Relationships among frogs of the genera Alytes, Bombina, Discoglossus, and Baleaphryne were studied using the quantitative immunological micro-complement fixation technique. Albumins were compared among these genera as well as among several species of each genus. Our results indicate that the closest genetic relative of Baleaphryne muletensis is Alytes obstetricians. Moreover, the albumins of Baleaphryne and A. obstetricians are as similar or more similar to each other than the albumins of all four species of Bom bina, both species of Discoglossus, or the two species of Alytes available for study are to each other. We conclude that Baleaphryne is congeneric with Alytes. The distances measured among Alytes, Bombina, and Discoglossus suggest a Cretaceous (85-92 MYBP) divergence of Alytes from the lineage that later gave rise to Bombina and Discoglossus. These latter two genera appear to have diverged in the late Cretaceous, roughly 69-75 MYBP. Extant species of Bombina began diverging in the mid- to late-Miocene, as did Alytes obstetricans and A. cistemasii.
Discoglossus pictus and D. sardus in Europe last shared a common gene pool in the Pliocene. Albumins of individuals of D. pictus from Spain compared with northwestern African D. pictus suggest that these populations have been separated for some 9-10 million years, and are probably not conspecific. Our findings do not support Lanza et al.’s (1975, 1976) suggestions that Bombina and Alytes belong in the separate family Bombinidae.