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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 DNA sequences. 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 (Sonoran Mountain Kingsnake) 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. |
