Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds

2014/07/31 by Michael S. Y. Lee, Andrea Cau, Darren Naish +1 · 9 citations
Earth and Planetary Sciences · Mathematics · #Paleontology and Evolutionary Biology #Evolution and Paleontology Studies #Morphological variations and asymmetry

paper · doi:10.1126/science.1252243

openalex publication_date 2014/07/31 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/23

Abstract

Recent discoveries have highlighted the dramatic evolutionary transformation of massive, ground-dwelling theropod dinosaurs into light, volant birds. Here, we apply Bayesian approaches (originally developed for inferring geographic spread and rates of molecular evolution in viruses) in a different context: to infer size changes and rates of anatomical innovation (across up to 1549 skeletal characters) in fossils. These approaches identify two drivers underlying the dinosaur-bird transition. The theropod lineage directly ancestral to birds undergoes sustained miniaturization across 50 million years and at least 12 consecutive branches (internodes) and evolves skeletal adaptations four times faster than other dinosaurs. The distinct, prolonged phase of miniaturization along the bird stem would have facilitated the evolution of many novelties associated with small body size, such as reorientation of body mass, increased aerial ability, and paedomorphic skulls with reduced snouts but enlarged eyes and brains.

Citations

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Cited by

• The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): dromaeosaurid or flightless bird?
• Coos, booms, and hoots: The evolution of closed‐mouth vocal behavior in birds
• Dinosaurs in decline tens of millions of years before their final extinction
• Dinosaur Macroevolution and Macroecology
• A molecular mechanism for the origin of a key evolutionary innovation, the bird beak and palate, revealed by an integrative approach to major transitions in vertebrate history
• An integrative approach to understanding bird origins
• Decelerated dinosaur skull evolution with the origin of birds
• Bird [wikipedia]
• Theropoda [wikipedia]