[♪ INTRO] Today, the last living lineage of dinosaurs,
the birds, are masters of flight. But 200 million years ago or so, giant reptiles
called pterosaurs ruled the skies. And a new study suggests flight wasn’t the
only trait they shared with modern birds. Just this week, paleontologists published
evidence of what they say are feathers from pterosaur fossils, pushing back the origin
of feathers some 70 million years, and suggesting that all dinosaurs
may have had some kind of feathers. A slew of well-preserved fossils with
simple feathers in the late 1990s cemented the idea that birds are dinosaurs,
and that some dinosaurs sported plumage. Since then, paleontologists have been trying
to figure out when feathers first evolved. The most recent evidence pointed to the first
feathers occuring on the common ancestor of ornithischian dinosaurs, the group that contains
Triceratops and Stegosaurus, and the coelurosaurs, the group of dinosaurs which includes the
ancestor of today’s birds. And that would mean those first feathers likely emerged
somewhere around 150 to 180 million years ago. But these new findings, described in the journal
Nature Ecology and Evolution, suggests they evolved much earlier, like 230 to 250 million
years ago, because that is about when the pterosaurs split off from the rest of their
reptilian kin. Now, it’s been known for some time that
pterosaurs were somewhat fuzzy. Fossils have suggested they were covered in
pycnofibers, a kind of, like, single-filament fluff that looks a bit like mammalian hair. But until this point, pycnofibers hadn’t
been considered true feathers because they didn’t branch at all and didn’t look much
the quills from dinosaurs. In fact, scientists weren’t really sure
what they were at all, which is why they gave them
a totally different name. In this latest paper, the researchers literally
put two pterosaur specimens from China under the microscope; they found four different
forms of pycnofibers. These included little bundles of fibers that
branch from the base, making them look a lot like down feathers, and larger, unbranched
‘bristles’ that are similar to feathers found on dinosaurs and modern birds. Paleontologists still aren’t sure of the
exact function of these so-called feathers, but most likely, they were used for insulation. Pterosaurs were active fliers and had to keep
their muscles warm enough to power that flight. It’s also possible they streamlined the
animal’s bodies, making them more aerodynamic, or that those bristles, which were found near
the pterosaurs’ mouths, may have helped their sense of touch while flying or when
handling prey, kind of like whiskers on a cat. Whatever the function, if these pycnofibers
are truly feathers, then the origin of feathers happened a lot further back than paleontologists
thought. The authors of this paper think they first appeared in
an ancient ancestor of both pterosaurs and dinosaurs. And that would mean even non-bird-like dinosaurs
might have had quills or modified feathers, or the genes to make them, anyway. Like how pigs and whales technically have
hair, even though they aren’t, like, fuzzy. But other scientists have criticized this
research, saying that it’s more likely that pterosaurs independently evolved, like, a
neat skin covering that helped them keep warm. Some even doubt that the pycnofibers are for
warmth. Instead of being feather or fur-like, the
fibers could have strengthened their wings somehow. So this paper has started a pretty heated
discussion in the paleontology community, and let me tell you, the paleontology community
can have some heated discussions. And this is one that isn’t gonna cool down
until a lot more fossils are found and examined. In other dinosaur related news, scientists
now believe that armored ankylosaurs used their elaborate nasal passages to regulate
their body temperature. Ankylosaurs are probably better known for
their club-like tails than their fancy noses, but that didn’t stop scientists from wondering
what those pipes were for. Mammals use convoluted nasal passages called
turbinates as a kind of air conditioner, warming and humidifying air when it’s breathed in
and cooling and drying air when it’s breathed out. Because ankylosaurs had a single long, bendy
tube, rather than the many winding passages of turbinates, paleontologists thought they
might use them for vocalizations instead. In this latest paper published in PLoS One,
they put the heat exchange hypothesis to the test by making 3D digital reconstructions of the fossilized nasal passages from two ankylosaur species. Then, they computer modelled how air moved through
their noses and what happened to heat along the way. What they found was that all those twists
and turns likely recovered a lot of heat from the air when the animals exhaled which could
then be used to warm the next breath coming in. And ultimately, their noses would use 65 to
84 percent less energy, which is pretty similar to the energy mammals save with their turbinates. When the researchers digitally straightened
out the ankylosaur nasal passages, the energy savings were gone, telling them that the twists
and turns were important. As well as heating air coming in to the lungs,
the long, twisted passages could also shed excess body heat from the dinosaurs’ brains. Because, you know, it’s important to keep a cool
head when you’re roaming around in the Cretaceous. While it is difficult to be certain of all
of this without, like, a live ankylosaur in the lab, these simulations get scientists
pretty close to understanding the ecology of these armoured creatures. Similar, twisted nasal passages have also
been seen in other big dinosaurs like sauropods, making scientists question which came first,
big bodies or elaborate nose holes. And regardless of whether its feathery fluff
or elaborate noses, our picture of evolution is constantly changing as new fossil evidence
is dug up or scientists find new ways to peer closer at the fossils they already have. Thanks for watching this episode of SciShow
News! We’re all going to be taking the weekend
off here at SciShow, and if that leaves you really just jonesing for more SciShow
content, more amazing science, we have a podcast for you,
it’s called SciShow Tangents, it’s a weekly podcast produced in
collaboration with WNYC studios. Every Tuesday, four of the people who work
on SciShow YouTube channels, including me, pick a theme and we all try to one-up each
other with awesome science facts and research we find based on that theme. The show has different segments, like one
where someone presents a true fact alongside two that definitely are not true, and everyone
has to guess which ones were made up. We usually end up going on a bunch of tangents,
hence the name of the podcast, and we try to end every episode with a fact about butts. We’ve been having a ton of fun with it! I love listening to it, which is, I feel like,
a little bit weird to say, cuz I’m there while we record it. But I love it, and if you want to hear yourself,
you can look for SciShow Tangents wherever you get your podcasts! [♪ OUTRO]
