Geographic range: Neotropical: Endemic to Mexico and Guatemala. Some populations occur from low moderate elevations of the Sierra de los Tuxtlas in southern Veracruz, México to Central Guatemala. This species occurs on the Volcan Santa María and Volcan San Martín and is known from elevations of 530- 1100 m., it is also known from Cerro Baúl, Oaxaca and north of Chiapas and Baja Verapaz.

Physical characteristics: Stout, terrestrial pitviper, males are known to reach 62 cm, females 77 cm. The dorsal ground color between the dorsal blotches is red, reddish gray or orange tan, a dark brown postocular stripe extends diagonally from the lower posterior edge of the eye to the ventrolateral surface of the head. A pair of elongate, dark brown nuchal blotches that are usually not fused posteriorly, is followed by 19-23 dark brown , rhomboidal or diamond shaped dorsal blotches, that are often fused, especially on the posterior part of the body.

Food habits: Poorly known, some juveniles feed on orthopterans and adults feed on small mammals.

Reproduction: Little is known on reproduction, this species is viviparous. There is no information available for litter size and reproduction season for this species.

Behavior: Some individuals are typically alert by night, but also frequently active by day. This snake is shy and tends to lower and hide the head at initial contact, if it greatly irritated, it will raise the head and vibrate the tail.

Habitat: Upper rainforest ( lower montane wet forest) and cloud forest, which occurs above 1000 m on the four largest volcanoes in the Sierra de los Tuxtlas.

text: © Alfonso Delgadillo