Scary times

Dear Readers:

This is to let you know of some upcoming changes.

Some of you might know I also write over at Substack, and over there have focused mainly on writing, fiction, storytelling, and how stories and mythology have woven their way through history.  I've noticed that in the last year or two, this site (and Blogger in general) has been swamped with bots and AI scrapers, and I think it's time to switch platforms, and only write through Substack.

I welcome you all to subscribe to my site at the link above (for free!).  The plan is on Mondays and Thursdays, I'll focus on stories, storytelling, and language, and on Tuesdays and Fridays I'll write the science news and critical thinking posts you've found here at Skeptophilia.  Wednesdays and Saturdays will be anyone's guess!  Sometimes one, sometimes the other, sometimes wherever my chaotic brain takes me.

At some point I'll be offering in addition some paid-subscriber-only content, like audio chapters from one of my books, some quick video mini-lessons on a topic in critical thinking, or something else fun and extra.  But for now, everything's free for everyone.

If you've been accessing Skeptophilia through social media (Facebook or Bluesky), no worries -- I'll still be posting links there, so you don't have to do anything different.  The links will look a bit different, but that's the only change.

This week, I'll have Tuesday's and Friday's posts in both places, but Friday will be the last post here at Skeptophilia.  Starting next week, I'll only be posting to Substack.  However, my old Skeptophilia posts will still be available here to browse through!

I hope you'll join me over there, subscribe, and continue to comment and interact!

I've been at this for sixteen years -- thanks for the encouragement that keeps me going.

Best,

Gordon

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It's an interesting question to consider how long a human life expectancy would be if we had a time machine (or, as my friend Andrew Butters would correct me, a space-time machine).

There are all the possibilities during recorded history, some of which would be dramatically worse than others (depending, of course, on exactly where you decided to go).  Southeastern Europe in the mid-fifth century would be a poor choice, given the fact that Attila the Hun was kind of trampling the place, causing chaos amongst the Goths (who were already there) and the Romans (who wished the whole lot of them would just go away).  Just about anywhere and any time, of course, would have been worse if you were poor; the "nasty, poor, brutish, and short" quip about people's lives in the past is all too accurate, and worse still if you didn't have privilege (a condition that sadly hasn't changed much).

But if you could add in prehistoric times, there are choices that would be a great deal worse than any time in recorded history.  And that's even assuming you're eliminating periods prior to the Great Oxidation Event, when the Earth's atmosphere would have killed you rapidly if you didn't think to bring along an oxygen supply.  Likewise, let's put out of the running the Late Ordovician (Hirnantian) Glaciation Event, when damn near the entire Earth was covered in glacial ice, and events like the Chicxulub Meteorite Collision.  Hard to imagine how we could survive either one of those.

One time period that often comes up in these discussions is the Carboniferous.  This was the era of the enormous arthropods -- dragonflies like Meganeura with its 75-centimeter wingspan, and the two-meter-long millipede Arthropleura -- which are thought to have evolved because of the favorable conditions of warmth, moisture, and an oxygen concentration in the atmosphere that may have exceeded thirty percent.  But honestly, there's no certainty these things would have been all that dangerous to something the size of a human; so other than the "ooh, icky, creepy-crawlies with lots of legs" issue, the Carboniferous would probably not have been all that bad.

For my money, the odds-on winner is the mid- to late-Cretaceous.  Not, perhaps, for the reason you're thinking; that period of Earth's (pre)history always brings to mind the Tyrannosaurus rex and the Velociraptor, which were certainly scary beasts.  But they are far from the only thing you'd have to worry about, should your space-time machine drop you off there.

I wrote just last month about the Kem Kem Formation in Morocco, a shale and limestone deposit formed when that part of the world was a shallow ocean, and what is now the Sahara was a tropical rain forest.  This place was, to put not too fine a point on it, a fucking nightmare.  It was home to the schoolbus-sized theropod Carcharadontosaurus, which had twenty-centimeter teeth serrated like steak knives; twenty-meter long crocodilians like Aegisuchus; and the pterodactyloid Apatorhamphus, with a five-meter wingspan and dozens of needle-sharp teeth.

Carcharodontosaurus skull [Image licensed under the Creative Commons Matthew Deery, Ultimate Dinosaurs Carcharodontosaurus, CC BY 2.0]

Oh, so don't head to Morocco, then!  We'd be fine!  Right?

Not really.  The region bordering the  Western Interior Seaway, which bisected North America from north to south during the same time period (and is why Montana, the Dakotas, Nebraska, and Kansas are such great places to find fossils), was no better.  There was a horrific fish called Xiphactinus that was five meters long.  The Seaway was also home to mosasaurs, carnivorous reptiles that could get to be over twice that length.  The plesiosaurs, whose shape will be familiar to aficionados of the Loch Ness Monster, were longer still.

If you were to visit the Cretaceous, going for a nice skinnydip would not be recommended.

Xiphactinus skeleton [Image licensed under the Creative Commons Jonathan Chen, Xiphactinus AMNH, CC BY-SA 4.0]

The reason this stuff all comes up is a rather ghastly set of fossils from that time period that was the subject of a paper in Nature this week.  A group of paleontologists, let by Jongyoon Jung of the University of Texas - Austin, discovered sets of tracks at a Cretaceous-age site in South Korea.  One of the sets has been analyzed and found to come from an azhdarchid pterosaur that is new to science.  The team named it Jinjuichnus procerus, and from its tracks they've concluded that (1) it seems to have come down to the ground to hunt, (2) walked on its knuckles while it was doing so, and (3) had an eight-meter wingspan.  If that's not bad enough, there's a second set of tracks, from an unidentified small terrestrial vertebrate.  The two sets of tracks intersect, and there's a confused mess of marks at their intersection.

Guess what that means.

If our imaginations weren't bad enough, the scientists have kindly provided us with the following artist's rendition of the event:

[Image credit: artist Jun Seung Yi, Creative Commons CC BY 4.0 License]

Just in case you needed some more fuel for your dreams tonight.

So.  Yeah.  Dinosaur enthusiast though I am, I would not jump at the chance for a trip back to the Cretaceous.  In fact, considering what I know about most of Earth's geological time periods, I think I'll stay put right here where there are not many creatures with Big Nasty Pointy Teeth, and there are nice features like modern medicine, water purification systems, and indoor plumbing.

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The hills are shadows

One of the reasons I became a speculative fiction novelist is because I love to think about how the world would be if the rules were different.  What if we could pick up from inanimate objects the emotional impressions of the last person who held them?  What if time travel into the past were possible?  What if the force of someone's desires could alter reality, without their being aware of it?

The difficulty is that this dreaminess about tampering with the laws of the universe runs headlong into my desire to understand what the actual rules are, and which ultimately led me to dedicate my life to science.  After an unfortunate time in my teenage years when I worked really, really hard to convince myself that all the weird paranormal shit I'd immersed myself in was the truth, I was forced by the modicum of intellectual honesty I had back then to admit that the evidence for all of it was nil, and to give the whole thing up as a bad job.

So I ended up teaching science and critical thinking, and simultaneously writing paranormal fiction.  Seemed like a good compromise.

But this push to explore the fringes still shows up.  I'm most attracted to the areas of science that are strange and counterintuitive.  Regular readers of Skeptophilia will attest to this, given my near obsession with things like quantum physics and the behavior of black holes.  And there's one other realm of science that allows me to do what journalist Kathryn Schulz calls "seeing the world as it isn't" -- and that's paleontology.

Because after all, things in the distant past were very, very different than they are now.  We're so used to looking around us and seeing The World As It Is that we don't often consider that this brief point in time is part of a continuum of geological and biological change, and is framed on both sides -- past and future -- by worlds that were and will be wildly different from the one we live in.

As an example, consider a paper in the journal ZooKeys, which is about the fauna of the Sahara.  Immediately I said that name, I'm guessing you pictured sand dunes, perfectly clear blue skies, no plant life (maybe a palm tree or two, if there was an oasis in your imagination), and perhaps a camel or a white-robed Bedouin.

Turn the chronometer back a hundred million years, though, and you wouldn't even know it was the same place.

At that point, the Sahara was a tropical forest, with a huge bay of the Tethys Ocean (the remnant of which we now call the Indian Ocean) right in the middle.  The Atlantic Ocean had only recently opened up, and western Africa was separated from South America by a narrow strait.  What is now an unbroken swath of desert was a large island in the west, a smaller island in the middle of the central bay, and a big chunk of land to the east that is now the remainder of the continent of Africa.

A map of the continents during the late Cretaceous Period [Image licensed under the Creative Commons Mannion, P. D. (2013). "The latitudinal biodiversity gradient through deep time".  Trends in Ecology and Evolution 29 (1). DOI:10.1016/j.tree.2013.09.012., LateCretaceousMap, CC BY-SA 3.0]

But that just scratches the surface.  The paper I referenced above, "Geology and Paleontology of the Upper Cretaceous Kem Kem Group of Eastern Morocco," by a team led by Nizar Ibrahim of the University of Detroit, describes the fossil finds in the Kem Kem Group, a dazzlingly rich fossil bed that is only now beginning to be investigated thoroughly.

What this fossil bed shows us is a world that's not only drastically different from how we picture the Sahara today, it's drastically different from anything currently on Earth.  "This was arguably the most dangerous place in the history of planet Earth," Ibrahim said in an interview in Science Daily, "a place where a human time-traveller would not last very long."

Such a time-traveller, in their short remaining life expectancy, would meet up with such beasts as Carcharodontosaurus -- the name means "jagged-toothed lizard" -- which averaged eight meters from tip to tail, just shy of the length of an average school bus.  Its signature teeth were twenty centimeters long and serrated like steak knives.  There were twenty-meter-long crocodilians such as Aegisuchus, which were big enough to turn your average modern saltwater crocodile into saltwater taffy.  There was the fifteen-meter-long, twenty-ton Spinosaurus, another carnivore.  The skies were no safer -- there was a variety of pterodactyloids, including the flying hunter Apatorhamphus, which had a long, needle-toothed snout and a wingspan of five meters.

And that's just a sampler.

"Many of the predators were relying on an abundant supply of fish," said study co-author Professor David Martill from the University of Portsmouth.  "This place was filled with absolutely enormous fish, including giant coelacanths and lungfish.  The coelacanth, for example, is probably four or even five times larger than today's coelacanth [which averages two meters in length].  There is an enormous freshwater saw shark called Onchopristis with the most fearsome of rostral teeth, they are like barbed daggers, but beautifully shiny."

So if you went for a swim, at least you'd have something pretty to look at while you were being messily devoured.

But the vagaries of plate tectonics and climate eventually widened the Atlantic and closed off the bay in the mid-Sahara, and the place started to dry out.  It was green for a lot longer than you'd think, however.  There's evidence that as little as seven thousand years ago, the Sahara got a great deal more rain and was much more verdant than it is today, but a shift in the path of the African monsoon turned off the tap and converted the whole area into a vast, mostly-uninhabitable desert.

I'd like to close with the beautiful and poignant words Alfred, Lord Tennyson wrote in his poem "In Memoriam."  I've quoted them here before, but they are so apposite there's really no fitter way to end.  Read this, and think about the Sahara -- and what your own homeland might look like in a hundred million years' time.

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen?
There where the long road roars has been
The stillness of the central sea.
The hills are shadows, and they flow
From form to form, and nothing stands,
They melt like mists, the solid lands,
Like clouds, they shape themselves, and go.

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Lost and found

I'm currently reading Michael Novacek's fascinating book Dinosaurs of the Flaming Cliffs, which is about the expeditions led by Novacek into the backcountry of the Mongolian Gobi Desert in search of late Cretaceous dinosaur fossils.

And they found 'em.  In abundance.  The remains that Novacek's team unearthed changed our understanding of the evolution of dinosaurs and early mammals in central Asia -- I've already lost count of the number of new species his group found, and I'm only about a third of the way through the book.

What struck me, though, is the combination of physical and personal hardship that the team members were willing to tolerate to achieve their goals.  The Gobi Desert is, even today, largely untraveled and unmapped; the nomadic groups that live in its arid wastes have to keep moving to survive in a climate that is broiling hot in the summer and viciously cold in the winter, has little in the way of drinkable fresh water, and is thin pasturage for domestic animals even at the best of times.  These scientists launched into the arid badlands in old, Soviet-era trucks that broke down every time someone sneezed hard, with carefully-rationed food, water, and gasoline, and exactly zero margin for error.

The fact that they not only survived, but achieved their scientific goals (and then some), is downright astonishing.  And every other page, I've shaken my head and thought, "I would never have the courage to do something like this.  Not in a million years."

Keep in mind, too, that this is coming from someone who did his share of backcountry camping, mostly in the Cascades and Olympics of Washington State.  Being a teacher has its perks -- June, July, and August being top of the list -- and when I was in my twenties I frequently disappeared into the fir-shrouded forests during the summer for weeks at a time.  So I'm no stranger to sleeping outdoors and hiking with a heavy pack.  (Or at least I was.  Now that I am Of A Certain Age, I'm afraid my appreciation of the creature comforts has done nothing but increase.)

But still: I would never have been brave enough to take off into the wilds of Mongolia the way Novacek et al. did (repeatedly).  Which probably would have scotched any intent I might have had to become a paleontologist.

On the other hand, sometimes -- admittedly, it's probably rare -- great paleontological discoveries can come from merely opening the right drawer in a museum.  The reason the topic comes up (besides my current reading-in-progress) is the chance find by paleontologist Georgios Georgalis of the Institute of Systematics and Evolution of Animals of the Polish Academy of Sciences in Krakow, who was doing some research in London's Natural History Museum and stumbled across the bones of a very unusual fossil snake that had been overlooked for forty years.

Dubbed Paradoxophidion richardoweni -- "Richard Owen's paradoxical snake" -- it lived in England during the Eocene Epoch, something like 37 million years ago.  At that point, England was a great deal warmer than it is now.  The world was just exiting the Paleocene-Eocene Thermal Maximum, at eight degrees Celsius higher than today one of the highest global average temperatures ever recorded.  The hot times favored diversification of ectothermic animals -- such as snakes -- in what are now regions with much cooler climates.

"It was my childhood dream to be able to visit the Natural History Museum, let alone do research there," said study lead author Georgalis.  "So, when I saw these very weird vertebrae in the collection and knew that they were something new, it was a fantastic feeling.  It's especially exciting to have described an early diverging caenophidian snake, as there's not that much evidence about how they emerged. Paradoxophidion brings us closer to understanding how this happened."

The snake species, Georgalis said, seems to be related to a group called acrochordids now found only in southeast Asia and Australia -- although more study is needed to be certain.  And it also brought up the tantalizing question of what else might be hiding in museum drawers and cabinets.

"I'm planning to study a variety of snake fossils in the collection, including those originally studied by Richard Owen" Georgalis said.  "These include the remains of the giant aquatic snake Palaeophis, which were first found in England in the nineteenth century.  There are also several bones with differing morphology that haven't been investigated before that I'm interested in looking at.  These might represent new taxa and offer additional clues about snake evolution."

So I guess you don't need to endure sandstorms and blistering heat and terrible food to make significant contributions to the field.

This also highlights the critical importance of museums in the entire scientific enterprise.  I found out yesterday the amazing news that one of our best local museums, the Paleontological Research Institution/Museum of the Earth, has received enough donations to remain open -- funding cuts were looking likely to shutter it permanently.  On the one hand, I'm thrilled that enough people were willing to donate to keep this wonderful place going (and if you're willing, I encourage you to go to their website and do so as well -- even if they met their goal, they can still put every penny to good use).  On the other, though, isn't it sad that we never seem to run out of money for stuff like funding war and paying kickbacks to corporate billionaires, but cutting-edge scientific establishments that are inspirations to thousands basically have to hold a bake sale to stay in business?

[Image licensed under the Creative Commons Matt Wedel, Yale brontosaurus, CC BY 4.0]

In any case, here's another puzzle piece adding to the picture of what the Earth was like tens of millions of years ago, that had been hidden away in a museum cabinet for four decades.  I find the whole thing endlessly fascinating, which probably explains why the topic of paleontology is such a frequent flier here at Skeptophilia. 

But as interested as I am, I still don't think I'd be brave enough to venture into the Gobi Desert to study it.

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Scattered to the winds

One of the more puzzling aspects of evolutionary theory is the phenomenon of peripheral isolates.

This term refers to widely-separated populations of seemingly closely-related organisms.  One of the first times I ran into this phenomenon came to my attention because of my obsession with birdwatching.  There's a tropical family of birds called trogons, forest-dwelling fruit-eaters that are prized by birdwatchers for their brilliant colors.  There are trogons in three places in the world... Central and South America (27 species), central Africa (3 species), and southern Asia (11 species).

These are very far apart.  But take a look at three representatives from each group -- it doesn't take an ornithologist to see that they've got to be closely related:

The Elegant Trogon (Trogon elegans) of Central America [Image licensed under the Creative Commons dominic sherony, Elegant Trogon, CC BY-SA 2.0]

The Narina Trogon (Apaloderma narina) of central Africa [Image licensed under the Creative Commons Derek Keats from Johannesburg, South Africa, Narina Trogon, Apaloderma narina MALE at Lekgalameetse Provincial Reserve, Limpopo, South Africa (14654439002), CC BY 2.0]

The Red-headed Trogon (Harpactes erythrocephalus) of southeast Asia [Image licensed under the Creative Commons JJ Harrison (jjharrison89@facebook.com), Harpactes erythrocephalus - Khao Yai, CC BY-SA 3.0]

I know, I've gone on and on in previous posts about how misleading morphology/appearance can be in determining relationships, but you have to admit these are some pretty convincing similarities.

The question, of course, is how did this happen?  Where did the group originate, and how did members end up so widely separated?  To add to the puzzle, the fossil record for the group indicates that in the Eocene Epoch, fifty-ish million years ago, there were trogons in Europe -- fossils have been found in Denmark and Germany -- and the earliest fossil trogons from South America come from the Pleistocene Epoch, only two million years ago.

So are these the remnants of what was a much larger and more widespread group, whose northern members perhaps succumbed due to one of the ice ages?  Did they start in one of their homelands and move from there?

And if that's true, why are there no examples of trogons from all the places in between?

Another example of this is the order of mammals we belong to (Primata).  Primates pretty clearly originated in Africa and spread from there; the earliest clear primates were in the Paleocene Epoch, on the order of sixty million years ago, but the ancestor of all primates was probably at least twenty million years before that, preceding the Cretaceous Extinction by fourteen million years.  From their start in east Africa they seem to have spread both east and west, reaching southeast Asia around fifty million years ago.  Some of the earliest members to split were the lorises and tarsiers, along with the lemurs of Madagascar.

But the next group to diverge -- and the reason the whole topic of peripheral isolates came up -- are the "New World monkeys," the "platyrhines" of Central and South America.  It looks like this split happened during the Oligocene Epoch, around thirty million years ago... but how?

At that point, Africa was separated from South America by nine hundred miles of ocean -- narrower than the Atlantic is today, but still a formidable barrier.  But a paper in Science describes recently-discovered evidence from Peru of some fossilized primate teeth from right around the time the New World/Old World monkey split happened.

What this discovery suggests is staggering; all of the New World monkeys, from the spider monkey to the black howler monkey to the Amazonian pygmy marmoset, are descended from a single group that survived a crossing of the Atlantic, probably on a vegetation raft torn loose in a storm, only a little over thirty million years ago.

"This is a completely unique discovery," said Erik Seiffert, the study's lead author and Professor of Clinical Integrative Anatomical Sciences at Keck School of Medicine of the University of Southern California, in an interview with Science Daily.  "We're suggesting that this group might have made it over to South America right around what we call the Eocene-Oligocene Boundary, a time period between two geological epochs, when the Antarctic ice sheet started to build up and the sea level fell.  That might have played a role in making it a bit easier for these primates to actually get across the Atlantic Ocean."

So here we have a possible explanation for one of the long-standing puzzles of evolutionary biology.  Note that these puzzles aren't a weakness of the theory; saying "we still have some things left to explain" isn't the same as saying "the theory can't explain this."  There will always be pieces to add and odd bits of data to account for, but I have one hundred percent confidence that the evolutionary model is up to the task.

Now, I wish it could just come with an explanation for the trogons, because for some reason that really bothers me.

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Footprints in the boneyard

The difficulty with paleontology is its inherent limitations.

There are, of course, things it's very good at.  In the hands of a skilled expert, fossils can tell you a great deal -- not only direct information about the parts that are preserved, but indirect information (from spaces, gaps, muscle attachment points, and so on) about the parts that were not.  I'm currently reading the wonderful book by Jack Horner and Edwin Dobb, Dinosaur Lives: Unearthing an Evolutionary Saga, and was astonished to find out that many paleontologists now believe that the quintessential Big Scary Dinosaur, Tyrannosaurus rex, was primarily a scavenger and not a hunter -- based upon the fact that the interior of the skull shows that its brain had an enormous olfactory lobe and a correspondingly small visual cortex, similar to hyenas and vultures.

Even so, there's a lot that fossils have a harder time telling us.  Other than a few fortuitous exceptionally-preserved feathers, we know next to nothing about colors and markings; art featuring prehistoric animals is almost entirely basing those features on guesswork using the patterns we see in modern animals.  In addition, how ancient organisms fit into the bigger ecological picture is like trying to figure out the pattern in a thousand-piece puzzle when you only have a handful of pieces. Given that a very small percentage of the biological remains left behind ever become fossils, chances are there are tens of thousands of prehistoric species we know absolutely nothing about because they left no traces behind after the last of their kind died.

Behavior, too, is often a puzzle.  It was Jack Horner (the same Jack Horner who co-wrote Dinosaur Lives) who made the discovery of the nesting and parental care behavior in the duckbilled dinosaur Maiasaura (the name means "good mother lizard"), based upon a group of fifteen fossilized juveniles and one adult that had been killed simultaneously in a volcanic ashfall.  But despite what Jurassic Park would have you believe, we really know very little about the behavior of prehistoric animals.  (Dilophosaurus, for example, almost certainly didn't have a retractable frill and poisonous spit.  Spit rarely fossilizes.)

The reason the topic comes up, actually, is because of a different volcanic eruption that left behind a treasure trove of fossils; a "supereruption" of the Yellowstone volcanic system twelve million years ago that smothered (and preserved) a huge herd of the prehistoric North American rhinoceros species Teleoceras.  The site -- in what is now northeastern Nebraska -- has been nicknamed "the rhino Pompeii."

"The eruption was so massive that ash would have fallen like snow 1,600 kilometers from the eruption site in Idaho," said Ashley Poust, a curator of vertebrate paleontology at the University of Nebraska State Museum, who gave a talk on the find last week at the annual meeting of the Society for Vertebrate Paleontology.  "This would have darkened the skies, buried plant life and water sources, and been a real hazard to anything with a delicate respiratory system."

A paleontologist working on unearthing Teleoceras fossils in the Ashfall Fossil Beds [Image credit: Ashley Poust]

What's most amazing about this find, though, is that the study also uncovered footprints in the ash -- the traces of two species of "bone-crushing dogs," Aelurodon taxoides and Epicyon saevus, which apparently somehow escaped being suffocated themselves and afterward made use of the huge amounts of free meat from the dead rhinos.  Aelurodon and Epicyon seem to have occupied the same niche as modern hyenas, but were a lot bigger; these prints were about eight centimeters long and seven centimeters wide.

Reconstruction of Epicyon [Image licensed under the Creative Commons Jarrod Amoore from Sydney, Australia, Epicyon, CC BY 2.0]

"There is some evidence that they may have scavenged among the animals who didn't survive, using the buried rhinos as a food cache," Poust said.  "But since we haven't found the bones of these meat eaters, we aren't sure yet whether this was enough to see them through to better times, or whether they eventually had to depart to seek their fortunes elsewhere in the massive disaster zone that covered much of North America."

It's also uncertain how they survived.  Volcanic ash is nasty stuff.  Not only does it clog airways if inhaled, it's made of sharp slivers of something very much like glass.  Even walking through a recent ashfall would raise enough dust to cause significant health risk, much less living through it while it was actively falling out of the sky.  Interesting that there haven't been any fossils of the dogs found at the site -- although research is ongoing, and it's anyone's guess about what's left there to discover.

So here's another case where we can made at least some tentative inferences about behavior from twelve million year old fossils.  Although the sad truth is that we still have access to information about only a tiny percent of the life that has ever existed on Earth, sometimes a chance discovery will give us a startling window into the past -- in this case about packs of scavengers that may have taken advantage of a catastrophic disaster.

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Life, not as we know it

I've written here before about unusual paleontological discoveries -- illustrations of the fact that Darwin's lovely phrase "many forms most beautiful and most wonderful" has applied throughout Earth's biological history.

We could also add the words "... and most weird."  Some of the fossils paleontologists have uncovered look like something from a fever dream.  A while back I wrote about the absolutely bizarre "Tully Monster" (Tullimonstrum spp.) that is so different from all other life forms studied that biologists can't even figure out whether it was a vertebrate or an invertebrate.  But Tully is far from the only creature that has defied classification.  Here are a few more examples of peculiar organisms whose placement on the Tree of Life is very much up for debate.

First, we have the strange Tribrachidium heraldicum, a creature of uncertain relationships to all species at the time or afterward.  It had threefold symmetry -- itself pretty odd -- and its species name heraldicum comes from the striking resemblance to the triskelion design on the coat of arms of the Isle of Man:

Tribrachidium fossil from near Arkhangelsk, Russia [Image licensed under the Creative Commons Aleksey Nagovitsyn (User:Alnagov), Tribrachidium, CC BY-SA 3.0]

Despite superficial similarities to modern cnidarians (such as jellyfish) or echinoderms (such as sea urchins and starfish), Tribrachidium seems to be neither.  It -- along with a great many of the Ediacaran assemblage, organisms that dominated the seas during the late Precambrian Era, between 635 and 538 million years ago -- is a mystery.

The Ediacaran is hardly the only time we have strange and unclassifiable life forms.  From much later, during the Carboniferous Period (on the order of three hundred million years ago), the Mazon Creek Formation in Illinois has brought to light some really peculiar fossils.  One of the most baffling is Etacystis communis, nicknamed the "H-animal":

Reconstruction of Etacystis [Image is in the Public Domain]

It's an invertebrate, but otherwise we're still at the "but what the hell is it?" stage with this one.  Best guess is it might be a distant relative of hemichordates ("acorn worms"), but that's speculative at best.

Next we have Nectocaris.  The name means "swimming shrimp," but a shrimp it definitely was not.  It next was thought to be some kind of primitive cephalopod, perhaps related to cuttlefish or squid, but that didn't hold water, either.  They had a long fin down each side that they probably used for propulsion, and a feeding tube shaped like a funnel (that you can see folded to the left in the photograph below):

Photograph of a Nectocaris fossil from the Burgess Shale Formation, British Columbia [Image is in the Public Domain]

All of the Nectocaris fossils known come from the early Cambrian.  It's possible that they were a cousin of modern chaetognaths ("arrow worms"), but once again, no one is really sure.

Another Cambrian animal that has so far defied classification is Allonnia, which was initially thought to be related to modern sponges, but their microstructure is so different they're now placed in their own order, Chancelloriidae.  You can see why the paleontologists were fooled for a while:

Reconstruction of Allonnia from fossils recovered from the Chengjiang Formation, Yunnan Province, China [Image licensed under the Creative Commons, Yun et al. 2024 f05 (preprint), CC BY 4.0]

At the moment, Allonnia and the other chancelloriids are thought to represent an independent branch of Kingdom Animalia that went extinct in the mid Cambrian Era and left no descendants -- or even near relatives.

Last, we have the bizarre Namacalathus hermanestes, which has been found in (very) late Precambrian shales in such widely-separated sites as Namibia, Canada, Paraguay, Oman, and Russia.  Check out the reconstruction of this beast:

[Image credit Zhuravlev, Wood, and Penny, Proceedings of the Royal Society B, November 2015]

It's been tentatively connected to lophophorates (which include the much more familiar brachiopods), but if so, it must be a distant relationship, because they look a great deal more like something H. P. Lovecraft might have dreamed up:

Unlike the, um, "Yuggothians," though, Namacalathus was quite real.  And, apparently, widespread.

The early Cambrian seas must have contained plenty of nightmare fuel.

And those are just five examples of organisms that would have certainly impelled Dr. McCoy to say, "It's life, Jim, but not as we know it."  Given how infrequently organisms fossilize -- the vast majority die, decay away, and leave no traces, and the vagaries of geological upheaval often destroy the fossil-bearing strata that did form -- you have to wonder what we're missing.  Chances are, for every one species we know about, there are hundreds more we don't.

What even more bizarre life forms might we see if we actually went back there into the far distant past?

I guess we'll have to wait until someone invents a time machine to find out.

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Old as the hills

In northwestern Australia, there's an administrative region called Pilbara.

Even though on a map, it looks kind of long and narrow, it's big.  The area of Pilbara is just shy of that of California and Nevada put together.  (I suspect that I'm like many non-Australians in consistently forgetting just how big Australia is.  It's the sixth largest country in the world, and is almost the same size as the continental United States.  Flying from Sydney to Perth is comparable to flying from Atlanta to Los Angeles.)

Pilbara is also extremely hot and dry, and very sparsely populated, with only a bit over sixty thousand residents total, most of whom live in the western third of the region.  The northeastern quadrant is part of the aptly-named Great Sandy Desert, one of the most inhospitable places on Earth.  There are only a few Indigenous tribes that somehow eke out a living there, most notably the Martu, but by and large it's uninhabited.

[Image licensed under the Creative Commons Brian Voon Yee Yap, aka Yewenyi, at en.wikipedia]

What brings up the topic, though, is that Pilbara is interesting for another reason than its hostile climate.

It is the home to some of the oldest rocks on Earth.

The Pilbara Craton -- a craton is a contiguous piece of continental crust -- is estimated to be around three and a half billion years old.  For reference, the Earth's crust only solidified 4.4 billion years ago.  Since that time, plate tectonics took over, and as I've described before, tectonic processes excel at recycling crust.  At collisional margins such as trenches and convergent zones, usually one piece slides under the other and is melted as it sinks.  Even in places where two thick, cold continental plates run into each other -- examples are the Alps and the Himalayas -- the rocks are deformed, buried, or eroded.

The result is we have very few really old rocks left.  The only ones even on the same time scale as Pilbara are the Barberton Greenstone Belt of South Africa and the Canadian Shield (and even the latter has been heavily metamorphosed since its formation).

This makes Pilbara a great place to research if you're interested in the conditions of the Precambrian Earth -- as long as you can tolerate lots of sand, temperatures that often exceed 36 C, and a fun kind of grass called Triodia that has leaf margins made of silica.

Better known as glass.

Frolicking in a field of Triodia is like running through a meadow made of Exacto knives.

Be that as it may, geologists and paleontologists have begun a thorough study of this fascinating if forbidding chunk of rock.  The most recent reconstructions suggest that both Pilbara and the aforementioned Barberton Greenstone were once part of an equatorial supercontinent called Vaalbara (which preceded the supercontinent most people think of -- Pangaea -- by a good three billion years).  And those might be the only chunks of that enormous piece of land left intact.

There are two other reasons Pilbara is remarkable.

It contains numerous fossilized stromatolites, which are layered sedimentary structures formed by cyanobacteria, thought to be the earliest photosynthetic life forms.  There are still stromatolites forming today -- probably not coincidentally, in shallow bays in Western Australia.

[Image licensed under the Creative Commons photographer Paul Harrison (Reading UK), March 2005, Stromatolites growing in Hamelin Pool Marine Nature Reserve, Shark Bay in Western Australia.]

As such, the Pilbara stromatolite fossils are the oldest certain traces of life on Earth, dating to 3.48 billion years ago.

The other reason is that it's also home to a massive impact crater dating to 3.47 billion years ago.  Shortly after those earliest, tentative life forms were living and thriving in the warm shallow ocean waters, a huge meteorite struck near what is now the town of Marble Bar, forming a crater and shatter cone between 16 and 45 kilometers in diameter (because of erosion, it's hard even for the geologists to determine where its edges lie).  The resulting Miralga Impact Structure blew tremendous amounts of molten debris up into the air, and some of it landed on that chunk of Vaalbara that would eventually end up in South Africa -- only to be recovered by geologists almost three and a half billion years later.

So there's a place in Australia that gives new meaning to the phrase "old as the hills."  Given its remoteness and inhospitable climate, I'm unlikely ever to visit there, but there's something appealing about the idea.  Walking on rock that is an intact remnant of a continent from over three billion years ago is kind of awe-inspiring.  Even if all the other rock is still here somewhere -- melted and reformed and eroded multiple times -- the idea that this chunk of the Earth has somehow lasted that long more or less intact is mighty impressive.

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Mental models and lying stones

Richard Feynman famously said, "The first principle is that you must not fool yourself -- and you are the easiest person to fool."

This insightful statement isn't meant to impugn anyone's honesty or intelligence, but to highlight that everyone -- and I'm sure Feynman was very much including himself in this assessment -- has biases that prevent them from seeing clearly.  We've already got a model, an internal framework by which we interpret what we experience, and that inevitably constrains our understanding.

As science historian James Burke points out, in his brilliant analysis of the scientific endeavor The Day the Universe Changed, it's a trap that's impossible to get out of.  You have to have some mental model for how you think the world works, or all the sensory input you receive would simply be chaos.  "Without a structure, a theory for what's there," Burke says, "you don't see anything."

And once you've settled on a model, it's nearly impossible to compromise with.  You're automatically going to take some things as givens and ignore others as irrelevant, dismiss some pieces of evidence out of hand and accept others without question.  We're always taking what we experience and comparing it to our own mental frameworks, deciding what is important and what isn't.  When my wife finished her most recent art piece -- a stunning image of a raven's face, set against a crimson background -- and I was on social media later that day and saw another piece of art someone had posted with a raven against red -- I shrugged and laughed and said, "Weird coincidence."

Quoth the Raven, pen/ink/watercolor by Carol Bloomgarden (2025) [Image used with permission]

But that's only because I had already decided that odd synchronicities don't mean anything.  If I had a mental model that considered such chance occurrences as spiritually significant omens, I would have interpreted that very, very differently.

Our mental frameworks are essential, but they can lead us astray as often as they land us on the right answer.  Consider, for example, the strange, sad case of Johann Beringer and the "lying stones."

Johann Bartholomeus Adam Beringer was a professor of medicine at the University of Würzburg in the early eighteenth century.  His training was in anatomy and physiology, but he had a deep interest in paleontology, and had a large collection of fossils he'd found during hikes in his native Germany.  He was also a devout Lutheran and a biblical literalist, so he interpreted all the fossil evidence as consistent with biblical events like the six-day creation, the Noachian flood, and so on.

Unfortunately, he also had a reputation for being arrogant, humorless, and difficult to get along with.  This made him several enemies, including two of his coworkers -- Ignace Roderique, a professor of geography and algebra, and Johann Georg von Eckhart, the university librarian.  So Roderique and von Eckhart hatched a plan to knock Beringer down a peg or two.

They found out where he was planning on doing his next fossil hunt, and planted some fake fossils along the way.

These "lying stones" are crudely carved from limestone.  On some of them, you can still see the chisel marks.

More outlandish still, Roderique and von Eckhart carved the word "God" in Hebrew on the backs of some of them.  Making it look like the artisan had signed His name, so to speak.

One colleague -- who was not in on the prank -- looked at the stones, and said to Beringer, "Um... are you sure?  Those look like chisel marks."  Beringer dismissed his objections, and in fact, turned them into evidence for his explanation.  Beringer wrote, "...the figures... are so exactly fitted to the dimensions of the stones, that one would swear that they are the work of a very meticulous sculptor...[and they] seem to bear unmistakable indications of the sculptor's knife."

They were so perfect, Beringer said, that they could only be the work of God.

So as astonishing as it may seem, Beringer fell for the ruse hook, line, and sinker.  Roderique and von Eckhart, buoyed up by their success, repeated their prank multiple times.  Finally Beringer had enough "fossils" that in 1726, he published a scholarly work called Lithographiae Wirceburgensis (The Writing-Stones of Würzburg).  But shortly after the book's publication -- it's unclear how -- Beringer realized he'd been taken for a ride.

He sued Roderique and von Eckhart for defamation -- and won.  Roderique and von Eckhart were both summarily fired, but it was too late; Beringer was a laughingstock in the scientific community.  He tried to recover all of the copies of his book and destroy them, but finally gave up.  His reputation was reduced to rubble, and he died twelve years later in total obscurity.

It's easy to laugh at Beringer's credulity, but the only reason you're laughing is because if you found such a "fossil," your mental model would immediately make you doubt its veracity.  In his framework -- which included a six-thousand-year-old Earth, a biblical flood, and a God who was perfectly capable of signing his own handiwork -- he didn't even stop to consider it.

The history of science is laden with missteps caused by biased mental models.  In 1790, a report of a fireball over France that strewed meteorites over a large region prompted a scientific paper -- that laughingly dismissed the claim as "impossible."  Pierre Bertholon, editor of the Journal des Sciences Utiles, wrote, "How sad, is it not, to see a whole municipality attempt to certify the truth of folk tales… the philosophical reader will draw his own conclusions regarding this document, which attests to an apparently false fact, a physically impossible phenomenon."  DNA was dismissed as the genetic code for decades, because of the argument that DNA's alphabet only contains four "letters," so the much richer twenty-letter alphabet of proteins (the amino acids) must be the language of the genes.  Even in the twentieth century, geologists didn't bother looking for evidence for continental drift until the 1950s, long after there'd been significant clues that the continents had, in fact, moved, largely because they couldn't imagine a mechanism that could be responsible.

Our mental models work on every level -- all the way down to telling us what questions are worth investigating.

So poor Johann Beringer.  Not to excuse him for being an arrogant prick, but he didn't deserve to be the target of a mean-spirited practical joke, nor does he deserve our derision now.  He was merely operating within his own framework of understanding, same as you and I do.

I wonder what we're missing, simply because we've decided it's irrelevant -- and what we've accepted as axiomatic, and therefore beyond questioning?

Maybe we're not so very far ahead of Beringer ourselves.

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