Albumin Evolution and Its Phylogenetic Implications in the Plethodontid Salamander Genera Plethodon and Ensatina

Abstract

Comparative studies were made of albumin evolution in all species of the salamander genera Plethodon and Ensatina. The albumins of all species were compared by the quantitative micro-complement fixation technique. Ensatina was seen to be phyletically remote from all species of Plethodon. The eastern large and eastern small Plethodon were shown to be more similar to one another than to the species of western Plethodon. P. neomexicanus was closest to the western species of Plethodon. Two distinct subsets were disclosed within the eastern small assemblage of Plethodon. Within the eastern large assemblage of Plethodon, P. wehrlei and P. punctatus were found to constitute a separate lineage. We suggest that Ensatina diverged from the lineage giving rise to Plethodon near the beginning of the Tertiary. A late Eocene divergence for the eastern and western Plethodon species is indicated. Overall these salamanders appear to have been experiencing considerable molecular evolution, without equivalent morphological change, throughout their Cenozoic duration.