Side-blotched lizard

Side-blotched lizards are lizards of the genus Uta. They are some of the most abundant and commonly observed lizards in the deserts of western North America. They commonly grow to six inches including the tail, with the males normally being the larger sex. As well, males often have bright throat colors, ranging from blue to orange. During the breeding season, the male's tails turn blue, probably to attract females.

These lizards are territorial, with each male holding from one to several females in his territory. The males will even boldly approach a human intruder, to give his female(s) a chance to escape. When she is safe, he will join her in a hole, or under a rock.

These lizards are a prey item for many desert species. Snakes, lizards and birds all make formidable predators to side-blotched lizards. Larger lizard species -- such as collared, leopard, and spiny lizards -- and roadrunners are the main predators. In turn, the side-blotched lizards eat insects, spiders, arthropods, and an occasional scorpion.

As a result of their high predation rate, these lizards are very prolific breeders. From April to June they breed, with the young emerging as early as late May. These inch-long young appear all through the summer, and into September.

The diploid chromosome number in most if not all species is 34, consisting of 12 macro- and 22 microchromosomes.

Systematics

The systematics and phylogeny of the side-blotched lizards is very confusing, with many local forms and morphs having been described as full species. Following the 1997 review of Upton & Murphy which included new data from mtDNA cytochrome b and ATPase 6 sequences, the following species can be recognized pending further research:

• Eastern Side-blotched Lizard, Uta stejnegeri - formerly included in U. stansburiana
• San Pedro Martir Side-blotched Lizard, Uta palmeri
• Angel de la Guarda Side-blotched Lizard (undescribed species, formerly included in U. stansburiana)
• Salsipuedes Side-blotched Lizard, Uta antiqua - formerly included in U. stansburiana
• Santa Catalina Side-blotched Lizard, Uta squamata - sometimes included in U. stansburiana
• San Esteban Side-blotched Lizard (undescribed species, formerly included in U. stansburiana)
• San Pedro Nolasco Side-blotched Lizard, Uta nolascensis
• Common Side-blotched Lizard, Uta stansburiana
• Western Side-blotched Lizard, Uta (stansburiana) elegans
• Enchanted Side-blotched Lizard, Uta encantadae - possibly belongs into U. stansburiana
• El Muerto Side-blotched Lizard, Uta lowei - possibly belongs into U. stansburiana
• Swollen-nosed Side-blotched Lizard, Uta tumidarostra - possibly belongs into U. stansburiana
• Socorro Side-blotched Lizard, Uta auriculata - possibly belongs into U. stansburiana
• Clarion Side-blotched Lizard, Uta clarionensis - possibly belongs into U. stansburiana
• Ornate Side-blotched Lizard, Uta mannophora - possibly belongs into U. stansburiana

Uta stellata and U. concinna are nowadays usually considered a subspecies of U. stansburiana. U. encantadae, U. lowei and U. tumidarostra might be subspecies of a distinct species (Las Encantadas Side-blotched Lizard) instead. Similarly, U. auriculata and U. clarionensis might be subspecies of a single species, the Revillagigedo Side-blotched Lizard.

Footnotes

References

• (1991): Viewpoint: a new taxonomic arrangement for some North American amphibians and reptiles. Herpetological Review 22(2): 42-43. PDF fulltext
• (1994): Three new species of intertidal side-blotched lizards (Genus Uta) from the Gulf of California, Mexico. Herpetologica 50: 451–474.
• (2002): The Nonavian Reptiles: Origins and Evolution. In: : A New Island Biogeography of the Sea of Cortés: 181-220. Oxford University Press. ISBN 0-19-513346-3 PDF fulltext Appendices 2-4
• (1943): The Status of Uta ornata lateralis Boulenger. Copeia 1943(2): 97-107. (First page image)
• (1968): Chromosome Number in the Lizard Genus Uta (Family Iguanidae). Chromosoma 24(4): 467-476. PDF fulltext
• (1997): Phylogeny of the side-blotched lizards (Phrynosomatidae: Uta) based on mtDNA sequences: support for midpeninsular seaway in Baja California. Mol. Phyl. Evol. 8(1): 104-113. PDF fulltext