>>CK,
>>Your using the terms 'subclade' made it a little difficult to follow your post but I believe I got the gist after reading a couple of times. I can see that respect to relative ages, I undoubtedly have misinterpreted the information contained in Javier's graphs. Oh well, back to the drawing board. >>

Every clade is really a subclade of a more inclusive clade, which is in turn a subclade of an even more inclusive clade. About the only clade that is not a subclade of something else is the clade that includes all life on earth.

>>Back in the mid 1990s and before I was on the internet, I wrote Glenn Stewart with my 'guess' that the Rubber Boa likely originated in Mexico. From there, over time it then dispersed northward as access to suitable habitat became available. I also mentioned in those letters that I felt the large morph evolved from the dwarf morph and gave a hypothesis as to what selective factors were involved that led to the large morph.>>

Very good guess. Without mtDNA data, it is next to impossible to guess where a species may have originated. For example, I thought that Elaphe guttata originated in the east and spread west, but mtDNA data shows the opposite. It originated somewhere in Texas and spread east to Florida.

>>To be able to intelligently speculate as to when, where, and why species evolve, it helps greatly to have a solid background in past geological and meteorological history. I am totally lacking in such background. Of course, that hasn't stopped me from guessing. With Javier's results of two major clades and the two subclades, that seems to have complicated matters considerably. >>

Rodriguez-Robles' two clades can be treated as two subclades, since C. bottae is a clade.

>>But from the current known distribution of the two major clades, it might seem that the Northern Clade arose from (budded off) from the Southern Clade south of the current distribution of the latter clade ----- perhaps even in Baja Calif. On the other hand, is it possible that the Southern Clade is younger and budded off the Northern Clade or that the two clades split off of some extinct parent type?>>

It is certainly possible that the rubber boa may have originated in Baja California, but there is no evidence of its presence there (could be due to lack of collecting). In the area where L. z. agalma now lives, there may well be rubber boas. As to the southern subclade having budded off from the northern subclade, that is not ruled out by the mtDNA data. However, the mtDNA data shows that the northern and southern subclades became separated from one another long before the northwestern and Sierra Nevada subclades evolved. The many populations found in Southern California are all relatively recently derived, but as a lineage it is an old one.

>>In either case, the Northern Clade dispersed up the coastal mountains of Calif. north and then west of San Diego and the Southern Clade up the interior Mts. northeast of San Diego. The species appears to have completely disappeared south of its current known southerly distributions, the Northern Clade in Ventura county and the Southern Clade in Riverside county.>>

I believe the expansion of the Mojave Desert in the past may have wiped the San Gabriel Mt. and Santa Monica Mountain area clean of rubber boas. And the appearance of Lichanura prevented the recolonization of these areas by C. bottae.

>>As mentioned, I have a hypothesis only for 'why' the large morph evolved but little hints as to where and no clue as to when. However, it would seem reasonable that the large morph likely arose north of the current distribution of the dwarf form Taking into account the current distribution of the two subclades in turns suggests that the large morph evolved twice, once from the Sierra Nevada subclade somewhere in the Sierra Nevada Mts. and once from the Northwestern subclade somewhere in the coastal mts. possibly from Baja
>>Baja Calif. or San Diego county to Monterey county.


Parmley, Dennis and Don Walker 2003. Snakes of the Pliocene Taunton Local Fauna of Adams County, Washington with the Description of a New Colubrid. Journal of Herpetology 37(2):235-244

The Northwestern subclade must have evolved more than 3 million years ago because of a fossil rubber boa found in Washington state, described in the paper above.

>>To switch gears, a couple of years ago, I exchanged messages with Robert Hansen and questioned the results reported by Kluge. Robert then informed me that recent information suggested that Charina and Calabaria were not all that closely related. Below is part of a recent e-mail from my youngest son Ryan in Utah. Perhaps it was the Noonan paper to which Robert Hansen was referring.
>>------------------------------------------------------------------------------------------
>>Bryce Noonan evaluated all boas relationships in a recent paper. See: http://bnoonan.org/Papers/Noonan_Chippindale_06a.pdf In this paper, he presents a phylogeny tree that shows Charina, Lichanura, and Exiliboa on the same branching. Bryce got the rubber boa for that study from me when he was at BYU a few years back doing post doctorate work.
>>----------------------------------------------------------------------------------------
>>
>>Richard F. Hoyer

I have seen quite a few papers that suggest Boa constrictor is actually more closely related to the rubber boa than either one of them is to the Calabar boa.

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