|Scientific Name:||Plestiodon callicephalus|
|Species Authority:||(Bocourt, 1879)|
Eumeces callicephalus Bocourt, 1879
E. brevilineatus and E. callicephalus were treated as subspecies of E. tetragrammus by Lieb (1985, 1990). Tanner (1987) maintained that callicephalus should be retained as a distinct species. Lieb (1990) noted that additional sampling and study of material from Chihuahua is needed to clarify the status of callicephalus. Meanwhile, Crother et al. (2003) listed E. callicephalus as a species, based on allopatry and morphological diagnosability relative to E. brevilineatus and E. callicephalus.
In a phylogenetic analysis of Eumeces based on morphology, Griffith et al. (2000) proposed splitting Eumeces into multiple genera, based on the apparent paraphyly of Eumeces. Smith (2005) and Brandley et al. (2005) formally proposed that all North American species (north of Mexico) be placed in the genus Plestiodon. This was accepted by Crother (2008) and Collins and Taggart (2009). The change has thus been extended to the Mexican species.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Hammerson, G.A., Frost, D.R., Ponce-Campos, P. & Gadsden, H.|
|Reviewer(s):||Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)|
Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.
|Range Description:||This species mainly in northwestern Mexico, extending into extreme southwestern United States (Lieb 1990, Stebbins 2003). In Mexico it is known from northwestern Chihuahua south through western slope foothills and barrancas of Sierra Madre Occidental of Chihuahua, Sonora, Durango, Sinaloa, Nayarit, northern Jalisco, and Zacatecas. It is also present on the coastal plain of central Sinaloa south through Nayarit, south to Bolaños and Gaudalajara in Jalisco. In the United States it is known from Pajarito, Baboquivari, Santa Rita, and the Huachuca mountains in Arizona, and from the Peloncillo Mountains (Guadalupe Canyon, Geronimo Trail) in New Mexico. Its elevational range extends from near sea level (in Mexico) to above 1,980 m, but it is generally above (1,220 m in the United States (Degenhardt et al. 1996, Stebbins 2003).|
Native:Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Lieb (1990) mapped 43 collection sites rangewide, all but 6 of which are in Mexico. This is a secretive species and relatively difficult to collect, so undoubtedly there are many more occurrences or subpopulations than currently are known. The total adult population size is unknown but surely exceeds several thousand. Overall it is reasonably common in Mexico. Skinks are secretive and can be numerous even in areas where they are difficult to detect by visual techniques. Pifall traps are needed to determine abundance. For example, Degenhardt et al. (1996) reported that most of the 89 specimens taken in New Mexico were obtained in pitfall traps. Population trends are poorly known but no major declines have been reported.|
|Habitat and Ecology:||In the United States, this skink inhabits rocky pine and oak habitats in the mountains, particularly in canyon riparian and hillside situations (Degenhardt et al. 1996, Stebbins 2003). In Mexico, it ranges down through western slope foothills and barrancas and is known from the coastal plain in the south (Lieb 1990). Eggs are laid under rocks and in similar sites and are attended by the female until after hatching (Tanner 1987) (live birth also reported). It is not found in agricultural habitats.|
|Major Threat(s):||The species is probably secure throughout most of its range in Mexico, although some local populations may be jeopardized by habitat loss. Potential threats in the United States include uncontrolled wildfire and intensive cattle grazing of riparian zones in the limited areas where this species occurs. But overall it is not significantly threatened.|
|Conservation Actions:||It occurs in a few protected areas. Other than general research, no direct conservation measures are currently needed for this species as a whole.|
|Citation:||Hammerson, G.A., Frost, D.R., Ponce-Campos, P. & Gadsden, H. 2007. Plestiodon callicephalus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 05 September 2015.|