A Word About Taxonomy of Mexicana Kingsnakes
In the species accounts that follow, we have treated each of the forms of Mexicana kingsnakes as species-level taxa. In doing so, we follow the original describers, who named alterna, greeri, leonis, mexicana, ruthveni, and webbi as distinct species. This arrangement is somewhat at variance with the current, though unsettled, state of affairs for this group of snakes. Nearly all authorities agree that the Gray-Banded Kingsnake should stand on its own as L. alterna, without subspecies. The Plateau Mountain Kingsnake (L. ruthveni) is likewise regarded as warranting distinct species status. Webb’s Kingsnake (L. webbi), the most recently described species, appears distinctive on the basis of pattern and mitochondrial DNA sequence differences. The situation with greeri, leonis, and mexicana is a bit more complicated, as these names, or the populations they represent, often are treated as a single, wide-ranging, highly variable taxon—L. mexicana, generally without subspecies. Our view, based on our own experiences both in the field and with captive specimens, is that such lumping greatly obscures biological reality. For the present, we find it more convenient to apply species-level labels to each as a means of facilitating discussion and study. However, definitive assessments of whether each of these forms deserves species rank must await publication of studies presently underway.
Additionally, we often refer to the “Mexicana Group” or the “Mexicana Complex” in allusion to this gathering of species. When applied in a taxonomic sense, such names imply a natural (= monophyletic) grouping, meaning that collectively, species in this group are more closely related to other group-member species than they are to species outside the group. Although some authors have suggested this to be the case, there really is not any compelling evidence to support this arrangement. Indeed, preliminary investigations of mtDNA sequences of various Mexican Lampropeltis suggest that some Mexicana kingsnakes might be more closely related to snakes presently included in the enormous composite species Lampropeltis triangulum (milksnakes) or to members of L. pyromelana / knoblochi (Sonoran Mountain Kingsnakes) and L. zonata (California Mountain Kingsnake)—certainly an intriguing possibility. Students of Mexican Lampropeltis eagerly await additional results from these and other studies.
To access a species account please click on links at top of page.