Ophryacus
The Mexican Horn Terciopelos ( Ophryacus ) are a snake genus of the subfamily of pit vipers. The genus comes with two types present in higher elevations in the Middle East and southern Mexico. The animals inhabit dry scrub, tropical deciduous forests and pine-oak forests with a pronounced dry season, and cloud forests. Mexican Horn Terciopelos are toxic, more on the toxicity in humans has so far, however, nothing is known. The German name refers to the striking, horn - or spike- like extended scales over the eyes.
- 6.1 Notes and references
- 6.2 Literature
Features
Physique
Mexican Horn Terciopelos are small to medium-sized, relatively strong snakes. The head is large, broad and distinct from neck. The snout is pointed and the canthus is formed sharp. The tail is not prehensile. The total lengths of species normally 37.5 to 50 cm, maximum 57.8 cm (O. melanurus ) or 55-70 cm (O. undulatus).
Squamation
The rostral is wider than high and clearly concave. There are three Praeocularia, of which the upper one is significantly larger than the other. Species show Suboculare 2-6, 2-4 and 1-4 Postoculare Supraoculare. A single Supraoculare above the eye is extended into a long, relatively thin sting or a flattened horn. Frequently also show adjacent shed light increases. The scales on the canthus and the Internasalia can also wear short thorns or have particularly high keels. The top of the head is covered with small, mostly warty keeled scales.
The animals have 9 to 20 Intersupraoculare. The number of supralabials is 10 to 14, the number of Infralabialia 9 to 14 The number of ventral scales ( Ventralschilde ) varies 141-178, the number of split in O. undulatus, in contrast, O. melanurus undivided Subcaudalia 36-57 and the number of dorsal scale rows in the middle of the body 21
Coloring
The basic color of the top is reddish brown, olive-brown or gray, can add orange, yellow or green color come share. Show on the back of the animals a fairly wide, dark zigzag pattern. Are including one or more rows of smaller and more diffuse spots on the flanks. The sides of the head are unsigned or show a not very distinct black Postokularstreifen, which extends from the rear edge of the eye to behind the muzzle angle.
Distribution and habitat
Mexican Horn Terciopelos are limited to high altitudes 1600-2800 m altitude in the Middle East and southern Mexico. The animals inhabit there dry bushes, tropical deciduous forests and pine-oak forests with a pronounced dry season, and cloud forests.
System
Campbell & Lamar recognize two types:
- Ophryacus melanurus (Müller 1923)
- Ophryacus undulatus (Jan 1859)
A molecular genetic analysis involving both species has confirmed the monophyly of the genus.
Lifestyle, diet, and reproduction
Both species are probably also active during the day due to the low night temperatures. O. melanurus is apparently only ground alive, O. undulatus, however, is at least partially arboreal and was regularly found in three to four meters above the ground. The previously known food range includes small lizards and mammals. All species are viviparous, young are usually born at the beginning of the rainy season. Between 3 and 13 pups per litter are proven.
Poison
Mexican Horn Terciopelos like all pit vipers poisonous, more on the toxicity in humans has so far, however, nothing is known.