Cyclura cornuta onchiopsis
|Cyclura cornuta onchiopsis (Navassa Island iguana)|
|Subspecies:||C. cornuta onchiopsis|
|Cyclura cornuta onchiopsis
Cyclura cornuta onchiopsis, commonly known as the Navassa Island iguana, was a subspecies of rhinoceros iguana of the genus Cyclura that was found on the Caribbean island of Navassa. It is "undoubtedly" extinct.
The generic name (Cyclura) is derived from the Ancient Greek cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. Its specific name, cornuta, is the feminine form of the Latin adjective cornutus, meaning "horned" and refers to the horned projections on the snouts of males of the species. The species was first described by American herpetologist Edward Drinker Cope in 1885.
In 1885, Cope first described the lizard as two species in the same paper: C. onchiopsis and C. nigerrima, due to the animal's almost black coloration. A year later he renamed it as C. onchiopsis. Herpetologists Albert Schwartz and Richard Thomas officially reclassified it as a subspecies of C. cornuta 90 years later, based on the writings of Thomas Barbour and Robert Mertens, yet presented numerous data relating to scale count that suggested otherwise. In 1977, Schwartz and Carey wrote “It is even conceivable that onchiopsis should be considered a species distinct from C. cornuta on the basis of this single character (distinctly smaller dorsolateral scales) (plus perhaps other modalities), but to do so would obscure its obvious affinities with the latter species.”
In 1999, Dr Robert Powell wrote that, based on these prior studies, this animal should be elevated to full species status, distinct from C. cornuta.
These lizards varied in length from 60 to 136 cm (24 to 54 in), with skin colors ranging from a steely gray to a dark green and even brown, and possessed a bony-plated pseudo-horn or outgrowth which resembled the horn of a rhinoceros.
Navassa Island was visited in 1966 and 1967 and no animals were present. An entomologist visited the island again in 1986 and saw no signs of any iguanas although he was not specifically looking for them. An extensive search again in 1999 failed to find any iguanas. Military occupation of the island prior to the 1960s may have been responsible for its demise, or years of mining guano for fertilizer; the introduction of feral dogs, goats, and rats may have been to blame. Dr Robert Powell's research while at the Department of Natural Sciences, Avila College, Kansas City, Missouri, suggests that the iguanas disappeared before the introduction of feral species, as a result of habitat change or hunting by man. Noted herpetoculturist David Blair maintains that some of these animals may remain in captivity somewhere in the world but admits they would be very aged specimens.
- Cope, E.D. (1885). "The large iguanas of the Greater Antilles". American Natural History. 19: 1005-1006
- Encyclopedia of Life. www.eol.org.
- The Reptile Database. www.reptile-database.org.
- Powell, R. (2000). Cyclura onchiopsis Cope Navassa Island Rhinoceros Iguana. Catalogue of American Amphibians and Reptiles. 710: 1-3.
- Sanchez, Alejandro. "Family Iguanidae: Iguanas and Their Kin". Father Sanchez's Web Site of West Indian Natural History Diapsids I: Introduction; Lizards. Kingsnake.com. Retrieved 26 November 2007.
- Cope, E.D. (1886). "On the species of Iguaninae". Proceedings of the American Philosopher's Society. 23 (122): 261-271
- Schwartz, A. and R. Thomas. (1975). A check-list of West Indian amphibians and reptiles. Carnegie Museum of Natural History. Pittsburgh.(1):1-216.
- Schwartz, A., and M. Carey. (1977). "Systematics and evolution in the West Indian iguanid genus Cyclura". Studies in Fauna of the Curaçao Caribbean Islands 53:15-97.
- Powell, Robert, "Herpetology of Navassa Island, West Indies" (PDF), Caribbean Journal of Science (University of Puerto Rico) 35 (1–2): 1–13, retrieved 2007-09-09
- Hollingsworth, Bradford D. (2004), "The Evolution of Iguanas: An Overview of Relationships and a Checklist of Species", Iguanas: Biology and Conservation (University of California Press): 37–38, ISBN 978-0-520-23854-1
- Blair, David, Navassa Island Iguana, archived from the original on 2007-10-08, retrieved 2007-09-09
- Navassa Island: A Photographic Tour, retrieved 2007-09-09