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Pterosaur integumentary structures with complex feather-like branching

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Matters Arising to this article was published on 28 September 2020

Abstract

Pterosaurs were the first vertebrates to achieve true flapping flight, but in the absence of living representatives, many questions concerning their biology and lifestyle remain unresolved. Pycnofibres—the integumentary coverings of pterosaurs—are particularly enigmatic: although many reconstructions depict fur-like coverings composed of pycnofibres, their affinities and function are not fully understood. Here, we report the preservation in two anurognathid pterosaur specimens of morphologically diverse pycnofibres that show diagnostic features of feathers, including non-vaned grouped filaments and bilaterally branched filaments, hitherto considered unique to maniraptoran dinosaurs, and preserved melanosomes with diverse geometries. These findings could imply that feathers had deep evolutionary origins in ancestral archosaurs, or that these structures arose independently in pterosaurs. The presence of feather-like structures suggests that anurognathids, and potentially other pterosaurs, possessed a dense filamentous covering that probably functioned in thermoregulation, tactile sensing, signalling and aerodynamics.

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Fig. 1: Integumentary filamentous structures in CAGS–Z070.
Fig. 2: Preservation, microstructure and chemistry of the integumentary filamentous structures in NJU–57003.
Fig. 3: Phylogenetic comparative analysis of integumentary filament and feather evolution in pterosaurs and archosaurs.
Fig. 4: Reconstruction of one of the studied anurognathid pterosaurs.

Yuan Zhang

Data availability

The data that support the findings of this study are available in the Supplementary Information.

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Acknowledgements

We thank Q. Ji, S. Ji and H. Huang for access to the specimen CAGS–Z070, as well as S. C. Kohn, Y. Fang, C. Wang and T. He for laboratory assistance. This work was supported by the National Natural Science Foundation of China (41672010 and 41688103) and Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB26000000) to B.J., Research Grant Council of Hong Kong-General Research Fund (17103315) to M.P., ERC-StG-2014-637691-ANICOLEVO to M.E.M. and Natural Environment Research Council Standard Grant NE/1027630/1 to M.J.B.

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Contributions

B.J. and M.J.B. designed the research. Z.Y., B.J. and X.X. systematically studied the specimens. Z.Y., S.L.K., M.E.M. and P.J.O. performed the SEM analysis. Z.Y. and B.J. performed the FTIR analysis. M.P. and T.G.K. performed the laser-stimulated fluorescence imaging, data reduction and interpretation. M.J.B. performed the maximum-likelihood analyses. Z.Y., B.J., M.J.B., M.E.M., X.X. and P.J.O. wrote the paper. All authors approved the final draft of the paper.

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Correspondence to Baoyu Jiang or Michael J. Benton.

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Yang, Z., Jiang, B., McNamara, M.E. et al. Pterosaur integumentary structures with complex feather-like branching. Nat Ecol Evol 3, 24–30 (2019). https://doi.org/10.1038/s41559-018-0728-7

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