Accelerated brain shape evolution is associated with rapid diversification in an avian radiation
Data files
Aug 31, 2020 version files 208.22 MB
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analysis_dryad.rmd
44.86 KB
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brain_warp_movies.zip
16.33 MB
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CoracTree.trees
191.71 MB
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Rcode.zip
33.48 KB
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trait_datasets.xlsx
99.89 KB
Jan 05, 2021 version files 208.22 MB
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analysis.rmd
44.86 KB
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brain_warp_movies.zip
16.33 MB
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coraciiform_posterior.trees
191.71 MB
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R_code.zip
33.48 KB
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trait_datasets.xlsx
99.98 KB
Abstract
Niche expansion is a critical step in the speciation process. Large brains linked to improved cognitive ability may enable species to expand their niches and forage in new ways, thereby promoting speciation. Despite considerable work on ecological divergence in brain size and its importance in speciation, relatively little is known about how brain shape relates to behavioral, ecological, and taxonomic diversity at macroevolutionary scales. This is due, in part, to inherent challenges with quantifying brain shape across many species. Here, we present a novel, semiautomated approach for rapidly phenotyping brain shape using semilandmarks derived from X-ray computed micro-tomography (microCT) scans. We then test its utility by parsing evolutionary trends within a diverse radiation of birds, kingfishers (Aves: Alcedinidae). Multivariate comparative analyses reveal that rates of brain shape evolution, but not beak shape, are positively correlated with lineage diversification rates. Distinct brain shapes are further associated with changes in body size and foraging behavior, suggesting both allometric and ecological constraints on brain shape evolution. These results are in line with the idea of brains acting as a "master regulator" of critical processes governing speciation, such as dispersal, foraging behavior, and dietary niche.