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Bayesian tip dating reveals heterogeneous morphological clocks in Mesozoic birds
1Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People's Republic of China.
Royal Society Open Science
|August 17, 2019
Summary
Early birds evolved rapidly, with significant morphological changes in specific body regions like the axial skeleton and pectoral girdle, enhancing flight capabilities.
Area of Science:
- Paleontology
- Evolutionary Biology
- Comparative Anatomy
Background:
- Comprehensive Mesozoic bird morphological datasets are now available.
- Statistically rigorous methods can now reveal finer evolutionary patterns.
Purpose of the Study:
- Estimate divergence times and evolutionary rates in early birds.
- Assess evolutionary rate heterogeneity across different body regions.
Main Methods:
- Bayesian tip dating under relaxed morphological clocks.
- Analysis of morphological characters from six body regions (skull, axial skeleton, pectoral girdle/sternum, forelimb, pelvic girdle/hindlimb).
Main Results:
- Observed extremely high rates of morphological change in early avian evolution.
- Identified significant rate heterogeneity among the six body regions.
- High rates in the axial skeleton (Pygostylia), pectoral girdle/sternum and forelimb (Ornithothoraces, Enantiornithes) correlate with flight refinement.
Conclusions:
- Bayesian tip dating in MrBayes is powerful for studying deep-time evolutionary dynamics.
- Morphological evolution in early birds was rapid and region-specific, driven by flight adaptations.
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