Pre-pleistocene refugia and differentiation between populations of the Caucasian salamander (Mertensiella caucasica)

A 350-bp fragment of the mitochondrial cytochrome-b gene was sequenced in t he Caucasian salamander, Mertensiella caucasica, representing 10 population s from across its range along the Black Sea coast. Five haplotypes were dis covered among 65 fragments analyzed, differing at 2-50 positions, The highe st differentiation between haplotypes was observed in animals from the east ern part of the species' range (Borjomi) compared to those from the remaind er of the species' range. Randomly amplified nuclear DNA revealed a pattern of spatial genetic variation similar to that of the mitochondrial genome. M, caucasica, as currently known, represents two evolutionary lineages that evolved independently, perhaps since the lower Pliocene, These lineages re present tare, possibly to be described as species, distributed in the Borjo mi area in central Georgia and in southwestern Georgia and northeastern Tur key. The multivariate analysis of morphological data did not reveal signifi cant differences between the taxa, However, substantial morphological diffe rentiation was observed within both lineages, showing parallel patterns in body proportions and coloration patterns. This variation is possibly associ ated with extant ecological conditions. Salamanders with reduced pigmentati on from southwestern Georgia were not genetically distinguishable from neig hboring populations. (C) 2000 Academic Press.