Climatic swings ignite rare bursts of passerine body-plan innovation
A Nature Ecology & Evolution study analyzes ~170,000 skeletal measurements across 2,057 passerine birds to reconstruct ~50 million years of body-plan evolution, finding that evolution has been driven by rare, hierarchically nested bursts of phenotypic innovation near the origins of major lineages. These bursts correlate with intervals of climatic instability and are mirrored in present-day latitudinal patterns, where higher-latitude assemblages show elevated rates of phenotypic evolution and more modular trait covariation, supporting the idea that climatic variability repeatedly fuels morphological diversification in passerines.
