We have discovered the world's oldest modern bird fossil.
This is a fossil from just a few
hundred thousand years before the asteroid struck and wiped out the
giant dinosaurs, about 66.02 million years ago.
So the fossil comes from 66.7 million years ago and it tells us a lot about
how and why modern birds came to be.
So we know that birds are descendants of
dinosaurs but trying to understand why dinosaurs went extinct 66 million years
ago, whereas their descendants the birds did not, is a major area of
paleontological research right now.
And because this new fossil, the 'Wonderchicken'
provides us with our best ever glimpse of a modern bird from the age of
dinosaurs, we can start to feel good about some of the features that the
'Wonderchicken' shows as potential features that would have helped birds
make it through that mass extinction event 66 million years ago.
And these include features like relatively small size, a toothless beak, probably a
generalised diet, an ability to fly and probably ground dwelling habits because
we know that forests were devastated in the aftermath of the extinction event.
So this fossil was found just across the Dutch border in Belgium which is really
amazing because the earliest modern bird fossils that we knew about so far had
come from Antarctica which basically supported this idea that birds perhaps
arose during the age of dinosaurs way down in the Southern Hemisphere away
from the Northern Hemisphere. But the fact that the 'Wonderchicken' which is
the oldest modern bird fossil known so far, comes from Europe really challenges
that idea and makes clear that future discoveries of modern birds from the age
of dinosaurs may be just as likely to come from the Northern Hemisphere as
from a place like Antarctica and raises questions about
where modern birds actually originated.
Initially we weren't very enthusiastic about this fossil so
we were basically given a pile of rocks. Basically four rocks with
little broken limb bones poking out. But it was clear that these were fossil bird
limb bones and birds are very rare from the very end of the age of dinosaurs so
we were interested in them even if it didn't look like a very promising fossil.
But in order to get a better look at those limb bones we decided to put those
rocks in a CT scanner to peer inside the rock and be able to visualise those limb
bones in three dimensions. And when we did that we were absolutely shocked to
discover a nearly complete skull preserved entirely within the rock
hidden from view at the surface and that skull has turned out to be one of the
best preserved bird skulls of any age, ever found in the world.
One of the amazing reasons why
this fossil is preserved as well as it is, is the fact
that the skull was never exposed to the environment. Because the skull is still
encased in these 66.7 million year old rocks by being able to visualise
the interior of the rock using CT scanning we never had to mechanically
chip away at the rock and risk damaging these fragile bones.
Well we started calling it the 'Wonderchicken'
because from the first time we glimpsed this
skull on the computer screen it was clear that the skull shared some
features with living chicken-like birds but it looked like a very weird chicken
and in fact when you study the skull in more detail you realise the skull is a
fascinating combination of features that we associate with chickens and their
relatives but also ducks and their relatives and because the 'Wonderchicken'
shows this fascinating combination of duck-like and chicken-like
features, we think that this fossil is pretty close to that common ancestor of
the duck and chicken groups.
Birds in the present-day are the most conspicuous
group of tetrapod animals, you can easily go through your day and see well
over a dozen living species even if you're not trying. So birds are around us
all the time to the extent that it might even be possible to tune them out.
And trying to understand how this incredible diversity and abundance of
modern birds initially came to be is a very challenging scientific question
because the earliest fossil record of modern birds is very sparse. And we've
come to think that the extinction event that wiped out the giant dinosaurs
66 million years ago was a key event in stimulating the modern radiation of
living birds but we haven't had much direct evidence
to substantiate that until now.
I probably can't repeat the words I actually uttered when this
incredible fossil skull popped up from the computer screen but it was
definitely the most exciting moment of my scientific career.
It's pretty much exactly what
I had been hoping to find ever since I started in the field of
paleontology and I mean it's just so important because bird fossils from this
point in Earth history are so rare, so to have this extremely well-preserved
really important bird fossil that we're able to study in incredible detail in
three dimensions using our CT scan data was an absolute dream come true.