- Common names: Mexican horned pitvipers.
Ophryacus is a genus of venomous pit vipers endemic to Mexico. The name is derived from the Greek word ophrys, which means "brow", and the Latin word acus, which means "needle", an allusion to the characteristic horn-like scales over the eyes. Currently, two species are recognized and no subspecies.
The larger of the two species, O. undulatus, grows to between 55 and 70 cm (22 and 28 in) 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.
They are restricted to the mountains of central and southern Mexico.
|Species||Taxon author||Common name||Geographic range|
|O. melanurus||(L. Müller, 1924)||Black-tailed horned pit viper||The mountains of southern Mexico (southern Puebla and Oaxaca) at elevations of 1600–2400 m (5,250-7,875 feet).|
|O. undulatusT||(Jan, 1859)||Mexican horned pit viper||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).|
- List of crotaline species and subspecies
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
- McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- "Ophryacus". Integrated Taxonomic Information System. Retrieved 4 November 2006.
- Cope, E.D. 1887. Catalogue of Batrachians and Reptiles [Batrachia and Reptilia] of Central America and Mexico.
Bull. U.S. Nat. Mus. 32: 1-98. ("Ophryacus Cope, gen. nov.", p. 88.)