Sourcing the geographic origin of the introduced Blue-crested lizard Calotes mystaceus Duméril & Bibron, 1837 (Squamata: Agamidae) in Hong Kong

The Blue-crested lizard, Calotes mystaceus, is an introduced species in Hong Kong and first appeared in the early 2000s.By examining genetic diversity of the mitochondrial cytochrome oxidase I (COI), we investigate the geographic origin of the established Calotes mystaceus populations in Hong Kong, so as to understand its introduced pathway to the territory.We found that all samples formed a single lineage with a sample from northern Thailand and showed no genetic divergence and phylogeographical structure despite being collected from eight scattered localities.Subsequent haplotype network identified the source population of all Hong Kong samples originates from Doi Saket district, Chiang Mai, northern Thailand.Horticultural import is believed to be the cause of the introduction of the species in Hong Kong, and we also discussed the potential introduction pathways of different established populations based on the genetic result.Relevant conservation recommendations are provided to prevent future continuous introductions of C. mystaceus and other exotic species in Hong Kong.A further assessment is needed to investigate this medium-sized exotic lizard's impact on native biota and ecosystem.