Top of the heap

I don't understand why, amongst prehistoric animals, dinosaurs get all the attention.

Don't get me wrong, I like dinosaurs just fine, but there are so many others that are insanely cool.  

Many of which would be no fun to meet close-up.

Take, for example, the gorgonopsians, that had their heyday in the mid to late Permian Period.  These creatures were serious badasses -- apex predators that predated most of the dinosaurs, and which actually are a sister clade to the one containing mammals (Cynodontia), making them far more closely related to us than they are to a velociraptor.  The name means "looks like a Gorgon" -- referring, of course, to the terrifying monster from Greek mythology.

[Image licensed under the Creative Commons Mario Lanzas, Inostrancevia reconstruction, CC BY-SA 4.0]

The above shows a size comparison between Inostrancevia, one of the largest gorgonopsians, and a human.  You have to wonder why this guy is willing to walk right behind it like that, hands in his jacket pockets, whistling a tune.  Of course, I'm reminded of observing human behavior around bison, elk, and even once a juvenile grizzly bear, when I was in Yellowstone National Park, where many people seemed to think the place was an enormous petting zoo.  We talked to an exasperated ranger, who told us that his main job in the park was "keeping stupid tourists from committing suicide by wild animal."

But I digress.

Anyhow, the selective pressures on carnivores triggered something like convergent evolution between the gorgonopsians and (much more recent) animals like saber-toothed cats.  Gorgonopsians had elongated canine teeth and serrated molars, perfect for killing and slicing up prey.  The jaw morphology indicated that they had something like a ninety-degree gape, allowing for an enormous bite force when they closed.

Inostrancevia latifrons, attacking what is about to be an ex-Scutosaurus [Image licensed under the Creative Commons Creator: Dmitry Bogdanov, Inostranc lati2DB, CC BY 3.0]

Gorgonopsian fossils have been found primarily in two places -- Russia and South Africa.  While they're pretty distant from each other now, keep in mind that in the Permian, they (and every other land mass on Earth) were a lot closer:

[Image licensed under the Creative Commons Massimo Bernardi, MUSE, Trento, Italy. Published by Michael J. Benton., Permian–Triassic paleoclimate, CC BY 4.0]

The gorgonopsians were the top-tier carnivores for over twenty million years -- which, to put it in perspective, is around a hundred times longer than anatomically-modern humans have been in existence.  And who knows how long that hegemony would have lasted, and what direction history (well, prehistory) would have taken, but catastrophe was on the horizon.  The powder keg had been filled to overflowing during the preceding period, the Carboniferous, when high temperatures and precipitation had fostered the formation of enormous swaths of rain forest and swamp, leading to the accumulation of vast coal beds.  The climate had been drying out through the entire Permian, but the fuse was lit with the eruption of the Siberian Traps, the biggest volcanic eruption ever recorded.  The outpouring of lava ripped through the coal seams, depleting oxygen and dumping gigantic amounts of carbon dioxide into the atmosphere, and spiking the global average temperature by an estimated fourteen degrees Celsius.

The result: 95% of life on Earth became extinct, including the gorgonopsians.  The biggest, meanest, most badass predators of the Permian were one of the many groups that didn't survive the cataclysmic bottleneck between the Permian and Triassic Periods.

What did survive was the group that was to dominate everything for the next 180 million years -- the dinosaurs.  And, obviously, our own ancestors, the cynodonts, who at that point were pretty much small, scurrying, shrew-like beasts that a visitor to Earth wouldn't think could ever amount to much.  But as you know, the dinosaurs had their heyday come to a sudden, unexpected, and violent end as well, 66 million years ago.

Just shows that nothing stays on top forever -- something our policymakers might do well to heed, because we're the only animals on Earth that have the intelligence to recognize that what we're doing might endanger our own survival, and potentially do something about it.

We're not immune to the fates of other groups that, in their time, seemed like they'd be permanently on the top of the heap.  

Let's hope we can learn from our planet's past history.

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