Crotalus willardi obscurus
Encyclopedia
- Common names: Animas ridge-nosed rattlesnake, New Mexican ridge-nosed rattlesnake.
Crotalus willardi obscurus is a venomous
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
pitviper
Crotalinae
The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...
subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
found in northwestern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the southwestern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.This is the only venomous snake listed as Threatened by the U.S. Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
.
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.Geographic range
Found in the AnimasAnimas Mountains
The Animas Mountains are a small mountain range in Hidalgo County, within the "Boot-Heel" region of far southwestern New Mexico, in the United States. They extend north-south for about 30 miles along the Continental Divide, from near the town of Animas to a few miles north of the border with...
and adjacent Peloncillo Mountains (Hidalgo County)
Peloncillo Mountains (Hidalgo County)
The Peloncillo Mountains of Hidalgo County, , is a major 35-mi long mountain range of southwest New Mexico's Hidalgo County, and also part of the New Mexico Bootheel region. The range continues to the northwest into Arizona as the Peloncillo Mountains of Cochise County, Arizona...
in extreme southeastern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
and extreme southwestern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and in the Sierra San Luis of extreme northwestern Chihuahua and extreme northeastern Sonora
Sonora
Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. The type locality given is "one canyon in the Animas Mountains" (New Mexico, USA).
Conservation status
This is the only venomous snake that is listed as Threatened by the U.S. Fish and Wildlife ServiceUnited States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
, and is therefore afforded protection by the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
. It is listed because of its limited geographic range and the supposed threat to it of overcollection for the reptile trade.