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Article: Structure and homology of Psittacosaurus tail bristles

Palaeontology Cover Image - Volume 59 Part 6
Publication: Palaeontology
Volume: 59
Part: 6
Publication Date: November 2016
Page(s): 793 802
Author(s): Gerald Mayr, Michael Pittman, Evan Saitta, Thomas G. Kaye, and Jakob Vinther
Addition Information

How to Cite

MAYR, G., PITTMAN, M., SAITTA, E., KAYE, T.G., VINTHER, J. 2016. Structure and homology of Psittacosaurus tail bristles. Palaeontology, 59, 6, 793-802. DOI: 10.1111/pala.12257

Author Information

  • Gerald Mayr - Ornithological Section Senckenberg Research Institute and Natural History Museum Frankfurt Frankfurt am Main Germany (Email:
  • Michael Pittman - Vertebrate Palaeontology Laboratory Department of Earth Sciences University of Hong Kong Hong Kong China (Email:
  • Evan Saitta - School of Biological Sciences University of Bristol Bristol UK (Email:
  • Thomas G. Kaye - Burke Museum of Natural History and Culture Seattle WA USA (Email:
  • Jakob Vinther - School of Biological Sciences University of Bristol Bristol UK (Email:

Publication History

  • Manuscript Accepted: 03 August 2016
  • Manuscript Received: 18 June 2016

Funded By

The Faculty of Science of the University of Hong Kong and the Dr. Stephen S.F. Hui Trust Fund. Grant Number: 201403173007

Online Version Hosted By

Wiley Online Library
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We examined bristle‐like appendages on the tail of the Early Cretaceous basal ceratopsian dinosaur Psittacosaurus with laser‐stimulated fluorescence imaging. Our study reveals previously unknown details of these structures and confirms their identification as integumentary appendages. For the first time, we show that most bristles appear to be arranged in bundles and that they exhibit a pulp that widens towards the bristle base. We consider it likely that the psittacosaur bristles are structurally and developmentally homologous to similar filamentous appendages of other dinosaurs, namely the basal heterodontosaurid Tianyulong and the basal therizinosauroid theropod Beipiaosaurus, and attribute the greater robustness of the bristles of Psittacosaurus to a higher degree of cornification and calcification of its integument (both skin and bristles). Although the psittacosaur bristles are probably homologous with avian feathers in their origin from discrete cell populations, it is uncertain whether they developed from a follicle, one of the developmental hallmarks of true feathers. In particular, we note a striking resemblance between the psittacosaur bristles and the cornified spine on the head of the horned screamer, Anhima cornuta, an extant anseriform bird. Similar, albeit thinner keratinous filaments of extant birds are the ‘beard’ of the turkey, Meleagris gallopavo, and the crown of the Congo peafowl, Afropavo congensis. All of these structures of extant birds are distinct from true feathers, and because at least the turkey beard does not develop from follicles, detailed future studies of their development would be invaluable towards deepening our understanding of dinosaur filamentous integumentary structures.

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