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Reptilia    Testudines    Emydidae  
Northwestern Pond Turtle
Actinemys marmorata (Baird and Girard, 1852)
AK-ti-NEH-meez — mar-moh-RAH-tah
Taxon Links
iNaturalist
The Reptile Database
Catalog of American Amphibians and Reptiles
NatureServe
GenBank
USGS Nonindigenous Aquatic Species Database

SSAR 9th Edition Comments:
 There are no current SSAR comments for this taxon.

(,   Museum Voucher) (,   Observation) (,   Literature Record), (,   Citizen Science), (  Fossil)
Open icons indicate questionable records, including those with coordinate uncertainty greater than 10,000 m (approximately 6 miles). Click a marker to view metadata.
Occurrences:; 7,786 Total; 1,649 Museum; 6,137 Other

The locality database contains 8,094,832 records, and geographic and taxonomic errors exist. Logged-in, registered users may report a potential issue directly from the marker popup.
Shaded range maps are based on curated specimens and provided gratis by CNAH. (Version: 2026.05.14.13.15.03)
Download map data (GeoJSON):
Polygon Range File Museum Literature Fossil Personal Observation Citizen Science

Province/State Distribution:
Canada: British Columbia
United States: California Nevada Oregon Washington

Taxonomic Etymology:
A pond turtle with marbled patterning.
Actinemys — From Greek aktis (ἀκτίς), “ray” or “beam,” and emys (ἐμύς), “freshwater turtle.” Possibly refers to the radiating pattern on the shell or the turtle’s basking habit.
marmorata — From Latin marmoratus, “marbled.” Refers to the marbled or mottled patterning on the turtle’s carapace.

First instance(s) of published English names:
Western Pond Turtle (Actinemys marmorata: Cooper, James G., George Suckley, William Cooper, George Gibbs, Asa Gray, and John L. Le Conte. 1859. The natural history of Washington territory, with much relating to Minnesota, Nebraska, Kansas, Oregon, and California, between the thirty-sixth and forty-ninth parallels of latitude, being those parts of the final reports on the survey of the Northern Pacific railroad route, containing the climate and physical geography, with full catalogues and descriptions of the plants and animals collected from 1853 to 1857. Bailliere Bros., London, H. Bailliere;, New York, New York. pp.); California Terrapin (Chelopus marmoratus: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Pacific Terrapin (Clemmys marmorata: Van Denburgh, John. 1897. The reptiles of the Pacific Coast and Great Basin: An account of the species known to inhabit California, and Oregon, Washington, Idaho, and Nevada. Occasional Papers of the California Academy of Sciences 5():9-236); Pacific Pond Turtle (Clemmys marmorata: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Pacific Pond Turtle (Clemmys marmorata marmorata: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.);


Selected References:
1852 Baird, Spencer F. and Charles Girard. Descriptions of new species of reptiles, collected by the U. S. Exploring Expedition under the command of Capt. Charles Wilkes, U. S. N., First Part including the species from the western part of America. Proceedings of the Academy of Natural Sciences of Philadelphia 6:174-177
1970 Bury, R. Bruce. Clemmys marmorata.. Catalogue of American Amphibians and Reptiles (100):1-3
2002 Seidel, Michael E. Hemoglobin variation and comments on systematic relationships in the turtle family Emydidae. Copeia 2002(4):1118-1121
2014 Spinks, Phillip Q., Robert C. Thomson, and H. Bradley Shaffer. The advantages of going large: Genome-wide SNPs clarify the complex population history and systematics of the threatened western pond turtle. Molecular Ecology 23(9):2228-2241
2015 Ashton, Donald T., James B. Bettaso, and Hartwell H. Welsh, Jr. Changes across a decade in size, growth, and body condition of Western Pond Turtle (Actinemys marmorata) populations on free-flowing and regulated forks of the Trinity River in northwest California. Copeia 103(3):621-633

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