[ ♪ intro ] Sometimes, evolution repeats itself. There are some classics that you just can’t
go wrong with -- traits that are so effective for certain functions that they’ve evolved
more than once. Think bats and birds and insects all evolving
wings. This process is called convergent evolution,
and it can help us understand the similarities between living species that aren’t closely
related. But when an animal in the fossil record starts
to look oddly familiar, convergent evolution can also help us look through time. Here are five ancient animals whose similarity
to living species has allowed us to learn some fascinating details about their lives. Pterosaurs -- the flying reptiles of the Mesozoic
Era -- had a variety of lifestyles, and a bunch of different faces to match. But one of the absolute weirdest faces belonged
to a pterosaur named Pterodaustro, which lived in Argentina over one hundred million years
ago during the Early Cretaceous Period. Its super-long, curved snout was filled with
around a thousand closely-packed, needle-like teeth, all at the business end of a flying
animal with an eight-foot wingspan. This odd structure might have totally thrown
scientists for a loop, except it is very similar to a very familiar living animal: flamingos. Flamingos have pretty odd faces themselves. Their long, crooked beaks are lined with thin
structures called lamellae. But we can watch flamingos as they eat, so
we know that these beaks are specially adapted for filter feeding. As flamingos pump water and mud through their
beaks, tiny aquatic morsels get caught between the lamellae. Pterodaustro seems equipped to do the same
thing, using its narrow teeth to filter food out of water. And it’s not alone. It belongs to a family of pterosaurs called
ctenochasmatids, all of whom had long snouts with tiny teeth for filter-feeding. And we don’t have to guess about that -- we
can look for evidence to support the idea that they were filter feeders. A study in 2019 described three coprolites
-- that is, fossilized poops -- from an ancient shoreline in Poland during the Late Jurassic
Period. The nearby sediment is covered in footprints
thought to belong to a different species of ctenochasmatid, and the poops are the right
size and shape to have been... pooped by those very reptiles. A scan inside the coprolites revealed that
they were full of tiny marine organisms called foraminifera, along with remains of little
worms and crustaceans. We see this same poop composition in some
modern-day flamingos. So not only did these ancient pterosaurs have
familiar faces for a familiar feeding style, they even left behind familiar feces. And just to complete this image of reptilian
flamingos, the abundance of footprints in varying sizes on that shoreline is an indicator
that these pterosaurs might have even in flocks.gathered And as to whether they were also pink… well,
we can hope, and maybe someday we’ll that, too.know Take a trip even further back in time, to
the Triassic Period, over two hundred million years ago, and you might come across some
reptiles that walk and act like crocodiles, but aren’t. Because while early relatives of crocs had
evolved, these aren’t those. They are phytosaurs, and even though they’re
not all that closely related to crocs, the resemblance is remarkable. Like crocs, phytosaurs have large bodies with
sprawling limbs, big powerful tails, and long snouts full of cone-shaped teeth. They even have bony armor covering their backs
like crocs do. Paleontologists suspect these croc-shaped
animals were living croc-like lifestyles as semi-aquatic predators, and there’s evidence
to back that up. Phytosaur fossils are commonly found in ancient
lake, river, or shoreline environments, and phytosaur footprints have been found on land
and in water. Their eyes and nostrils even sit on top of
the skull like crocs, though their eyes and nostrils are much closer together. This allows them to just wait below the surface
of the water while they hid from predators or stalked prey. The crocodile comparison becomes even more
detailed when we look at phytosaur jaws. Across phytosaur evolution, they developed
multiple mouth shapes for different feeding styles, from big and wide to long and slender,
just like the variety we see across modern-day crocodilians, like gators and gharials. And a 2019 study found that phytosaurs even
have their own version of a crocodile’s secondary palate. In crocs, the secondary palate is a structure
that provides extra reinforcement for the skull, allowing it to resist stress during
strong bites. Phytosaurs had a similar structure that strengthened
the skull: the premaxillary palate. When researchers ran stress tests on models
of phytosaur skulls, they found that if they removed the premaxillary palate, the skull
became much weaker. That makes phytosaurs and crocs an incredible
example of convergent evolution from tip to tail, inside and out. Our next animal is named Castorocauda lutrasimilis,
and if you’ve taken Latin, all six of you, you might have already guessed why it’s
on this list. Its name means “beaver tail, similar to
otters,” and it’s one of the oldest known mammal cousins to have lived a semi-aquatic
lifestyle. Beavers are rodents, while otters are part
of the weasel family, but Castorocauda is neither of those. It’s not even a true mammal, but a member
of a group called docodontans, close cousins of mammals that lived alongside dinosaurs
during the Mesozoic Era. Castorocauda was identified in 2006 from a
single fossil found in Jurassic rocks in China. The fossil is so well-preserved that it even
has impressions of skin and fur, and paleontologists could tell right away that this animal was
a swimmer. Its tail is long and flat, and the vertebrae
inside are wide and compressed, similar to the tails of beavers and otters. Because the fossil is so detailed, paleontologists
were able to identify evidence of webbing between its toes, and they could even see
that the tail was partially scaly -- just like a beaver tail. It was certainly using its feet and tail to
swim like a beaver, but it wasn’t gnawing on trees. The teeth in its mouth tell a different story
of convergent evolution. They’re pointy and angled backwards like
a predatory seal’s -- good for grabbing fish and aquatic invertebrates. Now, even though Castorocauda is named for
its similarities to beavers and otters, the best living comparison might actually be...
platypuses. Yes, those animals that are so weird you wonder
what evolution was thinking. Even they have parallels in the ancient world. Not only is Castorocauda roughly platypus-sized,
it also has strongly built front limbs that could have been useful for both swimming and
digging. Just like platypuses. Castorocauda even has a small spur on its
ankle, a feature platypuses use to defend themselves. It may not have been a true mammal, but Castorocauda
survived in the Age of Dinosaurs using the same evolutionary innovations we still see
in all kinds of aquatic mammals today. In 2017, scientists described another near-mammal
fossil, this one from slightly younger sediments in China. Jurassic [MIY-oh-puh-TAY-jee-uhm]
It was named Maiopatagium, and since this fossil also preserved evidence of skin and
fur, paleontologists could see that the animal was surrounded by a blanket of skin. This is an unusual feature, but once again
modern-day animals reveal its purpose: gliding. A flap of skin that forms an air-catching
surface actually has a name. It’s called a patagium. Bats have them, pterosaurs had them, and so
do lots of gliding mammals. In fact, gliding membranes have evolved in
multiple mammal groups: flying squirrels are rodents, sugar gliders are marsupials, and
colugos are relatives of primates. But Maiopatagium belongs to an extinct group
called haramiyidans, which -- like Castorocauda -- weren’t true mammals, but mammal cousins. Maiopatagium has skin flaps in spades: stretching
from its cheeks to its wrists, its wrists to its ankles, and its ankles to its tail. It even has little hooks on its ankles for
the skin to attach to, like bats do today! Modern mammalian gliders tend to be arboreal,
and Maiopatagium shares some features that suggest it was, too, such as long legs and
fingers. And the structure of its hands and feet are
a lot like what we see in bats and colugos, both of which have a habit of hanging upside-down
from trees. And Maiopatagium isn’t the only ancient
glider. A decade before Maiopatagium was described,
paleontologists reported an early mammal from China named Volaticotherium, also surrounded
by skin flaps and thought to be a glider. Personal wing-suits have evolved convergently
many times, not just among living mammals, but also their various extinct cousins. Some evolutionary tricks are so good they
just keep coming back. The last entry on our list is a group of ancient
insects that would make any butterfly fan swoon. They have big scaly wings with colorful eyespots,
and they have long mouths perfect for sipping fluids from plants. But here’s the thing -- they lived about
fifty million years before butterflies existed. Instead, these bugs are lacewings that lived
in China from the Middle Jurassic to the Early Cretaceous, between a hundred and sixty five
and a hundred twenty million ago.years Lacewings are still around today, but these
butterfly lookalikes are an extinct group called Kalligrammatidae. And thanks to incredibly preserved fossils,
we know a lot about them. Like butterflies, they had scaly wings and
colorful patterns that included eyespots. From studying butterflies, we know these resemble
large eyes to deter or distract predators. And they had long, tubular mouthparts for
collecting fluids from plants -- like what butterflies use to collect nectar from flowers. This suggests these insects were dealing with
similar predators and food to modern-day butterflies. But this raises the question of exactly what
plants they were feeding on. The types of flowering plants that cover the
planet today were very uncommon when these lacewings were around. Paleontologists suspect that instead of drinking
nectar like many modern insects, these lacewings were drinking from gymnosperm plants -- that
is, plants whose seeds aren’t surrounded by fruits, unlike many of our familiar plants
today. Gymnosperms don’t produce nectar quite like
modern plants, but they do produce pollination drops, a type of secretion used to catch pollen. What’s more, pollen was found fossilized
alongside some of these insects, so they were probably important pollinators in their time. These lacewings vanished around the time that
flowering plants began to take over global ecosystems and gymnosperm plants declined. Later, toward the end of the Mesozoic Era,
true butterflies evolved and formed their own close relationship with flowering plants,
feeding on their fluids and carrying their pollen. Not only is this an example of convergent
evolution in the body shape and lifestyles of these two groups of insects, it’s also
convergent evolution of an ecological relationship between plants and bugs. Evolution can be surprising and even confusing,
but it has patterns and it repeats itself. Which means even the strangest of ancient
ecosystems can hide something familiar, a clue from the present that’s invaluable
to understanding the past. Meanwhile, someone who’s helping us understand
all the things is this month’s President of Space, SR Foxley! Thanks for helping us make videos, and thank
you for doing it for years. You, too, could be President of Space one
day by supporting SciShow on Patreon. To get started, check out patreon.com/scishow. [ ♪ outro ]
