At least one herpetologist has considered the species a subspecies of Eumeces tetragrammus under the scientific name E. tetragrammus callicephalus, but the more common classification considers it a separate species based on differences in appearance and the distinct geographic distribution.
The Mountain Skink is a medium-sized skink reaching a maximum length from snout to vent of about 7.5 cm (3 inches). Its body is olive to brown in color, with black stripes on the sides. On the head, it features a distinctive, roughly Y-shaped light line pattern, which gave rise to its scientific name: callicephalus is Greek and means "beautiful head".
In the U.S., the species is very localized. In New Mexico, Mountain Skinks are found only in the southern Peloncillo Mountains of southwest Hidalgo County. It is known only from Geronimo Trail and Guadalupe Canyon, where it is uncommon in its limited habitat. In Arizona, Mountain Skink occurs in the Coronado National Forest. Throughout its range in Mexico, the species seems secure, although many local populations may be jeopardized by habitat loss.
In New Mexico, the species is classified as "critically impaired".
The Mountain Skink is found in a wide variety of habitat, ranging from sea level to nearly 2000 m (about 6560 ft). It prefers areas with abundant and well-rotted leaf litter, provinding cover and places for laying eggs.
Eumeces callicephalus is a terrestrial skink, spending most of its time foraging on the ground, hunting for small invertebrates. It is a good burrower, burrowing its own den.