at Fri Jul 1 00:01:33 2011 [ Report Abuse ] [ Email Message ] [ Show All Posts by RichardFHoyer ]
Actually, the Rubber Boa along with the Rosy Boa, are probably the two easiest species in N. America to identify to sex. Both species have spurs and if you know what to look for, adult Rubber Boas can be identified as male or female as fast as you can handle them. Only the small subadults and juveniles pose a problem where magnification may be needed to detect the presence or absence of spurs.
In most populations of the Rubber Boa I have examined, the spurs of most females are hidden behind scales or if present are exceedingly small in relation to overall body size. Male spurs are far more prominent and are larger in relation to body size. But of course, all of that take experience with handling the species so it is understandable that those not very familiar with the species can become mistaken. And as mentioned, the shape of female spurs (when visible and not hidden) are different from those of males. But to detect that difference, most individuals would need the use of a hand lens
The one region in which male spurs may be somewhat more difficult to detect are the populations of the species throughout S. Calif. in which the spurs of almost all males lack pigmentation and are clear or translucent similar to those of juveniles. However,in the vast majority of boa populations, male spurs are pigmented from tan to dark brown or even black and thus much easier to observe.
As for the species evolutionary lineage, a second mtDNA study was completed as a master thesis project about two years ago. The grad student who complete that project earlier this month had his thesis accepted by his committee. So the next step will be for his thesis to be transformed into a publishable draft and submitted to a herp journal.
For you or others that may know something about Rubber Boa taxonomy, the first mtDNA study of the species was published in 2001 and urged recognition of the subspecies Charina bottae umbratica be elevated to species level distinction, that is Charina umbratica or Southern Rubber Boa found only in the San Bernardino and San Jacinto Mts. of S. Calif.
To me, the adoption of the separate species scenario was premature as there was evidence at the time that the SRB was not all that unique with respect to the morphological traits that were suppose to define the SRB from all other boa populations. In addition, the most recent mtDNA study shows that the population of the Rubber Boa that inhabits the extreme southern end of the Sierra Nevada Mts., the Southern Kern Plateau, aligns with the Southern Clade or Southern Rubber Boa and not with the Northern Clade or Northern Rubber Boa. This revelation pretty much shoots down the separate species scenario and also may force a re-evaluation of the subspecies arrangement in Charina bottae as well.
Richard F. Hoyer
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