Genetic differentiation between hybridizing species Bombina bombina and Bombina variegata (Salientia, Discoglossidae) in Poland*

Abstract

NEI'S genetic distance estimate (D) between Polish Bombina bombina and B. variegata based on electrophoretic comparisions of 29 proteins encoded at 39 presumptive gene loci, is 0.487±0.127. This estimate suggests Pliocene separation of the species, in agreement with the fossil record. Remnants of B. bombina-like and B. variegata - like animals from Upper Pliocene have been found in Czechoslovakia, and B. bombina- like animals from the same period have also been found in Poland. Separation of European Bombina was probably connected with an ecological shift of ancestors of B. bombina, the most derived species of the genus, to lowland environment. The Pliocene divergence proposed here is considerably earlier than that postulated by MERTENS (1928) who linked Bombina speciation events to Pleistocene glaciations. Comparisons ofgenetic divergence measures and the fossil record for three other species pairs of European amphibians (Triturus cristatus/marmoratus, Bufo calamita/viridis and Rana lessonae/ridibunda) provide additional evidence that pre-Pleistocene speciations in the extant European amphibian fauna were more important than is traditionally believed.