Yucatán Whiptail, Aspidoscelis angusticeps angusticeps

Yucatán Whiptail, Aspidoscelis angusticeps angusticeps. Photograph taken within the Sian Ka’an Biosphere Reserve, Quintana Roo, March 2021. Photograph and identification courtesy of Marina Sutormina, Stockholm, Sweden.

The Yucatán Whiptail, Aspidoscelis angusticeps, is a member of the Teiidae Family of ground lizards, New World runners, racerunners, whiptails, and ameivas. The Teiidae Family consists of approximately two hundred forty-five species placed into forty genera. There are forty-four species and sixty-five subspecies in the Aspidoscelis genus. In Mexico they are known as Cuiji Yucateco and Huico Yucateco.

Yucatán Whiptails have tiny granular scales on their dorsum and sides. Their venter is covered with large, flat rectangular scales that are arranged in eight longitudinal rows. Sexual dimorphism is present with males and females displaying different colors and patterns. Adult males have a pink chin and gular area, and their venter is black or bluish black from the gular fold to the preanal scales. This black pigment extends onto the ventral surfaces of their fore and hind limbs. The venters of subadult males are less extensively blackened than those of mature males, and may be cream in color. Adult females and juveniles have a pale blue venter laterally that becomes cream or pale gray near the ventral midline. Their throat is blue, suffused with cream, and their preanal scales and ventral surfaces of their limbs are also cream. Dorsally, adult females and juveniles have six well-defined cream stripes on their back and sides. The dorsolateral stripes extend to a level about even with the posterior insertion of the hind limbs. The lateral stripes extend only to about the level of the anterior insertion of the hind limbs. These stripes are also present in young males, however, small spots appear between the stripes as they mature. These spots continue to enlarge with age until they eventually coalesce to form a tessellated pattern in adult males. Males also possess a broad median dorsal band that extends from their parietals to the base of their tail. In juveniles, females, and young males, the area between their stripes is immaculate brownish black, except for the space between the lower two stripes, which may be somewhat tessellated posteriorly. Juveniles of both sexes have an orange or reddish-brown tail dorsally. As they mature, it becomes brownish or blue-gray. Ventrally, their tail is pale to light gray. They reach a maximum length of 8.3 cm (3.3 inches), and weigh up to 41 g (1.4 oz).

Known for their running capabilities, Yucatán Whiptails are wary and very fast moving. They are diurnally active and can be observed basking on rocks. Reproduction is sexual and oviparous. Females are known to mate with Deppe’s Whiptail, Cnemidophorus deppei, and produce parthenogenetic all-female offspring. Yucatán Whiptails are primarily insectivorous, and they are preyed upon by predatory birds, larger lizards, mammals, and snakes. They rely on cryptic coloration, rapid flight skills, burrows, and heavy vegetation for defense. In addition, they have the ability to lose and regrow their tail. Dropping their tail provides a distraction that allows the rest of them to escape when threatened. The Yucatán Whiptail is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Yucatán Whiptail has a distinct identification that cannot be confused with any other species within its range.

From a conservation perspective the Yucatán Whiptail is currently considered to be of Least Concern due to their wide distribution, tolerance of a broad range of habitats, and presumed large population size. No major threats have been identified for this adaptable species. They are not utilized commercially nor traded by humans to any significant degree.