Fossil evidence showed that the Microraptor — a four-winged, flying dinosaur about the size of a pigeon — may have been a big fan of sashimi.

Scientists studying the fossilized guts of a Microraptor found in Liaoning province found fish bones bearing the marks of strong digestive acids near the fossil's ribs — the world's first evidence suggesting that Microraptors ate fish.

The research was jointly carried out by Chinese and Canadian scientists, and the results were published on Tuesday in the International Journal of Evolution.

"Microraptors may be the ancestors of birds. They lived in trees, and ate small birds and other animals living in trees. But we didn't know they also ate fish," said Xing Lida, one of the authors of the research report.

Xing added that the scientists are not sure how Microraptors were able to catch the fish.

Microraptors did not have well-developed big toes, such as ospreys for instance, so it wouldn't have been possible for them to catch deep-water fish.

Previous studies showed that Microraptors mainly ate small mammals and birds.

"We're not yet sure about how it caught the fish, but what we know is that it ate it," Xing said.

The dinosaur's fossilized teeth also showed signs that it ate fish: the front teeth stuck out, and jagged edges on the teeth were worn off.

"There are only two other good examples of dinosaurs with a taste for sashimi: the giant, crocodile-like spinosaurs and the tiny compsognathids," said Scott Persons, a co-author from the University of Alberta.

"So no, fish are not usually considered as staples of a dinosaur's diet," he said.

Microraptors, one of the smallest dinosaurs ever found, lived 120 million years ago.

The fish-eating Microraptor fossil was excavated in the early 1990s, but its restoration work was only completed last summer. The fossil is kept in the Qijiang National Geological Park Museum in Chongqing.

"The fossil is a perfectly preserved one with so many details intact, and it's the biggest Microraptor fossil ever found," said Wang Fengping, deputy director of land and resources authority of Qijiang.