Reidentification of the Chadronian supposed didelphid marsupial Alloeodectes mcgrewi as part of the deciduous dentition of the canid Hesperocyon

Abstract

Alloeodectes mcgrewi (Russell) 1984 is based on isolated teeth, from Chadronian (Late Eocene) localities in the Cypress Hills Formation of southwestern Saskatchewan, that were interpreted as the upper molars of a didelphid marsupial. These teeth are dP4,s of the canid Hesperocyon. The similarity between the last deciduous upper premolar of a canid and the upper molars of a peradectine didelphid results from (i) the differences between the deciduous and permanent dentitions in the Carnivora, and (ii) the apomorphic reduction in certain peradectines of features characteristic of the upper molars in didelphid marsupials.