Crotalus triseriatus
# Crotalus triseriatus

    Common names: Mexican dusky rattlesnake, dusky rattlesnake

Crotalus triseriatus is a venomous pit viper species found in Mexico. Two subspecies are currently recognized, including the nominate subspecies described here.

## Description

Adult male specimens of C. triseriatus commonly grow to a total length (including tail) greater than 60 cm (24 in), with females somewhat smaller. The maximum recorded total length is 68.3 cm (26.9 in).

## Geographic range

The species C. triseriatus is found in Mexico, along the southern edge of the Mexican Plateau in the highlands of the Transverse Volcanic Cordillera, including the states of Jalisco, México, Michoacán, Morelos, Nayarit, Puebla, Tlaxcala, and Veracruz. The type locality given by Wagler in 1830 is "Mexico". A restriction to "Alvarez, San Luis Potosí, Mexico" was proposed by H.M. Smith and Taylor (1950).

## Habitat

Crotalus triseriatus occurs in pine-oak forest, boreal forest, coniferous forest and, bunchgrass grasslands. On Volcán Orizaba, it is found at very high altitudes. There, the snow line comes down to about 4,572 m (15,000 ft), while green plants can be found up to 4,573 m (15,003 ft): the species has been found within this zone. However, it is most common at 2,700 to 3,350 metres (8,860 to 10,990 ft) in elevation.

## Conservation status

The species C. triseriatus is classified as Least Concern on the IUCN Red List of Threatened Species (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 population trend was stable when assessed in 2007.

## Feeding

Prey reportedly found in stomachs of C. triseriatus include a frog, a murid rodent (Neotomodon alstoni), lizards, other small mammals, crickets, and salamanders.

## Venom

Bite symptoms from C. triseriatus are reported to include intense pain, swelling, faintness, and cold perspiration.

## Subspecies

| Subspecies | Taxon author | Common name | Geographic range |
| - | - | - | - |
| C. t. armstrongi | Campbell, 1979 | western dusky rattlesnake | Mexico: Jalisco and Nayarit |
| C. t. triseriatus | (Wagler, 1830) | dusky rattlesnake | Mexico: Michoacán, Morelos, México, Puebla, Tlaxcala and Veracruz |

## Etymology

The subspecific name, armstrongi, is in honor of American herpetologist Barry L. Armstrong.

## Taxonomy

In the relatively recent past, two additional subspecies were described:

* C. t. anahuacus Gloyd, 1940 - currently regarded as a junior synonym of C. t. triseriatus
* C. t. quadrangularis Harris & Simmons, 1978 - currently regarded as a junior synonym of C. aquilus
