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.

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.

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.

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.

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.

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

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