Laser Fluorescence Illuminates the Soft Tissue and Life Habits of the Early Cretaceous Bird Confuciusornis

PLoS One. 2016 Dec 14;11(12):e0167284. doi: 10.1371/journal.pone.0167284. eCollection 2016.

Abstract

In this paper we report the discovery of non-plumage soft tissues in Confuciusornis, a basal beaked bird from the Early Cretaceous Jehol Biota in northeastern China. Various soft tissues are visualized and interpreted through the use of laser-stimulated fluorescence, providing much novel anatomical information about this early bird, specifically reticulate scales covering the feet, and the well-developed and robust pro- and postpatagium. We also include a direct comparison between the forelimb soft tissues of Confuciusornis and modern avian patagia. Furthermore, apparently large, fleshy phalangeal pads are preserved on the feet. The reticulate scales, robust phalangeal pads as well as the highly recurved pedal claws strongly support Confuciusornis as an arboreal bird. Reticulate scales are more rounded than scutate scales and do not overlap, thus allowing for more flexibility in the toe. The extent of the pro- and postpatagium and the robust primary feather rachises are evidence that Confuciusornis was capable of powered flight, contrary to previous reports suggesting otherwise. A unique avian wing shape is also reconstructed based on plumage preserved. These soft tissues combined indicate an arboreal bird with the capacity for short-term (non-migratory) flight, and suggest that, although primitive, Confuciusornis already possessed many relatively advanced avian anatomical characteristics.

MeSH terms

  • Animals
  • Birds / anatomy & histology*
  • Birds / physiology*
  • Bone and Bones / anatomy & histology
  • China
  • Flight, Animal / physiology*
  • Fluorescence*
  • Fossils*
  • Habits

Grants and funding

ARF was funded in part by a Fulbright Grant from the U.S. State Department, a Panorama small grant from the University of Kansas Natural History Museum and Biodiversity Institute, and the University of Kansas Department of Geology. Z. Zhou was supported by the National Basic Research Program of China (973 Program; 2012CB821906), the National Natural Science Foundation of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.