In Issues 2017
Toads, tall mountains and taxonomy: the Rhinella granulosa group (Amphibia: Anura: Bufonidae) on both sides of the Andes. pp. 267-278 plus Supplementary material.
Abstract. A toad in the Rhinella granulosa group has been recognized as present on Trinidad since 1933. In 1965, the Trinidadian population was described as a subspecies of Bufo granulosus, B. g. beebei. It has its type locality on the island and was eventually raised to species status as B. beebei (Beebe’s toad). Recently Beebe’s toad was synonymized with Rhinella humboldti, a species with a type locality in the Magdalena Valley of western Colombia. The Magdalena Valley is separated from the Orinoco Basin by the Eastern and Merida Cordilleras. These ranges have peaks that exceed 5,000 m and an almost continuous altitude at about 3,000 m. Here we examine the morphology, advertisement calls, and mtDNA from several populations of these lowland toads to test whether the western Colombian R. humboldti and the Orinoco-Trinidad R. beebei are conspecific and form a single taxon that occurs on both sides of the Andes. The morphological, molecular, and advertisement call analyses suggest that R. humboldti and R. beebei are distinct taxa composed of independent evolving lineages. Rhinella beebei is therefore resurrected from the synonymy of R. humboldti for the Trinidad and some of the adjacent mainland Orinoco populations in both Venezuela and Colombia. This increases the number of described species in the clade to fourteen. Rhinella humboldti and its sister R. centralis (Panama) are the only members of the R. granulosa group to occur west of the Andes, and our molecular results suggest the TMRCA for R. beebei and R. humboldti at about 9 Mya, a time when the Eastern Cordillera was much lower in altitude than it is today and the Merida Cordillera was in its early stages of formation.
Key words. Cryptic species, Janzen’s hypothesis, palaeoelevation, speciation, systematics, topographic barriers.