PHYLOGENY OF THE CARNIVORA: BASAL RELATIONSHIPS AMONG THE CARNIVORAMORPHANS, AND ASSESSMENT OF THE POSITION OF ‘MIACOIDEA’ RELATIVE TO CARNIVORA

Abstract

The relationships between the earliest members of the Carnivoramorpha and the crown-clade Carnivora are more firmly resolved. The data set for the phylogenetic analyses includes 99 cranial and dental characters from 40 taxa, representing a wide range of early Cenozoic fossil carnivoramorphan taxa traditionally included within the ‘Miacoidea’, representatives of extant Carnivora and outgroups. New fossils of Tapocyon and Oödectes, and more thorough anatomical analyses, significantly increase the taxon and character sampling available for the earliest members of the Carnivoramorpha. The first auditory region known for Oödectes is described. We test the monophyly of the Carnivoramorpha and various subclades, as well as interrelationships of ‘Miacoidea’ taxa relative to each other and to the Carnivora. The monophyly of the Carnivora and Carnivoramorpha is supported, relative to other Ferae (two hyaenodontid ‘creodonts’) and Eutherian outgroups. There is compelling evidence that ‘Miacidae’ and Viverravidae are not basal members of the Caniformia and Feliformia but rather are excluded from the Carnivora (as phylogenetically defined, Wyss & Flynn 1993, emended by Bryant 1996). A monophyletic Viverravidae is strongly supported, forming the nearest outgroup to all other Carnivoramorpha. ‘Miacidae’ is not monophyletic; rather it appears to represent a paraphyletic array of stem taxa, basal to the Carnivora. We discuss character evolution and transformations in the light of these new phylogenetic hypotheses. Basicranial characters are not significantly more useful (less homoplasious) than dental features and thus do not represent a ‘holy grail’ morphological character system for reconstructing carnivoramorphan phylogeny. The results indicate that the split between the Feliformia and Caniformia, now estimated at a minimum age of [similar]43 Ma, appears to have taken place more recently than many earlier studies suggested (see also Flynn 1996).