The oldest fossil of a modern bird, dating from the age of dinosaurs, has been discovered, a new study reports.
The tiny fossil, nicknamed the "wonderchicken," includes a nearly complete skull hidden inside nondescript pieces of rock, and dates to more than 66 million years ago.
That's less than 1 million years before the asteroid impact that killed off all the large dinosaurs.
"This is one of the best-preserved fossil bird skulls of any age, from anywhere in the world," he said. "We almost had to pinch ourselves when we saw it, knowing that it was from such an important time in Earth's history."
The seagull-size shorebird had features of both ducks and chickens as well as turkeys. Detailed analysis of the skull shows that it combines many features common to modern chicken- and duck-like birds, suggesting that the "wonderchicken" could be the last common ancestor of modern chickens and ducks.
Field describes the skull as a kind of "mash-up" of a chicken and a duck. The bird's face likely looked like a modern-day chicken, while from the back, it looked like a duck.
The creature was likely about the size of a small duck, weighing an estimated 14 ounces.
The first part of its official scientific name, Asteriornis maastrichtensis, is derived from Asteria – a Greek goddess of falling stars who turns into a quail. This reflects both the impending asteroid impact and the similarity of Asteriornis to fowl birds.
"This is an incredibly informative specimen," Amy Balanoff, a paleontologist at Johns Hopkins University who wasn’t involved in the study, told Science magazine.
Kevin Padian, a paleontologist at the University of California-Berkeley, who also wasn't involved in the research, said the fossil provides the best evidence yet of when and how the earliest ancestors of today’s birds evolved.
The research team said the fossils not only suggest modern bird evolution was in its early stages when the asteroid struck, according to the Guardian, but its discovery in Europe opens up the debate about whether modern birds emerged in the Southern Hemisphere, as has been proposed.
Scientists used CT scans to discover the skull embedded in the unassuming rocks, which were dug up in Belgium.
"Finding the skull blew my mind," said co-author Juan Benito, also from the University of Cambridge, who was CT scanning the fossils when the skull was discovered. "Without these cutting-edge scans, we never would have known that we were holding the oldest modern bird skull in the world."
The study was published Wednesday in the peer-reviewed British journal Nature.
Contributing: The Associated Press
This article originally appeared on USA TODAY: Wonderchicken: Oldest bird fossil discovered