Wonderchicken: meet the oldest ever fossil bird

When scientists at the University of Cambridge scanned a nondescript piece of rock dating from the end of the dinosaur era, they got the shock of their lives. Inside was a near-complete skull of a bird similar to modern day ducks and chickens. In fact, they’ve dubbed it “Wonderchicken”. Phil Sansom spoke to its discoverer Daniel Field about its significance...

Daniel - Well, it looks like a very strange bird skull, because it shows some features shared by living chickens and also living ducks. So in some ways the skull is a mash up of what you might think of as a chicken-like bird skull and a duck-like bird skull. If you hold it in your hand, it's tiny about the size of a large quail or a small partridge.

Phil - And how did you actually find it?

Daniel - The bones themselves were actually dug out in Belgium back in the year 2000, but the specimen doesn't look like much. It's basically just a few broken rocks with some nondescript, poorly preserved limb bones poking out. So the specimen wasn't studied until 2018. I CT scanned it with my PhD student, Juan Benito at Cambridge, which allowed us to peer inside the rock. And when we did, we were absolutely shocked to see that inside the rock. Totally invisible from the surface is this beautifully preserved bird skull from about 66.7 million years ago.

Phil - What were birds, and the rest of the world like, back so long ago?

Daniel - We're talking about rocks that date to the very end of the age of dinosaurs, when Tyrannosaurus Rex and Triceratops, some of the most iconic dinosaurs of all time, were still roaming the Earth. But what's fascinating and what we really didn't know that much about before, was the extent to which what we think of as modern birds were around at that point. And finding this fossil, which is the oldest, well-documented modern bird fossil ever discovered, tells us that there were at least a handful of major living lineages of birds around on the planet before that asteroid struck.

Phil - Now when you say modern bird, what do you mean? Because I heard dinosaurs come from birds.

Daniel - Well we have birds are of course..

Phil - The other way around. Birds come from dinosaurs, you know?

Daniel - That's right. Yup. But that's a very long, protracted process that we're talking about. So, you know, roughly 150 million years ago, we have Archaeopteryx, which a lot of people like to talk about is the first bird. It's a very bird-like dinosaur in that it's got feathered wings, but it also has tiny teeth in its mouth. And we know that bird-like animals that retained teeth persisted all the way to the age of dinosaurs, until the asteroid struck the earth and wiped them out. So when I talk about modern birds, I'm talking about the most recent common ancestor of all living birds and then all of that ancestor’s descendants. And we think this new fossil provides us with our best insights so far into what these early modern birds were like, coexisting with the very latest stages of non-avian dinosaur history.

Phil - Now you mentioned teeth. Is that crucial here?

丹尼尔- Wonderchicken,作为一个现代的bird, does not have teeth. So modern birds, as I've defined them, would have shared a bunch of features ancestrally that we associate with birds today. So that includes, of course, a toothless beak, feathered body and ancestral ability to fly, high metabolic rates, those sorts of things. But the beak of the Wonderchicken itself is interesting, because it doesn't seem to show any particular specialisation for a particularly specialised diet. So it sort of looks like the beak of a living chicken. And we know that most chicken-like birds are fairly generalist in terms of what they eat. And we're wondering if the shape of the beak in the Wonderchicken might suggest some features that might've helped the ancestors of modern birds survive in the aftermath of the extinction event.