Wikipedia
Ailuridae is a family in the mammal order Carnivora. The family comprises the red panda (the sole living representative) and its extinct relatives.
Frédéric Georges Cuvier first described Ailurus as belonging to the raccoon family in 1825; this classification has been controversial ever since. It was classified in the raccoon family because of morphological similarities of the head, colored ringed tail, and other morphological and ecological characteristics. Somewhat later, it was assigned to the bear family.
Molecular phylogenetic studies show that, as an ancient species in the order Carnivora, the red panda is relatively close to the American raccoon and may be either a monotypic family or a subfamily within the procyonid family. An in-depth mitochondrial DNA population analysis study stated: “According to the fossil record, the Red Panda diverged from its common ancestor with bears about 40 million years ago (Mayr 1986). With this divergence, by comparing the sequence difference between the red panda and the raccoon, the observed mutation rate for the red panda was calculated to be on the order of 10, which is apparently an underestimate compared with the average rate in mammals. This underestimation is probably due to multiple recurrent mutations as the divergence between the red panda and the raccoon is extremely deep.”
The most recent molecular- systematic DNA research places the red panda into its own independent family, Ailuridae. Ailuridae are, in turn, part of a trichotomy within the broad superfamily Musteloidea (Flynn et al., 2001) that also includes the Procyonidae ( raccoons) and a group that further subdivides into the Mephitidae ( skunks) and Mustelidae ( weasels); but it is not a bear (Ursidae).
Red pandas have no close living relatives, and their nearest fossil ancestors, Parailurus, lived 3-4 million years ago. There may have been as many as three different species of Parailurus, all larger and more robust in the head and jaw, living in Europe and Asia but possibly crossing the Bering Strait into the Americas. The red panda may be the sole surviving species - a specialized offshoot surviving the Ice Age in a Chinese mountain refuge.