Canids of the World by Castelló José R.; Sillero-Zubiri Claudio;

Canids of the World by Castelló José R.; Sillero-Zubiri Claudio;

Author:Castelló, José R.; Sillero-Zubiri, Claudio;
Language: eng
Format: epub
Publisher: Princeton University Press
Published: 2018-12-05T16:00:00+00:00

Red Fox-Like Canids

TRUE FOXES, BAT-EARED FOX AND RACCOON DOG

RECOGNITION Red Fox-like Canids, also called Vulpine Foxes, are a group of very small to small-sized Canids, characterized by a long, low body, with relatively short legs, a long pointed muzzle, large triangular ears, and a bushy tail that is at least half as long as the head and body. They have black, triangular face marks between eyes and nose, long black vibrissae, oval-shaped eyes with elliptical pupils, and the tip of the tail is often a different color from the rest of the coat. Color is usually reddish, sandy yellow or brown, with adults exhibiting more than one color, but in some species it may be completely white or black. Supracaudal gland is well developed. There is no marked sexual dimorphism, with males being slightly larger. Females usually have four pairs of nipples. Seasonal dimorphism may be sharp in some northern forms, but is revealed almost solely in degree of fur density and length. The skull is flattened in comparison with Canis, with an elongated rostrum. They exhibit the typical Canid dental formula, I 3/3, C 1/1, P 4/4, M 2/3 = 42, except Bat-Eared Foxes, which have six extra molars. Some species have a pungent odor, arising mainly from a gland located on the dorsal surface of the tail. Most species in this group belong to the monophyletic genus Vulpes (true Foxes). Vulpes was once considered a subgenus of Canis, but is now considered genetically distinct. Fennecus (Fennec Fox) and Alopex (Arctic Fox) are genetically so similar to the genus Vulpes that they are now included in this genus. The phylogenetic position of Otocyon (Bat-Eared Fox) and Nyctereutes (Raccoon Dog) is highly uncertain, but recent sequencing data suggests placement of both of these genera in the Vulpes-like clade.

PHYLOGENY During the late Miocene (ca. 10 Ma), the true Fox clade emerged and underwent modest diversification to initiate primitive species of both Vulpes and Urocyon. Vulpes spread out from North America, independent from the Canis clade, presumably via the Bering land bridge, and colonized Asia, and later, Africa and Europe. Vulpes species were widespread and diverse in Eurasia during the Pliocene. Red Fox and Arctic Fox appeared in North America only in the late Pleistocene, evidently as a result of immigration back to the New World. Up to 13 species of Vulpes have survived to the present time throughout Africa, Eurasia and North America, making it the most diverse living Canid genus. The Bat-Eared Fox may represent a late Pliocene immigration event to the Old World, independent of other Foxes (ca. 3 Ma), probably from India. The Raccoon Dog was an early immigrant to the Old World, with a useful fossil record in Asia and Europe dating from the late Miocene to the middle Pliocene (5.5 to 3 Ma); however, it is still far from clear what its original stock in North America was, with some studies suggesting that it is either more basal to the Vulpines or within the Fox lineage.

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