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Slevin’s Bunchgrass Lizard (Sceloporus slevini)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”1285″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Slevin’s Bunchgrass Lizard, Huachuca Mtns, AZ. Photo by Jim Rorabaugh[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1862″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Nearly patternless Slevin’s Bunchgrass Lizard, Huachuca Mtns, AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1863″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Hatchling Slevin’s Bunchgrass Lizard, Santa Rita Mtns, AZ. Photo by Larry Jones[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column width=”1/6″][/vc_column][vc_column width=”2/3″][vc_column_text]

Description

This small lizard is heard more often than seen. In many cases, the careful observer is first alerted to the animal’s presence by a rustling sound as it darts into a tussock of bunchgrass high in the Madrean Archipelago. This close association of Sceloporus slevini with high elevation Madrean bunchgrass habitat was first observed in 1920 by Slevin near the summit of Miller Peak in the Huachuca Mts. (in Van Denburgh 1922) and is repeated in many other early works covering lizards of the western U. S. (e.g., Smith 1946, Stebbins 1954). Surprisingly, it was over forty years later that Lowe (1964) first reported the occurrence of the species in desert-grassland in southeastern Arizona, and shortly thereafter Dixon and Medica (1965) noted its presence in sacaton in the Animas Valley, Hidalgo Co., New Mexico.

As currently recognized, the species ranges from Arizona and New Mexico south through Sonora and Chihuahua to Durango, Mexico (Watkins-Colwell et al. 2003).The known range of the species in the U.S. includes the Santa Rita, Whetstone, Dragoon, Huachuca, and Chiricahua Mountain ranges, and the Sonoita, Empire, Babocomari, and Canelo grasslands in Arizona; and the southern end of the Animas Valley in New Mexico (Ballinger and Congdon 1996, Degenhardt et al. 1996, Howland and Whittinghill-Howland 1995, Smith et al. 1998, Stebbins 2003; Watkins-Colwell et al. 2003). The populations in the U.S. appear to be sharply declining, attributed to over-grazing by cattle. This decline was first noted by Bock et al. (1990) and further documented by Ballinger and Congdon (1996) and Smith et al. (1998). Sceloporus slevini is not listed as a species of special concern in Arizona (Arizona Game and Fish Department 2004), but is considered endangered by the New Mexico Department of Game and Fish (Degenhardt et al. 1996).

For many years the Bunchgrass Lizard populations in the U.S. were considered Sceloporus scalaris, and much of the literature uses this species name. The subspecies Sceloporus scalaris slevini was originally described by Smith in 1937 to encompass populations in Arizona and northwestern Mexico. Tanner (1987) and Smith et al. (1996) elevated the subspecies to species on the basis of differences from the populations found in northeastern and central Mexico. To date, studies of allozymes (Mink and Sites 1996) and mitochondrial DNA (Benabib et al. 1997) are not based on a sufficient number of populations to fully test the systematic status of S. slevini. However, the existing data do not appear to refute recognition of it as a separate species.

To someone unfamiliar with the species, Sceloporus slevini might be confused with other small members of the genus in southern Arizona. The color pattern is quite variable and some individuals are nearly patternless (Smith et al. 1990). However, often a conspicuous black blotch surrounding a blue spot is present on the shoulder immediately anterior to the front limb, and the dorsum has four rows of brown blotches that are bordered posteriorly by a black crescent edged with yellow markings. The most definitive identifying features are the presence of femoral pore rows that are separated medially by only one or two scales and the presence of lateral scale rows that are parallel with the dorsal scales rows.

There is a rich literature on the ecology and evolution of Sceloporus slevini (under the name S. scalaris; summary in Watkins-Colwell et al. 2003) and some of the major contributors are members of the Tucson Herpetological Society, including Royce Ballinger, Kevin Bonine, Charles Cole, Stephen Goldberg, Ernest Liner, and Justin Congdon (My sincere apology goes to anyone I may have inadvertently omitted.) This brief account could serve as an introduction to subsequent papers in the Sonoran Herpetologist detailing various aspects of research on the species.

Acknowledgments

I thank Kit Bezy and Kathryn Bolles and for review of an earlier draft of this account, and Kit Bezy and Erik Enderson for preparation of the map.

Literature Cited

Arizona Game and Fish Department, Non-game Branch. 2004. Reptiles of Arizona. Sonoran Herpetologist 17:15-21.

Ballinger, R. E., and J. D. Congdon .1996. Status of the Bunch Grass Lizard, Sceloporus scalaris, in the Chiricahua Mountains of southeastern Arizona. Bulletin of the Maryland Herpetological Society 32:67-69.

Benabib, M, K. M. Kjer, and J. W. Sites, Jr. 1997. Mitochondrial DNA sequence-based phylogeny and the evolution of viviparity in the Sceloporus scalaris group (Reptilia: Squamata). Evolution 51:1262-1275.

Bock, C. E., H. M. Smith, and J. H. Bock. 1990. The effect of livestock grazing upon the abundance of the lizard, Sceloporus scalaris, in southeastern Arizona. Journal of Herpetology 24:445-446.

Degenhardt, W. G., C. W. Painter, and A. H. Price. 1996. Amphibians and Reptiles of New Mexico. University of New Mexico, Albuquerque.

Dixon, J. R. and P. A. Medica. 1965. Noteworthy records of reptiles from New Mexico. Herpetologica 21:72-75.

Howland, J. M., and J. M. Whittinghill-Howland. 1995. Sceloporus scalaris. Geographic Distribution. Herpetological Review 26:155.

Lowe, C. H. 1964. Amphibians and reptiles of Arizona, pp.153-174. In C. H. Lowe (ed.), The Vertebrates of Arizona. University of Arizona Press, Tucson.

Mink , D. G., and J. W. Sites Jr. 1996. Species limits, phylogenetic relationships, and origins of viviparity in the scalaris complex of the lizard genus Sceloporus (Phrynosomatidae; Sauria). Herpetologica: 52:551-571.

Smith, H. M. 1937. A synopsis of the scalaris group of the lizard genus Sceloporus. Occasional Papers of the Museum of Zoology of the University of Michigan (361):1-8.

Smith, H. M.1946. Handbook of Lizards. Lizards of the United States and of Canada. Comstock, Ithaca, New York.

Smith, H. M., C. E. Bock, and J. H. Bock. 1990. Notes on reproduction and coloration in the Bunchgrass Lizard, Sceloporus slevini, in southeastern Arizona. Bulletin of the Maryland Herpetological Society 26:64-67.

Smith, H. M., J. G. Watkins-Colwell, E. A. Liner, and D. Chiszar. 1996. Sceloporus scalaris auctorum a superspecies. Bulletin of the Maryland Herpetological Society 32:70-74.

Smith, H. M., D. Chiszar, A. Chiszar, D. L. Auth, J. Auth, C. Henke, C. E. Bock, J. H. Bock, J. A. Rybak, R. E. Holland, K. Bonine, and G. J. Watkins-Colwell. 1998. Slevin’s Bunchgrass Lizard (Sceloporus slevini) decimated on the Sonoita Plain, Arizona. Herpetological Review 29:225-226.

Stebbins, R. C. 1954. Amphibians and Reptiles of Western North America. McGraw-Hill, New York. Stebbins, R. C. 2003. A Field Guide to Western Reptiles and Amphibians. 3rd ed. Houghton-Mifflin, Boston.

Tanner, W. W. 1987. Lizards and turtles of western Chihuahua. Great Basin Naturalist 47:383-421.

Van Denburgh, J. 1922. The reptiles of western North America. Vol. I. Lizards. Occasional Papers of the California Academy of Sciences (10):1-611.

Watkins-Colwell, G. J., H. M. Smith, and D. Chiszar. 2003. Sceloporus slevini. Catalogue of American Amphibians and Reptiles 771:1-6.

Author: Robert Bezy

Originally published in the Sonoran Herpetologist 2004 17(6):62-63

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