Sinocalliopteryx feeding on Confuciusornis, left, and Sinornithosaurus. (Cheung Chungtat/PLoS One )
Two fossil dinosaur specimens from China have revealed the animals' last meal: feathered, flying dinosaurs, along with fish, a lizard and the remains of unidentified mammals. The dinos might have been scavengers, but the near-complete remains of two of the flying dinosaurs in one of the animal's stomachs suggests instead that the beast was a skillful predator, said paleontologist Philip R. Bell of the Pipestone Creek Dinosaur Initiative in Clairmont, Canada, lead author of a report appearing in the online journal PLoS One.
[For the record, 9:34 a.m. Sept. 4: The original version of this story identified Philip J. Currie as a researcher at the Pipestone Creek Dinosaur Initiative. Currie, a co-author, is at the University of Alberta in Edmonton, Canada. Philip R. Bell of Pipestone Creek was the lead author.]
The two dinosaurs were specimens of Sinocalliopteryx gigas, which were 4 to 6 feet long and covered with small feathers to provide warmth. Fossils of the flightless dino were found in the Jianshangou Beds of the lower Yixian Formation in Liaoning, China. Examination of the 120-million-year-old fossils by Bell and his colleagues from the Chinese Academy of Geological Sciences in Beijing showed that the digestive system of one of the specimens contained a partial leg of a member of the dinosaur species Sinornithosaurus, a cat-sized, feathered, meat-eating dinosaur that could fly for short distances.
The second contained the remains of two Confuciusornis, crow-sized primitive birds that could also fly short distances. The fact that both remains in the second dinosaur were in a similar state of digestion indicates that they were consumed about the same time, suggesting that they were hunted rather than scavenged. The stomach also contained bones from another, unidentified dinosaur that were acid-etched, suggesting that they had been largely digested.
The presence of prey in the stomach of dinosaur fossils is relatively rare, but is valuable to scientists because it is one of the few direct indicators of interactions between species, Bell said.