The Colorado Plateau Province in Utah, Colorado, New Mexico and Arizona is one of the most diverse, beautiful, and ecologically untouched regions remaining in the United States.
This province was one of the last places in the continental US to be mapped and even today the portion located in Utah has the largest roadless area in the lower 48 states (BLM 2002). Statistics such as these show that this region is bona fide wilderness. Overall, this province has escaped the negative impact from human encroachment longer than most.
The vast diversity of physical attributes has resulted in spatial overlay of vegetation in variable composition providing the conditions for numerous local adaptations by rattlesnakes and prey (Douglas et al. 2002). Thus, snakes and other wildlife have been adapting to these dramatic microhabitats within the province which has produced some major natural history divergences in a relatively constricted geography.
The Colorado River bisects the region providing a central axial reference. Both the Colorado and the Green River have thought to have contributed to the distribution of biota (Douglas et al. 2002). The Colorado Plateau has a major and distinct ecological fingerprint. This complexity has yielded a diverse group of rattlesnakes known originally as the Crotalus confluentus group (Klauber 1930), and later as the Western Rattlesnakes or “viridis / oreganus” complex (Douglas et al. 2002).
Six species / subspecies from the “Crotalus oreganus complex” reside in the Colorado Plateau Province:
Crotalus viridis - Prairie Rattlesnake
Crotalus viridis - Prairie ‘nuntius-type’ Rattlesnake
Crotalus oreganus concolor - Midget Faded Rattlesnake
Crotalus oreganus abyssus - Grand Canyon Rattlesnake
Crotalus oreganus lutosus - Great Basin Rattlesnake
Crotalus cerberus - Arizona Black Rattlesnake
All six species / subspecies have been observed within various areas of Coconino Co, AZ which encompasses the Grand Canyon, Lake Powell, Glen Canyon, Flagstaff and others districts. This county is considered a taxonomic hot spot. As a result, DNA analysis may be the only effective way to determine what species / subspecies a particular specimen maybe (Houston 2006). For the field biologist, this situation is troublesome with regards to visual identification. A method for field identification MUST follow any conclusions found in the genetic realm. However, while more analysis is being conducted to finalize some of the closely related specimens there is little that can be done with certainty without DNA work.
For further information on a specific species / subspecies go to the “SPECIES NOTES” section of this site.
Acknowledgements. - The author would like to thank R.C. Houston for aiding in field research.
Literature Cited
Bureau of Land Management (BLM). 2002. BLM - Environmental Education - The Colorado Plateau. [web application]. Available: http://www.blm.gov/education/colplateau/. (Accessed: 05 SEPT 2008)
Douglas, M. E., M. R. Douglas, G. W. Schuett, L. W. Porras, and A. T. Holycross. 2002. Phylogeography of the Western Rattlesnake (Crotalus viridis) Complex, with Emphasis on the Colorado Plateau. In Scheutt et al. [ eds. ], Biol. of the Vipers 2002: 11-50.
Frey, W. E. and A. M. Frey. 1987. Federal Lands of the Colorado Plateau Region. A map.( Pub: Underhill Foundation and Grand Canyon Trust) in Ridge, J. 2003. Exploring the Colorado Plateau [web application]. Available: http://www.lightrainproductions.com/index.htm. (Accessed: 05 SEPT 2008).
Houston, T.C. 2006. The Midget Faded Rattlesnake, Crotalus concolor. Reptilia. 45: 33-37.
Houston, T.C. 2005. The Midget Faded Rattlesnake (Crotalus concolor). Southeastern Hot Herp. Soc. [web application] Available http://www.venomousreptiles.org/articles/213. (Accessed: August 30, 2008)
Klauber, L. M. 1930. New and renamed subspecies of Crotalus confluentus Say, with remarks on related species. Transactions of the San Diego Society of Natural History. 6(3):95-144, 4 plates
NatureServe. 2006. NatureServe Explorer: An online encyclopedia of life [web application]. Version 6.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: June 19, 2008).
