Common names: Mexican horned pitvipers.[1]
Ophryacus is a genus of pit vipers endemic to Mexico. The name is derived from the Greek word ophrys (ὀφρύς), which means "brow", and the Latin word acus, which means "needle", an allusion to the characteristic horn-like scales over the eyes.[1] Currently, three species are recognized and no subspecies.
The larger of the two species, O. undulatus, grows to between 55and in length. They are characterized by the presence of a single scale over the eye that takes the shape of either a long and relatively slender spine, or a flattened horn. Often, other supraocular scales are also shaped in such a way that they project slightly.[1]
They are restricted to the mountains of eastern, central and southern Mexico.
| Species | Taxon author | Common name | Geographic range | |
|---|---|---|---|---|
| O. smaragdinus | Grünwald, Jones, Franz-Chávez & Ahumada-Carrillo, 2015 | Emerald Horned Pitviper | Eastern Mexico. | |
| O. sphenophrys | (L. Müller, 1924) | Broad-horned Pitviper | The mountains of Oaxaca. | |
| O. undulatusT | (Jan, 1859) | Slender-horned Pitviper | The mountains of central and southern Mexico (Hidalgo, Veracruz, Oaxaca, and Guerrero) west of the Isthmus of Tehuantepec at elevations of 1800–2800 m (5,900–9200 feet). |