Crotalus simus

Common names: Middle American rattlesnake,^[1] Central American rattlesnake.^[3]

Crotalus simus is a venomous pitviper species found in Mexico and Central America. The specific epithet is Latin for "flat nosed"; likely an allusion to the fact that its head is relatively blunt when compared with the lanceheads (Bothrops). Currently, 3 subspecies are recognized, including the nominate subspecies described here.^[4]

Additional recommended knowledge

Essential Laboratory Skills Guide

How to quickly check pipettes?

Correct Test Weight Handling Guide: 12 Practical Tips

Description

Adults commonly exceed 130 cm in length, with males growing larger than females. Large males reach 140-160cm in some populations. The maximum reported length is 180 cm.^[1]

The body has an exceedingly rough appearance as the normal dorsal scale keels are accentuated into protuberances or tuberculations. This is most apparent on the scale rows to either side of the vertebral scales, with a decreasing intensity in the lower rows. The vertebral scales are about as prominently keeled as the fourth row down on the flanks (with the vertebral scales as the first row).^[3]

Geographic range

Found from Mexico in southwestern Michoacán on the Pacific coast, and Veracruz and the Yucatan Peninsula on the Atlantic coast, south through Belize, Guatemala, El Salvador, Honduras and Nicaragua to west-central Costa Rica. It is absent from Panama, but apparently does occur on the Atlantic side of Colombia.^[1] The type locality given is "Ceylan," which is incorrect.^[2]

Habitat

Usually found in regions that are semiarid, including tropical forests that are dry or very dry, thorn woodland and arid scrub forest. It also occurs in mesic forests with relatively dry open areas.^[1]

Venom

Bites from this species are similar to rattlesnake bites in the United States. Local symptoms may be severe, with pain, massive swelling, blistering and necrosis that often lead to physicians performing fasciotomies and in some cases amputations. Systemic effects involving hemostatic disturbances are rare, as are renal failure and neurotoxicity. Only venom from neonates contains crotoxin; a constituent typically found in C. durissus venom that produces to neurotoxic symptoms.^[5]

Subspecies

Taxonomy

Previously, the description for this form was listed as the nominate subspecies for the tropical rattlesnake, C. durissus.^[2]

See also

• List of crotaline species and subspecies
• Crotalus by common name
• Crotalus by taxonomic synonyms
• Crotalinae by common name
• Crotalinae by taxonomic synonyms
• Snakebite

References