Getting to the guts of the dinosaur.

Italian paleontologists have identified a dinosaur fossil so well preserved that it displays the intestine, muscle fibers, and perhaps even the liver of a beast that died 113 million years ago.

An amateur fossil hunter found the specimen near Naples, mistook it for a bird, and tried to sell it illegally. After watching the movie Jurassic Park he recognized it as a dinosaur and turned it over to authorities. Cristiano Dal Sasso of the Civic Museum of History in Milan and Marco Signore of the University of Bristol in England have studied the fossil and report their findings in the March 26 Nature.

The specimen, only 24 centimeters long, represents a young dinosaur just hatched from its egg before it died. The animal was a bipedal carnivore from a previously unknown species, which the researchers named Scipionyx samniticus. It is related to a group of agile predators called maniraptorans.

The fossilization process normally preserves only hard body parts, such as bones and teeth. In the case of the Italian dinosaur, the animal died and was washed into oxygen-deprived waters, where sediment quickly buried it. The exceptional quality of the Italian find makes it one of the most important fossil vertebrates ever discovered, say the scientists.

From studies of the soft body parts that have been preserved, scientists may learn more about the physiology of dinosaurs. The specimen's gut is relatively short but wide, indicating that it may have absorbed nutrients quickly, in a manner similar to that of birds, Signore told Science News.

In the future, he and Dal Sasso plan to take a closer look at the fossil with an electron microscope, possibly even probing inside the gut to explore its contents. The researchers also discovered a reddish, iron-rich patch behind the animal's sternum that they think is its liver.