There's nothing cuter than baby animals, even when those babies are fossils of what remains of a potential dinosaur nest. Even cuter is that these dinosaurs appeared to have an older dinosaur taking care of them, a potential babysitter.
The fossils were first discovered in 2004 by a group of amateur paleontologists in northeast China. They were part of a rock slab that included 24 small baby psittacosaurs fossils, along with one older psittacosaur skull.
The fossils, which are about 120 million years old, caught the attention of the University of Pennyslvania's Brandon P. Hedrick and Peter Dodson, who initially saw a photo of the fossil bed.
Hedrick and Dodson examined the fossil bed in more depth by analyzing the material around the dinosaurs' fossils. They looked at pieces of rock from the bed under a microscope and discovered that it was volcanic rock.
They believed the material was flowing at the time, because, generally, in the event of a flowing material like that, the fossils' orientations are all the same, and in this case, they were. However, the material wasn't lava, but possibly mud, which is also associated with volcanoes.
The most interesting discovery about the nest, though, was that two of the 24 smaller fossils appeared entangled with a larger skull, from the same dinosaur family. This suggests that the animals had a close relationship at the time of death.
Scientists estimated that the 24 fossils were not from eggs, as no egg shell particles remained on the slab, and that the babies were old enough to move around. The older skull appears at about four or five years old, suggesting that this wasn't the parent of the babies, as psittacosaurs didn't usually mate until they were older. However, the team of paleontologists believes it could belong to an older sibling, who acted as a "caretaker" for the hatchlings.
Although, the fossil bed seems to indicate a nest, the University of Pennyslvania team isn't convinced, as they found no evidence as such.
"It certainly seems like it might be a nest, but we weren't able to satisfy the intense criteria to say definitively that it is," says Hedrick. "It's just as important to point out what we don't know for sure as it is to say what we're certain of."
The team plans to continue to study the bones, with hopes of proving definitively that they were all at the same developmental stages. Those results might confirm the nest theory.
