Dinosaur Looked, Behaved Like a Parrot
Wednesday, June 17, 2009 at 2:43 
A newly-found dinosaur, Psittacosaurus gobiensis, resembled a modern parrot on steroids, but it was likely not a close relative. Here a skull of a modern macaw is shown next to that of the parrot-beaked dinosaur, Psittacosaurus gobiensis. Photo: Mike HettwerPolly might have craved a huge cracker back in the Cretaceous Era, since researchers have just identified an over 3-foot-long dinosaur that looked, ate and behaved very similar to today's parrots.
The new dinosaur, Psittacosaurus gobiensis, resembled a modern parrot on steroids, but it was likely not a close relative.
"Psittacosaurus discovered the delights of nut eating 110 million years ago, at least 60 million years before the first parrot arrived," lead author a Paul Sereno told Discovery News.
Sereno, a University of Chicago paleontologist, with colleagues Zhao Xijin and Tan Lin analyzed the remains of the parrot-like dinosaur, which was first unearthed in the western Gobi Desert of inner Mongolia back in 1922. The fossils represent the first and most complete dinosaur excavated in that region at the time.
Sereno and his team, whose findings are published in the latest Proceedings of the Royal Society B, not only identified the new species, but they were also able to determine how, and what, it ate.
Analysis of its skull shows it had reinforcements and "enhanced attachment areas for powerful jaw muscles," as today's parrots do around their beaks. These clues, along with visible tooth wear, allowed the scientists to figure out how the dinosaur bit down on its food.
"Parrot-beaked dinosaurs chewed by sliding their lower jaw forward and then drawing it upward and backward against its upper teeth -- very unusual," said Sereno. "The vast majority of reptiles either just clamp the jaws shut or slide them forward and backward to grind."
The grinding didn't stop there. Gastroliths, or stones used during digestion, were found in the dinosaur's gut. Like grit used by modern parrots, the stones helped to break down tough foods, such as nuts, nutshells and seeds.
The researchers believe the dinosaur was a vegetarian, perhaps also eating some plant material, "because it had a rounded, rather than pointed, bill for cropping plants."
An artistic rendering of the newly discovered species of parrot-beaked dinosaur, Psittacosaurus gobiensis. Scientists first discovered psittacosaurs in the Gobi Desert in 1922, calling them "parrot-beaked" for their resemblance to parrots. Psittacosaurs evolved their strong-jawed, nut-eating habits 60 million years before the earliest parrot. Picture: Todd Marshall
It's known that flowering plants were rare in Mongolia during the dinosaur's Lower Cretaceous lifetime. Plants in general, however, were plentiful, and the climate was relatively stable.
The environment must have been perfect for psittacosaurs, which once flourished in this now desert site.
Jack Horner, a professor and curator of paleontology at Montana State University's Museum of the Rockies, has found at least 180 psittacosaurus skeletons in Mongolia. He said he and his team have "excavated as many as 80 in one week."
Horner and his colleagues suspect "many, many" more such remains are still to be found in Mongolia.
Despite the treasure trove of these proficient nut-cracking animals, experts believe their moment of evolutionary glory was short-lived.
The geographical range of parrot-like dinosaurs was limited to central Asia. Their time on earth might have spanned just 10 to 20 million years, a relative blip in animal kingdom history.