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

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

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.

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

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.

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

The former Appalachia

In my post a few days ago about scary predators, I mentioned a curious feature of the prehistory of North America -- the Western Interior Seaway, which for a bit over thirty million years in the mid- to late-Cretaceous Period split the continent in half, connecting the Arctic Ocean to the Gulf of Mexico.

[Image licensed under the Creative Commons Scott D. Sampson, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, Alan L. Titus, Map of North America with the Western Interior Seaway during the Campanian (Upper Cretaceous), CC BY 4.0]

This meant that a broad strip of land from current-day Alberta to east Texas was underwater.  In fact, Kansas -- which seldom comes to mind when you think of the ocean -- is one of the best places in the world to find late-Cretaceous-age marine fossils like mosasaurs, plesiosaurs, and scary-ass enormous carnivorous fish like Xiphactinus.

These mofos were around five meters in length.  Going for a nice skinnydip in the Western Interior Seaway would not have been recommended. [Image licensed under the Creative Commons Jonathan Chen, Xiphactinus AMNH, CC BY-SA 4.0]

The Seaway is thought to have formed because the Laramide Orogeny -- the combination of uplift and volcanism that created the Rocky Mountains -- caused downwarping of the continental crust to the east, allowing the ocean to flood inward.  The Laramide uplift eventually would be the Seaway's undoing, however; the upward push gradually shifted eastward, lifting what is now the American Midwest and leaving it high and dry.  (Of course, this final stage happened right around the same time as the Chicxulub Impact occurred, so living things at that point had other worries; but fossil beds in North Dakota that preserve evidence of the actual impact show that most of what had been the Seaway had already broken up into swamps, rivers, and shallow lakes.)

As you can see from the map, the Western Interior Seaway split North America into two continents, a western one (Laramidia) and an eastern one (Appalachia).  What's curious is that we know a great deal more about the paleontology of Laramidia than we do of Appalachia.  Most of what come to mind as the big, charismatic dinosaur species of the late Cretaceous, such as T. rex and Triceratops and Parasaurolophus, lived in Laramidia; and just this week, a paper appeared in PLOS One about one of the Laramidian mammals, a muskrat-sized marsupial called Heleocola.

So what was happening in Appalachia?

The answer is "we're not really sure," because the evidence is so slim.  A rapidly-rising mountain range, such as what Laramidia was experiencing at the time, results in a lot of eroded sediments and volcanic ash with which to bury recently-deceased organisms, making the western parts of North America prime places for hunting fossils.  The part of the continent east of today's Mississippi River is, on the whole, made up of rocks of far greater age.  (For example, where I live -- a bit down and to the right of the letter "C" in "Appalachia" on the map -- has rocks of Devonian age, which were already about three hundred million years old when the late Cretaceous dinosaurs were lumbering around.)

So old, stable crust with gentle topography = much less eroded sediment, and little to no formation of the sedimentary rock where you find fossils.

There have been a few finds here and there, even if nowhere near the fossil riches in the western half of the continent.  We know there were species from some of the familiar groups -- tyrannosaurids, hadrosaurs, coelurosaurs, ornithomimids, and lambeosaurs -- but on the whole, they were more like their ancestors (i.e. they had changed less over time, and still resembled the "basal" or "stem" lineages).  Why this happened is unknown.  There's a general rule that slow environmental change and low selection leads to very slow rates of evolutionary change (thus the oft-quoted statement that sharks have barely changed in overall form in two hundred million years, which is only true if you pick and choose which species to look at).  So were the inhabitants of Appalachia simply in a more congenial environment, as compared to the ones in the tectonically-active, rapidly-rising mountains of Laramidia?

It's certainly a possibility, but it's hard to make any real determinations based on a lack of evidence.  As I've pointed out before, even with the most favorable of conditions, only an extremely small fraction of organisms ever become fossils; what we don't know about the past vastly outweighs what we do know.  Still, it's mind-boggling to think about a time when things were so very different.  My home territory of the Finger Lakes Region of New York, now cool hardwood forests where the scariest denizens are foxes and black bears, were then warm, humid subtropical jungles, with a climate more like Central America, and populated by a huge assemblage of dinosaurs we're only beginning to understand.

Just as well things have changed, really.  I have a hard enough time keeping bunnies out of my vegetable garden, I can't imagine how I'd deal with my lettuce plants being munched by hadrosaurs.

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

Abominable mysteries

One of the most annoying things I run across regularly is when someone takes a perfectly good piece of scientific research and twists it to support their own highly unscientific pre-existing beliefs.

The latest in this long parade of frustration I found out about because of my good friend, the amazing writer Gil Miller, who is a frequent contributor of topics for Skeptophilia.  Gil sent me a link to a fascinating paper that came out a month and a half ago in Nature about one of the most perplexing puzzles in evolutionary biology -- the sudden diversification of flowering plants during the Cretaceous Period, something on the order of 150 million years ago.  They went on to outcompete every other plant group, now comprising ninety percent of the known plant species, totaling about 13,600 different genera.  If you look around you, chances are any plant you happen to see that isn't a moss, fern, or conifer is a flowering plant.

What caused their explosive rise and diversification, however, is still unknown.  Their success might well be due to coevolution with pollinators, especially insects, which had a sudden spike in diversity around the same time, but that's speculation.  The current study vastly expands the genetic data we have on current genera of flowering plants, rearranging a few groups and solidifying what we know about the branch points of different clades within the group.  However, it still doesn't solve the reason behind what Darwin called "the abominable mystery" of why it all happened -- something the authors are completely up front about.

[Angiosperm phylogenetic chart from Zuntini et al., Nature, April 2024]

Well, any time an evolutionary biologist says "we don't yet understand this" -- especially if it's something Darwin himself noted as odd or mysterious -- it's enough to get all the anti-evolution types leaping about making excited little squeaking noises, and it didn't take long for this paper to appear in an article over at Evolution News (don't let the name fool you; the site is sponsored by the staunchly creationist Discovery Institute).  The article (so I can save you the trouble of clicking the link and adding to their hit rate) glosses over all of the stuff Zuntini et al. did explain, and highlights instead the fact that they never accounted for the reason behind flowering plant diversification (which wasn't even the purpose of the study).  The article ends with, "Nature clearly did make jumps in the history of life and this cannot be explained with an unguided gradual accumulation of small changes over long periods of time, but requires a rapid burst of biological novelty that is best explained by intelligent design."

Basically, what we have here is yet another iteration of the God-of-the-gaps argument; "we don't yet understand it, so musta been that God did it."  The problem is, you can't base a conclusion on a lack of data.  For the intelligent design argument to work, you'd have to show that it explains the data better than other models do.  Simply saying "we don't know, therefore God" isn't actually an explanation of anything, something that atheist philosopher Jeffrey Jay Lowder brought into sharp focus:

The objection I have in mind is this: the design hypothesis is not an explanation because, well, it doesn’t explain. ...  [I]t seems to me that a design explanation must also include a description of the mechanism used by the designer to design and build the thing.  In other words, in order for design to explain something, we have to know how the designer designed it.  If we don’t know or even have a clue about how the designer did it, then we don’t have a design explanation.

Which is it exactly.  Science works because it not only self-corrects, it holds explaining things in abeyance until there's enough data there to warrant a robust explanation.  A mystery is just a mystery; maybe we'll figure it out at some point and maybe we won't, but until then, it doesn't prove anything.  Science doesn't simply look at a lack of information and then throw its hands in the air and say, "Well, must be X, then."

To quote eminent astrophysicist Neil deGrasse Tyson, "If you don't know what it is, that's where the conversation stops.  You don't go on and say it 'must be' anything."

Honestly, it's astonishing that the creationist types are still using the God-of-the-gaps approach, because the truth is, it's more damaging to their position than it is helpful.  The reason was noted by German theologian Dietrich Bonhoeffer: "[I]t is [wrong] to use God as a stopgap for the incompleteness of our knowledge.  If in fact the frontiers of knowledge are being pushed further and further back (and that is bound to be the case), then God is being pushed back with them, and is therefore continually in retreat."

But that line of reasoning -- from a respected theologian, no less -- doesn't seem to be slowing them down any.

So I'll apologize to Zuntini et al. on behalf of the entire human race for these unscientific yayhoos taking a really lovely piece of research and claiming it supports their beliefs.  The tl;dr summary of this post is: it doesn't.  At all.  At worst, the study indicates that there's still stuff we don't understand, which is a damn good thing because otherwise the scientists would be out of a job.

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

Birds down under

I've been an avid birdwatcher for many years, and have been fortunate enough to travel to some amazingly cool places in search of avifauna.  Besides exploring my own country, I've been to Canada (several times), Belize (twice), Ecuador (twice), Iceland (twice), England (twice), Scotland, Sweden, Finland, Denmark, Russia, Spain, Portugal, and Malaysia.

One place I've never been, though, is Australia, which is a shame because it's got some incredible animals.  And despite a pretty well-deserved reputation for having far more than their fair share of wildlife that's actively trying to kill you, most tourists come back from trips to Australia alive and with all their limbs still attached in the right places.

The main reason for Australia's unique ecosystems is that it's been isolated for a very long time.  During the breakup of Pangaea, the northern part (Laurasia, made up of what is now Europe, North America, and most of Asia) separated from the southern part (Gondwanaland, made up of what is now Africa, South America, Antarctica, Australia, and India), something on the order of 180 million years ago.  The other pieces gradually pulled apart as rifting occured, but Australia remained attached to Antarctica until around thirty million years ago.  At that point, the whole thing had a fairly temperate climate, but when the Tasman Gateway opened up during the Oligocene Period, it allowed the formation of the Antarctic Circumpolar Current, isolating and cooling Antarctica and resulting in the extinction of nearly all of its native species.  Australia, now separate, began to drift northward, gradually warming as it went, and carrying with it a completely unique suite of animals and plants.

The reason all this comes up is a sharp-eyed Australian loyal reader of Skeptophilia, who sent me a link to a news story about a recent discovery by a dedicated amateur fossil hunter and birdwatcher, Melissa Lowery, who was looking for fossils on the Bass Coast of Victoria and stumbled upon something extraordinary -- some 125 million year old bird footprints.

Lowery's bird footprints [Image by photographer Rob French, Museums Victoria]

At that point, the separation of Australia and Antarctica was some 65 million years in the future, the sauropod dinosaurs were still the dominant animal group, and Victoria itself was somewhere near the South Pole.  Lowery's find led to a full-scale scientific investigation of the area, and uncovered a great many more bird tracks, including some with ten-centimeter-long toes.  Also in the area were the footprints of dozens of kinds of non-avian dinosaurs.

"Most of the bird tracks and body fossils dating back to the Early Cretaceous are from the Northern Hemisphere, particularly from Asia," said Anthony Martin, of Emory University, who led the study.  "Our discovery shows that there were many birds, and a variety of them, near the South Pole about 125 million years ago."

Of course, being a birdwatcher, I'm intensely curious as to what these birds looked like, but there's only so much you can tell from a footprint, or even fossilized bones.  It's simultaneously intriguing and frustrating to think about the fact that these animals -- and all the other animals and plants that lived alongside them -- had every bit of the diversity, all the curious and wonderful and beautiful adaptations and behaviors, that our modern wildlife does.

Imagine what it would be like to transport yourself back to Australia in the early Cretaceous, and witness all of that with your own eyes and ears.  (With, of course, a guarantee of coming back alive and with all your limbs still attached in the right places.  Back then, Australia was a rougher place than it is now.)

So thanks to the reader who sent me the link -- it's renewed my desire to visit Australia.  If I can't see the amazing birds they had 125 million years ago, at least I can have a look through my binoculars at some of the ones they have today.

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

New jaws in an old bird

One difficulty in building evolutionary trees of life from fossil evidence is the fact that "simpler" doesn't necessarily mean "older."

It's an understandable enough mistake.  Taken as a whole, from life's first appearance some 3.7 billion years ago until today, there has been an overall increase in complexity.  The problem occurs when you try to apply that overarching trend to individual lineages -- and find that over time, some species have actually become less complex.

A good example is Subphylum Tunicata, less formally known as tunicates or sea squirts.  At a glance, tunicates look a little like sponges (to which they are only very distantly related); simple, sessile filter feeders.  It was only when biologists discovered their larvae that they realized the truth.  Tunicates are much more closely related to vertebrates than they are to simple invertebrates like the sponges and corals they superficially resemble.  The larvae look a bit like tadpoles, but as they develop the sequentially lose structures like the notochord (the flexible rod that supports the dorsal nerve cord; in us, it ends up becoming the discs between our vertebral bones), most of the muscle blocks, and in fact, just about all their internal organs except the ones involved in processing food and reproducing.

As evolutionary biologist Richard Dawkins put it, evolution is "the law of whatever works."  It doesn't always lead to becoming bigger, stronger, faster, and smarter.  If being small, weak, slow, and dumb works well enough to allow a species to have more surviving offspring -- well, they'll do just fine.

The reason this topic comes up is because of a paper in Nature about a re-analysis of a bird fossil found in a Belgian quarry two decades ago.  The comprehensive study found that one of the bones had been misidentified as a shoulder bone, but was actually the pterygoid bone -- part of the bony palate.  And that bone showed that the species it came from, a heron-sized toothed bird Janavis finalidens, had been misplaced on the avian family tree.

And that single rearrangement might restructure the entire genealogy of birds.

Artist's reconstruction of Janavis finalidens [Image courtesy of artist Philip Krzeminski]

There are two big groups of modern birds; neognaths, which have jaws with free plates allowing the bills to move independently of the skull, and paleognaths, whose jaw bones are fused to the skull.  The paleognaths -- including emus, cassowaries, tinamous, and kiwis -- were thought to be "primitive" in the sense of "more like the ancestral species."  (If you know some Greek, you might have figured this out from the names; paleognath means "old jaw" and neognath means "new jaw.")

But the new analysis of Janavis, a species dating to 67 million years ago -- right before the Chicxulub Meteorite hit and ended the Cretaceous Period and the reign of the dinosaurs -- shows that it was a neognath, at a time prior to the split between the two groups.

Meaning the neognaths might actually have the older body plan.

If this is true -- if the paleognaths evolved from the neognaths, not the other way around -- the puzzle is why.  The flexible beaks of neognaths seems to be better tools than the fused jaws of the paleognaths.  This, though, brings us back to our original point, which is that evolution doesn't necessarily drive species toward complexity.  It also highlights the fact that if a structure works well enough not to provide an actual survival or reproductive disadvantage, it won't be actively selected against.  A good example, all too familiar to the males in the audience, is the structure of the male reproductive organs -- with the urethra passing through the prostate gland (leading to unfortunate results for many of us as we age), and the testicles outside the abdominal cavity, right at the perfect height to sustain an impact from a knee, the corner of a table, or the head of a large and enthusiastic dog.  (If this latter example seems oddly specific, I can assure you there's a galumphing galoot of a pit bull currently asleep on my couch who is the reason it came to mind.)

Anyhow, it looks like we might have to rethink the whole "paleognath" and "neognath" thing.  Makes you wonder what else on the family tree of life might need some jiggering.  

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

A snapshot in amber

A few days ago I finished reading the wonderful new book by paleontologist Riley Black, The Last Days of the Dinosaurs: An Asteroid, Extinction, and the Beginning of Our World.  I can't say enough positive things about it -- it tells the gripping story of the impact of the seven-kilometer-wide Chicxulub Meteorite, which hit a spot just north of the Yucatán Peninsula so hard that most of the giant rock vaporized, what was left punched twenty kilometers into the Earth's crust, and it left an impact crater 180 kilometers across.

Artist's impression of the moment of impact [Image is in the Public Domain courtesy of artist Donald E. Davis and NASA/JPL]

Black gives us a vivid description of the event and its aftermath, each chapter from the point of view of one individual animal who experienced it (not necessarily lived through it, of course).  The day before the impact; the impact itself; the first hour; the first day; the first year; and so on, up until a hundred thousand years after the strike, at which point the Earth's ecosystems had largely recovered -- albeit with a completely different assemblage of species than it had before.

Black's contention, which is generally accepted by researchers, is that there's little truth to the old trope of the dinosaurs being a moribund group anyhow and the asteroid just finished them off.  The dinosaurs were doing just fine.  While some species were headed toward extinction, that had been happening during the group's 190 million year hegemony (and has happened in every single group of life forms ever evolved).  Dinosaurs as a group were still widespread and diverse -- and if it hadn't been for the impact, it's pretty likely that they would have remained in charge (as it were) for millions of years afterward.

Which means that it's probable that mammals would never have taken off the way they did.  (More accurately, "the way we did.")  It's also an incorrect understanding that mammals only launched after the dinosaurs were "out of the way."  Mammals had been around for a very long time themselves (the first ones, the morganucodontids and multituberculates, overlapped the dinosaurs by over a hundred million years).  What seems to be true, though, is that the dinosaurs occupied most of the large-apex-predator and giant-herbivore niches, so mammal groups were mostly small, and a lot of them were burrowers -- something that was an adaptation to there being a lot of carnivores around, but turned into a key to their survival during the searing infrared surge that swept across the world the day the asteroid hit.

What brings this up, besides my wanting to promote Riley Black's awesome book, is a link sent to me by a friend and loyal reader of Skeptophilia about a series of recent discoveries by paleontologist Robert DePalma at a dig site in Tanis, North Dakota.  What's stunning about these finds is that DePalma believes -- and the evidence seems strong -- that they represent the remains of organisms that died on the day of the Chicxulub Impact.

In other words, we're looking at a snapshot of the event that killed every non-avian dinosaur species, and changed the face of the world permanently.

Hard as it is to imagine, in the late Cretaceous, what is now North Dakota was a tropical wetland bordering the Western Interior Seaway -- an inlet of the ocean that has since vanished from a combination of uplift, the Rocky Mountain Orogeny, and simple evaporation.  Picture southern Louisiana, and you have an idea of what North Dakota looked like.

Then the meteorite struck.

Despite the fact that the distance between the impact site and the Tanis wetland is around four thousand kilometers, it only took an hour before there was a blast of heat, a rain of red-hot debris, and a series of earthquakes.  The first-mentioned is probably what did the most immediate damage; large animals that were too big to shelter were probably all dead within minutes after the the infrared surge started, as were just about all the terrestrial plants.  Even aquatic organisms weren't safe, though.  One of the more horrifying fossil finds was a turtle -- that had a stick driven all the way through its body.  The earthquakes triggered a series of seiche waves, which occur when an enclosed body of water is shaken laterally.  (Picture the sloshing of water in a metal tub if you jostle it back and forth.)  The seiche in the Western Interior Seaway and nearby lakes flung aquatic animals onto shore and then buried them under tons of debris -- DePalma and his team found layers of fish fossils right at the K-T Boundary Layer that were also victims of that awful day the impact occurred.

I've written about this event before, of course; I've always had a fascination with things that are big and powerful and can kill you.  But what made me decide to revisit it was a new discovery at Tanis of amber that contains glass spherules.  Amber, you probably know, is fossilized tree sap; it can contain other fossils, including pollen and animals that were trapped in the sap before it hardened (made famous by Jurassic Park, although it must be added that there's never been any found with intact DNA).  But these glass spherules were altogether different.  Silicate rocks turn to glass when they're melted and then cooled quickly; that's where the rock obsidian comes from.  But an analysis of the spherules showed something fascinating.  There were inclusions in the glass of tiny chips of two different kinds of rock; one type was high in calcium, while the other was largely metallic, with high content of chromium, nickel, and other heavy elements.

The first, DePalma says, are the remnants of the limestone bedrock from the spot in the Yucatán where Chicxulub hit, blasted into the air and landing four thousand kilometers away.

The other are the (thus far) only actual pieces of the meteorite itself which have ever been found.

It's absolutely astonishing that we can identify rocks and fossils that formed on a specific day 66 million years ago, and doubly so that it was a day when an event occurred that quite literally changed the course of life on Earth.  As horrifying as the Chicxulub Impact was -- Riley Black calls it "the worst day the Earth ever experienced," and it seems an apt description -- in a real sense, we owe our existence to it.

Without Chicxulub, it's pretty likely it'd still be a dinosaur-dominated world -- and one in which mammals were still small, furtive furballs that never had a chance to control their own destiny.

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

A flower in amber

Today's post comes to us purely from the "Okay, This Is Cool" department.

I've been fascinated with plant taxonomy since long before I knew the word.  I couldn't have been more than about seven years old when a friend of the family gave me a lovely old book by the early twentieth-century botanical illustrator F. Schuyler Mathews called Field Book to American Trees and Shrubs.  Not only did I use it to try to identify every tree in my neighborhood, I found out something about how plants are classified -- not by leaf shape (which at the time seemed to me the most logical characteristic to use) but by flower structure.  That's when I learned that beeches, oaks, and chestnuts are in the same family; so are rhododendrons, heather, blueberries, and cranberries; so are birches, alders, and hazelnuts; so, most surprisingly to me, are willows and poplars.

It was also my first introduction to how difficult the classification of organisms actually is, something I learned a great deal more about when I took evolutionary biology in college.  The standout from Mathews's book in that respect is the genus Crataegus, hawthorns, of which he lists (and illustrates with beautiful woodcuts) over a hundred species, many of which looked (and still look) exactly alike to my untrained eye.  Taxonomists argue vehemently over how particular species are to be placed and who is related to whom, although the advent of genetic analysis and cladistics has now provided a more rigorous standard method for classification.

What I didn't know, even after my umpteenth perusal of the Field Book, was that the strange and magical-sounding scientific names of plant families Mathews mentions are barely scratching the surface.  You go elsewhere in the world, all bets are off; you'll run into plants that are in families with no members at all in the United States.  An odd historical filigree is that one of the reasons the British colonizers felt so at home in northeastern North America was that the plants were familiar; oaks, ashes, beeches, birches, willows, maples, pines, and spruces are found in both places (although the exact species vary).  Go to southeast Asia, South America, or pretty much anywhere in Africa, though, and even someone well-versed in the plants of North America and western Europe might well not recognize a single species.  I found that to be the case in Malaysia -- a (very) little bit of reading about the flora of the places I visited gave me at least a name or two, but I'd say 95% of what I saw I couldn't even have ventured a guess about.

One of the many peculiar plants I saw in the rain forests of Malaysia -- I still don't know what it is, but it sure has a cool-looking leaf.

The reason this comes up is an article sent to me by a friend and loyal reader of Skeptophilia about a fossil from Myanmar that was the subject of a recent paper in The Journal of the Botanical Institute of Texas.  Encased in amber, the flower is almost perfectly preserved -- despite being just this side of one hundred million years old, a point at which the dinosaurs would still be in charge of everything for another thirty-four million years.

If it sounds like figuring out the taxonomy of modern plants is a challenge, it gets way worse when you start looking at plant fossils.  Not only do we not have living plants to analyze genetically, often what we're having to judge by is what's left of a leaf or two.  Fortunately, in this case what the researchers have is a preserved flower -- remember that flowering plants are classified by flower structure -- and that was enough to convince them that they were not only looking at a previously unrecorded species, but a previously unrecorded genus -- and possibly a whole new family.

The flower of the newly-named Micropetasos burmensis [Image by George Poinar of Oregon State University)

Most fascinating of all, the researchers aren't even sure how Micropetasos fits into known plant systematics.  The paper says about all we can say so far is that it seems to belong to the clade Pentapetalae -- which doesn't narrow it down much, as that same clade contains such distantly-related plants as roses, asters, cacti, cucumbers, and cabbage.

Long-time readers might recognize the name of the lead author of the paper -- George Poinar.  This isn't the first time he's pulled off this kind of botanical coup.  About a year and a half ago, I wrote about another of Poinar's discoveries in Burmese amber, a little flower called Valviloculus pleristaminis, which also was of uncertain placement amongst known plant families.  Amazing that in bits of fossilized tree sap we can find remnants that allow us to piece together the flora of the Cretaceous Period.

Of course, what it always brings up is the elegiac thought that however many fossils we find, the vast majority of species that have existed on Earth left no traces whatsoever that have survived to today.  If we were to take a time machine back a hundred million years, Micropetasos and Valviloculus we might perhaps recognize from Poinar's work; but there would be thousands more that are completely unfamiliar.  The lion's share of prehistory is unknown -- and unknowable.

But at least we have one more little piece, a tiny flower in amber.  When it was growing, there were triceratopses and T. rexes stomping around, and our closest ancestors were small, rodent-like critters that still had tens of millions of years of evolution before they'd even become primates.  That we can have any sort of lens into that distant, ancient world is astonishing.

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

Run like a dinosaur

One of my favorite movies, which I have seen I don't even know how many times, is Jurassic Park.

I'm honestly not much of a movie-watcher, but the first time I saw this one, it grabbed me from the opening scene and pretty much never let go.  Besides the great acting (Jeff Goldblum being top of the list... I've been known to swipe his line, "I hate it when I'm always right") and eye-popping special effects, it also gave us a window into something that has been the subject of speculation for centuries: the behavior of extinct animals.

Some of what Crichton, Spielberg et al. came up with was fanciful and almost certainly wrong; a case in point is the frill-waving, venom-spitting Dilophosaurus that ate the villainous Dennis Nedry.  Now, don't get me wrong; it's a great scene, and Nedry deserved everything he got, and more.  But we don't know if the crests of the Dilophosaurus were even retractable; this idea came from an only distantly-related reptile species, the Australian frilled lizard.  And the idea that it had venomous saliva is a complete fiction, given that spit doesn't fossilize all that well.

Dennis Nedry about to become dinner.  That'll teach him for saying "No wonder you're extinct.  I'm gonna run you over when I come back down."

Likewise the terrifying pack-hunting and deliberate, highly intelligent distraction behavior ("Clever girl") of the Velociraptors is entertaining fiction, based upon their relatively large cranial capacity, big nasty pointy teeth, and documented accounts of pack hunters like coyotes using a decoy to drive prey toward its waiting pack mates.  It's unlikely that Velociraptors (or any other dinosaur) were that smart, and I doubt seriously that any of them could figure out how to unlatch a freezer door.

What's cool, though, is that there are some inferences about dinosaur behavior (and the behavior of other extinct animals) we can make from fossil evidence alone.  The iconic scene where Alan Grant and his friends are nearly run over by a stampeding herd of Gallimimus was based upon a set of tracks that may represent exactly what the movie depicts -- a group of small dinosaurs fleeing a larger carnivorous one.  (Some paleontologists still dispute this interpretation, however.)  But the fact remains that we can use fossils to make some shrewd guesses about behavior.

Take, for example, the tracks found recently of a three-toed theropod dinosaur in the Rioja region of Spain.  The species is impossible to tell from the tracks alone, but based upon analysis of the sediment layers, the researchers learned four things:

• The tracks were made on the order of a hundred million years ago, in the early to mid-Cretaceous Period.
• The gait and depth indicates that it was running at about 45 kilometers per hour (right around the top speed Usain Bolt ever achieved).
• Whatever the dinosaur was, it was on the order of two meters tall and between four and five meters from tip to tail.
• Scariest of all, the pattern of tracks showed that as it ran, the animal was accelerating.

So chances are, it was chasing prey.  But there was no evidence to determine whether the prey got away or was turned into a Dennis-Nedry-style all-you-can-eat buffet.

A dangerous time, the mid-Cretaceous.  While a lot of us dinosaur aficionados would love a chance to go back in time and see what it was like, my guess is that once there, most of us would have a life expectancy of under six hours.  So as much as I love Jurassic Park, I'm just fine with not re-creating it.

In any case, it's exciting to know that even though a hundred million years has passed, we can still make some inferences about how these long-extinct animals behaved.  Fossils like the theropod tracks in Spain can give us a window into a long-vanished world, and the fascinating, beautiful, and terrifying animals that inhabited it.

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

I've mentioned before how fascinated I am with the parts of history that still are largely mysterious -- the top of the list being the European Dark Ages, between the fall of Rome and the re-consolidation of central government under people like Charlemagne and Alfred the Great.  Not all that much was being written down in the interim, and much of the history we have comes from much later (such as History of the Kings of Britain, by Geoffrey of Monmouth, chronicling the events of the fourth through the eighth centuries C.E. -- but written in the twelfth century).

"Dark Ages," though, may be an unfair appellation, according to the new book Matthew Gabriele and David Perry called The Bright Ages: A New History of Medieval Europe.  Gabriele and Perry look at what is known of those years, and their contention is that it wasn't the savage, ignorant hotbed of backwards superstition many of us picture, but a rich and complex world, including the majesty of Byzantium, the beauty and scientific advancements of Moorish Spain, and the artistic genius of the master illuminators found in just about every Christian abbey in Europe.

It's an interesting perspective.  It certainly doesn't settle all the questions; we're still relying on a paucity of actual records, and the ones we have (Geoffrey's work being a case in point) sometimes being as full of legends, myths, and folk tales as they are of actual history.  But The Bright Ages goes a long way toward dispelling the sense that medieval Europe was seven hundred years of nothing but human misery.  It's a fascinating look at humanity's distant, and shadowed, past.

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

A new kind of thagomizer

When I was an undergraduate, I think one of the most startling things I learned was how few prehistoric animals we actually know about.

Like many kids, I grew up with books on dinosaurs and other prehistoric animals, and I was captivated by the panoramic artistic recreations of the Cretaceous landscape, with lumbering triceratops and T. rexes, and pterodactyloids gliding overhead (and always, for some reason, with a smoldering volcano in the background).  It was my evolutionary biology professor who blew all this away.

Fossilization, he said, is ridiculously rare.  It takes a significant series of very unlikely events to result in a fossil at all, much less one that could last 66-plus million years.  The deceased organism has to land in, or be covered by, sediments; it can't be eaten up or otherwise destroyed by animals.  The sediments it's encased in have to be undisturbed long enough to harden into rock, then that rock has to avoid erosion and the other geological processes that eventually degrade most of the rocks the Earth produces.

Then, that surviving fossil-bearing rock has to be found by scientists.

So we're basing our picture of prehistoric landscapes upon a random sampling of a very small number of species.  It is, my professor said, like someone tried to put together a picture of the modern landscape using only the remains of a mouse, a maple tree, a deer, a sparrow, a bullfrog, and a great white shark.

The situation may not be quite that bleak, but it's not far off.  For every one pre-Cretaceous-extinction organism we know about, there are likely to be ninety-nine we have no record of.  Which is why even after a couple of hundred years of serious fossil-chasing, we still have surprises awaiting.

Take, for example, the discovery of a fossil in Chile that was so weird that for a while, paleontologists had reconstructed it as an entirely different animal.  It was a tail that had sharp plates on either side -- clearly some kind of defensive weapon.  The plates put the researchers in mind of the stegosaurus:

[Image licensed under the Creative Commons DataBase Center for Life Science (DBCLS), 202009 Stegosaurus stenops, CC BY 4.0]

The spiky tail of the stegosaurus is called the thagomizer -- which came, I kid you not, from Gary Larson's iconic The Far Side, specifically the one with some cave men looking at a diagram of a stegosaurus.  One of them is pointing to the tail, and says, "And this is called the thagomizer, after the late Thag Simmons."  The name stuck, and the thagomizer it's been ever since.

Well, when the paleontologists looked at the new fossil, they realized that the thagomizer on this puppy was in a class by itself.  This thing could have chopped a T. rex off at the knees.  But further analysis of the rest of the skeleton showed that it wasn't a stegosaurus relative at all; it was a type of ankylosaur, a group of tank-like dinosaurs, most of which had tails ending in clubs (formidable enough weapons in and of themselves).

"It's a really unusual weapon," said Alex Vargas, of the University of Chile, who co-authored the paper on the find this week in Nature.  "Books on prehistoric animals for kids need to update and put this weird tail in there. ... It just looks crazy."

The new species was christened Stegouros elengassen.  Here's an artist's reconstruction:

[Illustration by Luis Perez Lopez]

The fossil has been dated to about seventy-five million years ago, so less than ten million years before the Chicxulub Meteorite collision ended the non-avian dinosaurs' hegemony.  And the weirdest thing about it is that it's nowhere near any of the ankylosaurs we know about; most of that group were from western North America, which at the time was separated from what is now South America by a large swath of ocean.  There's some speculation that this might be a species that had relatives in Antarctica, which was much closer, but that continent is so poorly explored no one can be certain.  In any case, it once again highlights how little we actually know about prehistoric flora and fauna.

It gets me thinking about what surprises we'd have in store if we were to go back in time to see what the Cretaceous landscape really looked like.  Not only would we be shocked at the colors and body coverings (hair, fur, feathers, etc.), which rarely ever fossilize, but there would be a stunning diversity of plants and animals that we had no idea about.  And not to end on an elegiac note, but consider what that says about our current biodiversity -- what's lost is truly lost forever, most of it lost so completely our distant descendants a million years hence (assuming there are any) would never have an inkling that it had ever existed.

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

As I've mentioned before, I love a good mystery, which is why I'm drawn to periods of history where the records are skimpy and our certainty about what actually happened is tentative at best.  Of course, the most obvious example of this is our prehistory; prior to the spread of written language, something like five thousand years ago, most of what we have to go by is fossils and the remnants of human settlements.

Still, we can make some fascinating inferences about our distant ancestors.  In Lost Civilizations of the Stone Age, by Richard Rudgely, we find out about some of the more controversial ones -- that there are still traces in modern languages of the original language spoken by the earliest humans (Rudgely calls it "proto-Nostratic"), that the advent of farming and domestication of livestock actually had the effect of shortening our average healthy life span, and that the Stone Age civilizations were far more advanced than our image of "Cave Men" suggests, and had a sophisticated ability to make art, understand science, and treat illness.

None of this relies on any wild imaginings of the sort that are the specialty of Erich von Däniken, Zecharia Sitchin, and Giorgio Tsoukalos; and Rudgely is up front with what is speculative at this point, and what is still flat-out unknown.  His writing is based in archaeological hard evidence, and his conclusions about Paleolithic society are downright fascinating.

If you're curious about what it was like in our distant past, check out Lost Civilizations of the Stone Age!

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