But here’s the Hitch: Who really discovered that dinosaurs had feathers?

I grew up in the 1950s and 1960s reading books about the dinosaur “orthodoxy.” According to this traditional view, the dinos died out at the end of the Cretaceous because their beloved swamps dried up and the air became too cool. But the new conditions were perfect for us quick-thinking Mammalia, so we took over, along with the other hot-blooded class, feathered birds. That was the Official Scientific View until the 1970s.

Whew! It’s hard to believe that four decades ago paleontology could be so very, very wrong.

Us versus Them. The smart hot-blooded mammal Didelphodon defies a rex. The furball is saying “Just wait till yer swamps freeze....”

Us versus Them. The smart hot-blooded mammal Didelphodon defies a
rex. The furball is saying “Just wait till yer swamps freeze…”

Today we know that Tyrannosaurus rex was not a big lizard. It was the 10,000-pound roadrunner from hell, clothed in fine feathers. Tyrannosaurs and other dino-clans ranged far north and far south and survived icy winters just fine. We mammals were kept small all through Mesozoic times because the dinos, on average, were faster on their feet, quicker in their jaws, and had better hearts and lungs. Dinos won the roles of top predator and top herbivore fair and square. The humiliating truth is that we mammals are the class that won by default, taking over only because some external event removed our dinosaurian overlords.

Face the facts friends: we are furry carpet-baggers.

Question: Who first discovered that dinosaurs were part of the hot-blooded bird family tree?

Was it Dr. Bob Bakker, your faithful curator? Aww, nice of you to ask, but the original hot-blooded-dino guy was long before my time.

How ‘bout Yale’s John Ostrom, who dug up the raptor Deinonychus in 1964 and linked raptor-dinos to the early bird Archaeopteryx?

No, he wasn’t the first. (Oddly, John fought the idea that Deinonychus had feathers.)

Was the first dino-bird chap Thomas Henry Huxley, the pugnacious defender of Darwin in the late 1860s and 1870s? Huxley, who coined the term “agnostic,” was a favorite of my advisor at Harvard, Stephen J. Gould. Huxley did point out that hips and shoulders of dinos were very bird-like, and so were feet. Therefore, Huxley argued, some sort of dinosaur-oid was the ultimate ancestor of the bird class.

But no again. Huxley was not the first to see bird-ness in the dinosaurs.

T. H. Huxley, as portrayed in Punch. Among his many jobs, Huxley served on the Board of Fisheries.

T. H. Huxley, as portrayed in Punch. Among his many jobs, Huxley
served on the Board of Fisheries.

Got your notebook ready? Here comes the answer, and it makes most museum-goers raise an eyebrow.

The true discoverer of feathered dinos was… the Reverend Edward Hitchcock, State Geologist of Massachusetts, Professor at Amherst College, philosopher and Congregationalist pastor. Hitchcock figured out that dinos were a subclass of birds as early as 1838 — four years before the term “dinosauria” was invented!

First Director, Massachusetts Geological Society, Edward Hitchcock. His wry sense of humor and boundless joy in science is evident.

First Director of the Massachusetts Geological Society, Edward Hitchcock. His
wry sense of humor and boundless joy in science is evident.

How many skeletons did Hitchcock dig up? None. Not a one. But surely his lab got many well-preserved parts of dinos, right? Nope. Only after he retired did a partial skeleton show up, blown to bits by gunpowder used to excavate a well. Hitchcock came to the fundamental truth about dinosaurs entirely from fossil trackways.

Across the pond at Oxford, Hitchcock’s colleague, the Reverend William Buckland did dig hundreds of Jurassic and Cretaceous bones and some pretty good skeletons. The Oxford fossils inspired Buckland’s student, Richard Owen, to come up with the name “dinosaur” in 1842.

Sad to say, neither Buckland nor Owen realized that their restorations of dino skeletons were, in today’s parlance, “bass ackwards” — they put a huge bone in the shoulder, giving the critters a clumsy muscle-bound look in the forequarters. They didn’t realize that their “shoulder” was really part of the hips. Hitch*, on the other hand, without a single well-preserved osseous specimen, scrutinized the footprints and got dinos correct, fore and aft.

What a guy.

“Bass Ackward” dinosaur in the 1820‘s--1860’s. The restoration done under Richard Owen, with gigantically distorted forelimbs and flat feet. Painting by Luis Ray from our “Big Golden Book of Dinosaurs”.

“Bass ackward” dinosaur in the 1820s-1860s. The restoration done
under Richard Owen, with gigantically distorted forelimbs and flat feet.
Painting by Luis Rey from our Big Golden Book of Dinosaurs.

Hitchcock and Buckland were members of the “Pious Paleontologists,” thoughtful scholars of the early 1800s who took the record of the rocks and the record of Scripture seriously. Hitch was persuaded that earth history, written in pages of shale and sandstone, would make everybody better, more intelligent citizens. He wrote a delightful book for his Congregationalist flock,The Religion of Geology probably the finest rumination of how rocks and fossils can be integrated with piety.

Hitch won the reputation as an inspiring lecturer at Amherst. Emily Dickinson, among many others, was enraptured by the stories of prehistoric New England and how the past had shaped the woodlands and gardens of the present day.

When Hitch took over the Geological Survey, the Connecticut Valley was already famous for red Jurassic rocks. Quarries were dug for paving stones, excellent for walkways, and massive sandstone blocks, ideal for constructing “brownstone” homes, college dorms and courthouses. (Alas, as coal-fired furnaces became common, acid rain ate into the Triassic-Jurassic sandstones and many brownstone monuments began crumbling in the mid-20th Century.)

Hitch and his crew found petrified remains in these beds: some fern-like fronds, stems of horsetail reeds, bits of fish and a magnificent bug, the larva of some ferocious water insect. The red rocks had petrified weather, too: some surfaces had the delicate pattern of raindrops. Others showed deep cracks produced by prolonged drying.

But the most abundant remains were tracks, thousands of them. Some of the littlest footprints were made by flat-footed, lizard-oid critters with long, supple toes in fore and hind paws. Much more common, and often of giant size, were tracks made by somebody very different — mystery animals who grew as big as elephants and shared a common body plan that kept Hitchcock’s powers of deduction busy for his entire career. It was a great quest — he was on the trail of the creatures who ruled the Jurassic world on land.

Giant mystery tracks exposed along a county road in Massachusetts, with the local farmers using the one-horsepower field vehicle to visit the site.

Giant mystery tracks exposed along a county road in Massachusetts, with
the local farmers using the one-horsepower field vehicle to visit the site.

Hitch pondered the prints made by the mystery toes. Almost two centuries before Microsoft and Apple, Hitchcock began a digital revolution, inventing new methods of deciphering the details of paws. He and his son scoured libraries for anatomical details of the class Amphibia, the class Reptilia, and the hot-blooded classes, the Mammalia and Aves. Then they ran digital experiments, chasing all manner of animals across muddy fields — including barefoot boys with cheeks of tan — so they could draw the arrangement of toes.

All this research gave the Reverend Hitchcock more insight into the animal sole than anyone had obtained before. Step by step, Hitch filled a dossier of clues that would lead him to a final identification.

Bakker - Hitch Bird Dino pt1 6

Barefoot boy track as drawn in Hitchcock’s great monograph. Little dots are raindrop impressions. Hitch found drop marks on rock slabs with the mystery monster tracks. There was no evidence, pro or con, that the boy or the monsters carried slingshots, a la Bart Simpson.

First Clue: Bipeds. Nearly all the mystery tracks, even the biggest, were made by animals walking on their hind legs alone. That was unlike the locomotion of most lizards and mammals. And unlike the way dinosaurs were restored — with huge shoulders.

Second Clue: Toe-walkers, not flat-foots. Usually there was not a trace of the heel so it must have been held high off the ground. That eliminated dinosaurs because the dinos were flat-footed — so said the brightest and best of Europe’s bone-sleuths.

Bakker - Hitch Bird Dino pt1 7

Third Clue: Long Achilles tendons. This clue was the biggie. Over 99 percent of the tracks showed nothing of the ankle and nothing of the front paw, because the mystery beasts were strict toe-walkers. But in a precious few fossils, the tracks captured the mystery animal as it squatted down on all fours to drink or sniff the earth. Marvelous. The entire backside of the ankle was pressed into the mud — the Achilles tendon wasn’t wide and flat like a lizard’s. It was gracefully elongated and slender. The front paws were tiny, five-fingered and carried short, sharp claws. Maybe there was a mark left by a stumpy tail — the track wasn’t clear on this point.

Hitchcock’s mind raced. What prehistoric monsters had ankles and front feet built that way? Not mammoths or rhinos. Those giant hairy beasts always had front feet wider than the hind, and the ankle was always short. Well then, what about frog-oids? The hopping amphibians did have long, powerful hind limbs, strong calf muscles and small hands. The thought of multi-ton froggies stomping over the Jurassic meadows was … well, weird. And exciting.

If not frogg-oids, mebbe … bandicoot-oids? Australia was famous for “low-class” mammals, the marsupials, which on average were smaller in the brain than antelope, deer and other “normal” mammalians. Kangaroos and bandicoots had enlarged rear legs with super-strong calf tendons — plus little hands. Therefore, Hitchcock had to take seriously the idea of Massachusetts being overrun by Jurassic bandicoots bouncing about, as big as bull African elephants.

The Usual Suspects: Giant prehistoric beasts who might have made the tracks.

The Usual Suspects: Giant prehistoric beasts who might have made the
tracks.

And then there was the original suggestion made about 1800 by farmers who dug tracks on their land: Maybe it was Noah’s raven. The Flood Story in Genesis says Noah released a raven from the ark to test the depth of the water. The raven didn’t come back, so Noah concluded that some bare land had appeared. The Noah reference was a joke, an i.d. offered with a chuckle. But, indeed, to the un-trained eye, the Jurassic mystery tracks did have an avian gestalt …

… and Hitchcock could feel that he was getting close to the final answer. He needed just one more new type of CSI analysis, a quantitative sole-searching that would finger the culprit and reveal, once and for all, the identity of the Jurassic rulers.

Hitchcock’s Digital Data Base -- one page of the great monograph of 1858. Paleo-podiatry would enable the Reverend to solve the mystery of the Jurassic tracks.

Hitchcock’s Digital Data Base: one page of the great monograph of
1858. Paleo-podiatry would enable the Reverend to solve the mystery of the Jurassic tracks.

The guts stop here: Delve deeper into dinosaurian intestines with Dr. Bakker

Attention all Dino-Nerds! Put Your Anatomical Expertise to Work. Prestigious Careers Await in the Field of Gastroenterology.*”

Bakker Dino Guts 1

Where the guts fit in a T. rex. The pubic bone (yellow) sticks down and won’t let the intestines expand behind the hip socket.

Often, I get approached by parents who fret over their dino-fixated kid. “You gotta help us, Doc. All she wants to do is read about fossils. Will she ever find a respectable career in the real world?”

I can reassure Mom and Dad that studying dino anatomy can lead to well-paid and honorable occupations — for instance, as a professor of anatomy or a foot surgeon or a knee specialist. Or a gastroenterologist. Being a gut doctor is becoming especially attractive now because aging yuppies are suffering from decades of intestinal abuse from spicy nachos and a misplaced reliance on gluten-free pizza.

So, adults, encourage the children to delve deeply into the dinosaurian intestines. It’s fun. It’s educational. It might pay off — big time.

T. rex was a gut-less wonder

The first step toward a visceral understanding of dinos is to face the fact that T. rex was a gut-less wonder. Consider the rexian body cavity. The space available for guts is severely limited. That’s because the intestines must stop at the pubic bone, the big prong that points straight down from the hip socket. It’s inviolable anatomical law: No intestines can be behind the pubis!

In a rex, that means all the guts are in front of the hip socket and there just isn’t a lot of room here. You might argue that rexes were forced to be pure carnivores because they needed high protein food that could be digested with a minimum weight of gastric equipment.

(Vegan advice: A gentle admonition to all my vegan friends in Boulder, Colorado: High fiber plant food demands big, complicated gut compartments, a series of vats where the fodder is soaked and softened, worked upon by microbes that secrete the enzymes needed to break down fiber. That explains why Herefords and zebras, which are consummate digesters of grass, have naturally rotund tummies. Contrary to widespread myths, we humans, when we first evolved, were not adapted to high fiber, animal-free diets. When Australopithecus evolved into our genus Homo, the size of the gut shrank dramatically. So we had to specialize in protein-rich food, such as eggs, baby birds, grubs, turtles, bunnies and antelope carcasses scavenged from unwary saber-tooth tigers — plus, of course, nutritious fruits and nuts and tasty tubers excavated with digging sticks and roasted over the fire. Fire was domesticated at about the time our guts diminished in volume. Cooking releases food value otherwise unobtainable with our small-size intestines. Today, a modern human can indeed survive on a plant-based diet but you choose your veggies carefully. And cook ‘em.)

Bakker Dino Guts 2

Fowl guts.

Chickens that don’t fall over

Now that we’ve learned the basic laws of gut size, we are ready to unlock the mystery of the balanced chicken. You’ll remember from the previous post that barnyard fowl have exquisite balance on just two legs, despite the lack of a heavy tail.

Here’s another fowl mystery: Chickens have formidable digestion. They can extract food value out of raw grains and plant fiber far better than we humans can. The secrets to balance and digestion are one in the same — the gut-wrenching development of the pubic bone. When an embryonic bird in its egg is just beginning to develop a pelvic skeleton, the pubis points down, sorta like an adult T. rex pubis does. But when the chick hatches, the pubis has rotated completely around so it points backward and the guts expand behind the thigh.

Brilliant! The pubic re-alignment has doubled the potential room for intestines. And all that new weight of intestines is behind the hips, and therefore, confers perfect balance without any sort of ponderous tail.

Pubic-wrenching is a splendid osteological trick. Some dinosaurs did exactly the same thing. Stroll past our fine duckbill skeletons. Fix your gaze on the pubic bone. It’s rotated backward, just like a four-ton version of the barnyard fowl.

The duckbills go even further in gut expansion than do most birds. The pubis and ischium (the other lower hip bones) are so extended toward the rear that the guts gain another yard or two of length and allow another couple of chambers for microbial action on the food. All those extra digestive vats would let the duckbill G.I. tract break down even the toughest, most fibrous vegetables.

Duckbills win the award for longest gut tract of any dinosaur. And, probably, had the least constipation problems.

There’s a word every dino-nerd learns in the first grade: “ornithischians”. The simple meaning is “dinos with bird-style hips,” and that denotes the many species, like duckbills, that have undergone gut-wrenching. Stegosaurs wrenched their pubes, as did Triceratops.

Make a game of it! Go through our Fossil Hall with the children seeing how many different skeletons show the backwardly-bent pubes. Make the whole family pubo-literate!

Bakker Dino Guts 3

Before and after gut-wrenching experience: Top duckbill dinosaur shows how intestines would be limited if the animal had the primitive, vertical pubis. Bottom duckbill shows the real bent-back pubis and ischium.

When I skulk around our tour guides as they talk to school groups, my rib cage swells with pride. Our docents are the best! So I want to add an advanced bit of pubic-lore here. Stegosaurs and many other gut-wrenched herbivores do something tricky, pubis-wise.

After they evolved the backward-pointing pubis, these dinosaurs grew new pubic prongs — one on each side of the rib cage — that pointed forward and outward. This new set of prongs didn’t change the gut layout at all. The new prong lies outside the body cavity. The guts lay between the left and right new prongs.

What good did the new prong do? A stout muscle probably attached to it and ran back to the thigh to help swing the hind leg forward. If your child is considering med school, tell her that this muscle is what we call in humans the “psoas.

Bakker Dino Guts 4

Colorado State dino, Stegosaurus, showing the new prong of the pubis that points forward. Don’t confuse it with the true pubis!

And now, the ultimate Darwinian inquiry into gut-wrenching, the question that earns me sour stares from all my creationist relatives (37 full cousins on one side, 97% creationists)…

Here’s the query: When did pubic-twisting happen in the evolution of birds?

The chicken diagram I used earlier works pretty good for all modern day birds — every single one of the 10,000 species. From hummingbirds to ostriches, today’s avian species have the strongly wrenched pubic shaft and the attendant elongation of all things intestinal. No modern bird has the vertical pubis and short gut of a T. rex.

Bakker Dino Guts 5

Diagram of Archaeopteryx from Heilmann’s 1926 book “Origin of Birds”, modified by me in 1958. Heilmann explained the mix of bird and pre-bird features.

Archaeopteryx surprises

When first discovered in the 1860s, the Late Jurassic Archaeopteryx was an evolutionary celebrity, a missing link combining perfectly formed avian designs with archaic dinosaurian features. The first “Archie” skeleton excavated was jumbled but it certainly looked like the long, thin pubic bone was bent back in standard bird configuration. “Archie” also possessed another definitive bird device — the lagoonal, limestone-preserved imprints of fully-formed flight feathers.

Some dino characteristics were retained too: sharp little teeth, curved claws on the fingers, separate bones in the wrist (modern birds fuse up the individual bony units), and a long bony tail. The Archie was dubbed “Ur-Vogel” in German, an event which solidified the critter’s place in nature.

“Proof that creationism is wrong and Darwin is right!” shouted many an agnostic in 1868. In fact, the chap who coined the term “agnostic,” Thomas Henry Huxley, led the charge in proclaiming birds as descendants of wee dinos. Huxley’s favorite dinosaurian was Compsognathus, the original “Chicken-Dino,” a Late Jurassic carnivore extracted from the very same lagoonal rock that produced Archaeopteryx.

The Compy skeleton was cute as a button — so small that Huxley could imagine it perched on his shoulder during debates about Darwinism. When I began reading dinosaur books in the 1950s, the Compy was still the tweensiest dino known and several kids’ stories had a pet Compy following a second grader to school.

That image was just too cutesy-pootsy, too Disney, and the Compsognathus needed a makeover to give the species gravitas. The Jurassic Park franchise of the 1980s did just that. In the first Jurassic Park book, Compys are turd-eating pack-hunters that would jump up into a crib in a children’s hospital to bite off the kid’s nose and cheeks and rest of the face. That scene definitely stripped away the excess cutesy.

In the movie Jurassic Park, the Compys were upgraded to frilled little monsters that spat narcotizing pea-soup in the face of characters before biting off their noses, cheeks and rest of their faces. That scene ripped away the excess pootsy.

Movie villains can seem especially evil when they begin as pint-sized plush toys and then metamorphose into killers. Remember Gremlins and Chucky? (Maybe the writers of Jurassic Park scripts were trying to do to Compys what Miley Cyrus did for herself — take an adorable little star and remake the image so it seems more adult and more formidable. I believe that, when you go slow-motion through the Jurassic Park movie, you can see some of the Compys twerking.)

(Be advised: Jurassic Park books and film mix and match parts from three different dinos: (1) The true Compsognathus, beloved of agnostics; (2) The enigmatic pro-compsognathids known only from incomplete Triassic specimens; and (3) The distant compy cousin, the hefty 20-footer, Dilophosaurus, from the Early Jurassic. None were poisonous. None could spit. But recent discoveries from China reveal a raptor with teeth grooved like a gila monster’s — that means poison glands dripped venom down the grooves into wounds. Cool.)

Bakker Dino Guts 6In all three real dinos that inspired the Jurassic Park Compys, the pubis pointed downward and forward, the primitive configuration for carnivorous dinos and retained in our Texas Coelophysis. No gut expansion here.

Bakker Dino Guts 7

Bambiraptor, a little raptor-type dinosaur from the Late Cretaceous. Diagram done for Dr. David Burnham and me when Bambiraptor was named. Note that the pubis is bent back just a bit.

In the 1970s, Yale’s John Ostrom rediscovered Huxley’s insights. He used the recently discovered Deinonychus and its kin to prove that raptor-type dinos had hands, feet and a tail nearly identical to what Archaeopteryx possessed. But raptors still had primitive pubic bones that were bent back just a little bit. See the raptor-pubes for yourself in our “Julie-raptor” skeleton on display at HMNS or in the Bambiraptor skeleton in the lab (come by and take a look).

So, because of its superior pubic wrenching, Archaeopteryx was entitled to be hailed as more advanced than most raptors.

That made us all happy because we could make a nifty evolutionary scenario — an early raptor-like dino, a Jurassic version of Deinonychus, evolved into an Archaeopteryx-oid and then the Archie-oid evolved into a modern bird in the Early Cretaceous. Take that, my creationist-cousins!

(By the way, don’t let TV’s South Park mislead you; the plural of “pubis” is “pubes,” and it’s pronounced “pew-bays” and not “pewbs.”)

But then came the inevitable Oops Moment. That happens whenever we get too cocky.

Our friends at the Thermopolis Dinosaur Center in central Wyoming announced they had obtained a near perfect Archaeopteryx in 2006. I rushed up to ogle it, armed with a zillion photos of all the other Archie specimens. I stared at the pubes.

The new specimen and the other best specimens showed that the simple pelvic scenario was wrong. The real, undistorted Archaeopteryx pubis pointed straight down. No backward wrenching at all. In other words, Archies had no gut expansion whatever. The Ur-Vogel was no more advanced in this one key hip feature than an allosaur or a tyrannosaur.

Bakker Dino Guts 8

A very accurate diagram of Archaeopteryx, drawn by the magisterial paleontologist Peter Wellnhofer, who is the all-time expert on Jurassic pterosaurs and birds. Note the disturbingly vertical pubis.

Dang, dang, double dang

In this one famous feature, the backward wrenching of the pubis, Archaeopteryx turns out to be less like a modern bird than Bambiraptor or Deinonychus. Gosh … nearly every ornithischian dinosaur has more advanced pubic positions than does an Archaeopteryx.

We should’ve known. Evolution hardly ever goes in a neat, straight line. The origin of birds didn’t come about as one undivided line of dinos that gets better and better, more and more like a chicken, from the Triassic through the Jurassic and then into the Cretaceous. Darwinian family trees are much more complicated and much more confusing — more like tangled blackberry bushes, full of short branches going off in all directions. There are side branches and side branches coming off the side branches.

Archaeopteryx itself couldn’t survive by being a mere ancestor; it had to fit into its local environment; it had to be adapted to its immediate surroundings. The short gut and un-wrenched pelvis worked fine. A cluster of raptor-like dinos, with minor variations in pubic slant, shared the basic Archaeopteryx blueprint — and they too thrived for millions of generations. Even in the latest part of the Cretaceous, un-wrenched guts with vertical pubes contributed to the success of little Bambiraptor type predators.

Finally, after the Cretaceous ended, all the raptor-type dinos and all the birds with vertical pubes were extinct. Now, in today’s habitats all over the world, no bird or bird-like animal operates with the un-wrenched gut. Why? Did the short gut prove inadequate somehow in the long run? Could be. But we must remember that short-gutted birds and raptor-like dinos had done very well since the Mid Jurassic to Late Cretaceous, and that’s a full 100 million years. It’s not totally true, the old adage, “No guts, no glory.”

* It’s traditional for paleontologists to teach anatomy to pre-meds. I did that for years: at Harvard, then at Johns Hopkins. Thomas Henry Huxley, who worked out relations between little dinos and birds in the 1860s, also taught courses in basic dissection. It’s even more socially acceptable to be a genuine medical doctor who also digs fossils.

True story, not a Seinfeld episode: When I visit my mom at the retirement home, she introduces me as “my son, Dr. Bakker.” All the octogenarian ladies lean forward smiling. Then, politely, they begin to ask specific questions about certain medical conditions. Mom whispers, “He’s not a real doctor…” and all the ladies lean back with a slight curl of disapproval in their smiles.

Nota bene: The new book Ten Thousand Birds, (Princeton University Press), is wicked good — best ever done on our feathered species. Beautifully written. Everyone should get a copy.

The Ghost Sharks of The Jurassic

Fish Pieced Together by Committee

Our HMNS at Sugar land exhibition on Archaeopteryx is festooned with splendid finny fossils, the ichthyological gems of the Late Jurassic. Some of the Jurassic fish were new comers, recently evolved clans that were poised to conquer the watery ecosystem. Teleosts are one such progressive group.  But there are Jurassic living fossils. These are old, old clans that had evolved a hundred million years before the Jurassic, or more. And these groups had stalled out, in evolutionary terms, changing little.

Chimaeras, the “ghost sharks,” are the most exotic of the Jurassic living fossils. The label “Chimaera” evokes the mythological critter that was put together with spare parts from many species. The real chimaera fish do seem to be constructed that way. The huge eyes and  nibbling snout look like a rabbit’s, inspiring the label “Rabbit Fish.” The front fins are huge, resembling those of a butterfly-fish. The tail is long and thin, like a rodent’s – hence another nickname “Rat-Fish.”

In fact, Chimaeras are distant cousins of sharks and rays.

Chimaeras were already an antique group by the Jurassic, with an origin going back almost to 400 million years ago. The body form had been standardized by the Coal Age, 330 million years ago. The key feeding feature was the solid, strong, stiff heads. Teleost fish gained success by loosening up face and jaw bones, so the mouth could expand. Chimaera evolution went the other way. Their skulls were solidly knit together, with jaws, face and braincase units braced against each other.

Global paleogeographic reconstruction of the Earth in the late Carboniferous (“Pennsylvanian”)
period 300 million years ago.
Creative Commons License photo credit: Dr. Ron Blakey

The solid chimaera skull was co-evolved with flat, thick teeth that could crunch and crack crabs, clams and all sorts of other hard-shelled teeth. In other words, the chimaera was the fishy equivalent of a sea-otter. For protection, chimaeras were outfitted with a sharp, tall spine at the front of their dorsal fin.

Even though they hadn’t upgraded their adaptive equipment for a long time, Jurassic chimaeras continued to succeed as  bottom-hunting predators of shellfish. And they kept on going, and going, and going….

….surviving through Period after Period. They’re still around today. In their anatomy, the modern chimaeras are barely different from the Jurassic species. But habitats have changed dramatically. Jurassic chimeras thrived in shallow water of the Solnhofen lagoons and reefs. And the earlier chimaeras too were mostly inhabitants of the shallows. Most species alive now are  deep-water specialists. The same slide from shallow to deep water happened to one group of bony fish, the coelacanths.

That’s a general evolutionary principle: fish that ranged through upper waters in the past tend to get restricted to the deep today.  Why? Maybe new predators and competitors tend to evolve first in shallow water. And thus shallow water becomes the most dangerous place for old clans who don’t evolve fast. Going deep may free the old-style fish from many of the exuberant new clans.

Maybe….

Learn more about evolution by visiting our unique collection of fossils in Archaeopteryx: Icon of Evolution, now on display at HMNS at Sugar Land.

Archaeopteryx has arrived in Sugar Land!

Last week a version of the show Archaeopteryx: Icon of Evolution‘ arrived at the Houston Museum of Natural Science at Sugar Land.  There are around 70 authentic fossils on display including the Geosaurs, Guitar Fish, several fossilized corals, insects, fish, plants and a cast of the Thermopolis Archaeoptertyx.

Check out the HMNS exhibit in Focus On: The Thermopolis Archaeopteryx [Pete Larson] from HMNS on Vimeo.

There have been lots of posts in the past year on the Archaeopteryx show here on the blog so take some time to refresh your memory on all there is to know!  And then come down the HMNS at Sugar Land to see these amazing and one of a kind pieces for yourself!