WikipediaRead full entry
Desert grassland whiptail lizard
The Desert Grassland Whiptail lizard (Aspidoscelis uniparens) is an all-female species. It was formerly placed in the genus Cnemidophorus. A. uniparens have limited social stimuli, having only two basic needs: finding food and avoiding predators.A common predator of the whiptail lizard is the leopard lizard, who prey on A. uniparens by using ambush and stalking hunting tactics.These reptiles reproduce by parthenogenesis; eggs undergo a chromosome doubling after meiosis and develop into lizards without being fertilized. However, ovulation is enhanced by female-female courtship and "mating" (pseudocopulation) rituals that resemble the behavior of closely related to species that reproduce sexually.
The Desert Grassland Whiptail lizard is a relatively small reptile ranging from as small as 2¾ inches (69 mm) to as large as 5¼ inches (137 mm). Desert Grassland Whiptails are a very long and slim reptile. With a long thin tail that is longer than their body length. Their distinct identifying feature is the six yellowish lines that run the length of their body. The majority of their body tends to be an olive or brown color that fades to a faint blue/gray color on their tail. While the adolescent whip tails have a very bright and vibrant blue tail. Their bodies are lined with very small coarse scales, which gradually get larger as they approach the tail. While the scales on there bellies are much larger in size as well as much smoother.
The taxonomy of the genus was unknown until the 1950s to early '60's. A 1958 report confirmed that no male lizards had been discovered in a collection of specimens of C. tesselatus. That very year parthenogenesis was confirmed in the genus Lacerta of the family Lacertidae. Quickly thereafter, it was discovered that there were also no males in C. exsanguis, C. neomexicanus, or C. velox. Rather than subsume all cnemidophorine species in a single large genus, Lowe and Wright proposed a split that placed the North American "Cnemidophorus" clade in the monophyletic genus Aspidoscelis; under this arrangement, South American taxa remain in the genus Cnemidophorus. 
The Desert Whiptail Lizard is mostly found in the deserts of southern to central Arizona, and in New Mexico along the Rio Grande river. It is Also found into the deserts of northern Mexico. Aspidoscelis uniparens is commonly found in low valleys, grasslands, and slight slopes. Some have argued that the range is expanding due to overgrazing. A. uniparens are scarce in developed areas, especially where homeowners keep livestock.
Hybridization and Reproduction
All Grassland Whiptail Lizards are female. There is an absence of males in the species.The way they procreate does not need male fertilization but there have been observed pseudo-copulation that promotes fertilization during ovulation. They reproduce by parthenogenesis which is to say they basically clone a copy of themselves. Their clone however does not necessarily have the same chromosomal set as their mother. This is because the lizards start off with twice the amount of chromosomes as regular lizards. They maintain diversity by combining sister chromosomes instead of pairing their homologous chromosomes. With current studies this suggest the lizards can somehow distinguish between homologous and sister chromosomes. The lizard is a triploid unisexual species that reproduce asexually. They were a result from a cross breed of two bisexual species: the A. inornata and the A. burti. This then produced a diploid unisexual, which back crossed to inornata and produced triploid uniparens. The resulting offspring are exact genetic copies of their mother and can be considered clones, except for the handful of mutations for each batch of generation.
The primary diet for whiptail lizards consists of insects. For the most part these insects are spiders, termites, antlions, beetles, and short-horned grasshoppers. Dominant foods varied little between months and years. "Sexual variation was more evident; it may act to reduce intraspecific competition for food resources and may be associated with secondary sexual size dimorphism." (Best, Gennaro 1985. p. 257) 
- Eifler DA, Eifler MA (1998) Foraging Behavior and Spacing Patterns of the Lizard Cnemidophorus uniparens. J Herpetol 32:24–33
- Tollestrup K (1983) The social behavior of two species of closely related leopard lizards, Gambelia silus and Gambelia wislizenii. Z Tierpsychol 62:307–320
- Pietruszka RD (1986) Search tactics of desert lizards: how polarized are they? Anim Behav 34:1742–1758
- Eifler, D. A., Eifler, M. A., & Harris, B. R. (2008). Foraging under the risk of predation in desert grassland whiptail lizards ( Aspidoscelis uniparens). Journal Of Ethology, 26(2), 219-223. doi:10.1007/s10164-007-0053-0
- Crews, D. & Fitzgerald, K.T. (1980). "Sexual" behavior in parthenogenetic lizards (Cnemidophorus). Proceedings of the National Academy of Sciences, 77, 1. pp. 499-502.
- Crews, D., Grassman, M. & Lindzey, J. (1986). Behavioral Facilitation of Reproduction in Sexual and Unisexual Whiptail Lizards. Proceedings of the National Academy of Sciences, 83, 24. pp. 9547-9550.
- Grassman, M. & Crews, D. (1987). Dominance and reproduction in a parthenogenetic lizard. Behavioral Ecology and Sociobiology, 21. pp. 141-147.
- "Whiptails (Cnemidophorus Spp.)." Https://www.desertmuseum.org/books/nhsd_whiptails.php. Ed. Craig Ivanyi. Arizona-Sonora Desert Museum, 1 Jan. 2014. Web. 23 Oct. 2014.
- Brennan, Thomas C. "Desert Grassland Whiptail (Aspidoscelis Uniparens) - Reptiles of Arizona." Desert Grassland Whiptail (Aspidoscelis Uniparens) - Reptiles of Arizona. Reptiles of Arizona. Web. 23 Oct. 2014.
- Lowe, Charles H., 1993. Introduction to the biology of whiptail lizards (genus Cnemidophorus) . “Biology of Whiptail Lizards (Genus Chemidophorus)”
- Hammerson, G.A. & Santos-Barrera, G. 2007. Aspidoscelis uniparens. The IUCN Red List of Threatened Species. Version 2014.2. www.iucnredlist.org
- Audsley, Blake. American Midland Naturalist Volume: 155 Issue: 2 (2006-04-01) p. 395-401. ISSN: 0003-0031
- Harmon Katherine (2010) No Sex Needed: All-Female Lizard Species Cross Their Chromosomes to Make Babies. www.scientificamerican.com/article/asexual-lizards/
- Troy L. Best, A. L. Gennaro (1985) . “FOOD HABITS OF THE WESTERN WHIPTAIL LIZARD (CNEMIDOPHORUS TIGRIS) IN SOUTHEASTERN NEW MEXICO” “JSTOR”, 45(3):e527
Brennan, Thomas C. "Desert Grassland Whiptail (Aspidoscelis Uniparens) - Reptiles of Arizona." Desert Grassland Whiptail (Aspidoscelis Uniparens) - Reptiles of Arizona. Reptiles of Arizona. Web. 23 Oct. 2014.
Lutes, A. A., Neaves, W.B., Baumann, D. P., Wiegraebe, W., Baumann, P. (2010). Sister chromosome pairing maintains heteroozygosity in parthenogenetic lizards. nature.com. Web 22 Oct. 2014.
Mayer, Greg. (2010). Hybridization and Parthenogenesis in Whiptail Lizards. whyevolutionistrue.wordpress.com. Web 23 Oct 2014.
Harmon Katherine (2010) No Sex Needed: All-Female Lizard Species Cross Their Chromosomes to Make Babies. www.scientificamerican.com/article/asexual-lizards/ Tue 21 Oct 2014.
S. C. Woolley, J. T. Sakata D. Crews(2004) Tracing the Evolution of Brain and Behavior Using Two Related Species of Whiptail Lizards: Cnemidophorus uniparens and Cnemidophorus inornatus ilarjournal.oxfordjournals.org/content/45/1/46.full Tue 21 Oct 2014.
Maryanne E. Tocidlowski, Christine L. Merrill, Michael R. Loomis, and James F. Wright 2001 TERATOMA IN DESERT GRASSLAND WHIPTAIL LIZARDS (CNEMIDOPHORUS UNIPARENS). www.bioone.org/doi/pdf/10.1638/1042-7260(2001)032%5B0257:TIDGWL%5D2.0.CO%3B2 Tue 21 Oct 2014
"Whiptails (Cnemidophorus Spp.)." Https://www.desertmuseum.org/books/nhsd_whiptails.php. Ed. Craig Ivanyi. Arizona-Sonora Desert Museum, 1 Jan. 2014. Web. 23 Oct. 2014.