Uintacyon, Vassacyon, and Vulpavus are just a few more genera in the family Miacidae. Together they are comprised of 15 total species (8 in Uintacyon, 2 in Vassacyon, and 5 in Vulpavus). Uintacyon and Vassacyon are linked in that a species of Uintacyon was reevaluated and determined to be unique enough to warrant reclassification as a new genera called Vassacyon; U. promicrodon is the type species of Vassacyon and is synonymized with V. promicrodon Wortman and Matthew 1899 (according Gingerich 1983). Vassacyon is considered to be the largest members of the family and some of the largest early mammals of the Eocene. Uintacyon, however, had a larger distribution and was in abundance throughout the Eocene and Paleocene as well, though with a much more limited North American range in the latter ages of the genus' existence. Vulpavus is the oldest named of the three genera (Type: Vulpavus palustris Marsh 1871 ). Weighing in at about 1.2 kg and with a distribution that encompassed most of North America from upper Canada to the southern United States, Vulpavus was a successful arboreal predator in that 92, a modest number of records, partial skeletal discoveries are attributed to Vulpavus across North America.
P. D. Gingerich. 1983. Wyoming Geological Association Guidebook34