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No diurnal reptilian species is more characteristic of North American desert habitats and adjacent arid areas than Aspidoscelis tigris (Tiger Whiptail). It is widely distributed in northern Mexico, the western United States, and islands east and west of Baja California, occurring in desert, woodland, chaparral, and even grassland communities. Within the vast range of this taxon, which is defined by a unique combination of morphological, karyotypic, and biochemical characters, there are many different color patterns previously used in part to delineate subspecies. Nonetheless, detailed descriptions of variation in color patterns in systematic and morphological studies of continental populations of A. tigris typically have been lacking, and treatment of this subject has been relegated to a few general statements. Recently, we observed that samples from populations separated by > 500 km in Mohave County, Arizona, and San Juan County, New Mexico, presently allocated to A. tigris septentrionalis (Plateau Tiger Whiptail), were characterized by strikingly different color patterns throughout ontogeny. Thus, we devised a formalized system for capturing and expressing the details of these ensembles of color pattern (i.e., referenced herein as strongly contrasted in Mohave County compared with faded [= weakly] contrasted in San Juan County) to understand the nature of the observed variation and its relevance to the currently recognized subspecies. Discovery of these divergent populations also indicated that a single widely distributed taxon may include distinctive regional components that are separately worthy of evaluation for conservation status.