Genetic variability and phylogenetic relationships of Cnemidophorus parecis (Squamata, Teiidae) from Cerrado isolates in southwestern Amazonia

We investigated the genetic structure of Cnemidophorus parecis, and its phylogenetic relationships with other South American teiids using allozyme data. Because of southward expansion of Amazon Forest, populations of C. parecis presumably have been isolated in Cerrado enclaves during the last 3000 years. We scored 18 presumptive electrophoretic loci in Tupinambis merianae, Kentropyx altamazonica, Ameiva ameiva, Cnemidophorus ocellifer, and C. parecis, estimating genetic diversity through allelic richness, mean number of alleles per locus, proportion of polymorphic loci, and mean heterozygosity. To make interspecific comparisons independent of sample sizes, we also used a rarefaction analysis of allelic richness. C. parecis had relatively low values of genetic variability among the five studied species, but the results do not corroborate the hypothesis that enclave populations experienced a severe bottleneck. Therefore, geographic isolation affected the genetic variability of C. parecis, but Rondônia enclaves were apparently large enough to maintain adequate populations of this species, preserving some of the original genetic diversity. We also conducted a phylogenetic analysis adding data from Cnemidophorus lemniscatus and Cnemidophorus gramivagus previously reported in literature and using T. merianae as outgroup. Results indicated that C. parecis is more closely related to A. ameiva than to other congeneric species, corroborating the view that South American Cnemidophorus form a paraphyletic assemblage.