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Xantusia gracilis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA XANTUSIIDAE

Scientific Name: Xantusia gracilis
Species Authority: Grismer & Galvan, 1986
Common Name(s):
English Sandstone Night Lizard
Synonym(s):
Xantusia henshawi subspecies gracilis Grismer & Galvan, 1986
Taxonomic Notes: Grismer and Galvan (1986) described Xantusia henshawi gracilis on the basis of morphological, electrophoretic, and ecological differences from other subspecies. Lovich (2001) used mtDNA data to examine the phylogeography of X. henshawi populations in southern California and concluded that the allopatric subspecies Xantusia henshawi gracilis should be recognized as a distinct species, Xantusia gracilis. This conclusion is supported by previously published allozyme data (showing fixed allelic differences) and a compatible historical biogeographical scenario.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Hammerson, G.A.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Vulnerable because it is known from only a single location.

Geographic Range [top]

Range Description: This species is endemic to the southwestern United States. Its known range is confined to the Truckhaven Rocks area (an area of about 3 km by 1.3 km), in the Anza-Borrego Desert State Park, on the southeastern flank of the Santa Rosa Mountains, San Diego County, California; elevation 240 to 305 m (787 to 1,000 feet) (Grismer and Galvan 1986, Lovich 2001, Lovich and Grismer 2003).
Countries:
Native:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: One known occurrence exists, 32 km from the nearest known locality for Xantusia henshawi (Grismer and Galvan 1986). The total adult population size is unknown. Population trends are unknown.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Habitat consists of sandstone crevices and burrows primarily in and along the canyons that cur through the Truckhaven Rocks (Lovich and Grismer 2003). Some "were unearthed in what appeared to be rodent burrows atop piles of hardened siltstone" (Grismer and Galvan 1986).
Systems: Terrestrial

Threats [top]

Major Threat(s): No major threats have been identified, other than those inherent in the very limited distribution.

Conservation Actions [top]

Conservation Actions: The one occurrence is in a state park.

Citation: Hammerson, G.A. 2007. Xantusia gracilis. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 October 2014.
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