Genetic verification of Thai Calotes cf. versicolor (Squamata: Agamidae) within the putative Calotes irawadi species complex

Since the designation of Calotes versicolor sensu stricto and its restricted distribution in India, the status of Calotes cf. versicolor has been the subject of several taxonomic studies throughout its former distribution range, including Thailand. Among recently described species, C. irawadi was alleged to have been distributed from eastern India to Indochina. Based on subsequent studies, genetic variation obtained from limited set of samples suggested the potential existence of a species complex rather than a single taxonomic unit. Calotes cf. versicolor is commonly found in various habitats throughout Thailand. Therefore, the clarification of its taxonomic status is of importance. In this study, the degree of genetic variation among Thai C. cf. versicolor was investigated and compared to C. irawadi using the mitochondrial 16S rRNA gene (438 bp) to ascertain its position within the C. irawadi complex. DNA samples of C. cf. versicolor specimens from various regions of Thailand were examined. Based on the ML and BI phylogenetic trees, Thai C. cf. versicolor formed several closely related subclades, some of which shared the same subclade with C. irawadi from Myanmar and India. Substantial uncorrected p-distances (0.46–3.09%) were detected among Thai C. cf. versicolor suggesting the presence of several taxonomical units within the putative C. irawadi species complex.