Evolution of Acoustic Behaviour in African Bufo (Anura: Bufonidae)
Mating calls are known for 29 species of African Bufo belonging to 11 species groups. Twenty-five African species, representing eight species groups (including four groups or complexes having 2N=22) have calls which Martin (1972) termed Type I. This call type is also found in Schismaderma carens, Nectophrynoides tornieri and N. occidentalis. It is known in only four species of Bufo outside Africa and in Odontophrynus americanus which is thought to be closely related to leptodactylids that gave rise to the genus Bufo. Four African species of Bufo have Type II calls.
Geographic distribution of three call types indicates large radiations of one or two call types in South America, North America and Africa. The European and Asian Bufo faunas appear to be derived primarily from American radiations.
The radiation of bufonids in Africa appears to be equal to that of South America. An explanation of this may be that Bufo or its progenitor evolved prior to the continental separation of South America and Africa.