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Birds Got Their Colorful, Speckled Eggs From Dinosaurs

The rainbow of hues seen in modern bird eggs probably evolved into birds' dinosaur ancestors, which had eggs with colorful…

The rainbow of hues seen in modern bird eggs probably evolved into birds’ dinosaur ancestors, which had eggs with colorful and speckled shells.

That’s according to a new study of fossil eggs in the journal Nature . Researchers found that birds’ close dinosaur relatives had eggs with traces of two pigments-a red-brown one and a blue-green one. This same pair of pigments mixes and matches in today’s bird eggs to produce colors ranging from robin’s egg blue to red to yellow to green.

“For a long, long time people have assumed that egg color is a feature that is unique to our modern birds,” says Jasmina Wiemann, a paleontologist at Yale University. Hun sier at antagelsen var basert på at fuglens nærmeste levendefamilie, de krokodiler, “har helt unfarvede, unpigmenterede æg.”

To see if colored eggs might actually go further back in history, she and her colleagues started by looking at the eggs of oviraptors&#821

1; a relative of the velociraptor made famous in the movie Jurassic Park.

“This dinosaur is especially interesting because oviraptors are the first dinosaurs that built open nests,” she says, explaining that earlier dinosaurs buried eggs underground, where color would not be expected to make any difference.

“Once you start to build an open nest, your eggs are exposed to the environment,” she notes. Out there, colors and patterns could provide camouflage or help dinosaurs recognize their own eggs.

Inside some 66-million-year-old oviraptor egg fossils, her team found small concentrations of both pigments that color modern bird eggs. That was intriguing. Still, it was just one dinosaur.

Now the researchers have analyzed egg shells from more. “We tried to cover the major branches of dinosaurs to get a good idea for all non-avian dinosaurs,” she says.

They found no pigments in birds’ distant dinosaur relatives, such as the groups that include triceratops and the long-necked diplodocus.

The red-brown and blue-green pigments were present, however, in eggshells from the group of dinosaurs that include birds and their close relatives. These pigments were built into the shells in the same sophisticated way that they are in modern birds’ eggs – and Wiemann thinks this can not be a coincidence.

“We have, very likely, a single evolutionary origin of egg color,” she says.

What’s more, the analysis of pigments showed that dinosaur eggs even had spots and speckles. And that surprised Mark Hauber, an ornithologist and expert on eggs at the University of Illinois, Urbana-Champaign.

“We not only know that dinosaur eggs were colorful, but they were speckled, which is a whole different aspect of diversity,” says Hauber.

Dinosaurs may have needed these fancy eggs for all the same reasons as birds, suggesting that their behavior could have been just as complex.

“Dinosaur eggs could have been camouflaged, they could have been individually recognized, they could have been mimetic,” says Hauber. “Så der er alle de funktioner som er forbundet med spotting mønstre på egg som vi ikke engang vurdert for dinosaur egg.”

Plus, says Hauber, maybe distinctive colors and markings were linked to some egg-related dinosaur business we have not even thought of. A certain egg color might have been warned-be predators of danger, he says, “and that could be that the mummy dinosaur comes back, or papa dinosaur comes back, and will beat you up.”

Copyright 2018 NPR. To see more, visit http://www.npr.org/ .

AILSA CHANG, HOST:

Bird eggs can be amazingly colorful, everything from robin’s egg blue to green, even red. Scientists used to think colored egg shells evolved with modern birds. But NPR’s Nell Greenfieldboyce reports these colors go back further.

NELL GREENFIELDBOYCE, BYLINE: The closest living relative of modern birds is the crocodile, and it has white, uncolored eggs. So biologists long thought that colored egg shells were a bird invention. Jasmina Wiemann is a paleontologist at Yale University. Hun undret if colored egg shells were older, maybe as old as birds’ dinosaur ancestors. Take the oviraptor. It’s a relative of the velociraptor made famous in the movie “Jurassic Park.”

JASMINA WIEMANN: This dinosaur is particularly interesting because oviraptors were the first dinosaurs that built open nest.

GREENFIELDBOYCE: Instead of burying its eggs underground.

WIEMANN: Wiemann says, out there, color could provide camouflage or help dinosaurs recognize their own eggs. So she and some colleagues studied 66 million-year-old egg fossils, searching for the two pigments – a red one and a blue one – that’s known to mix and match in bird eggs, creating all the beautiful colors. [19659019] WIEMANN: And we found very, very small concentrations preserved of both pigments.

GREENFIELDBOYCE: That was intriguing. Still, it was just one dinosaur, so Wiemann and her colleagues analyzed egg shells from more.

WIEMANN: We tried to cover the major branches of dinosaurs to get a good idea for, like, all non-avian dinosaurs. [19659019] GREENFIELDBOYCE: In the journal Nature, they report that they found no pigments in birds’ distant dinosaur relatives, such as the groups that include triceratops and the long-necked diplodocus. The red and blue pigments were present, however, in egg shells from the group of dinosaurs that include birds and their close relatives.

WIEMANN: We have, very likely, a single evolutionary origin of egg color.

GREENFIELDBOYCE: What’s more, her team showed that dinosaur eggs even had spots and speckles. And that surprised Mark Hauber. He is an ornithologist and expert on eggs at the University of Illinois at Urbana-Champaign.

MARK HAUBER: We are not only aware that dinosaur eggs were colorful, but they were speckled, which is a whole other aspect of diversity. [19659019] GREENFIELDBOYCE: He says it looks like dinosaurs may have needed these fancy eggs for all the same reasons as birds and maybe some egg-related dinosaur business we have not even thought of. Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.

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