Common side-blotched lizard

The common side-blotched lizard (Uta stansburiana) is a species of side-blotched lizard in the family Phrynosomatidae. The species is native to dry regions of the western United States and northern Mexico. It is notable for having a unique form of polymorphism wherein each of the three different male morphs utilizes a different strategy in acquiring mates. The three morphs compete against each other following a pattern of rock paper scissors, where one morph has advantages over another but is outcompeted by the third.

The specific epithet, stansburiana, is in honor of Captain Howard Stansbury of the US Corps of Topographical Engineers, who collected the first specimens while leading the 1849-1851 expedition to explore and survey the Great Salt Lake of Utah.

The systematics and taxonomy of the widespread and variable lizards of the genus Uta is much disputed. Countless forms and morphs have been described as subspecies or even distinct species.

The common side-blotched lizard is a species of small iguanid lizard. Males can grow up to 60mm (2.4 inches) from snout to vent, while females are typically a little smaller. The degree of pigmentation varies with sex and population. Some males can have blue flecks spread over their backs and tails, and their sides may be yellow or orange, while others may be unpatterned. Females may have stripes along their backs/sides, or again may be relatively drab. Both sexes have a prominent blotch on their sides, just behind their front limbs. Coloration is especially important in common side-blotched lizards, as it is closely related to the mating behavior of both males and females.

The different throat morphologies that the side-blotched lizard adopts also affects their sprinting speed. Across all three morphs, sprinting speed is positively correlated with blue hue, the brightness of the yellow throat, and the level of saturation of the orange throats. While aspects of throat coloration are positively related to sprinting speed and mass of the lizard, they do not affect the lizard’s snout-vent and hind limb length. Researchers from Utah State University have suggested that this relationship between physical capabilities and coloration plays a role in sexual competition amongst male side-blotched lizards.

The speed of these male lizards during the end of their reproductive seasons is dependent on their body temperature. The maximum sprinting speed of these lizards is achieved when the body temperature is between 35-38 degrees Celsius.

When comparing populations within wind farms and in neighbouring control sites, no differences in oxidative stress are seen in the side-blotched lizard. In females oxidative stress also increases with the number of yolk follicles produced.

Analysis of DNA nuclear microsatellites has provided genetic evidence for the rock-paper-scissors behavior pattern of male side-blotched lizard competition. In populations where all three morphs are present, shared paternity between yellow- and blue-throated individuals occurs at a rate significantly below random chance, while shared paternity between yellow- and orange-throated males occurs at a rate significantly above chance. In addition, blue-throated males often shared paternity with orange-throated males, despite having mostly yellow-throated neighbors.