Taxonomic changes for Sceloporus undulatus
Sceloporus tristichus. Formerly Sceloporus undulatus tristichus. Archuleta County, Colorado.
© Lauren Livo / Steve Wilcox. |
Sceloporus consobrinus. Formerly Sceloporus undulatus garmani. Photo by Tom Mathies
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Until 2002, fence lizards in Colorado were regarded as a single species, Sceloporus undulatus, with four distinct subspecies in the state (Hammerson 1999). Recognition of subspecies was based on morphological analyses. In this scheme, S. u. elongatus occupied the western tier of counties in Colorado. S. u. tristichus entered the state only in Archuleta County in southwestern Colorado. S. u. erythrocheilus extended along the rocky foothills of the Front Range from Wyoming southward to the San Luis Valley in south-central Colorado and eastward to Prowers and Baca counties. S. u. garmani, was restricted to sand sage habitats on the eastern Plains. There are also areas in the state where there are intergrades between subspecies: between S. u. elongatus and S. u. tristichus (in La Plata County) and between S. u. tristichus and S. u. erythrocheilus (in Rio Grande and Conejos counties).
Recent molecular studies by Leaché and Reeder (2002) resulted in a major rearrangement of species recognition in the Sceloporus undulatus species complex. They recognized two species within Colorado, S. tristichus primarily in the west, and S. consobrinus in the east. No subspecies were recognized.
Under this new arrangement, S. tristichus incorporates all Colorado populations of S. u. tristichus, S. u. elongatus, and some populations of S. u. erythrocheilus. The second Colorado species, S. consobrinus, incorporates all other populations of S. u. erythrocheilus and S. u. garmani. This arrangement has not been entirely satisfactory because the genetic data of Leaché and Reeder (2002) fits poorly with the geographic distributions of the formerly recognized subspecies. The inclusion of the “erythrocheilus” morphotype within S. consobrinus combination is particularly problematic. First, the “erythrocheilus” morphotype more closely resembles S. tristichus in its appearance and habitat than it does S. consobrinus. Second, populations of the “erythrocheilus” morphotype and S. tristichus adjoin and intergrade in southern Colorado, whereas the ranges of the “erythrocheilus” and “garmani” (= S. consobrinus) morphotypes are not known to intergrade or contact in the state (Hammerson 1999, but see Smith et al. 1991).
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Generalized ranges of Sceloporus tristichus (Pink) and Sceloporus consobrinus (Yellow) after Leaché and Reeder (2002).
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Third, sampling by Leaché and Reeder (2002) in eastern Colorado was sparse (two populations of “erythrocheilus” and one of “garmani"). With respect to S. tristichus, it unlikely that it ranges as far east as Chaffee, Fremont, Custer, and Huerfano counties, as shown in the map above, because these counties are east of the Continental Divide. The form found in these counties therefore more likely aligns with S. consobrinus.
Cited Resources
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- Hammerson, G. A. 1999. Amphibians and reptiles in Colorado. 2nd ed. University Press of Colorado, Boulder, Colorado. 484 pp.
- Leaché, A.D. and T.W. Reeder. 2002. Molecular systematics of the eastern fence lizard (Sceloporus undulatus): a comparison of parsimony, likelihood, and Bayesian approaches. Systematic Biology 51:44-68.
- Smith, H.M., M.S. Rand, J.D. Drew, B.D. Smith, D. Chiszar, and C.M. Dwyer. 1999. Relictual Intergrades between the Northern Prairie Lizard (Sceloporus undulatus garmani) and the Red-Lipped Plateau Lizard (S. u. erythrocheilus) in Colorado. Northwestern Naturalist 72:1-11.
Suggested Citation
Colorado Partners in Amphibian and Reptile Conservation. 2014. Taxonomic changes for Sceloporus undulatus in Colorado. Compiled by Tom Mathies and Joseph Ehrenberger. http://www.coparc.org/plateau-fence-lizard.html [accessed date here].
Colorado Partners in Amphibian and Reptile Conservation. 2014. Taxonomic changes for Sceloporus undulatus in Colorado. Compiled by Tom Mathies and Joseph Ehrenberger. http://www.coparc.org/plateau-fence-lizard.html [accessed date here].