Newly-Discovered Cretaceous Bird Lived Among Dinosaurs, Was Strong Flier

Sci-News.com ^ | Nov 13, 2018 | News Staff / Source

[ETL]

All birds evolved from feathered theropods — the two-legged dinosaurs like T. rex — beginning about 150 million years ago, and developed into many lineages in the Cretaceous period, between 146 and 65 million years ago.

But after the cataclysm that wiped out most of the dinosaurs, only one group of birds remained: the ancestors of the birds we see today.

Why did only one family survive the mass extinction? The newly-discovered fossil from one of those extinct bird groups, enantiornithines, deepens that mystery.

..."

Mirarce eatoni’s breast bone or sternum, where flight muscles attach, is more deeply keeled than other enantiornithines, implying a larger muscle and stronger flight more similar to modern birds.

The wishbone is more V-shaped, like the wishbone of modern birds and unlike the U-shaped wishbone of earlier avians and their dinosaur ancestors. The wishbone or furcula is flexible and stores energy released during the wing stroke.

“What is most exciting, however, are large patches on the forearm bones. These rough patches are quill knobs, and in modern birds they anchor the wing feathers to the skeleton to help strengthen them for active flight,” Dr. Atterholt said.

This is the first discovery of quill knobs in any enantiornithine bird, which tells us that Mirarce eatoni was a very strong flier.

“We know that birds in the early Cretaceous, about 115 to 130 million years ago, were capable of flight but probably not as well adapted for it as modern birds,” Dr. Atterholt said.

“What this new fossil shows is that enantiornithines, though totally separate from modern birds, evolved some of the same adaptations for highly refined, advanced flight styles.”

If enantiornithines in the late Cretaceous were just as advanced as modern birds, however, why did they die out with the dinosaurs while the ancestors of modern birds did not?

[Bellflower]

All birds evolved from feathered theropods.....

Yaah, right, this is surely a fact, they were there so we can count on it. Oh, they’re soooooo scientific!