CT scans of toothed bird fossils lead to startling discovery | fossils

Paleontologists have cooked up the goose as one of the key doctrines in bird evolution after finding a pre-modern bird more than 65 million years ago that could move its beak like modern birds.

This toothy animal was discovered in the 1990s by an amateur fossil collector in a quarry in Belgium and dates back to about 66.7 million years ago – shortly before the date. asteroid strike that wiped out the dinosaurs other than birds.

While the fossil was first described in a study some 20 years ago, researchers who re-examined the specimen say they made an unexpected discovery: The animal had a movable palate.

“If you imagine how we open our mouths, the only thing we can do is… [move] Our lower jaw. Our upper jaw is completely fused to our skull – it is completely immobile, said Dr Daniel Field, senior author of the research from the University of Cambridge.

Non-avian dinosaurs, including tyrannosaurs, also had a fused palate, as do a few modern birds such as ostriches and kuswaris. By contrast, the vast majority of modern birds including chickens, ducks, and parrots are able to move their lower and upper jaws independently of the rest of the skull and of each other.

This, Field says, makes the beak more flexible and precise, which helps with preparation, nest building and food finding. “This is a really important innovation in the evolutionary history of birds. But it has always been thought of as a relatively recent innovation.

“The assumption has always been … that the ancestral state of all modern birds was this fused state which is distinguished by ostriches and their relatives simply because they appear simpler and more reminiscent of non-avian reptiles,” Field added.

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Birds with a movable palate are called neognaths, or “new jaws,” while birds with a movable palate are called paeognaths, or “old jaws.”

the study, which was published in the journal NatureRuffled feathers would be expected, not only to suggest that the movable palate predates the origin of modern birds but that the immediate ancestors of ostriches and their relatives went on to evolve a fused palate.

“Why the ostrich’s ancestors and relatives lost this useful plate formation, at this point, remains a mystery to me,” Field said.

The discovery was made when Field and his colleagues examined the fossils using tomographic scanning techniques. Researchers have discovered that bone previously thought to be from the animal’s shoulder was actually from its roof.

Janavis final palate compared to pheasant and ostrich.
palate final janavis Compared to a pheasant and an ostrich. Photography: Dr Juan Benito and Daniel Field, University of Cambridge

The team classified the newly discovered animal final janavis a reference to the Roman god who looked back and forth, and a nod to the animal’s place in the bird family tree. Portmanteau of the Latin words for “final” and “teeth” reflects Presence Janavis shortly before toothed birds were wiped out in the subsequent mass extinction.

The location of his discovery means that he lived at roughly the same time and place as “Wonderchicken”, the oldest known modern birdalthough it weighs in at 1.5 kg (3.3 lb), Janavis It would have weighed nearly four times as much.

While the wondrous chicken’s palate bones were not preserved, Field said he was confident they would be similar to those from Janavis. However, he added, the difference in the creatures’ size could explain why the chicken’s wonder relatives survived the cataclysm 66 million years ago, but those from Janavis did not.

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“We think this mass extinction event was very selective in size,” he said. “Large-bodied animals in terrestrial environments had a terrible impact during this mass extinction event.”

Professor Mike Benton, a paleontologist at the University of Bristol who was not part of the research, said the study raised questions about the position on the avian family tree of three extraordinary extinct groups that lived after the mass extinction including the Dromornithidae, better known as the Devil. Ducks and Gastornithidae, thought to be a type of giant flightless bird.

“If this palate feature is rudimentary, I see it [these groups] It would have had earlier origins and may have survived from the Cretaceous period onwards.

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