships within the pecoran ruminants. Even its possible affinities with early cervoids and the North American blastomerycines are speculative. We favour the tentative association of Boreameryx within the Cervoidea. Rather than evolving hypsodonty to deal with abrasive northern foods, Boreameryx apparently retained plesiomorphic dental structures - even augmenting those structures in a unique morphological development. We hypothesize, based on recorded relationships and ranges (both geological and geographical) of several Beaver Pond site mammals, including Boreameryx, that they indicate a significant interval of endemic development in a high northern biotic province prior to 5 Ma. © 2007 NRC Canada.