Geometric morphometric and phylogenetic analyses of Arizona Sky Island populations of<i>S</i><i>caphinotus petersi</i> Roeschke (Coleoptera: Carabidae)

Scaphinotus petersi Roeschke, 1907 (Carabidae) is a ground beetle endemic to Sky Islands in south-eastern Arizona. Previous taxonomic studies described several subspecies with morphological differences inhabiting geographically isolated mountain ranges. We combined molecular sequence data and morphometric data, especially head and pronotum shape analyses, to examine the variation and divergence in subspecies and isolated montane populations. In this study, we employ a combination of distance morphometrics as well as geometric morphometrics to quantify the level of morphological variation, and to test the hypothesis that geographically distinct populations of S. petersi are phenotypically distinct. Results suggest that these isolated populations have diverged morphologically and genetically. Phylogenetic analyses identified two monophyletic lineages within the species that correspond generally to pronotum shape. We observed significant morphological variation among most montane populations in of S. petersi, with the pronotum shape as the clearest delimiting trait.