Parallel diversification of the African tree toad genus Nectophryne (Bufonidae)

African amphibian diversity remains underestimated with many cryptic lineages awaiting formal description. An important hotspot of amphibian diversification is the Guineo-Congolian rainforest in Central Africa, its richness attributable to present day and ancestral range fragmentation through geological barriers, habitat expansion and contraction, and the presence of steep ecological gradients. The charismatic Nectophryne tree toads present an interesting case study for diversification in this region. The two formally described species comprising this genus show nearly identical geographic distributions extending across most of the Guineo-Congolian rainforest, but show little morphological disparity. Both species harbour extensive genetic diversity warranting taxonomic revisions, and interestingly, when comparing the subclades within each, the two species show remarkably parallel diversification histories, both in terms of timing of phylogenetic splits and their geographic distributions. This indicates that common processes may have shaped the evolutionary history of these lineages.

Automated summary

The diversity of African amphibians is underestimated, with many cryptic lineages still awaiting formal description. The Guineo-Congolian rainforest in Central Africa is an important hotspot for amphibian diversification, influenced by geological barriers, habitat changes, and ecological gradients. The Nectophryne tree toads in this region show interesting patterns of diversification, with two closely related species having extensive genetic diversity and similar evolutionary histories.