Paleontologist from Canada and China reported the first physical evidence that feathered dinosaurs ate birds and dinosaurs in the August 29, 2012, peer reviewed open access journal Public Library of Science.
The researchers examined two skeletons of the large Sinocalliopteryx gigas that included intact abdominal contents. Both specimens came from the Jianshangou Beds of the lower Yixian Formation in Liaoning China. The fossils are approximately 125 million years old and date to the Lower Cretaceous Period.
Sinocalliopteryx gigas was a flightless dinosaur four to six feet long that was covered in small feathers or hair-like fuzz that is considered to have provided insulation to maintain the animal’s body temperature.
One of the Sinocalliopteryx fossil’s stomach contained the remains of three Confuciusornis. Confuciusornis was one of the earliest birds documented to be a bird by musculature and skeletal remains.
The second Sinocalliopteryx fossil’s stomach contained the remains of a Sinornithosaurus, a small feathered meat eating dinosaur that could fly short distances.
The researchers postulate that Sinocalliopteryx gigas may have scavenged the bird meals or was an opportunistic ambush hunter based on the stomach fossil evidence. The stomachs also contained fish, a lizard, and small unidentified mammals.
The fossil remains of the stomach contents of Sinocalliopteryx gigas indicates a digestive system that was capable of varying the acidic content dependent on the food being digested. This trait continues in modern day crocodiles.
This discovery is the first evidence that terrestrial dinosaurs ate birds and raptors.
Abdominal Contents from Two Large Early Cretaceous Compsognathids (Dinosauria: Theropoda) Demonstrate Feeding on Confuciusornithids and Dromaeosaurids
Lida Xing 1 , Phil R. Bell 2 *, W. Scott Persons, IV 1 , Shuan Ji 3 , Tetsuto Miyashita 1 , Michael E. Burns 1 , Qiang Ji 3 , Philip J. Currie 1
1 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, 2 Pipestone Creek Dinosaur Initiative, Clairmont, Alberta, Canada, 3 Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China
Citation: Xing L, Bell PR, Persons WS IV, Ji S, Miyashita T, et al. (2012) Abdominal Contents from Two Large Early Cretaceous Compsognathids (Dinosauria: Theropoda) Demonstrate Feeding on Confuciusornithids and Dromaeosaurids. PLOS ONE 7(8): e44012. doi:10.1371/journal.pone.0044012