Dinosaur skull changed shape during growth

ANN ARBOR, Mich.—The skull of a juvenile sauropod dinosaur, rediscovered in the collections of Pittsburgh's Carnegie Museum of Natural History, illustrates that some sauropod species went through drastic changes in skull shape during normal growth. Click image for high resolution - Diplodocus carnegii adult and juvenile feeding, Reconstruction illustration: Mark A Klingler / Carnegie Museum of Natural History University of Michigan paleontologists John Whitlock and Jeffrey Wilson, along with Matthew Lamanna from the Carnegie Museum, describe their find in the March issue of the Journal of Vertebrate Paleontology. The fossil offers a rare chance to look at the early life history of Diplodocus, a 150 million-year-old sauropod from western North America. "Adult sauropod skulls are rare, but juvenile skulls are even rarer," said Whitlock, a doctoral candidate in the U-M Museum of Paleontology. "What we do know about the skulls of sauropods like Diplodocus has been based entirely on adults so far." "Diplodocus had an unusual skull," said Wilson, an assistant professor in the Department of Geological Sciences and an assistant curator at the U-M Museum of Paleontology. "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.