Crotalus oreganus helleri

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Crotalus oreganus helleri

Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Viperidae
Subfamily:	Crotalinae
Genus:	Crotalus
Species:	C. oreganus
Subspecies:	C. o. helleri

Trinomial name

Crotalus oreganus helleri
Meek, 1905

Synonyms

Crotalus helleri - Meek, 1905
Crotalus viridis helleri - Klauber, 1949^[1]

Common names: Southern Pacific rattlesnake,^[2] black diamond rattlesnake,^[3] more.

Crotalus oreganus helleri is a venomous pitviper subspecies^[2] found in South-West California and south into Baja California.

1 Description
2 Common names
3 Geographic range
4 See also
5 References
6 Further reading
7 External links

[edit] Description

Adults are 24-55 inches (61-139 cm) in length.^[3]

C. o. helleri

The color pattern consists of a pale brown, gray-brown, or yellowish brown ground color overlaid with a series of large, dark brown dorsal blotches that may or may not have pale centers.^[4] The blotches are more diamond shaped, as opposed to those of C. o. oreganus that are more hexagonal,^[3] and are bordered by light scales. The tail rings are not clearly defined.^[5] In juveniles, the end of the tail is bright orange, but this turns to brown as the snakes mature. In adults, the base of the tail and the first segment of the rattle are brown. The postocular stripe is moderately to very clearly defined. In juveniles, this stripe is bodered above by a pale stripe, but as the snakes mature this turns to drab yellow or brown. A conspicuous pale crossbar is sometimes present across the supraoculars, after which the head is a uniform dark color. In some older snakes the head is mostly dark with almost no trace of the supraorbital crossbar, or none at all.^[4]

[edit] Common names

Southern Pacific rattlesnake,^[2]^[3] black diamond rattlesnake, black (diamond) rattler, gray diamond-back, mountain rattler, Pacific rattler, San Diegan rattler, timber rattler.^[3]

[edit] Geographic range

C. o. helleri, juvenile.

The United States in southern California, and Mexico in northern Baja California, west of the desert. In the north from the counties of San Luis Obispo and Kern, and south through the counties of Santa Barbara, Ventura, Los Angeles (including Santa Catalina Island), southwestern San Bernardino, Orange, western Riverside, San Diego and extreme western Imperial. From there its range extends south though Baja California to lat. 28° 30' North.^[6] According to Klauber (1956), the type locality is "San Jose, Lower California" [San José, lat. 31° N, Baja California (state), Mexico].^[1]

[edit] See also

[edit] References

^ ^a ^b 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).
^ ^a ^b ^c Crotalus oreganus helleri (TSN 683065). Integrated Taxonomic Information System. Retrieved on 28 November 2006.
^ ^a ^b ^c ^d ^e Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. ISBN 0-8014-0463-0.
^ ^a ^b Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. 2 volumes. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
^ Behler JL, King FW. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. LCCCN 79-2217. ISBN 0-394-50824-6.
^ 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.

[edit] Further reading

Ashton KG, de Queiroz A. 2001. Molecular systematics of the western rattlesnake, Crotalus viridis (Viperidae), with comments on the utility of the d-loop in phylogenetic studies of snakes. Molecular Phylogenetics and Evolution, Vol. 21, No.2, pp. 176-189. PDF at CNAH. Accessed 12 December 2007.