PARTHENOGENETIC CNEMIDOPHORUS-TESSELATUS COMPLEX (SAURIA, TEIIDAE) - A NEOTYPE FOR DIPLOID C-TESSELATUS (SAY, 1823), REDESCRIPTION OF THE TAXON, AND DESCRIPTION OF A NEW TRIPLOID SPECIES

Since 1967, the name Cnemidophorus tesselatus (Say, 1823) has been in use for a hybrid-derived complex of whiptail lizards known to include both diploid and triploid parthenogenetic populations distributed in p arts of Colorado, Oklahoma, New Mexico, Arizona, Texas, and Chihuahua (Mexico). Application of new binomial nomenclature to additional popul ations in the complex has long been delayed by philosophical disagreem ent among workers as to what constitutes a parthenogenetic species of Cnemidophorus in addition to the daunting operational challenge of con structing workable diagnoses for arguably different populations. We co ncur with a body of opinion that, presently, C. dixoni Scudday, 1973 i s the appropriate name for certain disjunct diploid populations of liz ards in Hidalgo County, New Mexico, and Presidio County, Texas, despit e the fact that some workers continue to allocate these populations to C. tesselatus. We have redefined the remaining diploid populations de rived from hybridization between C. marmoratus marmoratus (=C. tigris) and C. gularis septemvittatus (=C. septemvittatus) as an evolutionary species for which the name C. tesselatus was available. To affect sta bility in the assignment of this name, we designate a neotype and redi agnose the taxon which is geographically distributed in the states pre viously noted for the complex. We allocate triploid populations derive d from hybridization between normally parthenogenetic C. tesselatus an d gonochoristic C. sexlineatus to a cytogenetically and morphologicall y distinct new species restricted to parts of four counties in southea stern Colorado. We found no evidence that the triploid population of l izards in and near Ninemile Valley of the Purgatoire River, Otero Coun ty, Colorado should be assigned to a second triploid species as was re commended by some previous authors. All specimens of C. dixoni, C. tes selatus, and the new triploid species were identifiable by highly diag nostic features of dorsal color and/or pattern (i.e., configuration of the stripes on the body and pattern of spots and/or bars on the body, posterior surfaces of the thighs, and base of the tail) evident under both field and laboratory conditions. Each of these species includes either distinctive classes of color pattern or morphological variants subject to further evaluation for taxonomic recognition. Sympatry betw een C, tesselatus and the triploid species was noted only in and near Ninemile Valley, Colorado; sympatry between C. tesselatus and C. dixon i has been reported only in Pinto Canyon, Presidio County, Texas.