How reptilian were dinosaur eggs?

A dinosaur’s nest

DID dinosaur eggs hatch quickly, like those of birds (which are dinosaurs’ direct descendants), or slowly, like those of modern reptiles (which are dinosaurs’ collateral cousins)? That is the question addressed by Gregory Erickson of Florida State University and his colleagues in a paper just published in the Proceedings of the National Academy of Sciences. It is pertinent because it touches on the wider matter of just how “reptilian” the dinosaurs actually were. Researchers already know that many were warm-blooded, and that some had insulation in the form of feathers, even though they could not fly. Fast-developing embryos would drive a further wedge between them and their truly reptilian kin.

To investigate, Dr Erickson looked at two sets of fossilised dinosaur eggs. The first, from a Mongolian nest (pictured), was laid by Protoceratops andrewsi, a sheep-sized creature that lived 70m years ago. The second, from Canada, was laid by Hypacrosaurus stebingeri—a species contemporary with P. andrewsi that…Continue reading
Source: Economist