Scientists have uncovered a rare find: a 67-million-year-old mummified plant-eater that contains fossilized bones and skin tissue, and quite possibly muscle and organs.

Preserved by a natural fluke of time and chemistry, the four-ton mummified hadrosaur, a duck-billed herbivore common to North America, could reshape the understanding of dinosaurs and their habitat, its finders say.

"There is no doubt about it that this dinosaur is a very, very significant find," said Tyler Lyson, a graduate student in geology at Yale University who discovered the dinosaur in North Dakota.

Nicknamed Dakota, the hadrosaur is one of only five naturally preserved dinosaur mummies ever discovered. Unlike previous dinosaur mummies, which typically involve skin impressions pressed into bones, Dakota's entire skin envelope appears to remain largely intact.