California Reptiles & Amphibians

Xantusia gracilis - Sandstone Night Lizard

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Range in California: Red

Dot-locality Range Map

Adult, San Diego County

Habitat from a distance, San Diego County

Habitat, San Diego County

Description

Size

2.0 - 2.8 inches long from snout to vent (5.0 - 7.0 cm). (Lemm 2006)

Appearance

A small flat-bodied lizard with a flattened head, soft skin with fine granular scales, a long thin tail, lidless eyes with vertical pupils, and gular folds. Similar to and closely related to Xantusia henshawi, but with a narrower head, a body that is shorter between the limbs, and with thinner limbs.

The color is white to yellowish, with large dark brown spots on the upper surfaces, and irregular spots and bands on the tail. This species does not exhibit the light and dark phases seen in X. henshawi, looking more like the light phase of that species with more light coloring and smaller dark spots. The underside is white with minute black speckling only on the forepart. Males have enlarged femoral pores.

Behavior

Natural history is not well known.
Nocturnal, taking refuge during the day under exfoliating slabs of sandstone, in cracks, and in rodent burrows dug into the sandstone. More strictly nocturnal than X. henshawi. Probably active from spring to fall, taking cover during winter. More terrestrial and less restricted to climbing rocks than X. henshawi. This species probably developed a more slender body than X. henshawi to allow it to better exploit the wide range of microhabitats found in its sandstone habitat.

Diet

Diet is not well known but probably is similar to that of X. henshawi, consisting of small invertebrates such as ants, beetles, and bees. Captive individuals have been observed eating the eggs of Leaf-toed Geckos.

Reproduction

Reproduction is not well known but breeding probably occurs in May and June with live young born in September.

Range

Endemic to California. Occurs only in the Truckhaven Rocks area of San Diego County, in Anza-Borrego State Park.

Habitat

Inhabits a very small area of sandstone and mudstone. From 790 - 1,000 ft. (240 - 305 m).

Taxonomic Notes

In 1986 Grismer and Galvan published the first description of this species, classifying it a subspecies of Xantusia henshawi - Xantusia henshawi gracilis - Sandstone Night Lizard. It was elevated to a full species in 2001 by Lovich (2001 Herpetologica 57(4): 470-487).

Conservation Issues (Conservation Status)

Protected from collection by the state and the federal government and by the fact that its known range falls completely within the boundaries of Anza-Borrego State Park where it is also protected.

Taxonomy
Family	Xantusiidae	Night Lizards
Genus	Xantusia	Night Lizards
Species	gracilis	Sandstone Night Lizard
Original Description
Xantusia henshawi gracilis - Grismer and Galvan, 1986. from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Xantusia - honors Xantus, John gracilis - Latin - slender - referring to the body shape. from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Xantusia henshawi gracilis - Sandstone Night Lizard
Related or Similar California Lizards
X. henshawi - Granite Night Lizard X. r. reticulata - San Clemente Night Lizard X. vigilis - Yucca Night Lizard X. sierrae - Sierra Night Lizard X. wigginsi - Baja California Night Lizard
More Information and References
Natureserve Explorer California Dept. of Fish and Game Grismer, L. L., and M. A. Galvan. 1986. A new night lizard (Xantusia henshawi) from a sandstone habitat in San Diego County, California. Trans. San Diego Soc. Nat. Hist. 21(10):155-165. Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Lemm, Jeffrey. Field Guide to Amphibians and Reptiles of the San Diego Region (California Natural History Guides). University of California Press, 2006.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	DFG:SSC	California Species of Special Concern
Bureau of Land Management	None
USDA Forest Service	None
Natureserve Global Conservation Status Ranks	G1	Critically Imperiled
World Conservation Union - IUCN Red List	None