Fossilized 'last dinner' reveals dinosaur food chain

Chinese and Canadian scientists said dinosaur and bird skeletons found in the stomachs of two fossilized compsognathidaes have provided rare insights into the daily diet of the extinct species.

An article published on PLoS ONE, a science journal, said researchers found "intact stomach contents" from two specimens of Sinocalliopteryx gigas, or "Chinese beautiful-feather dinosaurs," found in northeast China.

The finding was announced after scientists from the University of Alberta and the Pipestone Creek Dinosaur Initiative, both based in Canada, and the Chinese Academy of Geological Sciences conducted joint research on fossils unearthed in Yixian county in Liaoning province.

The stomach of one specimen contained a set of leg bones, complete with foot and phalanx, which belonged to a dromaeosauridae, a bird-like carnivorous dinosaur, said Xing Lida from the University of Alberta.

"The leg appears very large in the abdomen, almost filling the entire cavity," Xing said.

The discovery proves that Chinese compsognathidaes, which lived around 124 million years ago during the Cretaceous period, preyed on dinosaurs more than one-third of their size, Xing said.

Sinocalliopteryx gigas are the largest among compsognathidaes. An adult dinosaur measures 2.4 meters in length, with its body covered in long feathers.

Stomach contents are extremely rare among dinosaur fossils, the researchers said.

"Apparently the compsognathidae died suddenly after consuming the dromaeosauridae, leaving behind its last dinner in fossil form," said Ji Shu'an, a researcher from the Chinese Academy of Geological Sciences.

Several stones were also found in the dinosaur's stomach, which scientists believe were deliberately ingested to aid its digestion.

A second specimen was found to have preserved in its abdomen a medley of bones, which are believed to belong to at least two primitive birds and a single bird-like dinosaur.

Paleontologists are still coming up with theories as to how earthbound dinosaurs were able to catch flying birds. One hypothesis states that the birds were actually scavenged, while others suggest that the ancient lizards were adept at jumping into the air and catching their prey.

"They might have stealthily approached alighting birds and launched a blitz," Xing said.