"So don't waste your thirst on highballs. Where did you get that lovely dress?" "Bonwit's--it's a wild extravagance." Genevieve Cranell laughed. She wore a blue woolen suit that actually looked like a wild extravagance. "You look so young, I don't suppose you'll mind if I ask how old you are." "I'm twenty-one." She rolled her eyes. "Incredible. Can anyone still be only twenty-one?" People were watching the actress. Therese was flattered, terribly flattered, and the flattery got in the way of what she felt, or might feel, about Genevieve Cranell. Miss Cranell offered her cigarette case. "For a while, I thought you might be a minor." "Is that a crime?" The actress only looked at her, her blue eyes smiling, over the flame of her lighter. Then as the woman turned her head to light her own cigarette, Therese knew suddenly that Genevieve Cranell would never mean anything to her, nothing apart from this half hour at the cocktail party, that the excitement she felt now would not continue, and not be evoked again at any other time or place. What was it that told her? Therese stared at the taut line of her blond eyebrow as the first smoke rose from her cigarette, but the answer was not there. And suddenly a feeling of tragedy, almost of regret, filled Therese. "Are you a New Yorker?" Miss Cranell asked her. "Vivy!" The new people who had just come in the door surrounded Genevieve Cranell and bore her away. Therese smiled again, and finished her drink, felt the first soothing warmth of the Scotch spreading through her. She talked with a man she had met briefly in Mr. Bernstein's office yesterday, and with another man she didn't know at all, and she looked at the doorway across the room, the doorway that was an empty rectangle at that moment, and she thought of Carol. It would be like Carol to come after all, to ask her once more. Or rather, like the old Carol, but not like this one. Carol would be keeping her appointment now at the Elysee bar. With Abby? With Stanley McVeigh? Therese looked away from the door, as if she were afraid Carol might appear, and she would have to say again, "No." Therese accepted another highball, and felt the emptiness inside her slowly filling with the realization she might see Genevieve Cranell very often, if she chose, and though she would never become entangled, might be loved herself. One of the men beside her asked, "Who did the sets for The Lost Messiah, Therese? Do you remember?" "Blanchard?" she answered out of nowhere, because she was still thinking of Genevieve Cranell, with a feeling of revulsion, of shame, for what had just occurred to her, and she knew she would never be. She listened to the conversation about Blanchard and someone else, even joined in, but her consciousness had stopped in a tangle where a dozen threads crossed and knotted. One was Dannie. One was Carol.


The Price of Salt -- Highsmith, Patricia -- d3477ce58404d2d159337a1eb92fe0db -- Anna’s Archive.11

One was Genevieve Cranell. One went on and on out of it, but her mind was caught at the intersection. She bent to take a light for her cigarette, and felt herself fall a little deeper into the network, and she clutched at Dannie. But the strong black thread did not lead anywhere. She knew as if some prognostic voice were speaking now that she would not go further with Dannie. And loneliness swept over her again like a rushing wind, mysterious as the thin tears that covered her eyes suddenly, too thin to be noticed, she knew, as she lifted her head and glanced at the doorway again. "Don't forget." Genevieve Cranell was beside her, patting her arm, saying quickly, "Six-nineteen. We're adjourning." She started to turn away and came back. "You are coming up? Harkevy's coming up, too." Therese shook her head. "Thanks, I--I thought I could, but I remember I've got to be somewhere else." The woman looked at her quizzically. "What's the matter, Therese? Did anything go wrong?" "No." She smiled, moving toward the door. "Thanks for asking me. No doubt I'll see you again." "No doubt," the actress said. Therese went into the room beside the big one and got her coat from the pile on the bed. She hurried down the corridor toward the stairs, past the people who were waiting for the elevator, among them Genevieve Cranell, and Therese didn't care if she saw her or not as she plunged down the wide stairs as if she were running away from something. Therese smiled to herself. The air was cool and sweet on her forehead, made a feathery sound like wings past her ears, and she felt she flew across the streets and up the curbs. Toward Carol. And perhaps Carol knew at this moment, because Carol had known such things before. She crossed another street, and there was the Elysee awning. The headwaiter said something to her in the foyer, and she told him, "I'm looking for somebody," and went on to the doorway. She stood in the doorway, looking over the people at the tables in the room where a piano played. The lights were not bright, and she did not see her at first, half hidden in the shadow against the far wall, facing her. Nor did Carol see her. A man sat opposite her, Therese did not know who. Carol raised her hand slowly and brushed her hair back, once on either side, and Therese smiled because the gesture was Carol, and it was Carol she loved and would always love. Oh, in a different way now, because she was a different person, and it was like meeting Carol all over again, but it was still Carol and no one else. It would be Carol, in a thousand cities, a thousand houses, in foreign lands where they would go together, in heaven and in hell. Therese waited.


The Price of Salt -- Highsmith, Patricia -- d3477ce58404d2d159337a1eb92fe0db -- Anna’s Archive.12

Then as she was about to go to her Carol saw her, seemed to stare at her incredulously a moment while Therese watched the slow smile growing, before her arm lifted suddenly, her hand waved a quick, eager greeting that Therese had never seen before. Therese walked toward her.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.1

The Rise and Fall of the Dinosaurs 1 The Dawn of the Dinosaurs Prorotodactylus Chapter Title art by Todd Marshall “BINGO,” MY FRIEND GRZEGORZ NIEDŹWIEDZKI shouted, pointing at a knife-thin separation between a slim strip of mudstone and a thicker layer of coarser rock right above it. The quarry we were exploring, near the tiny Polish village of Zachełmie, was once a source of sought-after limestone but had long been abandoned. The surrounding landscape was littered with decaying smokestacks and other remnants of central Poland’s industrial past. The maps deceitfully told us we were in the Holy Cross Mountains, a sad patch of hills once grand but now nearly flattened by hundreds of millions of years of erosion. The sky was gray, the mosquitoes were biting, heat was bouncing off the quarry floor, and the only other people we saw were a couple of wayward hikers who must have made a tragically wrong turn. “This is the extinction,” Grzegorz said, a big smile creasing the unshaven stubble of many days of fieldwork. “Many footprints of big reptiles and mammal cousins below, but then they disappear. And above, we see nothing for awhile, and then dinosaurs.” We may have been peering at some rocks in an overgrown quarry, but what we were really looking at was a revolution. Rocks record history; they tell stories of deep ancient pasts long before humans walked the Earth. And the narrative in front of us, written in stone, was a shocker. That switch in the rocks, detectable perhaps only to the overtrained eyes of a scientist, documents one of the most dramatic moments in Earth history. A brief instance when the world changed, a turning point that happened some 252 million years ago, before us, before woolly mammoths, before the dinosaurs, but one that still reverberates today. If things had unfolded a little differently back then, who knows what the modern world would be like? It’s like wondering what might have happened if the archduke was never shot. IF WE’D BEEN standing in this same spot 252 million years ago, during a slice of time geologists call the Permian Period, our surroundings would have been barely recognizable. No ruined factories or other signs of people. No birds in the sky or mice scurrying at our feet, no flowery shrubs to scratch us up or mosquitoes to feed on our cuts. All of those things would evolve later. We still would have been sweating, though, because it was hot and unbearably humid, probably more insufferable than Miami in the middle of the summer. Raging rivers would’ve been draining the Holy Cross Mountains, which were actually proper mountains back then, with sharp snowy peaks jutting tens of thousands of feet into the clouds. The rivers wound their way through vast forests of conifer trees—early relatives of today’s pines and junipers—emptying into a big basin flanking the hills, dotted with lakes that swelled in the rainy season but dried out when the monsoons ended.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.2

These lakes were the lifeblood of the local ecosystem, watering holes that provided an oasis from the harsh heat and wind. All sorts of animals flocked to them, but they weren’t animals we would know. There were slimy salamanders bigger than dogs, loitering near the water’s edge and occasionally snapping at a passing fish. Stocky beasts called pareiasaurs waddled around on all fours, their knobby skin, front-heavy build, and general brutish appearance making them seem like a mad reptilian offensive lineman. Fat little things called dicynodonts rummaged around in the muck like pigs, using their sharp tusks to pry up tasty roots. Lording over it all were the gorgonopsians, bear-size monsters who reigned at the top of the food chain, slicing into pareiasaur guts and dicynodont flesh with their saberlike canines. This cast of oddballs ruled the world right before the dinosaurs. Then, deep inside, the Earth began to rumble. You wouldn’t have been able to feel it on the surface, at least when it kicked off, right around 252 million years ago. It was happening fifty, maybe even a hundred, miles underground, in the mantle, the middle layer of the crust-mantle-core sandwich of Earth’s structure. The mantle is solid rock that is so hot and under such intense pressure that, over long stretches of geological time, it can flow like extra-viscous Silly Putty. In fact, the mantle has currents just like a river. These currents are what drive the conveyor-belt system of plate tectonics, the forces that break the thin outer crust into plates that move relative to each other over time. We wouldn’t have mountains or oceans or a habitable surface without the mantle currents. However, every once in a while, one of the currents goes rogue. Hot plumes of liquid rock break free and start snaking their way upward to the surface, eventually bursting out through volcanoes. These are called hot spots. They’re rare, but Yellowstone is an example of an active one today. The constant supply of heat from the deep Earth is what powers Old Faithful and the other geysers. This same thing was happening at the end of the Permian Period, but on a continent-wide scale. A massive hot spot began to form under Siberia. The streams of liquid rock rushed through the mantle into the crust and flooded out from volcanoes. These weren’t ordinary volcanoes like the ones we’re most used to, the cone-shaped mounds that sit dormant for decades and then occasionally explode with a bunch of ash and lava, like Mount Saint Helens or Pinatubo. They wouldn’t have erupted with the vigor of those vinegar-and-baking-soda contraptions so many of us made as science fair experiments. No, these volcanoes were nothing more than big cracks in the ground, often miles long, that continuously belched out lava, year after year, decade after decade, century after century. The eruptions at the end of the Permian lasted for a few hundred thousand years, perhaps even a few million.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.3

There were a few bigger eruptive bursts and quieter periods of slower flow. All in all, they expelled enough lava to drown several million square miles of northern and central Asia. Even today, more than a quarter billion years later, the black basalt rocks that hardened out of this lava cover nearly a million square miles of Siberia, about the same land area as Western Europe. Imagine a continent scorched with lava. It’s the apocalyptic disaster of a bad B movie. Suffice it to say, all of the pareiasaurs, dicynodonts, and gorgonopsians living anywhere near the Siberian area code were finished. But it was worse than that. When volcanoes erupt, they don’t expel only lava, but also heat, dust, and noxious gases. Unlike lava, these can affect the entire planet. At the end of the Permian, these were the real agents of doom, and they started a cascade of destruction that would last for millions of years and irrevocably change the world in the process. Dust shot into the atmosphere, contaminating the high-altitude air currents and spreading around the world, blocking out the sun and preventing plants from photosynthesizing. The once lush conifer forests died out; then the pareiasaurs and dicynodonts had no plants to eat, and then the gorgonopsians had no meat. Food chains started to collapse. Some of the dust fell back through the atmosphere and combined with water droplets to form acid rain, which exacerbated the worsening situation on the ground. As more plants died, the landscape became barren and unstable, leading to massive erosion as mudslides wiped out entire tracts of rotting forest. This is why the fine mudstones in the Zachełmie quarry, a rock type indicative of calm and peaceful environments, suddenly gave way to the coarser boulder-strewn rocks so characteristic of fast-moving currents and corrosive storms. Wildfires raged across the scarred land, making it even more difficult for plants and animals to survive. But those were just the short-term effects, the things that happened within the days, weeks, and months after a particularly large burst of lava spilled through the Siberian fissures. The longer-term effects were even more deadly. Stifling clouds of carbon dioxide were released with the lava. As we know all too well today, carbon dioxide is a potent greenhouse gas, which absorbs radiation in the atmosphere and beams it back down to the surface, warming up the Earth. The CO2 spewed out by the Siberian eruptions didn’t raise the thermostat by just a few degrees; it caused a runaway greenhouse effect that boiled the planet. But there were other consequences as well. Although a lot of the carbon dioxide went into the atmosphere, much of it also dissolved into the ocean. This causes a chain of chemical reactions that makes the ocean water more acidic, a bad thing, particularly for those sea creatures with easily dissolvable shells. It’s why we don’t bathe in vinegar.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.4

This chain reaction also draws much of the oxygen out of the oceans, another serious problem for anything living in or around water. Descriptions of the doom and gloom could go on for pages, but the point is, the end of the Permian was a very bad time to be alive. It was the biggest episode of mass death in the history of our planet. Somewhere around 90 percent of all species disappeared. Paleontologists have a special term for an event like this, when huge numbers of plants and animals die out all around the world in a short time: a mass extinction. There have been five particu larly severe mass extinctions over the past 500 million years. The one 66 million years ago at the end of the Cretaceous period, which wiped out the dinosaurs, is surely the most famous. We’ll get to that one later. As horrible as the end-Cretaceous extinction was, it had nothing on the one at the end of the Permian. That moment of time 252 million years ago, chronicled in the swift change from mudstone to pebbly rock in the Polish quarry, was the closest that life ever came to being completely obliterated. Then things got better. They always do. Life is resilient, and some species are always able to make it through even the worst catastrophes. The volcanoes erupted for a few million years, and then they stopped as the hot spot lost steam. No longer blighted by lava, dust, and carbon dioxide, ecosystems were gradually able to stabilize. Plants began to grow again, and they diversified. They provided new food for herbivores, which provided meat for carnivores. Food webs reestablished themselves. It took at least five million years for this recovery to unfold, and when it did, things were better but now very different. The previously dominant gorgonopsians, pareiasaurs, and their kin were never to stalk the lakesides of Poland or anywhere else while the plucky survivors had the whole Earth to themselves. A largely empty world, an uncolonized frontier. The Permian had transitioned into the next interval of geological time, the Triassic, and things would never be the same. Dinosaurs were about to make their entrance. AS A YOUNG paleontologist, I yearned to understand exactly how the world changed as a result of the end-Permian extinction. What died and what survived, and why? How quickly did ecosystems recover? What new types of never-before-imagined creatures emerged from the post-apocalyptic blackness? What aspects of our modern world were first forged in the Permian lavas? There’s only one way to start answering these questions. You need to go out and find fossils. If a murder has been committed, a detective begins by studying the body and the crime scene, looking for fingerprints, hair, clothing fibers, or other clues that might tell the story of what unfolded, and lead to the culprit. For paleontologists, our clues are fossils. They are the currency of our field, the only records of how long-extinct organisms lived and evolved.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.5

Fossils are any sign of ancient life, and they come in many forms. The most familiar are bones, teeth, and shells—the hard parts that form the skeleton of an animal. After being buried in sand or mud, these hard bits are gradually replaced by minerals and turned to rock, leaving a fossil. Sometimes soft things like leaves and bacteria can fossilize as well, often by making impressions in the rock. The same is sometimes true of the soft parts of animals, like skin, feathers, or even muscles and internal organs. But to end up with these as fossils, we need to be very lucky: the animal needs to be buried so quickly that these fragile tissues don’t have time to decay or get eaten by predators. Everything I describe above is what we call a body fossil, an actual part of a plant or animal that turns into stone. But there is another type: a trace fossil, which records the presence or behavior of an organism or preserves something that an organism produced. The best example is a footprint; others are burrows, bite marks, coprolites (fossilized dung), and eggs and nests. These can be particularly valuable, because they can tell us how extinct animals interacted with each other and their environment—how they moved, what they ate, where they lived, and how they reproduced. The fossils that I’m particularly interested in belong to dinosaurs and the animals that came immediately before them. Dinosaurs lived during three periods of geological history: the Triassic, Jurassic, and Cretaceous (which collectively form the Mesozoic Era). The Permian Period—when that weird and wonderful cast of creatures was frolicking alongside the Polish lakes—came right before the Triassic. We often think of the dinosaurs as ancient, but in fact, they’re relative newcomers in the history of life. The Earth formed about 4.5 billion years ago, and the first microscopic bacteria evolved a few hundred million years later. For some 2 billion years, it was a bacterial world. There were no plants or animals, nothing that could easily be seen by the naked eye, had we been around. Then, some time around 1.8 billion years ago, these simple cells developed the ability to group together into larger, more complex organisms. A global ice age—which covered nearly the entire planet in glaciers, down to the tropics—came and went, and in its aftermath the first animals got their start. They were simple at first—soft sacs of goo like sponges and jellyfish, until they invented shells and skeletons. Around 540 million years ago, during the Cambrian Period, these skeletonized forms exploded in diversity, became extremely abundant, started eating one another, and began forming complex ecosystems in the oceans. Some of these animals formed a skeleton made of bones—these were the first vertebrates, and they looked like flimsy little minnows. But they, too, continued to diversify and eventually some of them turned their fins into arms, grew fingers and toes, and emerged onto the land, about 390 million years ago.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.6

These were the first tetrapods, and their descendants include all vertebrates that live on land today: frogs and salamanders, crocodiles and snakes, and then later, dinosaurs and us. We know this story because of fossils—thousands of skeletons and teeth and footprints and eggs found all over the world by generations of paleontologists. We’re obsessed with finding fossils and notorious for going to great (and sometimes stupid) lengths to discover new ones. It could be a limestone pit in Poland or maybe a bluff behind a Walmart, a dump pile of boulders at a construction site, or the rocky walls of a ripe landfill. If there are fossils to be found, then at least some swashbuckling (or stupid) paleontologist will brave whatever heat, cold, rain, snow, humidity, dust, wind, bug, stench, or war zone stands in the way. That’s why I started going to Poland. I first visited in the summer of 2008, a twenty-four-year-old in between finishing my master’s and starting my PhD; I went to study some intriguing new reptile fossils that had been found a few years earlier in Silesia, the sliver of southwestern Poland that for years was fought over by Poles, Germans, and Czechs. The fossils were kept in a museum in Warsaw, treasures of the Polish state. I remember the buzz as I approached the capital’s central station on a delayed train from Berlin, night shadows covering the hideous Stalin-era architecture of a city rebuilt from ruins after the war. As I stepped off the train, I scanned the crowd. Somebody was supposed to be there holding a sign with my name. I arranged my visit through a series of formal e-mails with a very senior Polish professor, who badgered one of his graduate students into meeting me at the station and guiding me to the small guestroom where I would stay at the Polish Institute of Paleobiology, just a few stories above where the fossils were kept. I had no idea whom I was looking for, and because the train had been more than an hour late, I figured the student had escaped back to the lab, leaving me on my own to navigate a foreign city in the twilight, with the few words of Polish on the glossary page of my guidebook. Just as I was starting to panic, I saw a sheet of white paper flapping in the wind, my name hastily scrawled across it. The man holding it was young, with a close-cropped military hairstyle, his hairline just starting to recede like mine. His eyes were dark, and he was squinting. A thin veneer of stubble covered his face, and he seemed to be a little darker than most of the Poles I knew. Tanned, almost. There was something vaguely sinister about him, but that changed in an instant when he recognized me coming toward him. He broke into a huge smile, grabbed my bag, and gripped my hand firmly. “Welcome to Poland. My name is Grzegorz.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.7

How about some dinner?” We were both tired, I from the long train journey, Grzegorz from working the whole day describing a new batch of fossil bones that he and his crew of undergraduate assistants had just found in southeastern Poland a few weeks before, hence the field tan he was sporting. But we ended up knocking back several beers and talking for hours about fossils. This guy had the same raw enthusiasm for dinosaurs that I had, and he was full of iconoclastic ideas about what happened after the end-Permian extinction. Grzegorz and I became fast friends. For the rest of that week, we studied Polish fossils together, and then during the following four summers, I came back to Poland to do fieldwork with Grzegorz, often joined by the third musketeer in our band, the young British paleontologist Richard Butler. During that time we found a lot of fossils and came up with some new ideas about how dinosaurs got their evolutionary start in those heady days after the end-Permian extinction. Over the course of those years, I saw Grzegorz transition from an eager, but still somewhat meek, graduate student into one of Poland’s leading paleontologists. A few years before turning thirty, he discovered, in a different corner of the Zachełmie quarry, a trackway left by one of those first fishy creatures to walk out of the water and onto land, some 390 million years ago. His discovery was published on the cover of Nature, one of the world’s leading scientific journals. He was invited to a special audience with Poland’s prime minister and gave a TED talk. His steely face—not his fossil discoveries, him—graced the cover of the Polish version of National Geographic. He had become something of a scientific celebrity, but more than anything else Grzegorz enjoyed heading out into nature and looking for fossils. He called himself a “field animal,” explaining that he loved camping and hacking through brush much more than the genteel ways of Warsaw. He couldn’t help it. He grew up around Kielce, the main city of the Holy Cross Mountains region, and started collecting fossils as a child. He developed a particular talent for finding a type that many paleontologists ignore: trace fossils. Footprints, hand impressions, tail drags: the marks dinosaurs and other animals left when they moved across mud or sand, going about their daily business of hunting, hiding, mating, socializing, feeding, and loitering. He was absolutely enamored of tracks. An animal has only one skeleton, but it can leave millions of footprints, he would often remind me. Like an intelligence operative, he knew all the best places to find them. This was his backyard, after all. It was quite the backyard to grow up in, too, because it turned out that those animal-infested seasonal lakes that covered the area during the Permian and Triassic were perfect environments for preserving tracks. For four summers we indulged Grzegorz’s love of tracks.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.8

Richard and I tagged along as he led us to many of his secret sites, which were mostly abandoned quarries, bits of rock poking out of streams, and rubbish piles along the ditches of the many new roads that were being built in the area, where workmen would dump the slabs of stone they cut through when laying asphalt. We found a lot. Or rather, Grzegorz did. Both Richard and I developed an eye for the often small hand- and footprints left by lizards, amphibians, and early dinosaur and crocodile relatives, but we could never compete with the master. The thousands of tracks that Grzegorz found over his two decades of collecting, plus the pittance of new ones that Richard and I stumbled upon, ended up telling quite a story. There were many types of tracks, belonging to a whole slew of different creatures. And they didn’t come from just one moment in time, but from a sequence of tens of millions of years, beginning in the Permian, continuing across the great extinction into the Triassic, and even reaching the next stage of geological time, the Jurassic Period, which began about 200 million years ago. When the seasonal lakes dried up, they left vast mud flats that animals walked across, leaving their marks. The rivers would continuously bring in new sediment to cover up the mud flats, burying them and turning them to stone. The cycle repeated year after year after year, so there is now layer upon layer upon layer of tracks in the Holy Cross Mountains. For paleontologists this is a bonanza: an opportunity to see how animals and ecosystems were changing over time, particularly after the cataclysmic end-Permian extinction. Identifying what animals made which particular track is relatively straightforward. You compare the shape of the track to the shape of hands and feet. How many fingers or toes are there? Which ones are longest? Which way do they face? Do only the fingers and toes make an impression, or does the palm of the hand and arch of the foot also leave a mark? Are the left and right tracks really close together, as the trackmaker was walking with its limbs right under its body, or are they far apart, made by a creature with limbs sprawled out to the side? By following this checklist, you can usually figure out which general group of animals left the tracks in question. Pinpointing an exact species is almost impossible, but distinguishing the tracks of reptiles from amphibians, or dinosaurs from crocodiles, is easy enough. The Permian tracks from the Holy Cross Mountains are a diverse lot, and most were made by amphibians, small reptiles, and early synapsids, progenitors of mammals that are often annoyingly, and incorrectly, described as mammal-like reptiles (although they are not actually reptiles) in kids’ books and museum exhibits. Gorgonopsians and dicynodonts are two types of these primitive synapsids.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.9

By all accounts these latest Permian ecosystems were strong—there were many varieties of animals, some small and others more than ten feet long and weighing over a ton, living together, thriving in the arid climate along the seasonal lakes. There are, however, no signs of dinosaur or crocodile tracks in the Permian layers, or even any tracks that look like precursors to these animals. Everything changes at the Permian-Triassic boundary. Following the tracks across the extinction is like reading an arcane book in which a chapter of English follows one written in Sanskrit. The latest Permian and earliest Triassic seem to be two different worlds, which is remarkable because the tracks were all left in the identical place, in the same exact environment and climate. Southern Poland didn’t stop being a humid lakeland fed by raging mountain streams as the Permian ticked over into the Triassic. No, it was the animals themselves that changed. I get the creeps when looking at the earliest Triassic tracks. I can sense the long-distant specter of death. There are hardly any tracks at all, just a few small prints here and there, but a lot of burrows jutting deep into the rock. It seems the surface world was annihilated and whatever creatures inhabited this haunted landscape were hiding underground. Almost all of the tracks belong to small lizards and mammal relatives, probably not much larger than a groundhog. Many of the diverse tracks of the Permian are gone, particularly those made by the larger proto-mammal synapsids, and they never reappear. Things gradually start to improve as you follow the tracks up through time. More track types appear, some of the prints get larger, and burrows become rarer. The world was clearly recovering from the shock of end-Permian volcanoes. Then, about 250 million years ago, just a couple of million years after the extinction, a new type of track starts showing up. They’re small, just a few centimeters long, about the size of a cat’s paw. They are arranged in narrow trackways, the five-fingered handprints positioned in front of the slightly larger footprints, which have three long central toes flanked by a tiny toe on each side. The best place to find them is near a tiny Polish village called Stryczowice, where you can park your car at a bridge, scramble your way through thorns and bramble, and poke around the banks of a narrow stream littered with track-covered rock slabs. Grzegorz discovered the site when he was young and proudly took me there once, on a miserable July day of obscene humidity, bugs, rain, and thunder. After a few minutes of hacking through the weeds, we were soaked, my field notebook warping as ink started to run off the pages. The tracks found here go by the scientific name of Prorotodactylus. Grzegorz wasn’t quite sure what to make of them. They were certainly different from the other tracks found alongside them, and all of the tracks from the Permian.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.10

But what kind of animal made them? Grzegorz had a hunch they could have something to do with dinosaurs, because an elderly paleontologist named Hartmut Haubold had reported similar tracks from Germany in the 1960s and had argued that they were made by early dinosaurs or close cousins. But Grzegorz wasn’t sold on the idea. He had spent most of his young career studying tracks and hadn’t spent much time with actual dinosaur skeletons, so it was difficult for him to match the prints to a trackmaker. That’s where I came in. For my master’s degree, I constructed a family tree of Triassic reptiles, a genealogy showing how the first dinosaurs were related to the other animals of the time. I spent months in museum collections studying fossil bones, so I knew the anatomy of the first dinosaurs quite well. As did Richard, who wrote a PhD thesis on early dinosaur evolution. The three of us put our heads together to figure out what culprit was responsible for the Prorotodactylus tracks, and we did indeed conclude that it was a very dinosaurlike animal. We announced our interpretation in a scientific paper we published in 2010. The clues, of course, are in the details of the tracks. When I look at the Prorotodactylus trackways, the first thing that jumps out at me is that they are very narrow. There is only a little bit of space between the left and right tracks in the sequence, just a few centimeters. There’s only one way for an animal to make tracks like this: by walking upright, with the arms and legs right underneath the body. We walk upright, so when we leave footprints on the beach, the left and right ones are very close together. Same with a horse—take a look at the pattern of horseshoe impressions left by a galloping horse next time you’re on a farm (or wagering a few bucks at the track), and you’ll see what I mean. But this style of walking is actually quite rare in the animal kingdom. Salamanders, frogs, and lizards move in a different way. Their arms and legs stick out sideways from the body. They sprawl. That means their trackways are much wider, with big separation between the left and right tracks made by their spread-eagle limbs. The Permian world was dominated by sprawlers. After the extinction, however, one new group of reptiles evolved from these sprawlers but developed an upright posture—the archosaurs. This was a landmark evolutionary event. Sprawling is all well and good for cold-blooded critters that don’t need to move very fast. Tucking your limbs under your body, however, opens up a new world of possibilities. You can run faster, cover greater distances, track down prey with greater ease, and do it all more efficiently, wasting less energy as your columnar limbs move back and forth in an orderly fashion rather than twisting around like those of a sprawler.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.11

Grzegorz Niedźwiedzki examines a life-size model of the Prorotodactylus trackmaker: a proto-dinosaur very similar to the ancestor that gave rise to dinosaurs. Courtesy of Grzegorz Niedźwiedzki. A handprint overlapping a footprint of Prorotodactylus, from Poland. For scale, the handprint is about 1 inch long. Photo courtesy of the author We may never know exactly why some of these sprawlers started walking upright, but it probably was a consequence of the end-Permian extinction. It’s easy to imagine how this new getup gave archosaurs an advantage in the postextinction chaos, when ecosystems were struggling to recover from the volcanic haze, temperatures were unbearably hot, and empty niches abounded, waiting to be filled by whatever mavericks could evolve ways to endure the hellscape. Walking upright, it seems, was one of the ways in which animals recovered—and indeed, improved—after the planet was shocked by the volcanic eruptions. Not only did the new upright-walking archosaurs endure, but they thrived. From their humble origins in the traumatic world of the Early Triassic, they later diversified into a staggering variety of species. Very early, they split into two major lineages, which would grapple with each other in an evolutionary arms race over the remainder of the Triassic. Remarkably, both of these lineages survive today. The first, the pseudosuchians, later gave rise to crocodiles. As shorthand, they are usually referred to as the crocodile-line archosaurs. The second, the avemetatarsalians, developed into pterosaurs (the flying reptiles often called pterodactyls), dinosaurs, and by extension the birds that, as we shall see, descended from the dinosaurs. This group is called the bird-line archosaurs. The Prorotodactylus tracks from Stryczowice are some of the first signs of archosaurs in the fossil record, traces of the great-great-great-grandmother of this whole menagerie. Exactly what kind of archosaur was Prorotodactylus? Some peculiarities in the footprints hold important clues. Only the toes make an impression, not the metatarsal bones that form the arch of the foot. The three central toes are bunched very close together, the two other toes are reduced to nubbins, and the back end of the print is straight and razor-sharp. These may seem like anatomical minutiae, and in many ways they are. But as a doctor is able to diagnose a disease from its symptoms, I can recognize these features as hallmarks of dinosaurs and their very closest cousins. They link to unique features of the dinosaur foot skeleton: the digitigrade setup, in which only the toes make contact with the ground when walking, the very narrow foot in which the metatarsals and toes are bunched together, the pathetically atrophied outer toes, the hinge-like joint between the toes and the metatarsals, which reflects the characteristic ankle of dinosaurs and birds, which can move only in a back-and-forth direction, without even the slightest possibility of twisting. The Prorotodactylus tracks were made by a bird-line archosaur very closely related to the dinosaurs.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.12

In scientific parlance, this makes Prorotodactylus a dinosauromorph, a member of that group that includes dinosaurs and the handful of their very closest cousins, those few branches just below the bloom of dinosaurs on the family tree of life. After the evolution of the upright-walking archosaurs from the sprawlers, the origin of dinosauromorphs was the next big evolutionary event. Not only did these dinosauromorphs stand proudly on their erect limbs, but also they had long tails, big leg muscles, and hips with extra bones connecting the legs to the trunk, all of which allowed them to move even faster and more efficiently than other upright-walking archosaurs. As one of the first dinosauromorphs, Prorotodactylus is something of a dinosaur version of Lucy, the famous fossil from Africa that belongs to a very humanlike creature but is not quite a true human, a member of our species, Homo sapiens. In the same way that Lucy looks like us, Prorotodactylus would have appeared and behaved very much like a dinosaur, but it’s simply not considered a true dinosaur by convention. That’s because scientists decided long ago that a dinosaur should be defined as any members belonging to that group including the plant-eating Iguanodon and the meat-eating Megalosaurus (two of the first dinosaurs found by scientists in the 1820s) and all descendants of their common ancestor. Because Prorotodactylus did not evolve from this common ancestor, but slightly before it, it is not a true dinosaur by definition. But that’s just semantics. In Prorotodactylus we’re looking at traces left behind by the type of animal that evolved into dinosaurs. It was about the size of a house cat and would have been lucky to tip the scales at ten pounds. It walked on all fours, leaving handprints and footprints. Its limbs must have been quite long, judging from the big gaps between successive prints of the same hands and feet. The legs must have been particularly long and skinny, because the footprints often are positioned in front of the handprints, a sign that its feet were overstepping its hands. The hands were small and would have been good at grabbing things, whereas the long, compressed feet were perfect for running. The Prorotodactylus animal would have been gangly looking, with the speed of a cheetah but the awkward proportions of a sloth, perhaps not the type of animal you would expect the great Tyrannosaurus and Brontosaurus to ultimately evolve from. And it wasn’t very common either: less than 5 percent of all the tracks found at Stryczowice belong to Prorotodactylus, an indication that these proto-dinosaurs were not especially abundant or successful when they first arose. Instead, they were far outnumbered by small reptiles, amphibians, and even other types of primitive archosaurs. These rare, weird, not-quite-true-dinosaur dinosauromorphs continued to evolve as the world healed in the Early and Middle Triassic. The Polish track sites, stacked orderly in time sequence like the pages of a novel, document it all.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.13

Sites like Wióry, Pałęgi, and Baranów yield an equally unfamiliar array of dinosauromorph tracks—Rotodactylus, Sphingopus, Parachirotherium, Atreipus—which diversify over time. More and more track types show up; they get larger; they develop a greater diversity of shape, some even losing their outer toes entirely so that the center toes are all that remain. Some of the trackways stop showing impressions of the hand—these dinosauromorphs were walking on only their hind legs. By about 246 million years ago, dinosauromorphs the size of wolves were racing around on two legs, grabbing prey with their clawed hands, acting a whole lot like a pint-size version of a T. rex. They weren’t living only in Poland; their footprints are also found in France and Germany and the southwestern United States, and their bones start showing up in eastern Africa and later Argentina and Brazil. Most of them ate meat, but some of them turned vegetarian. They moved quickly, grew fast, had high metabolisms, and were active, dynamic animals compared to the lethargic amphibians and reptiles they were cohabitating with. At some point, one of these primitive dinosauromorphs evolved into true dinosaurs. It was a radical change in name only. The boundary between nondinosaurs and dinosaurs is fuzzy, even artificial, a by-product of scientific convention. The same way that nothing really changes as you cross the border from Illinois into Indiana, there was no profound evolutionary leap as one of these dog-size dinosauromorphs changed into another dog-size dinosauromorph that was just over that dividing line on the family tree that denotes dinosaurs. This transition involved the development of only a few new features of the skeleton: a long scar on the upper arm that anchored muscles to move the arms in and out, some tablike flanges on the neck vertebrae that supported stronger muscles and ligaments, and an open-window-like joint where the thighbone meets the pelvis. These were minor changes, and to be honest, we don’t really know what was driving them, but we know that the dinosauromorph-dinosaur transition wasn’t a major evolutionary jump. A far bigger evolutionary event was the origin of the swift-running, strong-legged, fast-growing dinosauromorphs themselves. The first true dinosaurs arose some time between 240 and 230 million years ago. The uncertainty reflects two problems that continue to cause me headaches but are ripe to be solved by the next generation of paleontologists. First, the earliest dinosaurs are so similar to their dinosauromorph cousins that it is hard to tell their skeletons apart, never mind their footprints. For instance, the puzzling Nyasasaurus, known from part of an arm and a few vertebrae from approximately 240-million-year-old rocks in Tanzania, may be the world’s oldest dinosaur. Or it may be just another dinosauromorph on the wrong side of the genealogical divide. The same is true of some of the Polish footprints, particularly the larger ones made by animals walking on their hind legs. Maybe some of these were made by real, true, honest-to-goodness dinosaurs.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.14

We just don’t have a good way of telling apart the tracks of the earliest dinosaurs and their closest nondinosaur relatives, because their foot skeletons are so similar. But maybe it doesn’t matter too much, as the origin of true dinosaurs was much less important than the origin of dinosauromorphs. The other, much more glaring issue is that many of the fossil-bearing rocks of the Triassic are very poorly dated, particularly those from the early to middle parts of the period. The best way to figure out the age of rocks is to use a process called radiometric dating, which compares the percentages of two different types of elements in the rock—say, potassium and argon. It works like this. When a rock cools from a liquid into a solid, minerals form. These minerals are made up of certain elements, in our case including potassium. One isotope (atomic form) of potassium (potassium-40) is not stable, but slowly undergoes a process called radioactive decay, in which it changes into argon-40 and expels a small amount of radiation, causing the beeps you’d hear on a Geiger counter. Beginning the moment a rock solidifies, its unstable potassium starts changing into argon. As this process continues, the accumulating argon gas becomes trapped inside the rock where it can be measured. We know from lab experiments the rate at which potassium-40 changes into argon-40. Knowing this rate, we can take a rock, measure the percentages of the two isotopes, and calculate how old the rock is. Radiometric dating revolutionized the field of geology in the middle of the twentieth century; it was pioneered by a Brit named Arthur Holmes, who once occupied an office a few doors down from mine at the University of Edinburgh. Today’s labs, like the ones run by my colleagues at New Mexico Tech and the Scottish Universities Environmental Research Centre near Glasgow, are high-tech, ultramodern facilities where scientists in white lab coats use multi million-dollar machines bigger than my old Manhattan apartment to date microscopic rock crystals. The techniques are so refined that rocks hundreds of millions of years old can be precisely dated to a small window of time, within a few tens or hundreds of thousands of years. These methods are so fine-tuned that independent labs routinely calculate the same dates for samples of the same rocks analyzed blindly. Good scientists check their work this way, to make sure their methodology is sound, and test after test has shown that radiometric dating is accurate. But there is one major caveat: radiometric dating works only on rocks that cool from a liquid melt, like basalts or granites that solidify from lava. The rocks that contain dinosaur fossils, like mudstone and sandstone, were not formed this way, but rather from wind and water currents that dumped sediment. Dating these types of rocks is much more difficult.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.15

Sometimes a paleontologist is lucky and finds a dinosaur bone sandwiched between two layers of datable volcanic rocks that provide a time envelope for when that dinosaur must have lived. There are other methods that can date individual crystals found in sandstones and mudstones, but these are expensive and time-consuming. This means that it’s often difficult to date dinosaurs accurately. Some parts of the dinosaur fossil record have been well dated—when there are enough interspersed volcanic rocks to give a timeline or the individual-crystal technique has been successful—but not the Triassic. There are just a handful of well-dated fossils, so we are not entirely confident of what order certain dinosauromorphs appeared in (especially when trying to compare the ages of species found in distant parts of the world) or when true dinosaurs emerged out of the dinosauromorph stock. ALL UNCERTAINTIES ASIDE, we do know that by 230 million years ago, true dinosaurs had entered the picture. The fossils of several species with unquestionable signature features of dinosaurs are found in well-dated rocks of that age. They’re found in a place far from where the earliest dinosauromorphs were cavorting in Poland—the mountainous canyons of Argentina. Ischigualasto Provincial Park, in the northeastern part of Argentina’s San Juan Province, is the type of place that just looks as though it should be bursting with dinosaurs. It’s also called Valle de la Luna—the Valley of the Moon—and you could easily imagine its being on some other planet, full of wind-sculpted hoodoos, narrow gullies, rust-covered cliffs, and dusty badlands. To the northwest are the towering peaks of the Andes, and far to the south are the dry plains that cover most of the country, where cows graze on the grass that makes Argentine beef so delicious. For centuries Ischigualasto has been an important crossing for livestock making their way from Chile to Argentina, and today many of the few people who live in the area are ranchers. This stunning landscape also happens to be the best place in the world for finding the oldest dinosaurs. That’s because the red, brown, and green rocks that have been carved and eroded into such magical shapes were formed in the Triassic, in an environment both full of life and perfect for preserving fossils. In many ways, this landscape was similar to the Polish lakelands that preserved the tracks of Prorotodactylus and other dinosauromorphs. The climate was hot and humid, although perhaps a little more arid and not pounded by such strong seasonal monsoons. Rivers snaked their way into a deep basin, occasionally bursting their banks during rare storms. Over a period of 6 million years, the rivers built up repeating sequences of sandstone, formed in the river channels, and mudstone, formed from the finer particles that escaped the river and settled out on the surrounding floodplains.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.16

Many dinosaurs frolicked on these plains, along with a wealth of other animals—big amphibians, piglike dicynodonts whose ancestors managed to make it through the end-Permian extinction, beaked plant-eating reptiles called rhynchosaurs (primitive cousins of the archosaurs) and furry little cynodonts that looked like a cross between a rat and an iguana. Floods would occasionally interrupt this paradise, killing the dinosaurs and their friends and burying their bones. The area is so heavily eroded today, and so little disturbed by buildings and roads and other human nuisances that cover up fossils, that the dinosaurs are relatively easy to find, at least compared to so many other parts of the world where we hike around for days just praying to find anything, even just a tooth. The very first discoveries here were made by cowpokes or other locals, and it wasn’t until the 1940s that scientists began to collect, study, and describe fossils from Ischigualasto, then still another few decades until intensive expeditions were launched. The first major collecting trips were led by one of the giants of twentieth-century paleontology, the Harvard professor Alfred Sherwood Romer, the man who wrote the textbook that I still use to teach my graduate students in Edinburgh. During his first trip, in 1958, Romer was already sixty-four years old and regarded as a living legend, yet there he was driving a rickety car through the badlands because he had a hunch that Ischigualasto would be the next big frontier. On that trip he found part of a skull and skeleton of a “moderately large” animal, as he so modestly put it in his field notebook. He brushed away as much rock as he could, coated the bones in newspaper, applied a coat of plaster that would harden and protect the bones, and chiseled them out of the ground. He sent the bones back to Buenos Aires, where they would be loaded on a ship to the United States, so he could carefully clean and study them in his lab. But the fossils took a detour. They were impounded for two years at the port in Buenos Aires before customs officials finally gave the go-ahead. By the time the fossils arrived at Harvard, Romer had occupied himself with other things, and it was only years later that other paleontologists recognized that the master had found the very first good dinosaur from Ischigualasto. Some Argentines weren’t so happy that a Norteamericano had come down to their neighborhood to collect fossils, which were being removed from Argentina and studied in the United States. That spurred a pair of up-and-coming homegrown scientists, Osvaldo Reig and José Bonaparte, to organize their own expeditions. They assembled a team and set out for Ischigualasto in 1959, and then again three times during the early 1960s. It was during the 1961 field season that Reig and Bonaparte’s crew met a local rancher and artist named Victorino Herrera, who knew the hills and crevasses of Ischigualasto the way an Inuit knows snow.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.17

He recalled seeing some bones crumbling out of the sandstone and led the young scientists to the spot. Herrera had found bones all right, lots of them, and clearly they were part of the back end of a dinosaur skeleton. After a few years of study, Reig described the fossils as a new species of dinosaur that he called Herrerasaurus in the rancher’s honor, a mule-size creature that could sprint on its hind legs. Later detective work showed that Romer’s impounded fossils belonged to the same animal, and future discoveries revealed that Herrerasaurus was a fierce predator with an arsenal of sharp teeth and claws, a primitive version of T. rex or Velociraptor. Herrerasaurus was one of the very first theropod dinosaurs—a founding member of that dynasty of smart, agile predators that would later ascend to the top of the food chain and ultimately evolve into birds. You might think this discovery would have encouraged paleontologists from throughout Argentina to flock to Ischigualasto in some kind of mad dinosaur rush. But it didn’t happen. After Reig and Bonaparte’s expeditions ended, things got quiet. The late 1960s and 1970s were not a prime time for dinosaur research. There was little funding and, believe it or not, little public interest. Things picked up again in the late 1980s, when a thirty-something paleontologist from Chicago named Paul Sereno put together a joint Argentine-American team of other ambitious young guns, mostly graduate students and junior professors. They set out in the footsteps of Romer, Reig, and Bonaparte, the latter meeting with the group for a few days to guide them to some of his favorite sites. The trip was a rousing success: Sereno found another skeleton of Herrerasaurus and many other dinosaurs, proving that Ischigualasto still had plenty of fossils to give up. Three years later, Sereno was at it again, bringing much of the same crew back to Ischigualasto to explore new territory. One of his assistants was a wisecracking student named Ricardo Martínez. While out prospecting one day, Martínez picked up a fist-size hunk of rock covered in a gnarly frosting of iron minerals. Just another piece of junk, he thought, but as he reached back to toss it aside, Martínez noticed something pointy and shiny sticking out of the cobble. They were teeth. Glancing back at the ground, dumbfounded, he realized that he had plucked the head off the nearly complete skeleton of a dinosaur, a long-legged, lightly built speed demon about the size of a golden retriever. They named it Eoraptor. Those teeth poking out from the skull turned out to be highly unusual: the ones in the back of the jaw were sharp and serrated like a steak knife, surely to slice through flesh, but the ones at the tip of the snout were leaf-shaped with coarse projections called denticles, the same type of tooth that some long-necked, potbellied sauropod dinosaurs would later use to grind plants.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.18

This hinted that Eoraptor was an omnivore and possibly a very early member of the sauropod lineage, a primitive cousin of Brontosaurus and Diplodocus. I met Ricardo Martínez many years later, around the time that I first laid eyes on the gorgeous skeleton of Eoraptor. I was an undergraduate student at the University of Chicago, training in Paul Sereno’s lab, when Ricardo came to work on a clandestine project, later announced as yet another new dinosaur from Ischigualasto, the terrier-size primitive theropod Eodromaeus. I took a liking to Ricardo right away. Paul was running an hour late, stuck in traffic on Lake Shore Drive, and Ricardo was literally twiddling his thumbs, hunched in the corner of the lab office. It was an incongruously disengaged posture from a man who very quickly revealed himself to be the very type of hot blooded, fast-talking, fossil-loving typhoon that I longed to be. He kind of looked like the Dude from The Big Lebowski: wild tangled hair, beard thick around the mouth, interesting fashion sense. He regaled me with stories of working in the wilds of Argentina, recounting with theatrical hand gestures how his hungry crew would sometimes hunt down stray cattle on their ATVs, delivering killing blows with the business end of their geological rock hammers. He could tell I was developing a romantic attraction to Argentina and told me to look him up if I ever came to visit. Five years later, I took him up on the offer when I attended the hardest-rocking scientific conference I’ve ever had the pleasure of speaking at. Usually conferences are fairly stale affairs, held in Marriotts and Hyatts in cities like Dallas and Raleigh, where scientists gather to listen to each other speak in cavernous banquet halls that usually host weddings, drinking overpriced hotel beer while catching up on field stories. The conference that Ricardo and his colleagues hosted in the city of San Juan was anything but. The dinner on the last evening was legendary, like one of those hedonistic house parties in a rap video. A local politician adorned with a sash opened the proceedings, managing to make an outrageous quip about some of the foreigners in attendance. The main course was a phonebook-size slab of grass-fed beef, washed down with copious amounts of red wine. After dinner was dancing, for hours, fueled by an open bar with hundreds of bottles of vodka, whiskey, brandy, and a local firewater whose name I can’t remember. At about three a.m., there was a break in the proceedings while a make-your-own taco bar was assembled outside, a tasty change from the humidity of the dance floor. We staggered back to our hotels as dawn broke. Ricardo was right. I would love Argentina. Before the debauchery of that evening, I spent several days in the collections of Ricardo’s museum, the Instituto y Museo de Ciencias Naturales in the lovely city of San Juan.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.19

Most of the riches of Ischigualasto are kept here, Herrerasaurus, Eoraptor, and Eodromaeus among them, but also many other dinosaurs. There’s Sanjuansaurus, a close cousin of Herrerasaurus that was also a fierce predator. In another drawer is Panphagia, similar to Eoraptor in being a primitive miniature cousin of the later colossal sauropods, and Chromogisaurus, a larger Brontosaurus relative that grew up to a couple of meters long and was something of a middle-of-the-food-chain plant-eater. There are also the scrappy fossils of a dinosaur called Pisanosaurus, a dog-size animal that shares some features of the teeth and jaws with the ornithischian dinosaurs—the group that would later diversify into a vast range of plant-eating species, from the horned Triceratops to the duck-billed hadrosaurs. And they’re still finding new dinosaurs in Ischigualasto, so who knows what new characters will be added if you are lucky enough to visit. As I was pulling open the specimen cabinet doors, carefully removing the fossils to measure and photograph them, I felt like something of an historian, one of those scholars who spends dark hours in the archives, scrutinizing ancient manuscripts. The analogy is deliberate, because the Ischigualasto fossils are indeed historical artifacts, primary-source objects that help us tell the story of deep prehistoric pasts, millions of years before monks started writing on parchment. The bones that Romer, Reig, and Bonaparte, and then later Paul, Ricardo, and their many colleagues, have pried from the lunar landscape of Ischigualasto are the very first records of true dinosaurs, living, evolving, and beginning their long march to dominance. These first dinosaurs weren’t quite dominant yet, overshadowed by the larger and more diverse amphibians, mammal cousins, and crocodile relatives that they lived alongside on those dry, occasionally flooded plains of the Triassic. Even Herrerasaurus probably wasn’t at the top of the food chain, ceding that title to the murderous twenty-five-foot-long crocodile-line archosaur Saurosuchus. But the dinosaurs had arrived on the scene. The three major groups—the meat-eating theropods, long-necked sauropods, and herbivorous ornithischians—had already diverged from each other on the family tree, siblings setting out to form their own broods. The skull of Eoraptor and the hand of Herrerasaurus, two of the oldest dinosaurs. Photo courtesy of the author The dinosaurs were on the march.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.1

The Rise and Fall of the Dinosaurs 2 Dinosaurs Rise Up Coelophyis Chapter Title art by Todd Marshall IMAGINE A WORLD WITH NO BORDERS. I’m not channeling John Lennon. What I mean is, envision a version of Earth where all of the land is connected together—no patchwork of continents separated by oceans and seas, just a single expanse of dry ground stretching from pole to pole. Given enough time and a good pair of shoes, you could walk from the Arctic Circle across the equator to the South Pole. If you ventured too far inland, you would find yourself many thousands of miles—tens of thousands, even—from the closest beach. But if you fancied a swim, you could take a dip in the vast ocean surrounding the big slab of land you called home and, theoretically at least, paddle from one coast all the way around the planet to the other coast without having to dry off. It may sound fanciful, but this is the world the dinosaurs grew up in. When the very first dinosaurs, like Herrerasaurus and Eoraptor, evolved from their cat-size dinosauromorph ancestors some 240 to 230 million years ago, there were no individual continents—no Australia or Asia or North America. There was no Atlantic Ocean separating the Americas from Europe and Africa, no Pacific Ocean on the flip side of the globe. Instead, there was just one huge solid unbroken mass of land—what geologists refer to as a supercontinent. It was surrounded by a single global ocean. Geography class would have been easy in those days: the supercontinent we call Pangea, and the ocean we call Panthalassa. The dinosaurs were born into what we would see as a totally alien world. What was it like to live in such a place? First, let’s think about the physical geography. The supercontinent spanned an entire hemisphere of the Triassic Earth from North Pole to South. It looked something like a gigantic letter C, with a big indentation in the middle where an arm of Panthalassa cut into the land. Towering mountain ranges snaked across the landscape at odd angles, marking the sutures where smaller blocks of crust had once collided to build the giant continent, the pieces of a jigsaw puzzle. This puzzle wasn’t put together very easily or very quickly. For hundreds of millions of years, heat deep inside the planet pushed and tugged on the many smaller continents that were home to generations of animals long before the dinosaurs, until all of the land was globbed together into one sprawling kingdom. And what about the climate? No better way to put it: the earliest dinosaurs lived in a sauna. The Earth was a whole lot warmer back in the Triassic Period than it is today. In part, that’s because there was more carbon dioxide in the atmosphere, so more of a greenhouse effect, more heat radiating across the land and sea. But the geography of Pangea exacerbated things.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.2

On one side of the globe, dry land extended from pole to pole, but on the other side, there was open ocean. That meant that currents could travel unimpeded from the equator to the poles, so there was a direct path for water baked in the low-latitude sun to heat up the high-latitude regions. This prevented ice caps from forming. Compared to today, the Arctic and Antarctic were balmy, with summer temperatures similar to those of London or San Francisco, and winter temperatures that barely inched below freezing. They were places that early dinosaurs and the other creatures with whom they shared the earth could easily inhabit. If the poles were that warm, then the rest of the world must have been a hothouse. But it’s not as though the entire planet was a desert. Once again the geography of Pangea made things much more complex. Because the supercontinent was basically centered on the equator, half the land was always scorching in the summer while the other half was cooling down in the winter. The marked temperature differences between north and south caused violent air currents to regularly stream across the equator. When the seasons changed, these currents shifted direction. That kind of thing happens today in some parts of the world, particularly India and Southeast Asia. It’s what drives the monsoons, the alternation of a dry season with a prolonged deluge of rain and nasty storms. You’ve probably seen images in the newspaper or on the nightly news: floods drowning homes, people fleeing from raging torrents, mudslides burying villages. The modern monsoons are localized, but the Triassic ones were global. They were so severe that geologists have invented a hyperbolic term to describe them: megamonsoons. Many a dinosaur was probably swept away by floodwaters or entombed by mud avalanches. But the megamonsoons also had another effect. They helped divide Pangea into environmental provinces, characterized by different amounts of precipitation, varying severity of the monsoonal winds, and different temperatures. The equatorial region was extremely hot and humid, a tropical hell that would make summer in today’s Amazon seem a trip to Santa’s workshop by comparison. Then there were vast stretches of desert, extending about 30 degrees of latitude on either side of the equator—like the Sahara, only covering a much broader swath of the planet. Temperatures here were well into the hundreds (over 35 degrees Celsius), probably all year long, and the monsoonal rains that pounded other parts of Pangea were absent here, offering little more than a trickle of precipitation. But the monsoons exerted a great impact in the midlatitudes. These areas were slightly cooler but much more wet and humid than the deserts, far more hospitable to life. Herrerasaurus, Eoraptor, and the other Ischigualasto dinosaurs lived in such a setting, smack in the middle of the midlatitude humid belt of southern Pangea. Pangea may have been a united landmass, but its treacherous weather and extreme climates gave it a dangerous unpredictability.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.3

It wouldn’t have been a particularly safe or pleasant place to call home. But the very first dinosaurs had no choice. They entered a world still recovering from the terrible mass extinction at the end of the Permian, a land subject to the violent whims of storms and the blight of blistering temperatures. So did many other new types of plants and animals that were getting their start after the mass extinction cleared the planet. All of these newbies were thrust onto an evolutionary battlefield. It was far from certain that dinosaurs were going to emerge triumphant. After all, they were small and meek creatures, nowhere near the top of the food chain during their earliest years. They were hanging around with lots of other species of small-to-midsize reptiles, early mammals, and amphibians in the middle of the food pyramid, fearful of the crocodile-line archosaurs, who held the throne. Nothing was handed to the dinosaurs. They were going to have to earn it. DURING MANY SUMMERS, I’ve journeyed deep into the subtropical arid belt of northern Pangea, on the hunt for fossils. Of course, the supercontinent itself is long gone, having gradually fractured into our modern continents during the more than 230 million years since the primeval dinosaurs started their evolutionary march. What I’ve been exploring is a remnant of old Pangea that can be found in the sunny Algarve region of Portugal, at the very southwestern corner of Europe. During those formative years when dinosaurs were navigating the megamonsoons and boiling heat waves of the Triassic, this part of Portugal was only 15 or 20 degrees north of the equator, about the same latitude as Central America today. As with so many adventures in paleontology, it was a random clue that put Portugal on my radar. After our first jaunt together in Poland, visiting Grzegorz and studying fossils of some of the dinosauromorph ancestors of dinosaurs, my British buddy Richard Butler and I developed something of an addiction. We became obsessed with the Triassic Period. We wanted to understand what the world was like when dinosaurs were still young and vulnerable. So we scoured the map of Europe looking for other places where there were accessible rocks of Triassic age, the type of sediments that could conceivably contain the fossils of dinosaurs and other animals living alongside them. Richard came across a short paper in an obscure scientific journal, describing some scraps of bone from southern Portugal that were collected by a German geology student in the 1970s. The student had been in Portugal to make a map of the rock formations, a rite of passage for all undergraduate geology majors. He had little interest in fossils, so he threw the specimens in his rucksack and hauled them back to Berlin, where they languished in a museum for nearly three decades until some paleontologists recognized them as skull pieces of ancient amphibians. Triassic amphibians. That was enough to get us excited.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.4

There were Triassic fossils in a beautiful part of Europe and nobody had been looking for them for decades. We had to go. That tip brought Richard and me to Portugal in the late summer of 2009, the hottest part of the year. We teamed up with another friend, Octávio Mateus, who wasn’t even thirty-five years old at the time but was already regarded as Portugal’s leading dinosaur hunter. Octavio grew up in a little town called Lourinhã, on the windy Atlantic coast north of Lisbon. His parents were amateur archaeologists and historians who spent weekends exploring the countryside, which just so happened to be strewn with Jurassic dinosaur fossils. The Mateus family and their ragtag band of local enthusiasts collected so many dinosaur bones, teeth, and eggs that they needed a place to put them, so when Octávio was nine years old, his parents started their own museum. Today, the Museu da Lourinhã houses one of the most important collections of dinosaurs in the world, many of which have been collected by Octávio—who went on to study paleontology and become a professor in Lisbon—and by his ever-expanding army of students, volunteers, and homegrown helpers. It was fitting that Octavio, Richard, and I set out in the August heat, because we were chasing the fossils of animals that lived in the very hottest and driest sector of Pangea. But it wasn’t very good strategy on our part. For several days, we hiked through the sun-baked hills of the Algarve, our sweat soaking the geological maps that we hoped would lead us to our treasure. We checked out nearly every speck of Triassic-age rock on the maps and relocated the site where the geology student had collected his amphibian bones, but all we saw were fossil crumbs. As our week in the field drew to a close, we were hot and exhausted, and staring down the barrel of failure. On the verge of defeat, we thought we should take one more hike in the area where the geology student made his discovery. It was a scorcher of a day, the thermometer on our handheld GPS units reaching 120 degrees Fahrenheit (50 Celsius). After an hour or so of prospecting together, we decided to split up. I stayed near the base of the hills, scrutinizing the fragments of bone scattered across the ground in a desperate attempt to trace them to their source. I had no luck. But then I heard an excited voice scream from somewhere up on the ridge. I detected a hint of a lyrical Portuguese accent, so it must have been Octávio. I rushed toward where I thought the voice was coming from, but now there was nothing but silence. Maybe I was imagining things, the heat playing tricks on my brain. Eventually I saw Octávio in the distance, rubbing his eyes like someone woken up by a phone call in the middle of the night. He was stumbling, giving off a bit of a zombie vibe.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.5

It was weird. When Octávio saw me, he gathered himself and burst into song. “I found it, I found it, I found it,” he repeated over and over. He was holding a bone. What he didn’t have was a water bottle. And suddenly it made sense. He had forgotten his water in the car, a bad thing for such a hot day, but he had happened upon the layer where the amphibian bones were coming out. The combination of exhilaration and dehydration had caused him to pass out for a moment. But now he was back into consciousness, and a few moments later, Richard had scrambled his way through the brush to join us. After exchanging excited hugs and high fives, we celebrated further by rehydrating with beers at a small café down the road. What Octávio had found was a half-meter-thick layer of mudstone full of fossil bones. We returned several times over the next few years to meticulously excavate the site, which turned out to be a chore because the bone layer seemed to extend infinitely into the hillside. I had never seen so many fossils concentrated together in one area. It was a mass graveyard. Countless skeletons of amphibians called Metoposaurus—supersize versions of today’s salamanders that were the size of a small car—were jumbled together in a chaotic mess. There must have been hundreds of them. Some 230 million years ago, a flock of these slimy, ugly monsters suddenly died when the lake they were living in dried up, collateral damage of the capricious Pangean climate. Giant amphibians like Metoposaurus were leading actors in the story of Triassic Pangea. They prowled the shores of rivers and lakes over much of the supercontinent, particularly the subtropical arid regions and midlatitude humid belts. If you were a frail little primitive dinosaur like Eoraptor, you would want to avoid the shorelines at all costs. It was enemy territory. Metoposaurus was there waiting, lurking in the shallows, ready to ambush anything that ventured too close to the water. Its head was the size of a coffee table, and its jaws were studded with hundreds of piercing teeth. Its big, broad, almost flat upper and lower jaws were hinged together at the back and could snap shut like a toilet seat to gobble up whatever it wanted. It would only take a few bites to finish off a delicious dinosaur supper. Salamanders bigger than humans seem like a mad hallucination. As bizarre as they were, though, Metoposaurus and its kin were not aliens. These terrifying predators were the ancestors of today’s frogs, toads, newts, and salamanders. Their DNA flows through the veins of the frog hopping around your garden or the one you dissected in high school biology class. As a matter of fact, many of today’s most recognizable animals can be traced back to the Triassic. The very first turtles, lizards, crocodiles, and even mammals came into the world during this time.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.6

All of these animals—so much a fabric of the Earth we call home today—rose up alongside the dinosaurs in the harsh surroundings of prehistoric Pangea. The apocalypse of the end-Permian extinction left such an empty playing field that there was space for all sorts of new creatures to evolve, which they did unabated during the 50 million years of the Triassic. It was a time of grand biological experimentation that changed the planet forever and reverberates still today. It’s no wonder many paleontologists refer to the Triassic as the “dawn of the modern world.” Excavating the Metoposaurus bone bed in Algarve, Portugal, with Octávio Mateus, Richard Butler, and our team. Photo courtesy of the author If you could put yourself into the tiny feet of our furry, mouse-size Triassic mammalian ancestors, you would be looking up at a world that was starting to show whispers of today. Yes, the physical planet itself was completely different—a supercontinent, marked by intense heat and violent weather. Nevertheless, the parts of the land not engulfed by desert were covered in ferns and pine trees. There were lizards darting around in the forest canopy, turtles paddling in the rivers, amphibians running amok, many familiar types of insects buzzing around. And there were dinosaurs, mere bit characters in this ancient scene but destined for greater things to come. AFTER SEVERAL YEARS of excavating the supersalamander mass grave in Portugal, we’ve collected a lot of bones of Metoposaurus, enough to fill the workshop in Octávio’s museum. But we’ve also found other animals that died when the prehistoric lake evaporated. We dug up part of the skull of a phytosaur, a long-snouted relative of crocodiles that hunted on land and in the water. We’ve scooped up many teeth and bones of various fishes, which were probably the primary source of food for Metoposaurus. Other small bones hint at a badger-size reptile. What we haven’t found yet are any signs of dinosaurs. It’s strange. We know dinosaurs were living south of the equator, in the humid river valleys of Ischigualasto, at the same general time that Metoposaurus was terrorizing the lakes of Triassic Portugal. We also know that many different types of dinosaurs were commingling in Ischigualasto: all of those creatures that I studied in Ricardo Martínez’s museum in Argentina. Meat-eating theropods like Herrerasaurus and Eodromaeus, primitive long-necked sauropod precursors like Panphagia and Chromogisaurus, early ornithischians (cousins of the horned and duck-billed dinosaurs). No, they weren’t at the top of the food pyramid. Yes, they were outnumbered by the jumbo amphibians and crocodile relatives, but they were at least beginning to make their mark. So why don’t we see them in Portugal? It could be, of course, that we just haven’t found them yet. Absence of evidence is not always evidence of absence, as all good paleontologists must continually remind themselves. Next time we go back into the scrublands of the Algarve and carve out another section of the bone bed, maybe we’ll find ourselves a dinosaur.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.7

However, I’m willing to bet against that, because a pattern is starting to emerge as paleontologists discover more and more Triassic fossils from around the world. Dinosaurs seem to be present and starting to slowly diversify in the temperate humid parts of Pangea, particularly in the southern hemisphere, during a slice of time from about 230 to 220 million years ago. Not only do we find their fossils in Ischigualasto, but also in parts of Brazil and India that were once in the Pangean humid zone. Meanwhile, in the arid belts closer to the equator, dinosaurs were absent or extremely rare. Just as in Portugal, there are great fossil sites in Spain, Morocco, and along the eastern coast of North America where you can find plenty of amphibians and reptiles, but nary a dinosaur. All of these places were in the parched arid sector of Pangea during those 10 million years when dinosaurs were beginning to blossom in the more bearable humid regions. It seems these first dinosaurs couldn’t handle the desert heat. It’s an unexpected story line. Dinosaurs didn’t just sweep across Pangea the moment they originated, like some infectious virus. They were geographically localized, held in place not by physical barricades but by climates they couldn’t endure. For many millions of years, it looked as if they might remain provincial rubes, stuck in one zone in the south of the supercontinent, unable to break free—an aging high school football hero of faded dreams, who could have been something if only he’d been able to get out of his tiny hometown. Underdogs—that’s what these first humidity-loving dinosaurs were. They wouldn’t have been a very impressive bunch. Not only were they trapped by the deserts, but even where they were able to eke out a living, they were barely getting by, at least at first. True, there were several dinosaur species in Ischigualasto, but these made up only about 10 to 20 percent of the total ecosystem. They were vastly outnumbered by early mammal relatives, like the pig-mimic dicynodonts that ate roots and leaves, and by other types of reptiles, most notably rhynchosaurs, which chopped plants with their sharp beaks, and crocodile cousins like the mighty apex predator Saurosuchus. At the same time but slightly to the east, in what is now Brazil, the story was much the same. There were a few different types of dinosaurs closely related to species in Ischigualasto: the carnivorous Staurikosaurus was a cousin of Herrerasaurus, and the small long-necked creature Saturnalia was very similar to Panphagia. But they were quite rare, again overwhelmed by masses of proto-mammals and rhynchosaurs. Even farther to the east, where the humid zone continued into what is now India, there were a handful of primitive long-necked sauropod relatives, like Nambalia and Jaklapallisaurus, but once again they were role players in ecosystems ruled by other species. Then, when it appeared that dinosaurs were never going to escape their rut, two important things happened that gave them an opening.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.8

First, in the humid belt, the dominant large plant-eaters, the rhynchosaurs and dicynodonts, became less common. In some areas they disappeared entirely. We don’t yet fully understand why, but the consequences were unmistakable. The fall of these herbivores gave the plant-eating primitive sauropod cousins like Panphagia and Saturnalia an opportunity to seize a new niche in some ecosystems. Before long they were the main herbivores in the humid regions of both the southern and northern hemispheres. In the Los Colorados Formation of Argentina, a unit of rock laid down from about 225 to 215 million years ago that was formed directly after the Ischigualasto dinosaurs left their fossils, the sauropod antecedents are the most common vertebrates. There are more fossils of these cow-to-giraffe-size plant-guzzlers—among them Lessemsaurus, Riojasaurus, and Coloradisaurus—than any other type of animal. In all, dinosaurs comprise about 30 percent of the ecosystem, while the once dominant mammal relatives dip below 20 percent. It wasn’t only a southern Pangean story. Across the equator in primeval Europe, then part of the Northern Hemisphere humid sector, other long-necked dinosaurs were also thriving. As in Los Colorados, they were the most common large plant-eaters in their habitats. One of these species, Plateosaurus, has been found at over fifty sites throughout Germany, Switzerland, and France. There are even mass graves like the Metoposaurus bone bed in Portugal, where dozens (or more) of Plateosauruses died together when the weather turned rough, a sign of just how many of these dinosaurs were flocking across the landscape. The second major breakthrough, around 215 million years ago, was that the first dinosaurs began arriving in the subtropical arid environments of the Northern Hemisphere, then about 10 degrees above the equator, now part of the American Southwest. We don’t know exactly why dinosaurs were now able to migrate out of their safe humid homes and into the harsh deserts. It probably had something to do with climate change—shifts in the monsoons and the amount of carbon dioxide in the atmosphere made the differences between the humid and arid regions less stark, so dinosaurs could move more easily between them. Whatever the reason, at long last dinosaurs were making inroads into the tropics, expanding into parts of the world that had previously eluded them. The best records of desert-living Triassic dinosaurs come from areas that are once again deserts today. Across much of the postcard-pretty landscape of northern Arizona and New Mexico are hoodoos, badlands, and canyons carved out of colorful red and purple rocks. These are the sandstones and mudstones of the Chinle Formation, a third-of-a-mile-thick rock sequence formed from the ancient sand dunes and oases of tropical Pangea during the last half of the Triassic, from about 225 to 200 million years ago.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.9

Petrified Forest National Park, which should be on the itinerary of any dino-loving tourist visiting the southwestern states, has one of the best exposures of the Chinle Formation, full of thousands of enormous fossilized trees that were uprooted and buried in flash floods right around the time that dinosaurs were starting to settle in the area. Some of the most exciting paleontological fieldwork over the past decade has targeted the Chinle Formation. New discoveries have painted a striking new image of what the first desert-dwelling dinosaurs were like and how they fit into their broader ecosystems. Leading the charge is a remarkable group of young researchers, who were all graduate students when they began exploring the Chinle. The core of the group is the four-man band of Randy Irmis, Sterling Nesbitt, Nate Smith, and Alan Turner. Irmis is a bespectacled introvert but a beast of a field geologist; Nesbitt is an expert on fossil anatomy who’s always wearing a baseball cap and quoting television comedy shows; Smith is a smooth-dressing Chicagoan who likes to use statistics to study dinosaur evolution; and Turner, an expert on building family trees of extinct groups, is affectionately called Little Jesus because of his flowing locks, bushy beard, and moderate stature. The quartet is a half generation ahead of me on the career path. They were working on their PhDs when I was starting to do research as an undergraduate. As a young student, I was in awe of them, as if they were a paleontology Rat Pack. They traveled in a herd at research conferences, often with other friends of theirs who worked in the Chinle: Sarah Werning, a specialist on how dinosaurs and other reptiles grew; Jessica Whiteside, a brilliant geologist who studied mass extinctions and ecosystem changes in deep time; Bill Parker, the paleontologist at Petrified Forest National Park and an expert on some of the close crocodile relatives who lived with early dinosaurs; Michelle Stocker, who studied some of the other proto-crocodiles (and whom Sterling Nesbitt later convinced to marry him—proposing on a field trip, no less—forming a different sort of Triassic dream team). They were the hotshot young scientists whom I looked up to, the type of researchers I wanted to become. For many years, the Chinle Rat Pack has been spending summers in northern New Mexico, in the pastel drylands near the tiny hamlet of Abiquiú. In the mid-1800s, this outpost was an important stop on the Old Spanish Trail, a trade route that linked nearby Santa Fe with Los Angeles. Today only a few hundred people remain, making the area feel like a remote backwater within the world’s most industrialized country. Some people like that kind of seclusion, though. One of them was Georgia O’Keeffe, the modernist American artist famous for her paintings of flowers that were intimate to the point of abstraction. O’Keeffe was also drawn to sweeping landscapes, and she was moved by the striking beauty and incomparable hues of natural light in the Abiquiú area.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.10

She bought a house nearby, on the sprawling grounds of a desert retreat called Ghost Ranch. There she could explore nature and experiment with new painting styles without being bothered by anyone. The red cliffs and colorful candy-striped canyons of the ranch, bathed in sparkling sunbursts, are common motifs in the work she produced here. After O’Keeffe died, in the mid-1980s, Ghost Ranch became a pilgrimage site for art lovers hoping to catch some of that desert spark that so inspired the old master. Few of these cultured travelers probably realize that Ghost Ranch is also bursting with dinosaur bones. But the Rat Pack knew. They understood that in 1881 a scientific mercenary named David Baldwin had been sent to northern New Mexico by the Philadelphia paleontologist Edward Drinker Cope, with the singular mission to find fossils that Cope could stick in the face of his Yale rival, Othniel Charles Marsh. The two Easterners were engaged in a bitter feud known to history as the Bone Wars (of which, more later), but by this stage of their careers, neither of them particularly liked to brave the elements and Native American war parties—Geronimo would continue raiding New Mexico and Arizona until 1886. Rather than look for fossils themselves, they relied on a network of hired guns. Baldwin was the type of character they often employed: a mysterious loner who would jump on his mule and head deep into the badlands for months at a time, even during the bleak winter, and eventually emerge loaded up with dinosaur bones. In fact, Baldwin had worked for both of the pugnacious paleontologists: he was once a trusted confidant of Marsh’s, but now his loyalties were with Cope. Thus it was Cope who was the lucky recipient of the collection of small, hollow dinosaur bones that Baldwin pried out of the desert near Ghost Ranch. These bones belonged to a totally new type of dog-size, lightweight, fast-running, sharp-toothed, primitive Triassic dinosaur Cope later called Coelophysis. Like Herrerasaurus from Argentina, which would be found many decades later, it was one of the earliest members of the theropod dynasty that would eventually produce T. rex, Velociraptor, and birds. The Chinle Rat Pack also knew that a half century after Baldwin’s discovery, another East Coast paleontologist, Edwin Colbert, took a liking to the Ghost Ranch area. He was a much more pleasant individual than Cope or Marsh. When Colbert set out for Ghost Ranch in 1947, he was in his early forties, already ensconced in one of the top jobs in the field: curator of vertebrate paleontology at New York City’s American Museum of Natural History. That summer, while O’Keeffe was painting mesas and rock sculptures only a few miles away, Colbert’s field assistant George Whitaker made an astounding discovery. He came across a Coelophysis graveyard, hundreds of skeletons in all, a pack of predators buried by a freak flood.


The rise and fall of the dinosaurs [eBook - NC Digital -- Steve Brusatte -- 1, 2018 -- William Morrow -- 9780062490421 -- 819b642fffa68675f9e07cf3af773125 -- Anna’s Archive.11

I can imagine he must have felt something similar to our unbridled joy when we found our Metoposaurus bone bed in Portugal. Overnight Coelophysis became the quintessential Triassic dinosaur, the creature that immediately came to mind when people envisioned what the earliest dinosaurs looked like, how they behaved, and what environments they lived in. For years the American Museum crew kept digging and digging, hacking out blocks of the bone bed, which were distributed to museums around the world. Odds are, if you go see a big dinosaur exhibit today, you’ll see a Ghost Ranch Coelophysis. The Chinle Rat Pack also knew of one final, and perhaps most important, clue. Because so many Coelophysis skeletons were found together, excavating the mass grave site diverted everyone’s attention for decades. It sucked up most of the money for fieldwork, most of the time and energy of the field crews. But it was merely a single site in the expanse of Ghost Ranch, tens of thousands of acres covered by fossil-rich Chinle rocks. More must have been out there. So it was no surprise to them when, in 2002, a retired forest manager named John Hayden discovered some bones while hiking less than half a mile from the main gate of Ghost Ranch. A few years later, the team of Irmis, Nesbitt, Smith, and Turner returned to the spot, got out their tools, and started digging. It took a lot of time and a lot of sweat. Once, when I was catching up with the quartet in a New York City Irish pub, Nate Smith turned to me, cocked his head up toward the ceiling, and said with a hint of cheeky machismo, “The amount of rock we removed that summer, yeah, it would fill up this bar.” But the toil was worth it. The crew confirmed that there were indeed fossil bones at the site. Then they kept finding more and more of them, hundreds, thousands. It turned out to be a river channel deposit, where currents had dumped the skeletons of many unlucky creatures swept into the water some 212 million years ago. With the right cocktail of good detective work and a drive to make their own discoveries even though they were still students, the Rat Pack had unearthed a treasure trove of Triassic fossils. The site—nicknamed the Hayden Quarry after the sharp-eyed forester who noticed the first fossil eroding out of the ground—has become one of the world’s most important Triassic fossil localities. The skull of Coelophysis, the primitive theropod found in abundance at Ghost Ranch. Courtesy of Larry Witmer. The quarry provides a snapshot of an ancient ecosystem, one of the first deserts that dinosaurs were able to live in. It wasn’t the picture the Chinle Rat Pack was expecting. When the young mavericks started digging in the mid-2000s, the prevailing wisdom was that dinosaurs conquered the deserts soon after they arrived in the Late Triassic.