A Guide to the Amphibians
and Reptiles of California

Urosaurus ornatus symmetricus - Colorado River Tree Lizard

Click on a picture for a larger view

Range in California: Red

Dot-locality Range Map

Adult female, Yuma County, Arizona

Adult, Imperial County
© William Flaxington

Adult, introduced into San Bernardino County. © William Flaxington

Adult, introduced into San Bernardino County. © Jonathan Hakkim

Back scales - There is a wide band of large scales down the middle of the back, which is split in the center by smaller scales. Compare with Urosaurus graciosus.

Habitat

Habitat next to Colorado River,
Imperial County

Habitat along Colorado River,
Yuma County, Arizona

Colorado River, Imperial County

Desert oasis habitat at Corn Springs, Riverside County

Habitat near Colorado River,
Imperial County

Habitat next to Colorado River,
Yuma County, Arizona

Similar Subspecies

The pictures belowshow Urosaurus ornatus schottii - Schott's Tree Lizard, the subspecies found east of the range of the Colorado River Tree Lizard. Without a magnifying glass, the appearance is the same. Some researchers do not recognize any subspecies of this lizard or any important differences between these subspecies.

Adult, Pima County, Arizona

Adult male, Santa Cruz County, Arizona

Adult, Coconino County, Arizona

Adult, Maricopa County, Arizona

Adult male, Pima County, Arizona

Adult female, Cochise County, Arizona

Short Videos
(of other subspecies)

Tree Lizards beside a creek in Coconino County, Arizona.

Tree Lizards in Coconino County, Arizona, doing territorial push-up displays.

Two tree lizards running around on buildings. The first in Coconino County, Arizona, the second in Pima County, Arizona.

Description

Size

1.5 - 2.25 inches long from snout to vent (3.8 - 5.7 cm). (Stebbins 2003)

Appearance

A small slim climbing lizard with a long thin tail, usually seen on rocks and trees. The scales on the back are small and granular, with two bands of enlarged scales down the middle of the back with a band of smaller scales between them. (On the subspecies U. o symmetricus, the band of narrow scales on the mid back is wider than the width of one of the bands of enlarged scales, and the belly patches are separated.) There is a gular fold across the throat and a fold of skin on each side of the body.

Color is brown, tan, gray, rusty, or nearly black with dark blotches or irregular narrow crossbars on the upper surfaces. The coloring usually matches the surrounding environment, and changes from a dark to a light phase.

Males have a blue, green, orange, or yellow throat patch, blue or green patches on the sides of the belly which do not usually connect, and enlarged postanal pores. Females have a white belly and a white, orange or yellow throat.

Behavior and Natural History

Diurnal. Active spring through fall when it becomes inactive during late fall and winter cold. Tree lizards have been found overwintering in aggregations. Often seen basking on rocks in the morning with the head pointing downward. Despite the name, this lizard seems to prefer rocks as basking sites. Escapes by climbing out of reach up a rock or tree and running to the other side. Shelters in vegetation, under rocks, and in crevices in rock.

Diet

Eats small invertebrates including beetles, ants, flies, grasshoppers, and spiders. Typically sits on shrubs, trees, and rocks and waits for prey to approach.

Reproduction

Breeding occurs in spring, with 1 to 6 clutches of 2 - 16 eggs laid from March to August.

Range

Urosaurus ornatus symmetricus is found in the far southeast part of California along the Colorado River, and also "ranges inland to Corn Spring area on ne. slope of Chuckwalla Mts." (Stebbins 2003).

There is also a population of U. ornatus in the city of San Bernardino. These were certainly introduced, but their origin is not known. More information will be available after the publication of this distribution note:
Hakim, J. and J. Bass: Urosaurus ornatus symmetricus. Distribution note in Herpetological Review (in press December 2010)

Beyond California,Urosaurus ornatus is found in much of Arizona, New Mexico and Texas, as well as in extreme southern Nevada and Utah, extreme southwest Wyoming, western Colorado, and in extreme northeast Baja California and into the states of Sonora, Chihuahua, Sinaloa, Coahuila, and Tamaulipas, in Mexico.
Found at elevations from sea level to around 9,000 ft. (2,770 m). (Stebbins 2003)

Habitat

Found in desert habitats with or without trees, which include mesquite, tamarisk, oaks and cottonwoods. Often seen on buildings and fence posts. Especially attracted to the edges of rivers, streams and washes.

Taxonomic Notes

A number of subspecies of Urosaurus ornatus have been recognized, with 6 found in the U. S. A. Many researchers choose not to recognize any subspecies.

Conservation Issues (Conservation Status)

None.

Taxonomy
Family	Phrynosomatidae	Zebra-tailed, Earless, Fringe-toed, Spiny, Tree, Side-blotched, and Horned Lizards
Genus	Urosaurus	Tree & Brush Lizards
Species	ornatus	Ornate Tree Lizard
Subspecies	symmetricus	Colorado River Tree Lizard
Original Description
Urosaurus - Hallowell, 1854 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 7, p. 92 Urosaurus ornatus - (Baird and Girard, 1852) - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 126 (part) Urosaurus ornatus symmetricus - (Baird, 1858) - Proc. Acad. Nat. Sci. Philadelphia, Vol. 10, p. 253 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Urosaurus - Greek - oura - tail and saurus - lizard ornatus - Latin - ornamented symmetricus - Latin - balanced or equal - referring to the regular series of larger dorsal scales from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Urosaurus ornatus - Ornate Tree Lizard (with no subspecies recognized)
Related or Similar California Lizards
Urosaurus nigricaudus - Baja California Brush Lizard Urosaurus graciosus - Long-tailed Brush Lizard
More Information and References
Natureserve Explorer California Dept. of Fish and Game Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998. 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. St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. Lone Pine Publishing, 2002. Brennan, Thomas C., and Andrew T. Holycross. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, 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. This animal is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	None
Bureau of Land Management	None
USDA Forest Service	None
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List

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