mspaleoartoftheday:

Cotylorhynchus – Early Permian (279-272 Ma)

Before the Mesozoic Era, millions of years before dinosaurs
even thought about showing up, was a 50 million year-long period called the
Permian. You probably know that already. The Permian was the first real boom in
vertebrate diversity on land. Terrestrial vertebrates had come a long way
during the Carboniferous, and made several important adaptations that helped
them conquer the earth during the following period. Among them was the evolution
of waterproof, hard shelled, or, “amniote,’ eggs. The ability to reproduce on
land let vertebrates spread all over the continent of Pangea. This is
especially helpful, because the Permian was drier than the Carboniferous.

Despite popular belief, the Permian wasn’t an age of reptiles.
There were big reptiles, for sure, but they weren’t the majority. The majority
was the other branch of amniotes, the synapsids. They were in charge, and had
free rein to turn into all sorts of weird shapes. That’s how something like Cotylorhynchus happens.

This was the biggest guy around in the early Permian, which
wasn’t as big as you might think. Think a cow that’s closer to the ground, and
you have Cotylorhynchus. Oh, and
shrink its head a bunch, too. Do you want to know why its head was so tiny? So
do I.

Yeah, its head was just kind of like that. Its body was
massive for a reason, though. Well, a few reasons. Like I mentioned a minute
ago, Cotylorhynchus was a built
motherfucker. It was significantly bigger than anything around it, even Dimetrodon, which was only about half
its size without the sail. Cow-sized was enough to be absolutely massive back
then, and its sheer bulk kept it safe. It also housed a powerful digestive
system to break down plant matter. It was one of nature’s first examples of the
walking glacier archetype, and it even reminds me of the Pokémon Avalugg, which
is a literal walking glacier. And would you believe that the best way to beat
both is to not even bother challenging their defense? Just set them on fire and
they’ll both go down.

But really, Cotylorhynchus
was essentially indestructible in the eyes of your average early Permian
predator. It’s also worth mentioning that it had a cousin called Casea, which basically looked the same
but was the size of an iguana. This begs the question, which came first, the
big one, or the small one? Were they all tiny with tiny heads, or did they just
shrink down to that size after a while? Cotylorhynchus
and Casea lived at the same time, so
it’s hard to say. We do know that there were members of their family who had
reasonably-sized heads, on top of that.

Some other features worth mentioning: It had really broad
shoulders and dexterous hands. It probably dug up roots and such as part of its
diet. The shape of its skull implies it was really good at smelling, which is a
good thing to be when you’re hungry all the time and constantly looking for
food to nourish your colossal body. It also had long fingers and broad,
paddle-like hands. Yes, I’m going there. From what we can tell about its range
of motion and everything listed above, it was probably semi-aquatic. Yeah, it’s
not really streamlined in any way whatsoever, but did it need to be? Manatees
can get away with it. Cotylorhynchus
probably swam more like a turtle, by drifting and propelling itself with its
limbs. It wasn’t much more graceful underwater than it was on land, but it
really didn’t have to be, if you ask me.