|Scientific Name:||Plestiodon tetragrammus Baird, 1859|
Eumeces tetragrammus (Baird, 1859)
|Taxonomic Notes:||Plestiodon brevilineatus and P. callicephalus were treated as subspecies of P. tetragrammus by Lieb (1985, 1990). Lieb (1990) indicated intergradation between tetragrammus and brevilineatus in southern Texas and northeastern Mexico. Dixon (1987) and Conant and Collins (1991) accepted the conspecific relationship between tetragrammus and brevilineatus. Tanner (1987) maintained that callicephalus should be retained as a full species. Lieb (1990) noted that additional sampling and study of material from Chihuahua is needed to clarify the status of callicephalus. Crother et al. (2000) listed P. callicephalus and P. tetragrammus as distinct species, with brevilineatus as a subspecies of P. tetragrammus.
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 name is thus also used for Mexican species.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Hammerson, G.A., Lavin, P. & Mendoza-Quijano, F.|
|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, tolerance of a degree of habitat modification, 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 occurs in the southern United States and in northeastern Texas. The subspecies E. t. tetragrammus ranges from southern Texas to northern Veracruz and Queretaro, and west to Coahuila (Conant and Collins 1991). Subspecies E. t. brevilineatus occurs from central and southwestern Texas south through northern Coahuila and northern Nuevo Leon, with an isolated population in the Sierra del Nido, Chihuahua (Lieb 1990, Conant and Collins 1991).The species reaches an elevation of around 2,300 m (7,550 feet) in the Chisos Mountains (Conant and Collins 1991). The two subspecies intergrade in southern Texas and adjacent northeastern Mexico.|
Native:Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is represented by a large number of occurrences or subpopulations. For example, Lieb (1990) mapped well over 100 collection sites rangewide. Dixon (2000) indicated occurrences in virtually all of the several dozen counties within the range in Texas. This lizard is very secretive, and it is difficult to determine the size and robustness of individual occurrences or subpopulations. The total adult population size is unknown but certainly exceeds 10,000, and is probably much more. Population trends are unknown, but probably the extent of occurrence, area of occupancy, number of subpopulations, and population size are relatively stable.|
|Current Population Trend:||Stable|
|Habitat and Ecology:||This lizard inhabits rocky hillsides in arid and semi-arid country, brushlands, grasslands, thornscrub, edges of open pine-oak woodlands, pond edges, gullies near small streams, gallery forest of riparian corridors, tropical deciduous forests (in southern range area), and trash piles and dumps; it is often in leaf litter, rotting brush, old packrat houses, cactus clumps, or other debris, such as that around isolated dilapidated houses; may take cover in water (Smith 1946, Conant 1975, Bartlett and Bartlett 1999). Eggs are laid probably in a nest dug under rocks, logs, or other cover, or in loose soil. Individuals burrow underground or at least become difficult to find on the surface during the hottest summer weather (Bartlett and Bartlett 1999).|
|Major Threat(s):||No major threats have been identified. However, in some parts of the range the species is killed under the erroneous belief that it is venomous.|
|Conservation Actions:||It occurs in many protected areas, both in the United States and in Mexico. Other than raising public awareness, no direct conservation measureas are needed for this species as a whole.|
|Citation:||Hammerson, G.A., Lavin, P. & Mendoza-Quijano, F. 2007. Plestiodon tetragrammus. The IUCN Red List of Threatened Species 2007: e.T64241A12757814.Downloaded on 18 October 2017.|
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