Abstract  Elaine Anderson first established in the early 1970s a close relationship between the late Miocene Chinese Martes palaeosinensis and living North American fisher M. pennanti, based on their shared presence of an external rootlet on the upper carnassial. Such a recognition paved the way for their elevated status as a distinct genus of their own, Pekania, an implicit relationship increasingly corroborated by molecular phylogenetics, which tend to show that the living fisher is either a sister to the northern Holarctic wolverine (Gulo) or a stem group bracketed between Central and South American tayra (Eira) and a Gulo-Martes clade. We describe an upper jaw of Pekania palaeosinensis from the late Miocene (Baodean) Baogeda Ula Formation of Nei Mongol. We take this opportunity to review the molecular relationships, divergence time, and the fossil record of the Pekania clade. Although the Chinese records of the fishers are in close agreement with divergence time estimates of 5−8 Ma for the Pekania clade based on molecular clock estimates, a deep fossil record for the wolverines, on the other hand, suggests a much more ancient divergence time and by extension, for the fishers as well.

Key words  Nei Mongol, China; Baodean, Miocene; Baogeda Ula Formation; Pekania, Martes, Gulo, zoogeography, molecular phylogeny, divergence time