By This e-mail address is being protected from spam bots, you need JavaScript enabled to view it , Special to LiveScience

27 November 2007 

A fossilized shark that swallowed a crocodile-like amphibian that, in turn, had gobbled up a fish has now been unearthed.

This exceptional find marks the first time scientists have found direct evidence of such a complex, extinct food chain.

In the past, researchers had uncovered evidence of what past species ate based on the fossilized contents of their guts or droppings. For instance, fossilized dung, or "coprolites," have revealed some dinosaurs ate grass.

"Prey, especially in the gut or intestines of fossil organisms, are very rarely preserved," said paleobiologist Jurgen Kriwet at Humboldt University of Berlin in Germany. At most, only a single victim or perhaps several of the same species are preserved, he added.