>>About agalma, there is a significant size difference between the Juarez population and the San Pedro Martir population. The latter is much smaller in average. I recently read that the two probably will be divided taxonomically pretty soon since DNA testing shows that they are really not that alike. Brian Hubbs states that DNA results indicate that the San Pedro Martir kind might even get to be a separate species.>>



What the mitochondrial DNA really shows is that the Baja California populations are reproductively isolated from one another for long periods of time, despite their close proximity to one another. There are people who believe that if two populations are geographically isolated from one another then they are different species. Others, with a more traditional view of what a species is, would not share the same opinion.



The mtDNA data also shows that L. z. pulchra and L. z. parvirubra are only recently (geologically speaking) derived from L. z. agalma. On the basis of geographic distribution, one would expect L. z. parvirubra and L. z. puchra to be derived from L. z. multifasciata (or vice versa) and one would expect L. z. agalma to be derived from L. z. pulchra. Instead the mtDNA shows that L. z. agalma share a distant relationship with L. z. multifasciata, and that these two subspecies split from one another early in the evolutionary history of the species. Both multifasciata and agalma share the red snout, which is probably the ancestral condition in this species, meaning that the black snouted populations are derived, and indeed that is what the mtDNA data shows.



L. z. agalma must have had a much more extensive distribution in the past, probably once occupying the current range of L. z. parvirubra and L. z. pulchra. A catastrophic event appeared to have wiped the San Gabriel, Santa Ana, San Bernardino and San Jacinto, and Laguna mountains clean of many species of herps, including L. zonata and probably Charina bottae. This catastrophic event was probably the formation and expansion of the Mojave Desert. L. z. agalma took refuge in the Baja California mountain "islands" and only recently (geologically speaking) L. zonata recolonized the mountains of southern California, as evidenced by the relatively young ages of L. z. pulchra and L. z. parvirubra lineages.



L. zonata has had a complex distributional history and its range has expanded and contracted many times in the past. The availability of mtDNA data has allowed us to gaze into this past, but unfortunately some people have abused this data by trying to delimit species using mtDNA data. The two populations of L. z. agalma are not only the same species, but they are the same subspecies. Despite their mtDNA differences, they remain morphologically similar, meaning they haven't changed for long periods of time. The fact that multifasciata, the distant relative of L. z. agalma shares the red snout of agalma is further evidence that L. z. agalma is a "living fossil", a populaton that closely resembled the ancestral form that had given rise to all other populations of L. zonata.

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