Data from: Multilocus phylogeographic assessment of the California Mountain Kingsnake (Lampropeltis zonata) suggests alternative patterns of diversification for the California Floristic Province

Phylogeographic inference can determine the timing of population
divergence, historical demographic processes, patterns of migration, and
when extended to multiple species, the history of communities. Single
locus analyses can mislead interpretations of the evolutionary history of
taxa and comparative analyses. It is therefore important to revisit
previous single-locus phylogeographic studies, particularly those that
have been used to propose general patterns for regional biotas and the
processes responsible for generating inferred patterns. Here we employ a
multilocus statistical approach to re-examine the phylogeography of
Lampropeltis zonata. Using nonparametic and Bayesian species delimitation,
we determined that there are two well supported species within L. zonata.
Ecological niche modeling supports the delimitation of these taxa,
suggesting that the two species inhabit distinct climatic environments.
Gene flow between the two taxa is low, and appears to occur
unidirectionally. Further, our data suggest that gene flow was mediated by
females, a rare pattern in snakes. In contrast to previous analyses, we
determined that the divergence between the two lineages occurred in the
late Pliocene (ca. 2.07 ma). Spatially and temporally, the divergence of
these lineages is associated with the inundation of central California by
the Monterey Bay. The effective population sizes of the two species appear
to have been unaffected by Pleistocene glaciation. Our increased sampling
of loci for L. zonata, combined with previously published multi-locus
analyses of other sympatric species, suggest that previous conclusions
reached by comparative phylogeographic studies conducted within the
California Floristic Province should be reassessed.