The titan

One thing science teaches us is that just about everything is interesting if you look at it carefully enough.  Still, there's an ingrained human tendency to be overawed by superlatives -- the biggest, the heaviest, the brightest, the strongest, the most powerful.

It's why a recent fossil discovery from Somerset, England has made the headlines.  The rocks in Somerset, in the southwest of England, are mostly of Triassic age; it's not far from the famous "Jurassic Coast," which begins around Exmouth with Triassic sedimentary rocks that gradually become younger as you head west.  It's the site that the brilliant nineteenth century paleontologist Mary Anning studied -- becoming one of a very long list of talented women scientists who struggled for recognition by their male peers with tragically little success.

Somerset, which is a bit north from there, is also a great site for Mesozoic fossils, and some amateur fossil hunters recently found a doozy.  Father-and-daughter team Justin and Ruby Reynolds were searching along the north Somerset coast and saw what turned out to be a fossilized jawbone...

... of a creature which is estimated to have been twenty-five meters long.  (For my fellow Americans, twenty-five meters is about 130 bananas long.)

The animal was a type of ichthyosaur, a group that reached their height of diversity in the late Triassic Period.  We've known for a long time that ichthyosaurs were bizarre animals.  They were streamlined predators that look remarkably like dolphins, although they are only distantly related (making the two groups a great example of convergent evolution).  A number of them had an even stranger feature, which is the largest eye-diameter-to-body-size ratio of any animal known -- the well-named Ophthalmosaurus (Greek for "eye lizard") was six meters long and had eyes the size of basketballs.

But this new species could have eaten an Ophthalmosaurus as an appetizer and still had plenty of room for the entrée.  It's been dubbed Ichthyotitan severnensis -- more or less, "gigantic fish-thing from the Severn."  The fossil dates to about 202 million years ago.

[Image credit: artist Sergey Krasovskiy]

"I was highly impressed that Ruby and Justin correctly identified the discovery as another enormous jawbone from an ichthyosaur," said Dean Lomax, paleontologist at the University of Manchester, who verified the find and helped to classify it, in an interview with Science Daily.  "They recognized that it matched the one we described in 2018. I asked them whether they would like to join my team to study and describe this fossil, including naming it.  They jumped at the chance.  For Ruby, especially, she is now a published scientist who not only found but also helped to name a type of gigantic prehistoric reptile.  There are probably not many fifteen-year-olds who can say that!  A Mary Anning in the making, perhaps."

The Ichthyotitan, though, was one of the last of its kind; it, and a great many other species, were victims of the Late Triassic Mass Extinction, a poorly-understood extinction event that occurred around 201 million years ago and was only slightly smaller than the much better-known Cretaceous-Tertiary Extinction that would happen 135 million years later.  The most likely explanation of the Late Triassic event is volcanism and outgassing from the Central Atlantic Magmatic Province, the mantle upwelling from which would ultimately split up Pangaea and open the Atlantic Ocean, but that point is still being argued over by geologists and paleontologists.

Whether this particular Ichthyotitan was killed during the extinction event itself is, of course, impossible to tell, but the fossil dates to almost exactly the right time.  Its discovery also ramps up the search for more fossils along the north Somerset coast.  "It is quite remarkable to think that gigantic, blue whale-sized ichthyosaurs were swimming in the oceans around what was the UK during the Triassic Period," Lomax said.  "These jawbones provide tantalizing evidence that perhaps one day a complete skull or skeleton of one of these giants might be found.  You never know."

It's a hell of a find -- a bone from a creature in contention for the largest animal known.  I don't know about you, but it's hard even to imagine a predator that big.  The late Triassic must have been an impressive-looking place...

... observed, of course, from a safe distance.

****************************************

The long rain

Imagine going back 240 million years.

This would land you in the early Triassic Period.  By this time, the Earth would have had twelve million years to recover from the cataclysmic Permian-Triassic Extinction, the largest mass extinction on record.  Life had rebounded some -- two of the dominant terrestrial animal groups were the terrifying crurotarsans (picture a long-legged on-land crocodile) and the dicynodonts (which looked a little like a rhino with a parrot's bill -- and tusks).

Finding your way around the place would be confusing, if all you know is the current continental arrangement.  Pangaea was still locked together, and would be until rifting began to open up the Atlantic Ocean -- but that was still forty million years in the future.

[Image licensed under the Creative Commons Fama Clamosa, Pangaea 200Ma, CC BY-SA 4.0]

Because virtually all the land masses of the world were jammed together into one supercontinent, the climate was really dry.  There probably was a reasonable amount of rainfall along the coastline, but most places were very far away from the coast.  The result is that one of the major early Triassic sedimentary rocks is the "Triassic red sandstone" formed from wind-blown layers of sand deposited in conditions that resembled today's Sahara Desert.  But instead of being restricted to a part of a single continent, this was what it was like in the interior of Pangaea -- i.e., the entire land mass on planet Earth.

But even the Sahara isn't lifeless, and neither was the continental interior of Pangaea during the early Triassic.  Organisms found a way to cope with the dry conditions, and -- all things considered -- life was doing okay.

Then -- 234 million years ago -- it started to rain.

I'm not talking about your short-lived desert thunderstorm, here, nor even the kind of "atmospheric river" event that hit the Central Valley of California this year, causing not only flooding but an explosive burst of wildflowers.

This rainstorm lasted two million years.

It's called the "Carnian Pluvial Episode," and evidence for it can be seen in a sudden shift in sedimentary geology, a change in the isotope concentrations in carbonate rocks (like limestone), and a huge spike in heavy elements (like osmium and mercury) that are much more common in deep-mantle rocks.  The last bit is a clue to what happened -- there was a massive eruption called the Wrangellia Flood Basalts in what would eventually become southern Alaska and western British Columbia.  I've written before about two other flood basalt provinces, the Siberian Traps (implicated in the Permian-Triassic Extinction) and the Deccan Traps (contributory to the Cretaceous Extinction), and while the Wrangellia event isn't as big as either of those, it is many orders of magnitude larger than anything you probably picture as a volcanic eruption.  The Wrangellia Flood Basalt injected huge quantities of carbon dioxide into the atmosphere, largely through the lava burning through limestone, coal, and any organic matter on the surface.  This spiked the atmospheric temperature, increased seawater evaporation...

... and it started to rain.

Imagine being an animal adapted to living in Arizona, and all of a sudden, you find you're living in the Amazon lowlands.  That's pretty much what happened.

The result was another extinction.  Both the crurotarsans and dicynodonts bit the dust.  Or actually, at that point, the mud.  Let me emphasize that both groups were doing fine before the climatic shift; but having spent millions of years adapting to the early Triassic desert conditions, they couldn't handle it when the long rain started.

The winners here were the animals that had the flexibility to cope with the changing conditions -- in this case, dinosaurs, which would go on to dominate the place for another 165 million years.  The early mammals also made it, obviously, but they were still small at this point (and would remain so until the non-avian dinosaurs met their demise).  Interesting that the quintessential Mesozoic group, the dinosaurs, might never have taken off like they did if it hadn't been for a sudden geological event that triggered a climatic shift and knocked out the two main competitor groups.

And I would be remiss if I didn't mention that the rate at which the Wrangellia Flood Basalts injected carbon dioxide into the atmosphere is thought to be significantly smaller than the rate we're doing the same from burning fossil fuels.

Any wonder why environmentalists are worried?

We've already had our share of bizarre weather in the last few years; it seems like not a week goes by without my hearing someone say, "This hardly ever happens."  At the moment, here in upstate New York, it hasn't rained for a month, and we're getting spectacular sunsets (and difficulty breathing) because of a pall of wildfire smoke that's come all the way from central Quebec.  Vietnam and Laos have already set record high temperatures this year, reaching a devastating 44 C (with correspondingly high humidity), as did the Pacific Northwest of the United States, with Portland at a less dangerous but still scorching 35 C.  

Weather isn't climate, something I feel obligated to remind the climate change deniers every time we have a cold snap in January; but as anomalous weather happens over and over and over, these kinds of patterns begin to add up to something significant.  As a Louisiana native, I'm already worried about this year's hurricane season -- especially given that the most recent sea surface temperatures are (in the words of Australian climatologist Matthew England) "heading off the charts."

To judge by the geological record of events like the Carnian Pluvial Episode, it looks like we might be in the last half of "fuck around and find out."

****************************************

Imaging behavior

When I first started teaching biology -- thirty-four years ago, which kind of seems impossible to me -- I always prefaced any discussion of fossils and extinct animals by emphasizing what fossils don't tell us.

"All the kids' books about prehistoric animals," I told my classes, "illustrate what the living animals looked like by making inferences based on current species.  A hundred years ago, the paleontologists thought of the dinosaurs as being big lizards; in fact, the word dinosaur comes from the Greek words for 'terrible lizard.'  Since that time we've discovered their relationship to birds, and it seems like there were a number of species covered with feathers, not scales.  The truth is, we have extraordinarily limited information about what the dinosaurs looked like from the outside, and almost nothing in the way of knowledge about their behavior.  Fossils just don't give us that information."

Well, I was wrong.

Maybe not in general; your average triceratops thigh bone doesn't tell you anything about the color of the animal it came from.  But paleontologists are getting better and better at figuring out amazing detail about the appearance and behavior of prehistoric animals using nothing but the preserved bones, and some astonishingly sensitive equipment to study them with.

Take the recent study of a wonderfully well-preserved skull of Thecodontosaurus, which lived about 205 million years ago and was an earlier cousin of such behemoths as Brachiosaurus and Diplodocus.  Thecodontosaurus itself wasn't that big -- about 1.5 meters tip-to-tail -- and little was known about its appearance and behavior, even such broad-brush features as whether it was bipedal or quadrupedal.

We now have some much better data to work from, thanks to a paper that appeared in the Zoological Journal of the Linnean Society last week.  A team made up of Antonio Ballell, J. Logan King, Emily Rayfield, and Michael Benton (of the University of Bristol) and James Neenan (of Oxford Univeristy) did a phenomenally detailed study of the skull, which was itself found near Bristol.  Using a combination of CT scans and imaging software, they reconstructed what the animal's brain -- long since decayed away -- looked like.

And from that, to determine how it behaved while it was alive.

"Even though the actual brain is long gone, the software allows us to recreate brain and inner ear shape via the dimensions of the cavities left behind," study lead author Antonio Ballell said, in a press release in Phys.org.  "The braincase of Thecodontosaurus is beautifully preserved so we compared it to other dinosaurs, identifying common features and some that are specific to Thecodontosaurus.  Its brain cast even showed the detail of the floccular lobes, located at the back of the brain, which are important for balance.  Their large size indicate it was bipedal.  This structure is also associated with the control of balance and eye and neck movements, suggesting Thecodontosaurus was relatively agile and could keep a stable gaze while moving fast...  This could also mean Thecodontosaurus could occasionally catch prey, although its tooth morphology suggests plants were the main component of its diet.  It's possible it adopted omnivorous habits."

Amazingly, all this was done without removing the skull from the rock that encased it, a process that often damages fine structures even if the researchers are as careful as possible while extracting it.  The CT scanner was able to see not only inside the rock but inside the skull itself, distinguishing the fossil from the sedimentary rock outside and inside, and the imaging software helped to clarify minuscule details of the interior of the brain case -- and thus details of the brain it once enclosed.

Study co-author Michael Benton said, "It's great to see how new technologies are allowing us to find out even more about how this little dinosaur lived more than 200 million years ago."

Thinking about prehistory has been a positive fascination of mine since I was a kid, and I remember how disappointed I was to find out that all the stripy and spotted and colorful pictures in my dinosaur books were "artists' renditions" -- i.e., made up and very probably wrong.  We're still not there with color, yet, although a single feather from Eocoracias, a kingfisher-relative that lived 47 million years ago, was so well-preserved that scientists were able to make a shrewd guess that it was blue in color, like many of its modern relatives.

We still have a long way to go, and it's likely that the ravages of time have erased the vast majority of the information that could clue us in on prehistoric animal behavior and appearance.  The fact that we can ascertain anything is itself remarkable.  And I'd wager that if we ever do time-travel back to the distant past, we'd be in for some serious surprises at how different everyone looked than the way we'd always pictured them.

*********************************************

If you, like me, never quite got over the obsession with dinosaurs we had as children, there's a new book you really need to read.

In The Rise and Fall of the Dinosaurs: A New History of a Lost World, author Stephen Brusatte describes in brilliantly vivid language the most current knowledge of these impressive animals who for almost two hundred million years were the dominant life forms on Earth.  The huge, lumbering T. rexes and stegosauruses that we usually think of are only the most obvious members of a group that had more diversity than mammals do today; there were not only terrestrial dinosaurs of pretty much every size and shape, there were aerial ones from the tiny Sordes pilosus (wingspan of only a half a meter) to the impossibly huge Quetzalcoatlus, with a ten-meter wingspan and a mass of two hundred kilograms.  There were aquatic dinosaurs, arboreal dinosaurs, carnivores and herbivores, ones with feathers and scales and something very like hair, ones with teeth as big as your hand and others with no teeth at all.

Brusatte is a rising star in the field of paleontology, and writes with the clear confidence of someone who not only is an expert but has tremendous passion and enthusiasm.  If you're looking for a book for a dinosaur-loving friend -- or maybe you're the dino aficionado -- this one is a must-read.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]