:''Common names: New Mexico ridge-nosed rattlesnake.''Crotalus willardi obscurus''
at U.S. Fish and Wildlife Service. Accessed 13 August 2007.'' Animas ridge-nosed rattlesnake,Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. . ''Crotalus willardi obscurus'' is a

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

pitviper

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

found in northwestern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

and the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

Description

The color pattern consists of a gray or brownish gray ground color with scattered dark punctations. The facial stripes that are characteristic of this species may be completely absent. In the Sierra San Luis population, traces of the pale upper facial stripe may be visible on the posterior upper labials, but there is no pale stripe on the lower labials.Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. 2 volumes. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .

Geographic range

Found in the Animas and adjacent

Peloncillo Mountains (Hidalgo County) The Peloncillo Mountains of Hidalgo County, (Spanish language ''pelo'', hair, ''pelón'', hairless, bald; ''peloncillo'', Little Baldy), is a major long mountain range southwest of New Mexico's Hidalgo County, and also part of the New Mexico Bo ...

in extreme southeastern

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

and extreme southwestern

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, and in the Sierra San Luis of extreme northwestern Chihuahua and extreme northeastern

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

. The type locality given is "one canyon in the Animas Mountains" (New Mexico, USA).

Conservation status

This species is listed as Threatened by the U.S. Fish and Wildlife Service, and is therefore afforded protection by the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

. It is listed because of its limited geographic range and the supposed threat to it of overcollection for the reptile trade.

References

External links

''Crotalus willardi obscurus''
{{Taxonbar, from=Q5188965 willardi obscurus ESA threatened species