I see this forum is not as lively as it use to be. At any rate, I will pose a problem similar to what I addressed here 2- 3 years ago.

I recently came across the following quote. "Subspecies are defunct in modern systematic theory and have no place in current classification! "

Below, I describe the most recent findings regarding the Rubber Boa (Charina bottae) and then pose a question dealing with taxonomy.

1) A dwarf form of the Rubber Boa (Charina bottae) has been discovered to occur throughout parts of S. Calif. from the southern tip of the main Sierra Nevada Mts. south about 100 miles to the southern most limits of the species range in the San Jacinto Mts. southeast of Riverside, Calif..

North of the extreme southern part of the Sierra Nevada Mts., all other live and preserved Rubber Boa populations that have been examined in California and elsewhere in the species distribution in North America represent the large morph of the species.

2) Dwarf morph females and males reach maximum lengths of about 22 inches and 19 1/2 inches respectively. All dwarf populations exhibit relatively low mean ventral and maximum dorsal scale row counts.

Large morph females and males examined from preserved material attain lengths of at least 25 and 21 inches respectively. Keep in mind that considerable shrinkage occurs with preservation. From live samples, females of 27 - 30 inches and males of 22 - 24 inches have been recorded. Mean ventral and maximum dorsal scale row counts of the large morph are measurably higher than the dwarf form.

3) According to the mtDNA study by Javier Rodriguez-Robles, Glenn Stewart, and Ted Papenfuss, the Rubber Boa is represent by a southern clade and a northern clade which were estimated to have been isolated from one another for 4 - 7 million years. The paper urged the recognition of two species, the Northern Rubber Boa (Charina bottae) and the Southern Rubber Boa (Charina umbratica) representing the two clades.

4) The southern clade is composed of just two populations of the dwarf morph that occur in the San Jacinto and San Bernardino Mts. All other populations of the dwarf morph (with both size and scalation features similar to the San Jacinto and San Bernardino populations), along with all populations of the large morph, were assigned to the northern clade.

It would appear that a conflict exists between the mtDNA evidence and nuclear DNA (morphological traits) evidence. With or without using subspecific designations, is there anyone that is willing to pose a plausible taxonomic explanation / solution to the situation described above?

Richard F. Hoyer (Corvallis, Oregon)

P.S. I can post a somewhat more detailed version if anyone believes that might help.

[ Reply To This Message ] [ Subscribe to this Thread ] [ Show Entire Thread ]