Department of Earth Sciences, University of Oxford, Oxford, United Kingdom; Zoology Division, School of Environmental and Rural Sciences, University of New England, Armidale, Australia
Yan Wang
Institute of Geology and Paleontology, Linyi University, Linyi, China
Paul G McDonald
Zoology Division, School of Environmental and Rural Sciences, University of New England, Armidale, Australia
Stephen Wroe
Zoology Division, School of Environmental and Rural Sciences, University of New England, Armidale, Australia
Jingmai K O'Connor
Field Museum of Natural History, Chicago, United States; Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China; Chinese Academy of Sciences Center for Excellence in Life and Paleoenvironment, Beijing, China
Alexander Bjarnason
Department of Earth Sciences, University of Oxford, Oxford, United Kingdom
Joseph J Bevitt
Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
Xuwei Yin
Shandong Tianyu Museum of Nature, Linyi, China
Xiaoting Zheng
Institute of Geology and Paleontology, Linyi University, Linyi, China; Shandong Tianyu Museum of Nature, Linyi, China
Zhonghe Zhou
Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China; Chinese Academy of Sciences Center for Excellence in Life and Paleoenvironment, Beijing, China
Roger BJ Benson
Department of Earth Sciences, University of Oxford, Oxford, United Kingdom
The Early Cretaceous diversification of birds was a major event in the history of terrestrial ecosystems, occurring during the earliest phase of the Cretaceous Terrestrial Revolution, long before the origin of the bird crown-group. Frugivorous birds play an important role in seed dispersal today. However, evidence of fruit consumption in early birds from outside the crown-group has been lacking. Jeholornis is one of the earliest-diverging birds, only slightly more crownward than Archaeopteryx, but its cranial anatomy has been poorly understood, limiting trophic information which may be gleaned from the skull. Originally hypothesised to be granivorous based on seeds preserved as gut contents, this interpretation has become controversial. We conducted high-resolution synchrotron tomography on an exquisitely preserved new skull of Jeholornis, revealing remarkable cranial plesiomorphies combined with a specialised rostrum. We use this to provide a near-complete cranial reconstruction of Jeholornis, and exclude the possibility that Jeholornis was granivorous, based on morphometric analyses of the mandible (3D) and cranium (2D), and comparisons with the 3D alimentary contents of extant birds. We show that Jeholornis provides the earliest evidence for fruit consumption in birds, and indicates that birds may have been recruited for seed dispersal during the earliest stages of the avian radiation. As mobile seed dispersers, early frugivorous birds could have expanded the scope for biotic dispersal in plants, and might therefore explain, at least in part, the subsequent evolutionary expansion of fruits, indicating a potential role of bird–plant interactions in the Cretaceous Terrestrial Revolution.
