Crotalus mitchellii is a venomous pit viper species found in the Southwestern United States and northern Mexico. It was named in honor of Silas Weir Mitchell (1829–1914), a medical doctor who also studied rattlesnake venoms. Five subspecies are currently recognized, including the nominate subspecies described here.
Generally, this species does not exceed 100 cm (39 in) in length, with large males measuring between 90 and 100 cm (35 and 39 in). The race on Angel de la Guarda Island is known to become larger, the maximum recorded length for a specimen there being 136.7 cm (53.8 in). In contrast, the population on El Muerto Island only reaches a maximum of 63.7 cm (25.1 in) in length.
This species is found in the southwestern United States and in northwestern Mexico. In the US, its range includes east-central and southern California, southwestern Nevada, extreme southwestern Utah, and western Arizona. In Mexico, it is native in most of Baja California, including Baja California Sur. It also inhabits a number of islands in the Gulf of California, including Angel de la Guarda Island, Carmen, Cerralvo, El Muerto, Espíritu Santo, Monserrate, Piojo, Salsipuedes, and San José, as well as on Santa Margarita Island off the Pacific coast of Baja California Sur.
Subspecies and taxonomy
|Subspecies||Taxon author||Common name||Geographic range|
|C. m. angelensis||Klauber, 1963||Angel de la Guarda Island speckled rattlesnake||Mexico, on the island of Ángel de la Guarda|
|C. m. mitchellii||(Cope, 1861)||San Lucan speckled rattlesnake||Mexico, in Baja California Sur and on the islands of Santa Margarita, Cerralvo, Espíritu Santo, San José, Monserrate, and Carmen|
|C. m. muertensis||Klauber, 1949||El Muerto Island speckled rattlesnake||Mexico, on the island of El Muerto|
|C. m. pyrrhus||(Cope, 1866)||Southwestern speckled rattlesnake||The US in southern California, southern Nevada, southwestern Utah, and western Arizona, Mexico in northwestern Sonora and northern Baja California|
|C. m. stephensi||Klauber, 1930||Panamint rattlesnake||East-central California and southwestern Nevada|
The nominate subspecies (C. m. mitchellii) is classified as "Least Concern" on the IUCN Red List of Threatened Species. The population trend was stable when assessed in 2007. Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category.
- List of crotaline species and subspecies
- Crotalus by common name
- Crotalus by taxonomic synonyms
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
- Frost, D.R. (2007). "Crotalus mitchellii". IUCN Red List of Threatened Species. Version 2014.3. International Union for Conservation of Nature. Retrieved 5 March 2015.
- McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- U.S. Navy. 1991. Poisonous Snakes of the World. US Govt. New York: Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.
- Ditmars RL. 1933. Reptiles of the World. Revised Edition. The MacMillan Company. 329 pp. 89 plates.
- "Crotalus mitchellii". Integrated Taxonomic Information System. Retrieved 25 February 2007.
- Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. First published in 1956, 1972. University of California Press. Berkeley. ISBN 0-520-21056-5.
- 2001 Categories & Criteria (version 3.1) at the IUCN Red List. Accessed 13 September 2007.
- Cope, E.D. 1861. Contributions to the Ophiology of Lower California, Mexico and Central America. Proc. Acad. Nat. Sci. Philadelphia 13: 292-306. (Caudisona mitchellii, pp. 293-294.)
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