A new feather type in a nonavian theropod and the early evolution of feathers

2009/01/12 by Xing Xu, Xiaoting Zheng, Hai‐Lu You · 12 citations
Earth and Planetary Sciences · Environmental Science · #Fish biology, ecology, and behavior #Ichthyology and Marine Biology #Paleontology and Evolutionary Biology

paper · doi:10.1073/pnas.0810055106

openalex publication_date 2009/01/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04

Abstract

All described feathers in nonavian theropods are composite structures formed by multiple filaments. They closely resemble relatively advanced stages predicted by developmental models of the origin of feathers, but not the earliest stage. Here, we report a feather type in two specimens of the basal therizinosaur Beipiaosaurus, in which each individual feather is represented by a single broad filament. This morphotype is congruent with the stage I morphology predicted by developmental models, and all major predicted morphotypes have now been documented in the fossil record. This congruence between the full range of paleontological and developmental data strongly supports the hypothesis that feathers evolved and initially diversified in nonavian theropods before the origin of birds and the evolution of flight.

Citations

• The Evolutionary Origin And Diversification Of Feathers
• The origin and early evolution of birds: discoveries, disputes, and perspectives from fossil evidence
• An exceptionally well-preserved theropod dinosaur from the Yixian Formation of China

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• Morphology and distribution of scales, dermal ossifications, and other non‐feather integumentary structures in non‐avialan theropod dinosaurs
• Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution
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• Feathers, Dinosaurs, and Behavioral Cues: Defining the Visual Display Hypothesis for the Adaptive Function of Feathers in Non-Avian Theropods
• Rhetoric vs. reality: A commentary on “Bird Origins Anew” by A. Feduccia
• Maniraptora [wikipedia]