Wednesday, January 27, 2010

Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds

Fucheng Zhang(1), Stuart L. Kearns(2), Patrick J. Orr(3), Michael J. Benton(2), Zhonghe Zhou(1), Diane Johnson(4), Xing Xu(1) & Xiaolin Wang(1)

1. Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, China
2. Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
3. UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4, Ireland
4. Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

Correspondence to: Michael J. Benton(2) Zhonghe Zhou(1) Correspondence and requests for materials should be addressed to M.J.B. (Email: mike.benton@bristol.ac.uk) and Z.Z. (Email: zhonghe@yeah.net).

Spectacular fossils from the Early Cretaceous Jehol Group of northeastern China have greatly expanded our knowledge of the diversity and palaeobiology of dinosaurs and early birds, and contributed to our understanding of the origin of birds, of flight, and of feathers. Pennaceous (vaned) feathers and integumentary filaments are preserved in birds and non-avian theropod dinosaurs, but little is known of their microstructure. Here we report that melanosomes (colour-bearing organelles) are not only preserved in the pennaceous feathers of early birds, but also in an identical manner in integumentary filaments of non-avian dinosaurs, thus refuting recent claims that the filaments are partially decayed dermal collagen fibres. Examples of both eumelanosomes and phaeomelanosomes have been identified, and they are often preserved in life position within the structure of partially degraded feathers and filaments. Furthermore, the data here provide empirical evidence for reconstructing the colours and colour patterning of these extinct birds and theropod dinosaurs: for example, the dark-coloured stripes on the tail of the theropod dinosaur Sinosauropteryx can reasonably be inferred to have exhibited chestnut to reddish-brown tones.

Nature advance online publication 27 January 2010 doi:10.1038/nature08740; Received 21 September 2009; Accepted 10 December 2009; Published online 27 January 2010