for National Geographic News
A newly announced dinosaur discovery in China suggests that the prehistoric creatures put in some quality parenting time.
Last year researchers unearthed the fossil remains of a Psittacosaurus, a plant-eating, parrotlike dinosaur that grew to be a meter (three feet) tall. The adult was surrounded by 34 juveniles, a close association that indicates that the dinosaur continued to care for its young even after they hatched from eggs.
The discovery suggests that the care that crocodiles, birds, and other modern descendents of archosaurs give to their young may be an ancestral characteristic. (Archosaurs are a subclass of reptiles that includes dinosaurs, pterosaurs, and crocodilians.)
"People often thought that parental care evolved in birds. But now we're accumulating evidence for parental care in dinosaurs," said David Varricchio, an assistant professor of earth sciences at Montana State University in Bozeman.
The growing data "argues that parental care is a much more primitive thing that birds really just inherited from dinosaurs," Varricchio said. His findings appear in tomorrow's issue of the science journal Nature.
The Psittacosaurus lived in northeastern Asia more than a hundred million years ago. Also known as a "parrot lizard" for its parrotlike beak, the herbivore was a strong, agile dinosaur that walked on its two hind legs. It ate mostly tough stems and fruit.
The Psittacosaurus fossils, which are 125 million years old, were found by farmers in the northeast Chinese province of Liaoning, and are now housed in the province's Dalian Natural History Museum.
The specimens are in excellent condition. The researchers found no separated bones or partial skeletons, which suggests that the dinosaurs were rapidly entombed while still alive.
"They are not in a typical death pose, where animals die on the side," Varricchio said. "These specimens are upright with their heads exposed."
Varricchio speculates that the animals may have been buried by volcanic debris, trapped in a collapsed burrow, or flooded in their nest.
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