''Urocyon'' (Greek: "tailed dog") is a genus of

Canidae Canidae (; from Latin, ''canis'', "dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamilies found within th ...

which includes the gray fox (''Urocyon cinereoargenteus'') and the island fox (''Urocyon littoralis''). These two fox species are found in the Western Hemisphere. Whole genome sequencing indicates that ''Urocyon'' is the most

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

genus of the living canids. Fossils of what is believed to be the ancestor of the gray fox, '' Urocyon progressus'', have been found in Kansas and date to the Upper Pliocene, with some undescribed specimens dating even older.

Extant species

Cozumel fox

The Cozumel fox is a critically endangered or extinct small gray fox found on the island of Cozumel, Mexico. The last reported sighting was in 2001, but surveys focusing on this species have not yet been carried out. The Cozumel fox has not been scientifically described, but is a dwarf form as is the island fox, but slightly larger being up to three-quarters the size of the gray fox. No skins or complete skulls of the Cozumel fox exist in any museum exhibitions, so scientists have mainly examined sub-fossils collected during archaeological excavations of Mayan civilizations who inhabited the island about 1,500–500 years ago. Upon evaluating bones from about 12 adult individuals, scientists have concluded that the Cozumel fox is extremely small – approximately 60-80% the body size of other mainland specimens. The fox had been isolated on the Island of Cozumel for at least 5,000 years, and probably far longer. This would indicate that ''Urocyon'' had colonized the island before the first arrival of humans there.

Extinct species

References

Foxes Mammal genera Taxa named by Spencer Fullerton Baird {{canid-stub