Histoincompatibility between Clonal Complexes A and B of ParthenogeneticCnemidophorus laredoensis: Evidence of Separate Hybrid Origins

Abstract

The Cnemidophorus laredoensis subgroup of parthenogenetic whiptail lizards comprises clonal complexes A and B, with each form having a mostly allopatric distribution area that includes only a few sites of syntopy with the other form and a distinctive ensemble of morphological characters. The evolution of these clonal complexes is most readily explained by the hypothesis of a hybrid C. gularis × C. sexlineatus derivation for form A, originally described from Laredo, Webb County, Texas, and a second hybridization involving these species to account for form B. Reciprocal skin-grafting, previously used in studies of genetic structure in the parthenogenetic species C. tesselatus, C. neomexicanus, C. uniparens, and C. velox, provides a methodology for differentiating between the descendants of different parthenogenetically capable interspecific hybrids. We used individuals of C. laredoensis A from six sites in Texas and individuals of form B from three of these sites in reciprocal skin-grafting experiments in which each lizard of clonal complex A rejected all grafts from B lizards and each lizard of clonal complex B rejected all grafts from A lizards. We accept these data as verification of separate hybrid origins for C. laredoensis A and B.