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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Relics of a lost age

If I can be allowed to geek out a little, today's post is about two new discoveries in the field of paleontology.

The mid-Permian period was (1) a challenging time to live, when the climate was rapidly warming and drying, and (2) at 270 million years before the present, was a really long time ago.  Not only was the climate getting dicey, the world was heading for catastrophe -- the lockup of the supercontinent Pangaea, as all the world's land masses fused into one and the rest of the Earth was covered by a giant ocean, is thought to have been the kickoff to the largest wipeout the Earth has ever seen -- the Permian-Triassic extinction.  Not only did the formation of the supercontinent (and superocean) 252 million years ago drastically change the climate, the event coincided with the formation of the Siberian Traps, when four million cubic kilometers of basaltic lava flowed out over what is now eastern Russia.  The resulting massive burning of organic matter spiked the carbon dioxide content of the atmosphere, simultaneously causing the oxygen content to crash and triggering a warm-up that resulted in average ocean surface temperatures of 40 C (104 F).

The result: 95% of the species on Earth became extinct.

Of course, one of the lineages that made it through the bottleneck was our own ancestors.  Back in the mid-Permian -- pre-mass-extinction -- there was a group of protomammals called Gorgonopsians, which included some seriously scary carnivores (one, Inostrancevia, had a 45-centimeter-long skull and saber teeth -- preceding the more famous "saber-toothed tiger" Smilodon by a good 260 million years).

Permian protomammal fossils are quite rare, however.  So it's pretty awesome that paleontologist Christian Kammerer, paleontology curator of the North Carolina Museum of Natural Sciences, discovered fossils of not one, but two new species of mid-Permian protomammals in a small museum in Russia.

Called Gorynychus matsyutinae and Nochnitsa geminidens, the two were drastically different in size.  Gorynychus was probably one of the apex predators of its time, with a 25-centimeter-long skull and big, nasty, pointy teeth.  Nochnitsa, also a predator, was weasel-sized.  The genera were both named after beasts from Russian mythology -- the three-headed dragon Zmey Gorynych and the malevolent, vampiric night spirit Nochnitsa.

Artist's reconstruction of Gorynychus and Nochnitsa [by Matt Celeskey @clepsydrops, from the press release from the North Carolina Museum of Natural Sciences; used with permission]

These lineages both made it through the bottleneck, but not unscathed.  Their descendants, eighteen or so million years later, underwent some rapid evolution during the Permian-Triassic extinction, especially with respect to size.  "In the age before the dinosaurs, when protomammals were the dominant life on land, you had two different groups that switch off on which is the top predator," Kammerer said.  "You have wolf- to lion-sized saber tooth animals wiped out by a mass extinction, and [the Nochnitsa-like animals] take over.  But [Gorynychus-like animals] aren’t wiped out altogether in this extinction, and they take over and become a small insect eating predator, not large carnivores anymore."

Kammerer and his co-author (and co-discoverer of the fossils), Vladimir Matsyutin of the Vyatka Paleontological Museum of Kirov, Russia, were excited not only about having found fossils of two hitherto-unknown species, but about the potential for other discoveries tucked away in museums.  "I would guarantee you there are thousands of undescribed species in museum collections,” Kammerer said.  "Most new species are found in museum collections for the sole reason that there are literally millions of species on Earth today and many more in the fossil record.  When you’re going out and collecting specimens, you won’t know those things.  The people in the museum knew they were protomammals but they didn’t know they were new species."

So that's today's cool science story, about some of our (very) distant relatives.  I've always been fascinated with the early mammals -- for some reason, much more than the charismatic megafauna that were just getting their start at the same time (the dinosaurs, of course).  And the fact that these critters were out doing their thing as the Earth was heading toward the largest catastrophic extinction ever just adds a nice little frisson to the discovery.  You kind of want to warn them about what's coming, you know?

Oh, well, probably wouldn't have helped.  It's not like you can hide from four million cubic kilometers of lava.

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This week's recommended read is Wait, What? And Life's Other Essential Questions by James E. Ryan.  Ryan frames the whole of critical thinking in a fascinating way.  He says we can avoid most of the pitfalls in logic by asking five questions: "What?"  "I wonder..." "Couldn't we at least...?" "How can I help?" and "What truly matters?"  Along the way, he considers examples from history, politics, and science, and encourages you to think about the deep issues -- and not to take anything for granted.