The Mexican lance-headed rattlesnake[3] or lance-headed rattlesnake[4] (Crotalus polystictus) is a venomouspit viperspecies found in central Mexico. No subspecies is currently recognized.[5]
Description
Adults usually grow to a total length of 60 to 70 cm (24 to 28 in), although exceptionally large specimens may be as much as 100 cm (39 in) long.[3]
Geographic range
The species is found on the plateau of central Mexico from southern Zacatecas and northeastern Colima east to east-central Veracruz. It occurs at elevations between 1,450 and 2,600 m (4,760 and 8,530 ft). The type locality given is "Table Land, Mexico", although a restriction to "Tupátaro, Guanajuanto, Mexico" was proposed by H.M. Smith and Taylor (1950).[2]
Conservation status
This species is classified as Least Concern on the IUCN Red List of Threatened Species (v3.1, 2001).[1] 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. The population trend was down when assessed in 2007.[6]
^ abMcDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN1-893777-00-6 (series). ISBN1-893777-01-4 (volume).
^ abCampbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN0-8014-4141-2.
^Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN0-8069-6460-X.
Cope, E.D. 1865. Third contribution to the HERPETOLOGY of Tropical America. Proc. Acad. Nat. Sci. Philadelphia 17: 185-198. (Caudisona polysticta, pp. 191–192.)
Smith, H.M. and E.H. Taylor. 1950. Type localities of Mexican reptiles and amphibians. Univ. Kansas Sci. Bull. 33: 313-380.