Western fence lizard | |
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S. o. taylori | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Iguania |
Family: | Iguanidae |
Subfamily: | Phrynosomatinae |
Genus: | Sceloporus |
Species: | S. occidentalis |
Binomial name | |
Sceloporus occidentalis Baird and Girard, 1852 |
The western fence lizard (Sceloporus occidentalis) is a common lizard of Arizona, California, Idaho, Nevada, Oregon, Utah, Washington, Northern Mexico, and the surrounding area. As the ventral abdomen of an adult is characteristically blue, it is also known as the blue-belly.
It is a member of the genus Sceloporus (the spiny lizards).
Taxonomy for the western fence lizard has been under much debate. S. occidentalis belongs in the order Squamata (snakes and lizards) and the suborder Iguania. The family in which it belongs is still under scrutiny. The family Phrynosomatidae, along with seven other families, used to be included in the single family Iguanidae, until Frost and Etheridge's (1989) analysis of iguanian systematics suggested the family be divided. Most literature, however, still place the phrynosomatids in Iguanidae.
Six subspecies are recognized, as follows:
Some authors have raised the island fence lizard to specific rank, Sceloporus becki. However, recent work in molecular systematics has suggested there are four clades and 11 genetically separable populations, and the subspecies will probably have to be redefined.
Western fence lizards measure 5.7-8.9 cm (snout-vent length) and a total length of about 21 cm. They are brown to black in color (the brown may be sandy or greenish) and have black stripes on their backs, but their most distinguishing characteristic is their bright blue bellies. The ventral sides of the limbs are yellow. These lizards also have blue patches on their throats. This bright coloration is faint or absent in both females and juveniles. In some populations the males also display iridescent, bright turquoise blue spots on the dorsal surface. The scales of S. occidentalis are sharply keeled, and between the interparietal and rear of thighs, there are 35-57 scales.