Cytotaxonomy and DNA taxonomy of lizards (Squamata, Sauria) from a tropical dry forest in the Chamela-Cuixmala Biosphere Reserve on the coast of Jalisco, Mexico

摘要

Tropical dry forests contribute to a substantial proportion of the herpetological diversity of Mexico. The south-western coast of Jalisco is one of the more important areas by number of endemics and the high presence of endangered and restricted species. In this paper we used a combined karyological and molecular genetic (sequences of mtDNA genes for NDH2, cytb or 16S rDNA) approach to genetically characterize 13 lizard species belonging to seven families that inhabit the dry forests of the Chamela-Cuixmala Biosphere Reserve (Anguidae: Gerrhonotus cf. liocephalus; Eublepharidae: Coleonyx elegans; Phyllodactylidae: Phyllodactylus lanei; Gekkonidae: Hemidactylus frenatus; Phrynosomatidae: Sceloporus melanorhinus, S. utiformis, Urosaurus bicarinatus; Polychrotidae: Norops nebulosus; Scincidae: Mabuya unimarginata, Plestiodon parvulus; Teiidae: Ameiva undulata, Aspidoscelis communis, A. lineattissima). The karyotypes of six species were here described for the first time (G. liocephalus, 2n = 38, 14 macrochromosomes and 24 microcromosomes; C. elegans, 2n = 24 FN = 26; N. nebulosus 2n = 30, 13 macro- and 17 microchromosomes; M. unimarginata 2n = 32, 18 macro- and 14 microchromosomes; P. parvulus 2n = 26, 12 macro- and 14 microchromosomes; A. undulata 2n = 50, 26 macro- and 24 microchromosomes). Chromosomal heteromorphism was found in C. elegans, N. nebulosus, and S. melanorhinus. For P. lanei we found a karyotype different from that previously described in other localities. This variation matched with a high genetic divergence usually found in different species. The DNA typing of mtDNA genes allowed the identification of the taxonomic affinities of five Mexican endemic species, namely: U. bicarinatus, A. nebulosus, P. parvulus, A. lineattissima and A. communis. The specimen of Gerrhonotus from Chamela is very divergent by 16S rDNA and probably does not belong to the so far studied species of Gerrhonotus. High genetic divergence has been also observed between samples of A. undulata and U. bicarinatus from different regions. In these latter two cases, additional data are needed to understand the taxonomic status of these populations.