DNA Barcoding-Based Evaluation of Genetic Diversity in Acanthodactylus (Daudin, 1802) (Lacertidae: Squamata) Species of Türkiye

Abstract Accurate species identification is essential for biodiversity studies, especially in reptile groups with complex taxonomy. The genus Acanthodactylus is one of the most diverse lacertid genera, yet its taxonomy in Türkiye has been little explored using molecular data. This study applies DNA barcoding of the mitochondrial COI gene to assess genetic diversity and phylogenetic relationships of four species distributed in Türkiye: A. boskianus, A. schreiberi, A. harranensis, and the recently described A. ilgazi. A total of 22 individuals were sequenced, and phylogenetic analyses (ML, BI) consistently recovered four monophyletic lineages. Species delimitation tests (bPTP, ABGD, mPTP, TCS) largely confirmed the recognition of four taxa, with only minor boundary differences. Pairwise distances showed A. boskianus and A. schreiberi as closest relatives (12.1%), while A. ilgazi and A. harranensis were the most divergent (20.8%). Five haplotypes were identified, including two within A. ilgazi, suggesting intraspecific variation. These findings confirm the validity of all four species and provide the first COI barcode reference library for Turkish Acanthodactylus, now available in BOLD. Overall, this study highlights the effectiveness of COI barcoding in resolving species boundaries and supporting conservation strategies.