Morphometric differentiation of the moor frog (Rana arvalis Nilss.) in Central Europe

Morphometric variation of 11 characters was studied in 14 samples of Rana a rvalis from allopatric population groups in Central Europe, representing tw o subspecies formerly recognised: R. a. arvalis and R. a. wolterstorffi. Al l samples from Poland (nine) were collected from the area, which is believe d to he populated by the nominal form. In addition, the isolated population of R. ulvalis from the Pastern Carpathians of Romania was classified to th at form. All the Hungarian samples fall into the range of R. a. wolterstorf fi. No significant differences in body size between sexes and among the pop ulations From the three geographic regions (Poland, Hungary and Romanian Ea stern Carpathians) were found. Multivariate analysis of the differences in body shape among groups showed that the populations from Hungary differed f rom the nominal Form mainly in the relative hindlimb length. However, subst antial overlap in overall shape differences resulted in a relatively low pe rcentage of correct classifications to the respective geographic groups in the Discriminant Analysis. Large intrapopulation variation in the values of the two ratios (SVL/TL and TL/IMT) formerly used for differentiate the two European subspecies of R. arvalis makes them unreliable characters for dis tinguishing the two forms. The pattern of morphometric variation does not m atch the overall genetic divergence of the R. arvalis populations, which su ggests that the body shape differences in this species result from the phen otypic plasticity correlated with local climatic factors.