Study suggests ‘wonderchicken’ is an ancestor of modern chickens and ducks
The 'wonderchicken' is a prehistoric bird which lived 66.7 million years ago, less than a million years before the asteroid impact that wiped out dinosaurs. Scientifically named Asteriornis maastrichtensis, its winged and beaked descendants survived mass extinction and formed a long lineage that includes both modern chickens and ducks.
Researchers have analysed fossil remains, consisting of an almost complete skull and some limb bones, and published their findings in the journal Nature.
According to a team of scientists from the University of Cambridge, the new fossil helps clarify why the birds survived the mass extinction in the late Cretaceous period.
Detailed analysis of the skull shows that the wonderchicken combines many characteristics comparable to the modern chicken and duck-like birds.
The fossil was found in a limestone quarry near the Belgian-Dutch border. This is a particularly significant find, as it is the first modern dinosaur-era bird to be discovered in the northern hemisphere.
“The moment I first saw what was beneath the rock was the most exciting moment of my scientific career,” said Dr. Daniel Field, a palaeontologist in the Department of Earth Sciences at the University of Cambridge.
“This is one of the best-preserved fossil bird skulls of any age, from anywhere in the world. We almost had to pinch ourselves when we saw it, knowing that it was from such an important time in Earth’s history.”
Dr. John Jagt, who is a researcher at the Maastricht Natural History Museum, added that “the discovery of Asteriornis maastrichtensis provides some vital evidence that Europe was a key area in the early evolutionary history of modern birds.”
Features
The wonderchicken’s skull has features similar to modern birds, despite belonging to a completely different geological era. The front part of the skull, including its beak, resembles that of a chicken.
As Field explained, the shape of the chicken's beak gives it the opportunity to consume a wide range of food, keeping their diet balanced. This is what would have helped the wonderchicken to to survive in arduous conditions, following a mass-extinction situation.
“A barnyard chicken will eat anything you put in front of it,” he notes.
“An unspecialised diet is the kind of feature that might have helped animals like the wonderchicken survive.”
Researchers also discovered that similar to ducks, the Asteriornis maastrichtensis had a bone that projected from the back of its skull towards its eye socket and another bone which was hooked at the back of the jaw.
The team says the discovery pushes back the date of the earliest known modern bird, helping to prove that previous molecular analysis of living suggesting modern birds evolved before the extinction of the dinosaurs is accurate. The record for the oldest bird was previously held by Vegavis whose fossils were discovered in Antarctica and dated to about 66.5m years ago.
Reference: Daniel J. Field, Juan Benito, Albert Chen, John WM Jagt, Daniel T. Ksepka. Late Cretaceous neornithine from Europe illuminates the origins of crown birds. Nature, 2020; 579 (7799): 397 DOI: 10.1038 / s41586-020-2096-0
