A new study conducted on dinosaur eggs has confirmed the evolutionary link between dinosaurs and birds.
Researchers at the University of Calgary and Montana State University conducted a study on dinosaurs' eggs to find an answer to their question on whether dinosaurs hatched their eggs buried in nest materials, like crocodiles or uncovered and in the open like birds. A small, bird-like North American dinosaur named Troodon provided an answer to this question during the study. The dinosaur was observed to have nurtured its eggs in a similar way to brooding birds.
"Based on our calculations, the eggshells of Troodon were very similar to those of brooding birds, which tells us that this dinosaur did not completely bury its eggs in nesting materials like crocodiles do," says study co-author Zelenitsky, assistant professor of geoscience. "Both the eggs and the surrounding sediments indicate only partial burial; thus an adult would have directly contacted the exposed parts of the eggs during incubation," lead author Varricchio, associate professor of paleontology, said.
The researchers counted and measured the pores in the shells of Troodon eggs to assess how water vapor was conducted through the shell compared with eggs from contemporary crocodiles, mound-nesting birds and brooding birds. They are optimistic their methods can be applied to other dinosaur species' fossil eggs to show how they may have been incubated.
"For now, this particular study helps substantiate that some bird-like nesting behaviors evolved in meat-eating dinosaurs prior to the origin of birds. It also adds to the growing body of evidence that shows a close evolutionary relationship between birds and dinosaurs," Zelenitsky said.
The findings were published in the spring issue of Paleobiology.
