>>CK.,
>>You mention the large morph Northwestern Clade 'no doubt' migrated west to the San Luis Obispo area and northward to Monterey Co. and beyond. If that scenario were true, then a number of events needed to take place in order to explain the current situation in which the dwarf morph of the Sierra Nevada subclade currently occupies extreme southwestern Kern County.>>

Yes, there is no doubt about it because the Central Valley is not the route of this migration, and because the Sierra Nevada appears to be closed to the migration of both L. zonata and C. bottae until after the coastal populations of both of these species have migrated north. The Sierra Nevada populations of both C. bottae and L. zonata have very little differences in their mtDNA over the entire range of this mountain from north to south, suggesting a recent divergence from their respective common ancestors and a rapid expansion of their ranges for both species.

After L. z. multifasciata and Northwestern subclade C. bottae made their ways north along the coast, the area around Kern, Ventura, Los Angeles, Orange, San Diego, and Santa Barbara Counties probably experienced climatic changes that made them uninhabitable for both C. bottae and L. zonata. The absence of C. bottae from Ventura and Santa Barbara Counties would support this scenario. There is also geological evidence that the San Francisco Peninsula moved north from southern California due to plate tectonics. Perhaps this movement isolated the coastal populations of both species from their southern Sierra Nevada relatives.

As I said before, the current Kern County Populations of C. bottae (samples 30-32) are rather recent lineages, derived from the ancestor of sample #26, which is located in Tulare County. This is evidence of a past contraction of the range of C. bottae in this area. Otherwise, we would see the exact reverse: the Tulare County boas should have been derived from the Kern County boas instead.

>>Also, nothing is known about San Luis Obispo population --- whether it belongs to the Northwestern or Sierra Nevada subclade or if it is of the dwarf or large form. As a matter of fact, very little is known about the boas that occur in Monterey County. >>
>>My printout from CAS shows only 5 boas from that county, all collected from near Carmel in the early 1900s. Three boas collected in 1904 and 1905 were lost to the earthquake and fire in S. F. I have examined the other two specimens that were collected in 1908 and 1915. >>

The Monterey area is probably little different from the nearby Santa Cruz County. Both C. bottae and L. zonata are known from this area. I am surprised so few specimens come from this county. Where L. zonata has been recorded in this area, C. bottae should also be present.

>>Both boas were females of 466 mm and 425 mm stretched lengths respectively. The preservation process shrinks specimens to varying degrees with larger specimens incurring a greater percentage of shrinkage than smaller specimens. If those two specimen incurred 10% shrinkage, their stretched live lengths would still be below the lengths of the largest dwarf females estimated to be about 558 mm (22 inches). Not having them in hand now, there is no way of determining whether those females were subadults, adults, or older adults. The only clue is that both had scarred tail tips suggesting they were adults. But even some subadult boas incur scarring of their tail tips.>>

If you like you can probably make a trip next year to the area and find your own specimens to determine their morph.

>>The only specimen in the MVZ collection from Monterey County was the DOR specimen found on Hwy. 1 in 1998 used in Javier's study. Depending on where specimens from Monterey County occur in other institutional collections (Smithsonian?), that particular boa my have established a new southerly distribution of the species in Monterey County. As best as I can determine from my de Lorme atlas software map, that specimens was found about 40 miles south of the CAS Carmel specimens and about 30 miles north of the San Luis Obispo County line. >>

C. bottae has also been reported in the Landels-Hill Big Creek Preserve, operated by UC. If you contact the biology department of UC Santa Cruz, perhaps they may have some specimens from this preserve, whether they are live or pickled. Students from UC Santa Cruz make frequent trips to this Preserve to conduct field research.

>>I also have examined that specimen which measured 496 mm. It also was a female with a scarred tail tip. Factoring in a 10% shrinkage factor, the specimen's live stretched length would have been 551 mm and below the est.. maximum length of dwarf form females. So at this point, it is not known if either the San Luis Obispo or Monterey County boa populations are of the large or dwarf form. The only known is that the one Monterey Co. specimen tested aligned with the Northwestern subclade.>>

Perhaps a bigger sample will show that they belong to the large morph.

>>There is a distance of about 70 miles between the specimen Javier tested in Monterey County and the San Luis Obispo County boa population. A distance of about 90 miles exists between that population and the nearest known boa population to the southeast on Mt. Abel west of Mt. Pinos. Almost a tossup as to which boa population the San Luis Obispo boas are related although it would be my guess that the more likely scenario is they would align with the Northwestern subclade.
>>
>>Richard F. Hoyer

Even though the distances are about the same, one must not forget that the Kern County boas have only recently (geologically speaking) arrived at their current positions from their ancestors' at Tulare County. At one time the gap between the Tulare County dwarf morph boas and any Northwestern subclade boa wer probably much greater. Further, the lack of boas between San Luis Obispo and southern Monterey Counties may be due to patchy nature of suitable habitat, difficult terrain (for human collectors), lack of roads in suitable areas and the remoteness of the area.

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