Crotalus basiliscus

Image:Mexican West Coast Rattlesnake 01.jpg, United States]]

C. basiliscus is one of the largest rattlesnake species. Specimens exceeding {{convert|150|cm|ft|abbr=on}} are not uncommon, while the maximum size reported is {{convert|204.5|cm|ft|abbr=on}} (Klauber, 1972). The body is moderately stout and rather rectangular in cross section.United States Navy (1991). Poisonous Snakes of the World. New York: US Government / Dover Publications Inc. 203 pp. {{ISBN|0-486-26629-X}}. Female rattlesnakes of the species are mature at a minimum length of {{convert|100|cm|ft|abbr=on}} and a weight of {{convert|700|g|lb|abbr=on}}.Loc Barragán, Jesús & Carbajal Márquez, Rubén & Woolrich-Piña, Guillermo & Navarro-Orozco, Roy. (2016). Crotalus basiliscus. Arboreal habitat use/ Litter size.. Mesoamerican Herpetology. 3. 494-496.

At midbody, 25-29 rows of strongly keeled dorsal scales occur. The ventral scales number 174-206 and the subcaudals 18-36.

The color pattern consists of brown or grayish ground color overlaid with 26-41 dark, rhombus-shaped (diamond) blotches with light edges. The head is a uniform grayish-brown except for its lighter labial scales and dark postorbital bar. No distinct pattern is found on the crown or neck areas. The tail may be gray, with darker bands, or almost uniform in color without any distinct markings. The belly is white or cream-colored. The young are mostly red, but adults eventually become an olive green. Within its range, this is the only rattlesnake with diamond-shaped dorsal markings.

This snake often occurs in the same areas as C. molossus, where the two appear to hybridize freely. While these two species are easily distinguished, identifying the hybrid specimens is problematic.

Common names for C. basiliscus include Mexican west coast rattlesnake, Mexican green rattler, Mexican west coast green rattlesnake,Mehrtens JM (1987). Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. {{ISBN|0-8069-6460-X}}. and in Spanish cascabel verde mexicana.

This rattler, C. basiliscus, is found in western Mexico from southern Sonora to Michoacán, where it is mostly restricted to the coastal plain. The type locality given is "Near Colima, Mexico".

Around Colima, where C. basiliscus is (or was at one point) particularly plentiful, the area has been described as mostly treeless and covered with short grass with scattered clumps of mesquite, acacias, and other thorny bushes, as well as plenty of large cacti. The habitat of C. basiliscus is mostly tropical thorn forest, with an extension into tropical deciduous forest.

The species C. basiliscus is classified as Least Concern on the IUCN Red List (v3.1, 2001). 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 trend for this species was stable when assessed in 2007.{{Redlist CC2001|date=13 September|year=2007}}

In the lowlands, C. basiliscus is primarily active during the rainy summer months, and most specimens are found crossing the roads at night. However, a few have been seen basking early in the morning. It has been reported to tame quickly in captivity.

Klauber reported that the stomachs of seven specimens of C. basiliscus contained mammal hair, probably belonging to rodents.

Crotalus basilicus is known to produce large amounts of highly toxic venom, and large specimens should be regarded as very dangerous.

Brown (1973) mentioned an average venom yield of 297 mg (dried venom), as well as {{LD50}} values of 11.1 mg/kg IV and 4.0 and 12.9 mg/kg IP.Brown JH (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. {{ISBN|0-398-02808-7}}.

In some populations, the venom may contain a component structurally related to Mojave toxin. The venom also contains proteases.Norris R (2004). "Venom Poisoning in North American Reptiles". In: Campbell JA, Lamar WW (2004). The Venomous Reptiles of the Western Hemisphere. Ithaca and London: Comstock Publishing Associates. 870 pp., 1,500 plates. {{ISBN|0-8014-4141-2}}. Antivenin is produced by the Instituto Nacional de Higiene in Mexico. In the US, [http://www.protherics.com/ Protherics] {{Webarchive|url=https://web.archive.org/web/20070219162834/http://www.protherics.com/ |date=2007-02-19 }} in Brentwood, Tennessee, produces an antivenin called "Crotalidae Polyvalent Immune Fab (Ovine)" containing a paraspecific antibody that protects against bites from this snake.[http://www.toxinfo.org/antivenoms/indication/CROTALUS_BASILISCUS.html Crotalus basiliscus] at [http://www.toxinfo.org/antivenoms/ Munich AntiVenom INdex]. Accessed 4 February 2007.

Before 1989, two subspecies were recognized: C. b. basiliscus and C. b. oaxacus. In that year, the latter was transferred to C. molossus by Campbell and Lamar. Occasionally, one may also encounter references to another subspecies, C. b. totonacus (Gloyd & Kauffeld, 1940), found in northeastern Mexico. It was more commonly considered to be a subspecies of C. durissus, until it was elevated to a full species by Campbell and Lamar (2004): Crotalus totonacus.{{ITIS|id=727494|taxon=Crotalus totonacus |access-date=27 August 2007}}

{{Reflist}}

• Cope ED (1864). "Contributions to the Herpetology of Tropical America". Proc. Acad. Nat. Sci. Philadelphia 16: 166-181. (Caudisona basilisca, new species, p. 166).

{{Commons}}

• {{NRDB species|genus=Crotalus|species=basiliscus|date=9 August|year=2007}}
• [http://www.vivanatura.org/Crotalus_basiliscusPhotos.html Crotalus basiliscus] at [http://www.vivanatura.org/ Biodiversity of Mexico]. Accessed 4 February 2007.
• [http://www.demogr.mpg.de/cgi-bin/longevityrecords/indexsearch.plx?category=2&data=3408 Longevity record for Crotalus basiliscus basiliscus] at [http://www.demogr.mpg.de/ Max Planck Institute for Demographic Research]. Accessed 4 February 2007.

{{Taxonbar|from=Q810157}}

basiliscus

Category:Taxa named by Edward Drinker Cope

Category:Reptiles described in 1864