Higher Level Relationships of the Arctoid Carnivora Based on Sequence Data and "Total Evidence"

Abstract

The relationships of the lesser or red panda, Ailurus, have remained elusive even as any doubts about the identity of the giant panda as a bear have been erased. While usually classified as a member of the Procyonidae (raccoons), recent anatomical studies have suggested that the red panda may not fall in any of the arctoid carnivore families but instead may reflect an early offshoot of the lineage leading to ursids (bears) and pinnipeds (seals, sea lions, and walruses). Sequence data from the cytochrome b and 12S genes for multiple representatives of all relevant families support this hypothesis. Such a systematic position makes this threatened species particularly worthy of conservation. Sequence data alone, as well as a combined analysis of the sequence and anatomical data, strongly support a single origin of pinnipeds and their aquatic adaptations, lending some resolution to the general disagreement about familial relationships in this group. These molecular data also support canids as the basal members of this caniform clade, but are unresolved with respect to whether mustelids or procyonids constitute the sister group to the (ursid, pinniped, Ailurus) clade. There is support for the notion that skunks are a genetically divergent and possibly nonmustelid lineage.