Alberta researchers reveal details of 'one of a kind' dinosaur nest

Alberta researchers have almost cracked the mystery of what kind of dinosaur builtthe 77-million-year-old fossilized nest found in Montana near the Alberta border in the 1990s.

The nestwas collected along withfragments of adozen eggs.Itbelongedto either a caenagnathid or a small raptor called a dromaeosaurid, according to a paper published Thursday in the journal Palaeontology.

Nests of meat-eating dinosaurs like these are rare, but thisis "one of a kind,"said Darla Zelenitsky, a University of Calgary paleontologist and the lead author ofthe paper.

"It is the first nest of its kind in the world," she said in a statement.

The nest is about half a metre across, and the eggs were about 12.5 cm long. Itwas acquired by the museum in 2006 from a private collector, butwas wrongly labelled as belonging to the more common hadrosaur, known as the duck-billed dinosaur.

The discovery "tells you a little bit more about how dinosaurs went about to buildtheir nests," said Franois Therrien, a co-investigator in the study and curator of dinosaur paleoecology at the Royal Tyrrell Museum in Drumheller, which will display the nest.

The female likely dug in the sand, possibly on the shore of a river, to build a mound, then laid her eggs over several days and sat on them.

"It fills in a gap in our understanding of the evolution of birds," he said in an interview with CBC News. "This new discovery of the new nest actually shows that modern birds did not acquire their characteristics suddenly. They actually just inherited structures and features that were present in their ancestors, the meat-eating dinosaurs."

The next step will be to test the egg shells, he said, "specifically, for the chemical composition of the egg shell, because that can tell us a lot of information about the climate that prevailed when this dinosaur laid its eggs."