'Wonderchicken' fossil from the age of dinosaurs reveals origin of modern birds

Artist's reconstruction of the world's oldest modern bird, Asteriornis maastrichtensis, in its original environment. 66.7 million years ago parts of Belgium were covered by a shallow sea, and conditions were similar to modern tropical beaches like The Bahamas. Asteriornis lived at the end of the Age of Dinosaurs, a time when mosasaurs (giant marine reptiles) swam in the oceans, and Tyrannosaurus rex lived on land. Asteriornis had fairly long legs and may have prowled the tropical shoreline. Credit: Phillip Krzeminski


The spectacular fossil, affectionately nicknamed the 'Wonderchicken', includes a nearly complete , hidden inside nondescript pieces of rock, and dates from less than one million years before the asteroid impact which eliminated all large dinosaurs.

Writing in the journal Nature, the team, led by the University of Cambridge, believe the new fossil helps clarify why survived the mass extinction event at the end of the Cretaceous period, while the giant dinosaurs did not.




Three-dimensional views of the skull of The Wonderchicken, Asteriornis maastrichtensis, a 66.7 million-year-old bird fossil from the end of the age of dinosaurs. It is the oldest modern bird fossil ever found. Credit: Daniel J. Field, University of Cambridge




The skull, despite its age, is clearly recognisable as a modern bird. It combines many features common to the group that includes living chickens and ducks—a group called Galloanserae. Field describes the skull as a kind of 'mash-up' of a chicken and a duck.

"The origins of living bird diversity are shrouded in mystery—other than knowing that modern birds arose at some point towards the end of the age of dinosaurs, we have very little fossil evidence of them until after the asteroid hit," said co-author Albert Chen, a Ph.D. student based at Cambridge. "This fossil provides our earliest direct glimpse of what modern birds were like during the initial stages of their evolutionary history."


Three-dimensional image of the skull of the world's oldest modern bird, Asteriornis maastrichtensis. The fossil is 66.7 million years old and is close to the most recent common ancestor of duck-like birds and chicken-like birds. Credit: Daniel J. Field, University of Cambridge

"We thought it was an appropriate name for a creature that lived just before the end-Cretaceous asteroid impact," said co-author Dr. Daniel Ksepka from the Bruce Museum in Greenwich, Connecticut. "In Greek mythology, Asteria transforms herself into a quail, and we believe Asteriornis was close to the common ancestor that today includes quails, as well as chickens and ducks."

The fact that Asteriornis was found in Europe is another thing which makes it so extraordinary. "The late Cretaceous fossil record of birds from Europe is extremely sparse," said co-author Dr. John Jagt from the Natuurhistorische Museum Maastricht in the Netherlands. "The discovery of Asteriornis provides some of the first evidence that Europe was a key area in the early evolutionary history of modern birds."

"This fossil tells us that early on, at least some modern birds were fairly small-bodied, ground-dwelling birds that lived near the seashore," said Field. "Asteriornis now gives us a search image for future fossil discoveries—hopefully it ushers in a new era of fossil finds that help clarify how, when and where modern birds first evolved."

The announcement of the Wonderchicken find coincides with a new exhibit at Cambridge's Sedgwick Museum of Earth Sciences, where visitors can learn more about Asteriornis and see the fossil up close. "Dawn of the Wonderchicken" runs from 19 March to 15 June. Admission is free.

Dr. Daniel Field is funded by a UKRI Future Leaders Fellowship. He is a University Lecturer in the Department of Earth Sciences at the University of Cambridge, and a Fellow of Christ's College Cambridge.

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More information: Late Cretaceous neornithine from Europe illuminates the origins of crown birds, Nature (2020). DOI: 10.1038/s41586-020-2096-0 , nature.com/articles/s41586-020-2096-0
Journal information: Nature

Citation: 'Wonderchicken' fossil from the age of dinosaurs reveals origin of modern birds (2020, March 18) retrieved 25 July 2021 from https://phys.org/news/2020-03-wonderchicken-fossil-age-dinosaurs-reveals.html

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