The classification of the American box turtles (Terrapene spp.) has remained enigmatic to systematists. Previous comprehensive phylogenetic studies have focused primarily on morphology. The goal of this study was to re-assess the classification of Terrapene spp. by obtaining DNA sequence data from a broad geographic range and from all four species and 11 subspecies within the genus. Tissue samples were obtained for all taxa except for T. nelsoni klauberi. DNA was extracted, and the mitochondrial DNA (mtDNA) cytochrome b (Cytb) and nuclear DNA (nucDNA) glyceraldehyde-3-phosphate-dehydrogenase (GAPD) genes were amplified via polymerase chain reaction and sequenced. The sequence data were analyzed using maximum likelihood and Bayesian phylogenetic inference, a molecular clock, AMOVAs, SAMOVAs, haplotype networks, and pairwise percent divergence comparisons. T. c. triunguis was paraphyletic to T. carolina and T. ornata ornata and T. o. luteola lacked distinction phylogenetically. T. nelsoni was confirmed to be the sister axon of T. ornata, and T. c. major, T. c. bauri, and T. coahuila were not well resolved but were closely associated with T. c. carolina. T. c. mexicana and T. c. yucatana were closely associated with T. c. triunguis. The results suggest that T. c. triunguis should be elevated to species status (T. mexicana), and mexicana and yucatana should be included in this group as subspecies. In addition, T. o. ornata and T. o. luteola should not be considered separate subspecies. Because conservation efforts are typically species-based, these results will be important for facilitating successful conservation management strategies.
Date of publication
Martin, Bradley T., "Molecular Phylogenetics and Phylogeography of the American Box Turtles (Terrapene SPP.)" (2012). Biology Theses. Paper 15.