''Crotalus pusillus'', or the Tancitaran Dusky Rattlesnake, 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 ...

pit viper The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfa ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

found in west-central

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. No

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are currently recognized.

Description

Adult males may grow to more than in length, while females are smaller. The largest recorded length for a specimen was .Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .

Behavior

Campbell and Lamar (2004) found this species only to be active during the day. Within its range, night temperatures are low and seem to restrict its activity.

Geographic range

It is found in west-central

in the Sierra de Coalcomán of southwestern

Michoacán Michoacán, formally Michoacán de Ocampo (; Purépecha: ), officially the Free and Sovereign State of Michoacán de Ocampo ( es, Estado Libre y Soberano de Michoacán de Ocampo), is one of the 32 states which comprise the Federal Entities of ...

, the Transverse Volcanic Cordillera of west-central Michoacán, and in adjacent

Jalisco Jalisco (, , ; Nahuatl: Xalixco), officially the Free and Sovereign State of Jalisco ( es, Estado Libre y Soberano de Jalisco ; Nahuatl: Tlahtohcayotl Xalixco), is one of the 31 states which, along with Mexico City, comprise the 32 Federal En ...

. It is probably also found in northeastern

Colima Colima (), officially the Free and Sovereign State of Colima ( es, Estado Libre y Soberano de Colima), is one of the 31 states that make up the Political divisions of Mexico, 32 Federal Entities of Mexico. It shares its name with its capital and ...

. Its type locality is reported as "Tancítaro, Michoacán, Mexico, altitude 5,000 ft" (5,000 ft = 1,524 m). It occurs at elevations between .

Conservation status

This species is classified as Endangered on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

of Threatened Species. The population trend was unknown when assessed in 2007.

References

External links

* {{Taxonbar, from=Q146494