A Guide to the Amphibians
and Reptiles of California

Texas Spiny Softshell - Apalone spinifera emoryi

(Agassiz, 1857)
Click on a picture for a larger view

Texas Spiny Softshell locations in California
Range in California: Red

observation link

This is an alien species that has been introduced into California. It is not a native species.

Texas Spiny Softshell Texas Spiny Softshell Texas Spiny Softshell
Adult, Imperial County © Gary Nafis. Specimen courtesy of Jeff Lemm & Rick Sturm
Texas Spiny Softshell Texas Spiny Softshell Texas Spiny Softshell
Adult Imperial county
© William Flaxington
Captive adult courtesy of Tim Burkhardt  © Gary Nafis
Texas Spiny Softshell Texas Spiny Softshell Texas Spiny Softshell
Adult, Kern County © John Reinsch
Texas Spiny Softshell    
Adult resting just below the surface of an irrigation canal in Imperial County
(that refused to surface whenever I tried to photograph it. They can be very wary.)
Texas Spiny Softshells From Outside California
Texas Spiny Softshell Texas Spiny Softshells  
Adult female,  Brewster County, Texas
© Dick Bartlett
Adult female (left) and male (right)
Brewster County, Texas © Dick Bartlett
Texas Spiny Softshell Habitat Texas Spiny Softshell Habitat Texas Spiny Softshell Habitat
Habitat, Colorado River, Imperial County Habitat, Imperial County lake Habitat, Colorado River, Imperial County
Texas Spiny Softshell Habitat
Texas Spiny Softshell Habitat Texas Spiny Softshell Habitat
Habitat, San Pablo Reservoir,
Contra Costa County
Habitat, agricultural drain, Imperial County
Habitat, Irrigation ditch,
Imperial County
  Texas Spiny Softshell Habitat  
  Habitat, Irrigation ditch, Imperial County  
5 - 21 inches in shell length (12.7 - 53.3 cm). (Stebbins 2003)

A very flat turtle with a rounded, leathery-skinned, flexible, shell which is keelless and unhinged.
The snout is long with open nostrils on the end.
The limbs are flat with broadly-webbed feet.
Color and Pattern
Color is olive, brown or grayish, sometimes with dark markings which fade with age.
The head and limbs are olive to gray with dark markings.
Two dark-bordered light stripes mark each side of the head, extending from the back of the eye and from the back of the angle of the jaw.
The shell has a yellowish border with a dark line around it.
The carapace is rimmed with pale coloring which is four to five times wider on the rear than on the front and sides.
There are pale conical spiny projections (tubercles) along the rear third of the shell.
The plastron is yellowish and unmarked.
Male / Female Differences
Males are smaller than females with a thick tail that extends beyond the carapace, and their pattern is more contrasted than that of females.
The shell has a sandpaper-like texture.

Females become more blotched and mottled as they get older and have a smoother shell with well-developed warts on the front edge.
Juveniles have prominent dark markings on the head and the limbs and black spots on the shell.

Life History and Behavior

Thoroughly aquatic, but basks out of the water.
Active most of the year, becoming dormant in cold temperatures.

Often remains hidden underwater with the snout extended up to the surface to breathe.
Difficult to approach, moves very fast on land and in the water.
Capable of scratching vigorously and producing a painful bite if handled.
Diet and Feeding
Predominately carniverous. Eat insects, crayfish, worms, snails, fish, frogs, tadpoles, and reptiles.
Both actively hunts its prey and sits still to ambush passing prey. May also scavenge its food.
From May to August, females crawl onto land to lay 1 or 2 clutches of 3 - 39 eggs on exposed, sunny, sandy banks. Hatchlings emerge from August to October.

Geographical Range
Introduced into the lower Colorado river, this turtle has extended its range west into the Imperial Valley and north to the Salton Sea in Imperial and Riverside Counties. It has also been introduced into San Pablo reservoir in Contra Costa County, Lower Otay Reservoir, the San Diego River, and elsewhere in San Diego County, the Santa Ana River in Orange County, the San Gabriel River and Long Beach in Los Angeles County, Coyote Creek in Santa Clara County, Bakersfield and Kern NWR in Kern County and irrigation canals north in Kings County, Montecito in Santa Barbara County, and in the Sacramento River System. It is not known if all of these specimens represent single waifs or breeding populations. (USGS)

Apalone spinifera emoryi, Texas Spiny Softshell, is native to the Rio Grande and Pecos River drainages in Texas and New Mexico, and the lower Rio Grande Valley in Texas, and northern Mexico. It has also been introduced into parts of Arizona, New Mexico, Nevada, Utah, and Baja California.

The species Apalone spinifera - Spiny Softshell, ranges widely through most of the central  and southeastern part of the United States with isolated populations in Montana and extreme southern Canada north of New York, and ranging south into northeastern Mexico.

Full Species Range Map
In California, it is found in permanent, not temporary, rivers, agricultural canals, drainage ditches, artificial lakes and ponds. Prefers still water with a muddy, sandy, or gravelly bottom, and aquatic vegetation.

Notes on Taxonomy

Six subspecies are recognized including one endemic in Mexico.
The former subspecies A. s. hartwegi - Western Spiny Softshell, was synonymized with A. s. spinifera in 2008 by McGaugh et al. (2008, Zoologica Scripta 37:289-304)

Formerly classified in the genus Trionyx (Trionyx spinifera emoryi)

Alternate and Previous Names (Synonyms)

Apalone spinifera - Spiny Softshell Turtle (Stebbins & McGinnis 2012)
Trionyx spiniferus emoryi - Texas Spiny Softshell (Stebbins 1985, 2003)
Trionyx spiniferus emoryi - Texas Softshell (Stebbins 1966)
Trionyx ferox emoryi - Spiny Soft-shelled Turtle (Stebbins 1954)

Conservation Issues  (Conservation Status)
Family Trionychidae Softshell Turtles Bell, 1828
Genus Apalone North American Softshells Rafinesque, 1832
Species spinifera Spiny Softshell (LeSueur, 1827)

emoryi Texas Spiny Softshell (Agassiz, 1857)
Original Description
Apalone spinifera - (Le Sueur, 1827) - Mem. Mus. Hist. Nat. Paris, Vol. 15, p. 258, pl. 6
Apalone spinifera emoryi - (Agassiz, 1857) - Contr. Nat. Hist. U. S., Vol. 1, p. 407; Vol. 2, pl. 6, figs. 4 and 5

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Apalone - Greek - apalos - soft, tender - referring to the soft shell
- Latin - spina- thorn or spine, and -ifer - bearing - refers to the spine-like tubercules along front edge of upper shell
emoryi - honors Emory, William H.

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Alternate Names
formerly Trionyx spiiferus emoryi

Related or Similar California Turtles
No other turtles, native or introduced, are similar in appearance to the Texas Spiny Softshell. However, sometimes other species of softshell turtles sold as pets or found in Asian food markets are released into the wild.

More Information and References
California Department of Fish and Wildlife

Resources List


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.

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.

Carr, Archie. Handbook of Turtles: The Turtles of the United States, Canada, and Baja California. Cornell University Press, 1969.

Ernst, Carl H., Roger W. Barbour, & Jeffrey E. Lovich. Turtles of the United States and Canada. Smithsonian Institution 1994. (2nd Edition published 2009)

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 and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.

This turtle is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.

Status Listing
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Wildlife
Bureau of Land Management
USDA Forest Service


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