An extensive analysis of 12 fossilised dinosaur eggshells from Asia, Europe, South and North America have detected a duo of pigments present in the eggs of colourful birds’ eggs of a group called eumaniraptorans, which consists of well-known carnivores like Velociraptor and the small feathered dinosaur ancestors of birds.
“We discovered that egg color is not a trait unique to our modern birds, but evolved in their non-avian dinosaur ancestors,” said Yale University paleontologist Jasmina Wiemann, who headed the study published in the journal Nature.
“Our study fundamentally changes our understanding of egg color evolution, and adds color to dinosaur nests in the real ‘Jurassic World’.”
For an instance, the predator named Deinonychus had a blue egg with brown blotches and the bird-like Oviraptor, famous for its toothless beak, had eggs that were dark blue in colour.
Birds evolved from eumaniraptoran dinos in the Jurassic Period consist of Archaeopteryx, the earliest-known bird that lived about 150 million years ago in Germany.
Egg colour provided a massive advantage to dinosaurs that had exposed nests for their eggs, rather than burying them into the ground similar to that of turtles and alligators, with a view of providing camouflage to protect against egg-eating predators, the researchers said.
Whereas, all other dinosaurs produced plain white eggs, making the evolutionary egg colour of eumaniraptoran dinosaurs more special.
In the eumaniraptorans, the researchers found evidence of a blue-green pigment named biliverdin and a red-brown pigment called protoporphyrin IX structurally integrated into the crystal matrix of the eggshell, as they are with birds.
“Some were uniformly colored,” said paleontologist and study co-author Mark Norell of the American Museum of Natural History in New York.
“Some were spotted and speckled. It was just like in living birds. A robin’s egg is uniformly blue, but a quail’s is spotted and speckled.”
Other features which were once assumed to have originated in birds, like wishbones and feathers also came from their dinosaur forebears, Norell said.
(With inputs from agencies)