Some dinosaur species changed skull shape during growth

Some dinosaur species went through drastic changes in their skull shape during normal growth because of different juvenile and adult feeding behaviours, a new research has showed.

After examining the fossil of a young sauropod dinosaur rediscovered in the collections of Carnegie Museum of Natural History, paleontologists at the University of Michigan found that the skull of diplodocus, a 150 million-year-old sauropod, went through drastic changes.

They said that these changes in skull shape may have been tied to feeding behaviour, with adults and juveniles eating different foods to avoid competition. Young diplodocus, with their narrower snouts, may also have been choosier browsers, selecting high quality plant parts.

The team led by John Whitlock and Jeffrey Wilson, who wrote their research in the Journal of Vertebrate Paleontology, said the fossil offers a rare chance to look at the early life history of Diplodocus which was found in western North America.

"Adult sauropod skulls are rare, but juvenile skulls are even rarer. What we do know about the skulls of sauropods like Diplodocus has been based entirely on adults so far," said Whitlock.

Wilson said, "Diplodocus had an unusual skull. Adults had long, square snouts, unlike the rounded or pointed snouts of other sauropods. Up until now, we assumed juveniles did too."

The small Diplodocus skull, however, suggests that major changes occurred in the skull throughout the animal's life.

"Although this skull is plainly that of a juvenile Diplodocus, in many ways it is quite different from those of the adults," Whitlock said.

"Like those of most young animals, the eyes are proportionally larger, and the face is smaller. What was unexpected was the shape of the snout -- it appears to have been quite pointed, rather than square like the adults ".

"This gives us a whole new perspective on what these animals may have looked like at different points in their lives."

They said, "This little Diplodocus skull was discovered in 1921, and more than 80 years passed before we recognised its significance.