CK.,
Of interest is the notion you proposed that at some point in time, the Rubber Boa may have dispersed southward in part of its range. Going one step further, perhaps at one time, all of the mountainous regions in Kern, Ventura, Los Angeles, San Bernardino, and Riverside Counties (and south into Mexico) of S. Calif. may have been too warm and dry for the existence of C. bottae. Could it be possible that the only remaining refuge for the species was in the high elevations of the southern Sierras in Tulare and Inyo Counties (Mt. Whitney region) and it was from there that the species then expanded in all directions when suitable environmental conditions returned to the mountainous regions to the south.

That is, I now wonder if the species was once extinct in the San Bernardino and San Jacinto Mts. (and elsewhere in S. Calif.) and those areas were recolonized from the dwarf morph that occurs in the southern Kern Plateau in Tulare County.

Perhaps the newest results indicate the reverse, that the dwarf Southern Clade boas in the Kern Plateau arose from the population in the San Bernardino Mts. It seems you have mentioned that age and lineage can be inferred from the raw mtDNA results or am I wrong in that respect?

Arguing against the north to south dispersal scenario is that the Mt. Pinos population seems to be closer morphologically (scale counts and configurations) to the San Bernardino boa population than the dwarf boas from Breckenridge Mt. to the north. On the other hand, just this past year, I did find a few boas from Mt. Pinos with maximum dorsal scale row counts in the 44 - 46 range which overlap the lower range of the large morph boas from the Sierras. That scenario does suggest an influence from more northern populations.

The sample of dwarf boas I have examined from the Kern Plateau is only about 8 - 10 specimens. So at this point, it is not possible to make a reliable comparison of scale counts and head scale configurations between that population and the populations that occur in the San Bernardino Mts.and elsewhere. At any rate, up to now, I had only been thinking of how the Southern Clade dwarf boas dispersed northward from the San Bernardino Mts. to the Kern Plateau and not the reverse.

Your point about having greater representation in areas were clades or subclades were likely to meet was the same argument I presented to Rick and Glenn. And that is why they agreed to test additional samples from the area near Mt. Lassen, from the southern and northern part of the Greenhorn Mts., and from the S. Kern Plateau in which the dwarf vs. large morph scenario was also at play.

And another intriguing aspect of the species is what mechanism(s) are at play that has kept the two morphs reasonably distinct in the Sierra Nevada Mts.? That is, why hasn't the large morph over-run the dwarf form in the southern Greenhorn Mts. and on the southern Kern Plateau? Or conversely, is the dwarf form expanding its distribution into large morph territory?

Richard F. Hoyer

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