Evolution leads to the darndest things sometimes!
Animals like Stegosaurus and Dimetrodon
are really very strange when you think about them
And if we only knew the Platypus from the fossil record we'd probably think it
was some kind of joke. But these adaptations didn't happen just for us to
be amused by them millions of years later. Even the strangest adaptations help an
animal fit into its environment to get food, make babies, and survive.
You might think a platypus looks weird, but it's mom probably think it's very handsome.
The same was true for these ten prehistoric animals: they might have been incredibly
odd, but they were also incredibly well-adapted to their environments.
Helicoprion is not only a candidate for weirdest fossil ever, but also for most
enduring scientific mystery. The 270 million year old fish was first
described in 1899 based on its buzzsaw- shaped whorl of teeth and nothing else.
Paleontologists figured the teeth belonged to some kind of shark, but beyond that
they were at a loss. They didn't even know where to stick the tooth whorl on
the fish's body... the end of its nose? the dorsal fin? the tail?
Eventually they came to the conclusion that the teeth belonged in the jaw which
is where you generally find teeth, but they still had no idea how the weird
looking to spiral was oriented or how the helicoprion used it. Then in 2013
researchers at Idaho State University turned their attention to a helicoprion
tooth whorl with some of the animals' jaw cartilage preserved around it.
The fossil was discovered in 1950 and left sitting in a museum for a while.
Scientists had waited until 1966 to formally described it but
even then the cartilage seem too mangled to be informative. Then CT scanners and
computer modeling came along. Using this technology the researchers decided the
whorl must have fit at the base of the creatures' jaw. They also found that
helicoprion isn't quite a shark
it's a closer relative to ratfish and chimaeras, the type of fish not the
mythological creature. But how on earth would a wheel of teeth be useful? Well
probably the same way a saw would be useful. Helicoprion probably fed on
soft-bodied organisms like squid. That round jaw wouldn't exactly spin like an
electric saw
but it would rotate a little bit as the animal closed its mouth, catching prey on
the teeth and dragging them inside. Quetzalcoatlus was a giraffe-sized
pterosaur named after an Aztec god. This huge flying reptile from the Cretaceous
period, between 65 and 145 million years ago, had a wingspan of more
than 10 meters!
It seems to have evolved the ability to walk on its front legs again
and even after its pterosaur ancestors evolved flight. So it walked on his front
feet but its last digit stuck out with the tip of the wing hanging off of it.
Fossil remains of Quetzalcoatlus are pretty fragmentary. We know that it was a
pterosaur and we know that it was big. But how big it was, what it ate, and
whether it could fly are still open questions in the pterosaur world. It's
hard to know how heavy a pterosaur was, because their bodies would have
contained air sacks to make them lighter. That means without more complete remains,
we don't know how much of it was tissue and how much of it was air, which would
have affected whether or not it could fly or if it had lost the ability to fly,
like an ostrich. It might have used its walking ability as a terrestrial
predator and scavenger, or it might have skimmed along the water and caught fish in its
jaw like a pelican. It had a very long neck, but it wasn't very flexible. It was
probably best suited for sweeping along the ground and snatching prey. Without
more fossils, it's hard to know much about the ecology of this thing and why
a carnivorous flying reptile would have had the approximate proportions of a
giraffe.
Imagine a toothless dinosaur covered in feathers... now give it a huge pot belly...
and now imagine it with burly forearms and meter-long claws that make it look
like Edward Scissorhands. You might think this could not possibly be real
but what you're imagining right now is Therizinosaurus.
Therizinosaurus belongs to the group of dinosaurs called theropods, which also includes ferocious
meat-eaters like T-rex and Deinonychus. But this Cretaceous misfit was a plant-eater.
It was big enough that it could probably sit on the ground next to trees and use
its claws to reach up and strip off vegetation. The big gut might seem out of
place but it's the best practical way to digest plant matter--that's why cows and
manatees have a similar big-bellied look. We don't know for sure why its claws
were so long but therizinosaurus' odd proportions would have made it very slow.
So in addition to using them to slice off vegetation, it may have needed them
to fend off predators and the giant arms, so different from a T-rex's, probably for
holding up the claws.
Microraptor was a very small dinosaur, as you might have guessed from the name.
Evolution didn't take a straight or simple path from dinosaurs to birds, and
Microraptor, another Cretaceous dinosaur that lived about 125 million
years ago was one of the more interesting detours.
Tiny dinosaur, the size of a crow,
Microraptor had glossy black feathers, it couldn't fly, but it could probably glide
using its four wings. Dinosaurs evolved feathers before flight, at first these
feathers were simple fuzz
later on they became asymmetrical in shape to accommodate flight and
Microraptor had these asymmetrical flight for theirs on both its
arms and legs, effectively giving it a second pair of wings. Which seems like a
lot of wings by the standard of today's birds. But Microraptor probably used the
second set of wings as stabilizers, spreading them out to make a kind of
second airfoil. Other lineages of birds evolved more efficient two-wing designs, so
the four-wing models became obsolete. Glyptodon was a giant relative of
armadillos, except unlike the small flexible armadillos of today you can be
excused for mistaking a Glyptodon for a Volkswagen Beetle. These animals from
the Pleistocene, about 12,000 to 3 million years ago, had a huge dome of
armor covering most of their bodies, as well as additional plates on their heads
and tails.
Some species even had tail clubs. So much protective armor might seem like
overkill, but fossils of Glyptodon have been found with holes in their skulls,
holes delivered by predators with giant teeth.
So when your neighbors are saber-toothed cats it seems you can't have too much
armor. We often refer to Glyptodon as a giant armadillo and they were related
but Glyptodons and armadillos as well as their relatives the Pampatheres are
distinct evolutionary lineages so Glyptodon wasn't really an armadillo
more of a separate sort of car tank thing it looks like a camel with a trunk
but macrauchenia isn't closely related to camels or elephants, it belongs to an
extinct group of South American mammals called litopterns which died out at
the end of the last ice age twelve thousand years ago. Litopterns are
technically ungulates meaning they're related to things like antelope and
camels but distantly. It might look a little silly but macro Kenny's
adaptations allowed to take advantage of any plant food came across the trunk was
good for plucking leaves and branches and its teeth were shape for grinding
tough grasses these adaptations allow it to spread throughout South America and
outlive all the other litopterns, possibly even outlasting the ice age I
guess it was worth looking a little strange
if it meant surviving this next animal actually is an elephant and it's a
pretty outlandish variation on the elephant body plan, but platybelodon,
an elephant from around eight to twenty million years ago takes the cake. It had
tusks and a trunk like a modern elephant but it also had this huge scoop shaped
lower jaw with a second pair of tusk. This animal has suffered from bad
reconstructions over the years paleontologist used to give it a wide
flat trunk to match its shovel shape lower jaw but according to more recent
research it had a relatively normal looking trunk and that's the secret to
what it's weird mouth was actually for. That lower jaw wasn't used for chewing.
The broad teeth show signs of wear right on
the front edge so scientists now believe it would grab hold of grasses with its
trunk and use the teeth to saw it off.
Voila! Instant both grass meal, no dirt included. The internet loves sloths,
they're just so slow and cute and small, but they weren't always small.
Those cute little guys that live in the treetops used to be earthbound grazers. Megatherium
was a ground sloth the size of an elephant
it lived between 12,000 and five million years ago like the therizinosaurus we
talked about earlier it used its large claws to reach up and pull down
vegetation that would have been out of reach to other animal it may also have
used them to dig up roots. The claws meant Megatherium couldn't walk very fast
on its front feet
so like therizinosaurus it would have been pretty slow but it was also so big
that most predators couldn't get their teeth into it so it didn't matter
you can just plot along and feed as slowly as it like I guess that's one
thing Megatherium and modern sloths have in common. If you're not a fan of creepy crawlies
you're not gonna like this one. Arthropleura was a millipede that could
grow up to two metres long and half a meter wide. That is longer than I am tall
luckily we know from it's fossilized poo it was probably a vegetarian if you're
wondering what possible reason a millipede could have to grow that big,
well, it was probably so big it didn't have any natural predators and like other
arthropods a category that includes insects and spiders and crustaceans
it was able to a bigger during the Carboniferous period 302 to 360 million
years ago because back then
earth had a higher percentage of oxygen in its atmosphere arthropods don't have
circulatory systems like we vertebrates do they need oxygen to diffuse through
their bodies instead. When oxygen is scarce, that requirement keeps them
relatively small but when there was a lot of it
here come the giant B-movie bugs! Animal life was just starting to get a
leg up in the Cambrian 485 to 540 million years ago
that meant some seriously strange body plans and new predators at the top of
the food chain. Anomalocaris, a name that means "weird shrimp," fit both of those
descriptions. It's related to modern arthropods though it's hard to tell how
closely. To give you an idea of how strange this thing is
paleontologists saw different parts of this creature and described them as a
shrimp a sea cucumber a jellyfish or a jellyfish on top of a sponge but all
those fossils belong to just two species of arthropod not half a dozen kinds of
smaller species with it's big eyes and grasping mouthparts they now figure
anomalocaris was a major predator
in the Cambrian seas. It probably snacked on trilobites. It could
reach a meter in length, which was gigantic by cambrian standards. In fact,
it's the biggest predator known from its time. You don't really see these
adaptations anymore because the environment has changed over time. They
help these animals survive in a situation that no longer exists but the
fossil record has preserved them so we can now see how animals used to get by
in all these useful ways even if they do seem very strange. Thanks for watching
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[preview] --and each year we're discovering new amazing species that are most at home in the ocean depths.
These are eight of the strangest deep sea creatures we've discovered just since--