Variations in call and morphology in male water frogs: taxonomic and evolutionary implications

In Anurans, the specific mate recognition system (SMRS), which contributes to prezygotic isolation, is mainly based on morphological and call features . This is why such criteria are used by zoologists for taxonomic identifica tion. In hybridogenetic water frogs (Rana ridibunda, R. lessonae, R. perezi , R. kl. grafi and R. kl. esculenta), hybridization opens up the question o f the efficiency of these criteria for taxon identification and of the spec ific recognition system in this context. Variation in both morphological an d call features revealed both significant mean differences among taxa but a lso large overlapping among individuals belonging to different taxa. Thus, using call or morphometrical features in order to identify water frogs may be hazardous. Moreover, species differ poorly in their specific mate recogn ition system, facilitating hybridization events, and therefore suggesting t hat postzygotic mechanisms may be prevalent over prezygotic mechanisms. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SA S.