Opluridae Biogeography: Iguanian UCE Sequences

The presence of a family of iguanas (Opluridae) on the Indian Ocean island of Madagascar has long been a biogeographic mystery. Though previous studies have sought to understand the origin of Opluridae on Madagascar, each study has supported a different hypothesis: Gondwanan vicariance, land-bridge vicariance, or overwater dispersal. Here we combine ultraconserved element sequence and morphological data in a fossilized birth-death framework, and we apply traditional node calibration divergence dating methods to understand the biogeographic history of the iguanas of Madagascar (family Opluridae). This comprehensive analysis addresses the phylogenetic relationships among iguanian taxa as well as the timing of familial divergences. We confirm Leiosauridae as the closest extant sister of Opluridae, and find that their divergence occurred about 60 Ma, necessitating that long-distance overwater dispersal explains the origin of iguanas on Madagascar. We additionally discuss potential dispersal scenarios for this group.