J. Younger, J. D. Maddox, K. Wacker, C. Kyriazis, M. J. Raherilalao, S. M. Goodman, S. Reddy. Diversification of two endemic avian radiations in the biodiversity hotspot of Madagascar. IOC, Vancouver 2018, Oral Presentation.
Abstract:
Madagascar is renowned as a global biodiversity hotspot, a region of exceptional species richness providing an ideal natural laboratory for investigating the processes of avian diversification. In this study, we aimed to compare and contrast the diversification processes of two endemic radiations on Madagascar, the Bernieridae and the Vangidae, to determine whether similar speciation mechanisms generated their remarkable diversity. We sequenced genomic data (4,000 ultra-conserved element (UCE) loci) for >200 individuals, encompassing all known and putative species. We used this large-scale genomic dataset to reconstruct the evolutionary relationships within the Vangidae and Bernieridae families on Madagascar, and with their continental relatives on Africa and Asia. We estimated speciation rates through time to test the hypothesis that both families experienced an early burst of speciation upon arrival to Madagascar, and found that both showed a rate-shift consistent with adaptive radiation. We also uncovered several previously undescribed cryptic species within both families (validated with morphological data), suggesting that rates of microendemism of Madagascar’s birds may be greater than currently thought. Our study highlights an urgent need for further studies to quantify biodiversity in hotspots in order to implement necessary conservation actions.