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The distributions of species radiations reflect environmental changes driven by both Earth history (geological processes) and the evolution of biological traits (critical to survival and adaptation), which profoundly drive biodiversity yet are rarely studied together. Modern toads (Bufonidae, Amphibia), an iconic radiation with global distribution and high phenotypic diversity, are an ideal group for exploring these dynamics. Using phylogenomic data from 124 species across six continents, we reconstruct their evolutionary history. Biogeographic analyses suggest modern toads originated in South America approximately 61 million years ago (Ma), later dispersing to Africa and Asia, thereby challenging hypotheses of dispersal via North America. Species diversification rates increased after leaving South America, linked to Cenozoic geological events and key innovations like toxic parotoid glands for predator defence. The emergence of parotoid glands coincided with the South American dispersal, promoting diversification and enabling toads to dominate both Old and New Worlds. In contrast, the evolution of other traits, despite being crucial to adaptation, did not promote species diversification (e.g. large body size) or were ambiguously associated with expansion into the Old World (e.g. developmental modes). These findings highlight the adaptability of modern toads and reveal the interplay between Earth’s history and phenotypic innovation in shaping biodiversity.
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Niche expansion and adaptive divergence in the global radiation of crows and ravens
Abstract The processes that allow some lineages to diversify rapidly at a global scale remain poorly understood. Although earlier studies emphasized the importance of dispersal, global expansions expose populations to novel environments and may also require adaptation and diversification across new niches. In this study, we investigated the contributions of these processes to the global radiation of crows and ravens (genus Corvus ). Combining a new phylogeny with comprehensive phenotypic and climatic data, we show that Corvus experienced a massive expansion of the climatic niche that was coupled with a substantial increase in the rates of species and phenotypic diversification. The initiation of these processes coincided with the evolution of traits that promoted dispersal and niche expansion. Our findings suggest that rapid global radiations may be better understood as processes in which high dispersal abilities synergise with traits that, like cognition, facilitate persistence in new environments.
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- Award ID(s):
- 1841470
- PAR ID:
- 10323001
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41467-022-29707-5
