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Arizona Striped Whiptail (Aspidoscelis arizonae)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”1302″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Arizona Striped Whiptail, Willcox Playa. Photo by Larry Jones[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1956″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Arizona Striped Whiptail, Cochise Co., 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=”1957″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Arizona Striped Whiptail habitat, NE side of Willcox Playa. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1959″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Juvenile Arizona Striped Whiptail, Willcox Playa. Photo by Larry Jones[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1958″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Juvenile Arizona Striped Whiptail, Cochise Co., AZ. Photo by Randy Babb.[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1960″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Juvenile Arizona Striped Whiptail, Cochise Co., AZ. Photo by Randy Babb[/vc_column_text][/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

The Arizona Striped Whiptail is a relatively small whiptail (< 75 mm SVL), usually (>90%) with seven cream or yellow stripes on a brown, rusty-brown, or tan dorsum.  The mid-dorsal stripe is sometimes fainter, lighter in color, or more diffuse than the lateral stripes, and in a few individuals, it is incomplete or broken into spots or dashes. There are no light spots in the dark fields between the stripes.  Anteriorly, the long tail is striped similar to the body (the mid-dorsal stripe frequently terminates above the vent), but towards the rear the stripes fade and are replaced by a sky blue coloration. Blue is often present on the sides of the head and body, as well, especially in adult males.  The venter is unmarked and predominantly blue, and again, that color is most intense in adult males. Number of dorsal scales around the mid-body ranges from 55-72, number of scales between the paravertebral stripes number 6-12 (mean = 9.2-9.7), and there are 26-37 femoral pores (total, both thighs).  The scales on the inside of the central rear surface of the forearm (postantebrachial scales) and just anterior to the gular scales on the throat (mesoptychial scales) range from being small and granular to moderately enlarged and angular. Individuals from the Willcox Playa area are lighter overall dorsally than those from the Bonita area.

The only other whiptails known to occur within the very limited range of the Arizona Striped Whiptail are the Tiger Whiptail (Aspidoscelis tigris) and the Desert Grassland Whiptail (A. uniparens).  Adult and older juvenile Tiger Whiptail lack distinct stripes on the body, the tail and body lack blue coloration, the venter shows at least some black markings, and the postantebrachial scales are not enlarged. Adults also grow to a much larger size (< 110 mm SVL in our area) than Arizona Striped Whiptails.  Hatchling and young juvenile Tiger Whiptails often have blue tails, but they only have 4-6 light dorsal stripes, and light spots or mottling is often present between the stripes, particularly on the sides.  The Arizona Striped Whiptail is most likely to be confused with the Desert Grassland Whiptail, and the two not uncommonly occur in close proximity (although they are rarely found together on the same site).  The latter species has abruptly enlarged postantebrachial and mesoptychial scales, the tail is blue-green towards the rear, although the color may be faint in adults, and typically there are only six light dorsal stripes.  A very few individuals have a partial seventh, mid-dorsal stripe on the anterior quarter of the back.  The Desert Grassland Whiptail is also a unisexual, parthenogenetic (all female) species, whereas both males and females are present in Arizona Striped Whiptail populations. Apparent hybrids between A. arizonae and A. uniparens were found at a site about 13.3 km southeast of Willcox (Sullivan et al. 2005).

The Arizona Striped Whiptail was described by John Van Denburgh in 1896 based on a single specimen from “Fairbank” in the Arizona Territory (currently along the upper San Pedro River at the Highway 82 crossing).  The taxonomy of this lizard is in flux. It was long considered a subspecies of the Little Striped Whiptail (A. inornata), but was elevated to species by the SSAR Lizard Systematist Group (Collins 1997).  However, in a comprehensive review of the molecular genetics of whiptails, Reeder et al. (2002) listed the Arizona Striped Whiptail as a subspecies of A. inornata, although no specimens of that taxon from southeastern Arizona were included in their analysis.  In a recent article, Sullivan et al. (2013) compared the Arizona Striped Whiptail and proximate populations of A. i. llanurus from New Mexico and found them to be virtually indistinguishable in terms of numbers of dorsal stripes, coloration, and other morphological features previously proposed to diagnose the two.  This finding contrasts with the work of Wright and Lowe (1993) who found enough differences, including number of dorsal stripes and other characters, to diagnose these two forms as subspecies (although Wright and Lowe did not sample populations of A. i. llanuras from southwestern New Mexico).  Crother (2012) considers the Arizona Striped Whiptail to be a full species, but whether the then unpublished work of Sullivan et al. (2013) was available to help make that determination is unknown.  Sullivan et al. conclude their article with “In the absence of morphological diagnosability, we are pursuing molecular analyses to provide additional insight in the relationships among LSWC (Little Striped Whiptail complex) members and A. arizonae.”  

After the initial collection in the 1890s, no additional Arizona Striped Whiptails specimens were collected until 1962, when Wright and Lowe (1965) found the species in the vicinity of Willcox.  A single specimen was collected in 1983 at the Hackberry Ranch in the Whitlock Valley about 65 km northeast of Willcox (UAZ 53496).  Surveys conducted during 2000-2003 found that the Arizona Striped Whiptail was still well represented at sites within 15 km of Willcox, but it was found neither in the Whitlock Valley (although the Hackberry Ranch site was not visited), nor at the Fairbank type locality (Sullivan et al. 2005).  Sullivan et al. (2005) also found Arizona Striped Whiptails at two sites near Bonita in the northern Sulphur Springs Valley, about 37 km north of Willcox. The authors surmised that the Fairbank locality was probably not where the original specimen was collected, but rather was a base camp for the W.W. Price biological expedition during which the specimen was collected.

The Arizona Striped Whiptail has one of the smallest ranges of any native amphibian or reptile in the 100-Mile Circle.  It is a species of valley semi-desert grasslands, sometimes where grasslands have been degraded by shrub invasion.  Most localities are on the eastern and northern edges of the Willcox Playa, in flat or rolling terrain, often on light-colored sandy, alkaline soils stabilized by a variety of grasses and shrubs.  In comparison to adjacent sites occupied the Desert Grassland Whiptail, the Arizona Striped Whiptail was found in areas with better grass cover and less shrub and mesquite cover (Sullivan et al. 2005).  The elevational range for the species in the Sulphur Springs Valley is about 1270-1400 m.  At the Hackberry Ranch, it was taken at 1146 m.

Arizona Striped Whiptails have been collected from early April to early October, but they are most active in May and then again during the summer rains.  Adults cease most activity before the first of September.  Mating occurs in the spring and one or two clutches of 1-3 eggs are laid in summer.  Hatchlings are seen from late August into October and measure about 100 mm total length (complete tail).  Arizona Striped Whiptails feed upon termites, ants, grasshoppers, and other insects.

With a valid Arizona hunting license, 20 Arizona Striped Whiptails can be collected per day or held in possession, in aggregate, alive or dead.  It is listed as near threatened on the IUCN’s 2013 Red List.  In 2007, the U.S. Fish and Wildlife Service (FWS) was petitioned by WildEarth Guardians to list 475 species as threatened or endangered with critical habitat under the Endangered Species Act (ESA).  The list included the Arizona Striped Whiptail. In a Federal Register notice dated 16 December 2009, the FWS found that listing of the Arizona Striped Whiptail may be warranted due to the present or threatened destruction, modification, or curtailment of its habitat or range resulting from development and improper livestock grazing.  The species’ status is in review and a decision regarding whether listing is warranted will be issued in a subsequent Federal Register notice.  The question of whether the Arizona Striped Whiptail is a full species or not does not preclude its possible inclusion on the ESA list.  Under the ESA, species, subspecies, and distinct population segments of vertebrates may be listed.

Sullivan et al. (2005) found that the current distribution of the Arizona Striped Whiptail had remained relatively stable over the previous 50 years, except at a site north of Willcox that had been developed for housing, and perhaps in the Whitlock Valley. Livestock grazing was often heavy at Arizona Striped Whiptail sites, yet the lizards seemed to persist and often thrive in these areas.  However, the species has occurred recently in three widely separated areas of southeastern Arizona, suggesting it was once more widely distributed.  Much of the Sulphur Springs Valley between the Willcox Playa and Bonita localities is developed into center-pivot agriculture, and it may be that much habitat for this species was lost in historical times due to that agricultural and rural development.  In addition, most of the localities around the Willcox Playa are on state or private lands with little opportunity for long-term conservation management, but with the threat of various types of development and habitat loss.

Although grasslands have been in decline for probably 4,000 years in our area (Van Devender 1995), over the last 140 years, dramatic desertification and shrub invasion of desert grasslands, likely driven by large-scale ranching, fire exclusion, introduction of non-native plants, and climate change, has occurred in southeastern Arizona and southwestern New Mexico, with concomitant decline of grassland species (Bahre 1995, Bodner et al. 2013).  These declines are likely to continue unless significant action is taken to reverse the trend (Bodner et al. 2013).  Because the Arizona Striped Whiptail is a species of semi-desert grasslands, it could very well decline as vegetation communities continue to change in our region.

The Arizona Striped Whiptail and other whiptails in the 100-Mile Circle were until recently placed in the genus Cnemidophorus.  Much of the literature on this species is under the name Cnemidophorus inornatus arizonae.

Suggested Reading:

Bahre, C.J. 1995. Human impacts on the grasslands of southeastern Arizona. Pages 230-264 in M.P. McClaran and T.R. Van Devender (editors), The Desert Grassland. University of Arizona Press, Tucson.

Bodner, G.S., P. Warren, D. Gori, K. Sartor, and S. Bassett. 2013. Sustaining the grasslands sea: Regional perspectives on identifying, protecting and restoring the sky island region’s most intact grassland valley landscapes. Pages 399-409 in G.J. Gottfried, P.F. Ffolliott, B.S. Gebow, L.G. Eskew, L.C. Collins (compilers), Proceedings: Merging science and management in a rapidly changing world: Biodiversity and management of the Madrean Archipelago III and 7th Conference on Research and Resource Management in the Southwestern Deserts. May 1-5 2012. Tucson, AZ. RMRS-P-67. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

Brennan, T.C., and A.T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZ.

Collins, J.T. 1997. Standard common and current scientific names for North American amphibians and reptiles. Fourth Edition. Society for the Study of Amphibians and Reptiles.

Crother, B.I. 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding, seventh edition. Society for the Study of Amphibians and Reptiles, Herpetological Circular (39):1-92.

Reeder, T.W., C.J. Cole, and H.C. Dessauer. 2002. Phylogenetic relationships of whiptail lizards of the genus Cnemidophorus (Squamata: Teiidae): a test of monophyly, reevaluation of karyotypic evolution, and review of hybrid origins. American Museum Novitates 3365:1-61.

Sullivan, B.K. 2009. Arizona Striped Whiptail, Aspidoscelis arizonae. Pages 326-329 in Jones, L.L.C., and R.E. Lovich (eds.), Lizards of the American Southwest: A Photographic Field Guide.  Rio Nuevo Publishers, Tucson, Arizona.

Sullivan, B.K., P.S. Hamilton, and M.A. Kwiatkowski. 2005. The Arizona Striped Whiptail: Past and present. Pages 145-148 in G.J. Gottfried, B.S. Gebow, L.G. Eskew, and C.B. Edminster (compilers), Connecting mountain islands and desert seas: biodiversity and management of the Madrean Archipelago II. Proceedings RMRS-P-36, Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

Sullivan, B.K., J.M. Walker, H.L. Taylor, J.E. Cordes, M.A. Kwiatkowski, K.O. Sullivan, J.R. Sullivan, M.R. Douglas, and M.E. Douglas. 2013.  Morphological diagnosability of Aspidoscelis arizonae (Squamata: Teiidae) as an indication of evolutionary divergence in the Aspidoscelis inornata Complex. Copeia 2013(3):366-377.

Van Denburgh, J. 1896. A list of some reptiles from southeastern Arizona, with a description of a new species of Cnemidophorus. Proceedings of the California Academy of Sciences 6:338-349.

Wright, J.W., and C.H. Lowe. 1965. The rediscovery of Cnemidophorus arizonae Van Denburgh. Journal of the Arizona-Nevada Academy of Science 3:164-168.

Wright, J.W., and C.H. Lowe. 1993. Synopsis of the subspecies of the Little Striped Whiptail, Cnemidophorus inornatus Baird. Journal of the Arizona-Nevada Academy of Science 27:129-157.

Author: Jim Rorabaugh

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