Molecular systematics of the genusSonora(Squamata: Colubridae) in central and western Mexico

Mexico possesses high levels of endemic biodiversity, especially for squamate reptiles. However, the evolutionary relationships among many reptiles in this region are not well known. The closely related genera of Sonora Baird and Girard 1853 and Procinura Cope 1879 are coralsnake mimics found from the central and western United States to southwestern Mexico and Baja California. Although species delimitation in this group has historically relied upon colour pattern and other morphological characters, many populations of these species display colour pattern polymorphism, which may confound taxonomy. We used molecular phylogenetics to assess the evolutionary relationships and delimit species within Sonora, focusing on the phylogenetic position of Procinura and the validity of S. mutabilis and aequalis. We sequenced two mitochondrial (ND4 and cytb) and two nuclear (c-mos and RAG-1) genes for the single species of Procinura and each of the four species of Sonora. We analysed these sequences using maximum parsi...