Urocyon progressus

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Urocyon progressus
Temporal range: Early Pliocene–Early Pleistocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Urocyon
Species: U. progressus
Binomial name
Urocyon progressus
Margaret Skeele Stevens, 1965

Urocyon progressus is an extinct canid carnivoran mammal of the genus Urocyon, and was most common in North America during the Blancan Stage on the geologic timescale. Fossil samples have been found in both Kansas and Texas. It may have been the ancestor of the modern gray fox.


The holotype of the species was found by Claude W. Hibbard during the summer of 1959. It was a complete left parietal bone, with two paratypes, being; an upper left molar and an incomplete left tibia. All of these were found in the Upper Pliocene Rexroad Formation in Meade County, Kansas. These became the oldest remains of the genus Urocyon discovered.[1] Additional examples were also found in the Love Formation, in Hudspeth County, Texas.[2] Margaret Skeele Stevens described the species in the Journal of Mammalogy in May, 1965.[1]


Foxes of the genus Urocyon differ from those of Vulpes by possessing larger molars, the wider separation of a series of ridges along the top of the skull and the shape of its jaw.[3] The collected material of progressus shows that it was slightly larger in size, although had a smaller skull than the modern Gray fox, of which it is presumed to be an ancestor.[3]

Range and ecology[edit]

The species ranged throughout the Blancan period in North America.[3] This stage is usually considered to start in the early-mid Pliocene epoch and end by the early Pleistocene.[4] It is thought to have inhabited terrain similar to that of the modern Gray Fox, including a mixture of forest, woodland and brushland.[3]


  1. ^ a b Stevens, Margaret Skeels (May 1965). "A New Species of Urocyon from the Upper Pliocene of Kansas". Journal of Mammalogy. 46 (2): 265. JSTOR 1377846. 
  2. ^ "Red Light (TMM 40855): Blancan, Texas". Paleobiology Database. Retrieved 20 August 2011. 
  3. ^ a b c d Kurtén (1980): p. 173
  4. ^ Kurtén (1980): p. xiii