Dinosaur with Nut-cracking Jaws
Skull of the parrot-beaked dinosaur, Psittacosaurus gobiensis, next to that of a living macaw © Mike Hettwer
National Geographic News reports on the findings of a group of scientists who have been examining the skeleton of a dinosaur with nut-cracking jaws. It was found in the Gobi desert in 2001 and seems to have eaten much as parrots do today.
The 3-foot-long (0.9-meter-long) Cretaceous creature had a boxlike skull and beaklike jaw that resemble those of modern parrots. The 110-million-year-old skull-as well as “a huge pile” of 50 stomach stones found with the fossil-suggests that the beast was chewing hard, fibrous nuts and seeds, the researchers say. Stomach stones are rocks ingested by some animals to grind food in their digestive systems.
If confirmed, Psittacosaurus gobiensis (“parrot reptile of the Gobi”) and its close cousins would be the world’s first known nut-eating dinosaur.
“Knowing what type of food a dinosaur ate is extremely rare,” said Paul Sereno PhD, a paleontologist at the University of Chicago, a National Geographic explorer-in-residence and the leader of the study. “Basically this solves a bit of a riddle for this dinosaur. We’ve now come closer to why it looks like it does.
“The skull once had giant jaw muscles attached to broad sheets of extremely rigid cheekbone, giving the animal a powerful bite,” said Dr Sereno, whose study on P. gobiensis appeared in the journal Proceedings of the Royal Society B in July. “Like a parrot, the dinosaur was able to move its jaws both vertically and horizontally, allowing it to ’shear’ tough plants.
Hans-Dieter Sues PhD, a paleontologist at the National Museum of Natural History in Washington, DC, said that scientists have wondered why such dinosaurs and their relatives, called psittacosaurs, had both robust jaws and so many stomach stones. “Usually animals that use stomach stones tend not to need tough beaks. For instance, chickens have puny beaks, relying on sand and gravel in their gizzards to grind down their unchewed food. Sereno’s ‘very compelling argument’ that the [new dinosaurs] were eating unusually hard food makes good sense to me,” Sues said.
Several species of psittacosaurs roamed Central Asia, where their fossils are now plentiful, scientists say. The creatures often had odd features, such as elaborate horns and porcupine-like tail bristles.
According to Dr Sereno, the psittacosaurs’ specialized diet might explain their success during that time.
“That’s because animals that take advantage of their environments-in this case, eating what few other animals could-have plentiful resources and are therefore more likely to branch into more species,” added Dr Sues. “The new research offers a very nice explanation about why these creatures are so diverse.”
