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A Guide to the Amphibians
and Reptiles of California


Sandstone Night Lizard - Xantusia gracilis

Grismer and Galvan, 1986
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Sandstone Night Lizard Range Map
Range in California: Red



observation link





Sandstone Night Lizard Sandstone Night Lizard Sandstone Night Lizard
  Adult, San Diego County  
Sandstone Night Lizard Sandstone Night Lizard Sandstone Night Lizard
Adult, San Diego County Adult, San Diego County
Sandstone Night Lizard Sandstone Night Lizard Sandstone Night Lizard
  Adult, San Diego County  
Sandstone Night Lizard Sandstone Night Lizard Great Basin Collared Lizard
Adult, San Diego County Adult, San Diego County
© Adam G. Clause
Animal captured and handled under state Scientific Collecting Permit and released at point of capture.
The Night Lizards, genus Xantusia, have small granular scales on soft skin.
X. henshawi is seen here.

     
Habitat
Sandstone Night Lizard Habitat Sandstone Night Lizard Habitat Sandstone Night Lizard Habitat
Habitat from a distance,
San Diego County
Habitat, San Diego County Habitat, San Diego County
Sandstone Night Lizard Habitat Sandstone Night Lizard Habitat Sandstone Night Lizard Habitat
Habitat, San Diego County Habitat, San Diego County Habitat, San Diego County
  Sandstone Night Lizard Habitat  
  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.
Color and Pattern
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. It looks more like the light phase of that species but with more light coloring and smaller dark spots.
The underside is white with minute black speckling only on the forepart
Male / Female Differences
Males have enlarged femoral pores.

Life History and Behavior

Activity
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 and Feeding
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.
One Sandstone night lizard was observed emerging from a crevice at night to prey on various invertebrates, retreating to the crevice after each strike. (Herpetological Review 46(1), 2015)
Breeding
Reproduction is not well known but breeding probably occurs in May and June with live young born in September.

Habitat
Inhabits a very small area of sandstone and mudstone.

Geographical Range
Endemic to California. Occurs only in the Truckhaven Rocks area of San Diego County, in Anza-Borrego State Park.
Elevational Range
From 790 - 1,000 ft. (240 - 305 m).

Notes on Taxonomy
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).


Alternate and Previous Names (Synonyms)

Xantusia henshawi gracilis - Sandstone Night Lizard (Stebbins 2003)

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 Baird, 1858
Genus Xantusia Night Lizards Baird, 1859 “1858”
Species

gracilis Sandstone Night Lizard Grismer and Galvan, 1986
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

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
California Department of Fish and Wildlife

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., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

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.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Jones, Lawrence, Rob Lovich, editors. Lizards of the American Southwest: A Photographic Field Guide. Rio Nuevo Publishers, 2009.

Smith, Hobart M. Handbook of Lizards, Lizards of the United States and of Canada. Cornell University Press, 1946.

Conservation Status

The following status listings come from the Special Animals List and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.



Organization
Status Listing
NatureServe Global Ranking G1 Critically Imperiled—At very high risk of extinction due to extreme rarity (often 5 or fewer populations), very steep declines, or other factors. Imperiled—At high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors.
NatureServe State Ranking S1

Critically imperiled in the state because of extreme rarity (often 5 or fewer populations) orbecause of factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.

U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife SSC Species of Special Concern
Bureau of Land Management None
USDA Forest Service None
IUCN VU Vulnerable

 

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