Discordant genetic and morphological differentiation between three Rana vidibunda populations from northern Greece

Morphological and genetic differentiation among three populations of the marsh frog, Rana ridibunda, from northern Greece was examined using selected morphometric characters and electrophoresis of polymorphic enzymes. Two discordant differentiation patterns emerged; while the Mahalanobis distances between the populations (range 0.6948* to 1.8824***) based on three morphometric discriminators were significantly correlated to altitudinal difference, the genetic differentiation in eight enzyme loci (0.011 ≤Nei's unbiased D≤0.096; 0.110≤ Rogers' modified distance ≤ 0.286; GST=17.4%) appeared random and grouped the populations differently. The overall pattern is interpreted as a response to different selection regimes in the morphometric phenotype (including presence of a syntopic congener), absent in the allozymes.