some of its subspecies, go back to as early as 1959, albeit under different taxa. Aspidoscelis costatus has 8 subspecies, all of which are endemic to Mexico. Taxonomy, History, and Etymology There are several genus of whiptail lizards in the family Teiidae. The genus of Aspidoscelis lizard was originally under the genus Cnemidophorus until 2002, when Reeder proposed that there are significant divergent characters, including morphological and genetic differences, for many species that warrant regrouping. Morphological deviations between Cnemidophorus and Aspidoscelis are detailed in the Physical Description section. Nomenclatural changes of genus unavoidably causes confusion and difficulties for researchers. To illustrate this dramatic change, the subspecies Aspidoscelis costata zweifeli was named Cnemidophorus sacki zweifeli when it was first reported by Duellman et al. in 1960. In this seminal 1960 publication, Duellman states “In recognition of the important contributions to the systematics of the genus Cnemidophorus made by Dr. Richard G. Zweifel, I propose that the subspecies of Cnemidophorus sacki in the Tepalcatepec Valley be names as follows: Cnemidophorus sacki zweifeli, a new subspecies.” That subspecies is the nowadays Aspidoscelis costata zweifeli. The subspecies name of “zweifeli” is still kept to in honor of Dr. Zweifel, an American herpetologist, who contributed immensely to the documentation of the nowadays Aspidoscelis costata species. Out of the eight costata subspecies, Dr. Zweifel reported/named five of them. Physical Description Western Mexico Whiptails have scaly skin with stripes, bowed legs, and pointed snout. It does not have any vertebral crests (spines). Western Mexico Whiptails are striped lizards. They have multiple straight dorsal stripes with varying color patterns on grey, brown, or black ground, often mixed with pale-hued spots, or bar-like pattern. Ventrally, the lizard has abdominal, and pelvic regions that are either cream colored, or sometimes light to medium blue, sometimes even red in the pelvic region. The gular (throat) region can have increased intensity of coloration that ranges from pink to red. These colors and pattens are subject to individual variation, ontogenetic (juvenile, adult) variation, sexual (male, female) dimorphism, and even seasonal changes. Males progressed through stages of dorsal pattern changes from pale stripes, dark intervening fields, no spots to spots, and diverse pale configurations set in a black ground color. Females in this population (females representing all stages of color patterns) showed similar changes but did not lose striping as they grew. Ontogenetic changes in ventral color patterns were also apparent, with males becoming