Chromosomes and Evolution of the Species Groups of Cnemidophorus (Reptilia: Teiidae)

Lowe, C. H. (Dept. Biol. Sci., Univ. Arizona, Tucson), Wright, J. W., Cole, C. J., and Bezy, R. L. 1970. Chromosomes and evolution of the species groups of Cnemidophorus (Reptilia: Teiidae). Syst. Zool, 19:128–141.—On the basis of chromosome data, the large and complex genus Cnemidophorus of the New World lizard family Teiidae is divided into five species groups (the deppei, lemniscaius, sexlineatus, tigris, and tesselatus groups). These species groups are, in the main, congruent with those customarily recognized on the basis of external morphology. The hyperythrus species group, however, is placed in the deppei group: (1) all species examined from these two groups have identical karyotypes which differ from those of all other species examined in the genus, and (2) the two groups were formerly distinguished primarily on the basis of a single variable morphological character. The tesselatus group contains two species (tesselatus and neomexicanus), each parthenogenetic and derived through intergroup hybridization. Both of these parthenospecies originated through hybridization between the same two species groups, but different parental species combinations were involved in the production of each of them. The karyotype of the deppei species group appears to be the most primitive among the extant species groups of the genus Cnemidophorus, and the karyotypes of the other species groups are readily derived from it primarily by means of Robertsonian centric fusions and unequal pericentric inversions. The phylogeny of the genus based on the observed pattern of karyotypic evolution is consistant with the overall ecologic and biogeographic distributions of the species.