"It may be the most important find in dinosaur hunting in recent years." "Previously unknown dinosaurs from a critical gap in their history." "Possible forefathers to the greatest carnivores ever to walk the Earth." "And an amazing discovery... skeletons stacked one on top of the other, piled four and five deep, in pits of death." "How did they end up together, frozen in time, for 160 million years?" "It would have been a quiet time in a dinosaur Eden." "A panorama of mysterious ancient creatures go about the business of life in the Jurassic... then grow uneasy." "The Earth begins to tremble." "The sky darkens." "Animals stampede..." "and catastrophe strikes." "In their last desperate moments, some voracious dinosaurs will turn on each other." "But in the end, they are all doomed." "The fabled Gobi Desert in north-western China." "One of the largest deserts in Asia, this arid landscape is eerily like Mars, and about as hospitable." "But for Dino hunters, it's a goldmine." "Here, time and wind and sand have scoured away the present and taken palaeontologists deep into the past, where they are meeting remarkable creatures." "Creatures that speak to them of an age that has long been silent nearly 100 million years before giants like T-Rex strode the world." "Dr. Xu Xing of the Chinese Academy of Sciences and Dr. James Clark of George Washington University are leading the search for new dinosaurs." "We targeted this area because it's a really important time period, right when the dinosaurs started to radiate and become big." "And at the same time, it's a very poorly known time period." "These fossils are very meaningful." "They will provide important information about the early evolution of dinosaurs." "Dr. Xu believes the fossils are a missing link." "For a very long time, the great jigsaw puzzle of the dinosaur record has been lacking vital pieces... right in the center of everything." "The dinosaurs made their first appearance during the Triassic, with turkey-sized predators like Coelophysis." "Then came the second age, the Jurassic, when dinosaur evolution went wild and started creating giants." "At the end comes the Cretaceous, where the giants ruled, like T-Rex and Triceratops." "But in between, in the middle of the Jurassic, there has long been a frustrating blank spot in the dinosaur record... where very few fossils have been found." "The evidence we have suggests that sometime during the middle of the Jurassic period was when dinosaurs really reached their truly gigantic sizes." "By the end of the Jurassic period, you have enormous dinosaurs... anywhere between 30 to 50, maybe to 80 tons in size, tens of times larger than the largest land animals we have today." "Lost somewhere in the blank spot in the middle of the Jurassic lies the answer to this riddle:" "how did some dinos go from this... to this?" "Clues are emerging from the rocky outcroppings of the Gobi." "Ever since excavations began here in 2001, the creatures just kept coming." "New species, most of them carnivores, and all from the lost age." "Paleontologists are stunned at the number of species they've dug up, including many previous unknown:" "A new stegosaur, those spike-backed favorites..." "A tree-grazing sauropod with a nine-meter neck..." "A new long-toothed pterosaur, a flying reptile..." "New raptors..." "Even a little mammal-like reptile." "They've also stumbled upon a remarkable mystery unlike anything they've ever seen before." "In the midst of all of the excavations, strange pits turned up where after one skeleton emerged, the scientists found another under it, and then another, and another." "Columns of death." "Some kind of catastrophe must have taken place here, catastrophe for dinosaurs, but for science, the mother lode." "Exceptionally preserved fossils, frozen in agonizing death throes." "We knew we had these interesting animals." "But then we also almost suddenly thought, well, what are they doing together?" "How in the world do you get like one skeleton, one foot above another skeleton, one foot above another?" "We call it a dinosaur death trap." "The fossil preservation is indeed very unique." "If we look at the dinosaur record from every continent on the planet, there is virtually nothing like this." "This is a very lucky find and a spectacular find." "From the first, these dinosaurs seemed different." "Some are raptors, fast-moving two legged meat-eaters." "And to find so many of them seemed too good to be true." "To learn what secrets they hold, the team sends hundreds of fossils to the labs in Beijing for autopsies." "Already, the fossils reveal glimpses of new predators, new prey, new weapons and counter weapons, new and bizarre accessories have begun to appear." "There are crests." "There are beaks." "There are boneheads." "And there are impressive spiked tails." "But the most pressing question for the scientists now, is who are the mysterious dinos in the pits, and how did they came to their demise." "Dr. Xu and Dr. Clark have enlisted geologist Dr. David Eberth to help solve this mystery." "We've collected more than 400 specimens." "Most of that comprises approximately 40 different species of dinosaur." "That's a lot of animals to find in these ecosystems." "Eberth turns his attention to the assortment of dinosaurs, to try to reconstruct how they ended up piled on top of each other in the pits of death." "When the palaeontologists first excavated the pits, they were just big blocks, about a meter wide and nearly a meter deep." "So far, they've found three pits, all with the strange stacking of dino upon dino." "Finding bone beds that just have the remains of small, meat-eating dinosaurs is extremely unusual and extremely rare and extremely exciting." "Raptors just stir the imagination." "And the raptor found on top is arousing much curiosity." "It's the largest one in the pit, about 3 meters long and weighing about 75 kilograms." "It had carnivorous dinosaur teeth, these kind of steak knife-like teeth... and then it had a crest on its head." "They dub him Guanlong, meaning crested dragon." "Who was this odd-looking creature... and why do his remains dominate the death pits?" "Guanlong's skeletal remains exposed on top of the pits show the typical S-shaped neck of a carnivorous raptor, along with the three-fingered claws and the teeth of a meat-eater." "Most exciting of all, the teeth are reminiscent of a very famous and dangerous dinosaur." "But this is just the beginning." "Underneath Guanlong the scientists find much more." "At least four more dinosaurs, also captured in three dimensions lay stacked over a meter deep." "When we first found this specimen we really had no idea of what we had." "We thought we were just collecting a single dinosaur." "And we started digging around the specimen, and on the sides of the block, we began to see the remains of yet another specimen, laying underneath the top dinosaur." "The first is another Guanlong." "A smaller one, perhaps a female, a juvenile." "Beneath that, jumbled remains of another dinosaur that they haven't yet been able to identify." "And then, two more new and mysterious creatures." "Once we got over our excitement with finding the new species, then we got excited about, well, how did they get there?" "They were suspended in the rock." "And that's very unusual." "We don't know of anything else like that in dinosaurs." "What kind of catastrophe would take down different kinds of dinosaurs?" "Dr. Eberth analyzes the clues found in the trace elements around the fossils." "He may be staring at evidence of a homicide, make that a dinocide." "The skeletal remains suggest that these deaths did not come easy, or without desperate struggle." "Twisted bodies, broken bones and grim poses litter the pits." "These animals must have been struggling in the mud." "There had to be some kind of movement that churned the mud up." "The most intriguing clue, some sharply dislocated skeletons seem to point to an "unnatural" cause of death." "Now here's a classic example of that kind of dislocation in the neck vertebrae..." "There's a very, very sharp dislocation, more then 90 degrees right here." "The only way that can occur is if some high impact force is applied." "It looks as though this carnivore had its neck snapped." "But how?" "What creature would have the nerve to break a ravenous raptor's neck?" "Perhaps they were drought victims." "Paleontologists have previously found dino bone beds where herds of plant-eaters were piled together, apparently killed by a drought and then washed up in a flood." "But if the death pit dinosaurs were flesh eaters, they would have hunted alone or in small packs." "And the number of species rules out a catastrophe descending on a single herd." "The fact that we're getting different kinds of therapods is telling us that these animals aren't part of a pack." "These animals are not coming to that deposit and being preserved in that deposit together." "There's also something that looks a lot like volcanic ash in this fossilized soil surrounding the dinosaurs." "Perhaps it was like Pompeii..." "but there are skeletons in the pits." "So something was at work other than just a volcano." "And it wasn't a flood." "What killed Guanlong and its unfortunate cohorts in the pits of death?" "Eberth has a theory." "But it's going to take some ingenuity, and a lot more knowledge about what these animals were like when they were alive and mobile." "First order of business, though, is to find a home for these creatures on the dino family tree." "That tree is essentially the history of every species of dinosaur and how it is connected and related to every other species of dinosaur." "And that's the framework we use for understanding anything about the evolution of dinosaurs." "At first glance, as we fly though the branches of the dinosaur tree, no immediate relations to Guanlong seem to pop out." "But there are ingenious ways of chasing down genealogies, of finding where the branches lead to." "With mounting excitement, the scientists compare Guanlong's well preserved skull with that of other carnivores down the line." "Something immediately jumps out:" "those teeth, with a peculiar D-shape and serrated edges." "They definitely run in the family." "And on closer inspection, Guanlong's pelvis has a large ridge in the middle of the main hip bone, also very telling." "To the paleontologists, these two traits are enough to jump across almost 100 million years and conclude:" "Guanlong is a tyrannosaur." "The tyrannosaurs ended up as gigantic animals at the end of the age of dinosaurs... with large heads, terrifying jaws and powerful bodies." "They're extraordinarily familiar, of course, because of T-Rex and its charismatic qualities... but they are a group that shares a set of characteristics." "The beginnings of the tyrannosaur tooth design are present even in Guanlong." "So something about its feeding was already similar to a T-Rex." "And so Guanlong takes up the mantle of the first of his kind, at the trunk of a formidable tree, as the earliest known ancestor in the tyrannosaur family." "A missing link from the long-lost Jurassic," "Guanlong's line may have given rise to 11 different species of tyrannosaurs, ending up with the fearsome Tyrannosaurus Rex." "But it is not the only new dinosaur found in the Gobi whose descendants have familiar names and strange shapes." "The scientists begin to track down the genealogies of the other new species discovered in this region." "These, too, come from the largely blank spot in the history of their kind and have equally important family ties." "They find a primitive ornithopod, an early beaked dinosaur who would evolve into the great duck-bills of the Cretaceous." "The scientists also uncover a primitive ceratopsian who they name Yin long." "It is the earliest known ancestor of the horned dinos, and would evolve into the mighty Triceratops, with the outlandish headgear who lived alongside Tyrannosaurus Rex." "It's quite possible that the much smaller Yin long was what Guanlong had for lunch." "There's another favourite family represented, but with a bizarre twist." "It's a stegosaur with a huge spike sticking out of each side." "We've got the oldest representatives, the oldest ancestors, if you will, to use the term very, very loosely, of these kinds of animals, and that's pretty darn exciting." "With the discovery of the Gobi dinosaurs, scientists now know more about where their gigantic descendants came from." "Also discovered nearby:" "the remains of a giant Mamenchisaurus, with a nine-meter neck, the longest of any dinosaur." "Mamenchisaurus was probably too big to tempt even Guanlong." "And then there's Junggarsuchus." "It may look like a hairless coyote but it's actually an agile land-dwelling ancestor of crocodiles, alligators and their cousins." "So many families of great reptiles are represented that, at a stroke, these dinosaurs have rewritten the history of the greatest giants ever to stride the Earth." "They draw the histories of those groups back in time." "And that's extremely helpful for us when we want to know how each of those groups evolved." "The team is working with biologists and artists to bring these new species to life." "And the resurrection of Guanlong in all of its glory will be one of the high points of the investigation, everyone wants to see it "in the flesh"." "Every single bone tells a story, but each needs to be assembled into a skeletal form first." "Then they determine how the joints connect and the range of motion they would have allowed." "From even the crudest lines representing bones and joints, computer programs can give lively impressions of how Guanlong might have moved." "Add in joints, tendons and muscle mass, and one can make a sort of cyber-Guanlong machine come alive." "It can waggle its head, gape, stick out its tongue." "Start to add in shoulders..." "hips... forearms... and legs... and the dinosaur begins to come alive." "Guanlong's potential prey, Yin long, also gives us a snapshot of dino evolution in action." "Yin long is a little ancestor of the giant dinosaurs like Triceratops." "But its head is only beginning to show the shape of things to come." "But to really know how these dinos might have behaved, paleontologists look at the biology of modern animals." "Birds, mammals, lizards, crocodiles, all share some comparable skeletal features and offer clues about the musculature of a dinosaur." "Paleobiologist Greg Erickson is eager to learn how Guanlong might have looked and moved while he was alive." "It's obviously a very athletic creature, just by looking at its body form." "The arms of Guanlong are quite long for the size of this animal." "They're about the size of my arm, with big claws." "Obviously these animals were using these to procure prey." "The powerful tyrannosaur traits are clearly beginning to appear." "What's striking though is the obvious evolutionary differences between Guanlong and his descendant, T-Rex." "He had those long arms and some serious claws." "T-Rex's arms were more like two-fingered stubs." "The interesting question is not so much what was Guanlong doing with its arms, but why did the weird arms of T-Rex evolve the way they did?" "With the discovery of Guanlong, the scientists can now see tyrannosaur evolution in action." "The forelimbs became less and less important in grabbing and grasping prey." "And instead the head and possibly the feet became more important in the actions of catching prey animals." "After years of study, analysis, reassembly, biological comparison and computer manipulation," "Guanlong is ready to walk again after 160 million years." "At about three meters long and muscular, it would have weighed about 75 kilograms, a lean mean eating machine, quick on its feet and agile as a cat." "Guanlong had the typical S-shaped neck found in most carnivorous dinosaurs, but its head was lower slung." "Its most surprising feature is the prominent crest on the top of its head." "Thin and fragile, the crest almost certainly couldn't have served a head-butting purpose." "It seems likely that the crest would have been a very visual structure." "That it would have allowed one Guanlong to recognize another Guanlong." "Guanlong, the great granddaddy of all tyrannosaurs." "Fleet of foot and equipped with impressive arms and claws." "Clearly, you wouldn't want to run into Guanlong in a dark alley... but he's relatively tiny on the tyrannosaur scale." "Somehow, the tyrannosaur family evolved from a small raptor to the nightmarish six-ton T-Rex." "T-Rex was just an enormous animal, 12.000, 15.000 pounds." "Guanlong was, you know, weighed in at the hundreds of pounds." "This is going to be a much swifter animal, much more agile at running down prey." "They probably went from being predators of relatively small animals to predators of bigger prey items with the capability of breaking even bones with their teeth." "These new Gobi dinosaurs really help us to understand that they must have started out as very small animals and evolved into very large sizes." "So we can now begin to ask well how and why did each of those groups get to be so gigantic?" "And that's the big-picture riddle of the Middle Jurassic, what super-sized the tyrannosaurs?" "For that matter, what super-sized many of the dinosaurs?" "Was this really a passive process or was there something driving them towards being very, very large?" "Right now, we simply seem to know that it happened." "Palaeontologist Dr. Matt Carrano of the Smithsonian's" "Museum of Natural History believes that whatever jump started the gigantism took place in the Middle Jurassic." "The new Gobi finds, including T-Rex ancestor Guanlong, seem to have heard the starting gun in the race to become colossal." "Something must have happened during the blank spot in the Jurassic that would transform these newly discovered ancient reptiles into behemoths." "Some have proposed that a major extinction event, like an asteroid crash or volcanoes gone wild, might have wiped out so many species that the ones left had little competition and plenty of elbow room to grow." "Geological evidence shows that there were colossal volcano eruptions at the time." "The catch, there is little evidence to show whether such a mass extinction had any effect on dinosaurs." "A second theory has to do with continental drift." "When the dinos were small, the world was all one continent, with a hot, dry climate." "But then the continents began to break apart, the climate got milder and wetter, leading to an explosion in plant life." "Could these new food sources have been the trigger?" "Perhaps." "But there may have been something else about the breakup of the continents that really revved the engines of evolution:" "isolation." "Just as the isolation of places like Australia have allowed evolution to experiment in strange new animals, so the isolation of the new continents could have caused the dinosaurs to diverge." "Normally we would think that this might keep the dinosaurs from getting big because the land areas are getting smaller." "But that's not what happens..." "They get larger and larger." "Isolation doesn't answer why anything would want to be huge in the first place." "Carrying around that heavy load required sturdier limbs and more energy." "Here are animals that are in many ways ten times bigger than the biggest land animals today, and yet they must have been subject to the same rules of physics that we have today." "Gravity hasn't changed." "The atmosphere hasn't changed very much." "And so how did they manage that?" "They're certainly structurally capable of walking and standing." "Dr. Don Henderson looks to modern animals for inspiration." "So, to study the largest land animals ever to set foot on Earth, he takes a page from the largest land animals on Earth today." "Elephants, as these large ground herbivores, are our best shot for sauropods." "Being large may have benefits:" "Large plant-eaters can get from place to place more efficiently because their strides are huge." "But they may have become big by necessity, from the tough-to-digest food they ate." "There weren't fruits and grasses like we have today." "There was a lot of low quality, very woody plant material." "And that needs a large digestive track to process it." "And to have a large digestive track, you need a large body to carry it." "Far and away, the best reason for a prey animal to become humongous may have less to do with eating, than with being eaten:" "it becomes virtually attack-proof." "If a lion is going to find a dinner, it's not going to tackle some five-ton monster." "Why not take a little 100 kilogram deer or something?" "It's just all around easier and safer." "Elephants are a great example." "Once they get past that first year of life, an elephant's really not susceptible to predation anymore." "Lions just can't kill an adult elephant." "So it makes sense for plant-eaters to become enormous." "But why didn't carnivores remain the light, agile and voracious predators of the dinosaur world?" "Hey big bomber, how are you?" "You hungry?" "Palaeobiologist Dr. Greg Erickson also studies gigantism, but he studies it from the other end of the food chain: the predators." "An animal like this can generate 2.000 pounds of bite force." "Imagine scaling this thing up to the size of Tyrannosaurus Rex, it's just mind-boggling to think about." "Crocodilians perfected their killing ways back before dinosaurs arrived on the scene, so evolution hasn't had to tinker with their design much." "And the St. Augustine Alligator Farm in Florida is the perfect place to study them." "It has every living species of crocodilian, from dwarfs to giants." "Like dinosaurs, crocodiles evolved into bigger creatures, over time." "This is the skull of a 160-million-year-old crocodilian and the thing I want you to notice is that the skull of this animal is about the same size of the head of this hatchling alligator." "This is an interesting pattern that we see in the fossil record time and time again." "Members of the Dinosauria, members of the Crocodilia, members of the Mammalia all started out off as very small organisms and only later diversified into much larger forms." "The new coyote-sized crocodilian Junggarsuchus illustrates the principle as well." "It was only one meter long." "But its supercroc descendant was 12 times longer and happy to eat gigantic dinosaurs." "Now that we have Guanlong," "Erickson can explore how tyrannosaurs became enormous." "He examines cross sections of the bones of Guanlong and its descendant T-Rex." "Like the rings in a tree, these show the animals' growth rates." "And he finds an astounding difference." "Guanlong was growing at about 50 grams per day;" "T-Rex 2.5 kilograms." "It was an animal growing at five pounds per day." "I mean, that's just mind boggling." "Just imagine how much flesh and bone that animal had to be consuming to sustain those rates." "So Guanlong provides the baseline, a starting point that paleontologists can use to see how growth rates changed as tyrannosaurs evolved into giant beasts." "If you look at the entire family tree of dinosaurs and you see the evolution of size laid onto that, one thing that's clear is that almost every different group of dinosaurs eventually becomes big." "As the prey animals got bigger, it seems so did the predators." "In the end, the real answer to what drove the super-sizing may lie in the harsh dance of eat or be eaten." "There's evidence of an arms race going on." "By getting gigantic you can escape predation;" "but as you get bigger and bigger prey items out there it opens up niches for bigger and bigger predators." "This went back and forth over millions of years, until both were really gigantic animals." "The defensive escalation of predator and prey culminated in the ultimate predator:" "T-Rex." "Its immense head and jaws, with a bite force rivaling anything seen in the animal world." "But the riddle of the stacks of predators one above the other, still remains to be solved." "How did Guanlong and its cohorts come to die in the pits of death?" "Nothing quite like the dinosaur death pits has ever been encountered before." "In the most exciting pit, two dinosaurs, possibly meat eaters, lay at the bottom, followed by an as-yet-unnamed dinosaur, and two tyrannosaurs," "Guanlong the crested dragon on top." "Finding their cause of death has not been easy." "When geologist Dr. David Eberth first examined the multi-layered corpses in the blocks, he found traces of ancient ash." "He also found that many of the skeletons were sharply dislocated, as in this apparent case of a broken neck." "It looks as though the animals had been trampled on while stuck in something gooey." "This is a point at which this skeleton was probably stepped on and folded in soft muds." "Had the ground been really hard, it's very, very difficult to preserve a specimen in three dimensions the way that this string of neck vertebrae are preserved." "But would different groups of light, agile and voracious carnivores march into a pile of goo?" "It seems from the reconstructions that they would have been strong animals, strong enough to slog through." "Perhaps ash and rain fell out of the sky, freezing the animals in their death throes, making this a true dinosaur Pompeii." "The X-ray analysis reveals that the ashy material found in the sediments from the pits was indeed volcanic." "We know that volcanoes were exploding from time to time in this area... we know that these volcanoes were nearby because some of the crystals are quite large and they wouldn't be able to travel that far in the air." "Eberth also finds evidence of giant marshes in Guanlong's home territory." "Any ash falling into it could have been a recipe for dinosaur disaster." "The sediment itself is really unusual." "The ash would have within it lots of glass, glass particles." "And those glass particles would settle down into this wetlands area creating a thick mud, a soupy mud." "The result, what you might call quickmud," "Eberth believes is just as deadly as quicksand or tar." "Could this mixture be gooey enough to trap a small, agile carnivore like Guanlong?" "We got very, very interested in whether or not this volcanic mud, this volcanic goo actually could trap a small therapod." "Time for a little muddy ingenuity." "With Don Henderson's help, Eberth concocts an unusual experiment, mixing water with volcanic ash." "What would happen if we took an animal that had a foot the size of a raptor and it walked into this soup y mixture ?" "And we scaled this foot to what we think the size of the animals that were getting trapped were." "They attach a foot to the apparatus and add weights to account for the mass of the animal." "Now we're gonna put on two 25-pound weights, which will give us a total of 120 pounds of weights, about 125 pounds for the whole apparatus." "125 pounds or 57 kilos is less than what an adult Guanlong would have weighed." "So if this "fake foot" goes through the mud easily, so would a foot of a life-size Guanlong." "Okay, so we're just gonna run her down and see what happens." "I would say that went right though." "Okay, so we 're gonna pull this thing out of here." "But removing it is a different story." "We gotta be careful we don't lift the entire pit of mud up." "If you look at the stress gauge, the number that's showing up is measuring the amount of force that it takes to remove the foot from the sediment." "It's giving us a good indication that this is pretty sticky stuff and would be difficult for you or me to pull our feet out of here." "Studies have shown that removing a human foot from quicksand could require the same amount of force that's needed to lift a medium-sized car." "This quickmud is not quite as viscous as quicksand, but the comparison is telling." "What we discovered surprised us." "We found that these muds are actually going to trap animals quite easily, more easily than we had anticipated." "What emerged is almost certainly what's known as a carnivore trap." "Such traps are extraordinarily rare in the fossil record." "The most famous one is the La Brea tar pits in California, where the viscous tar ensnared prey animals like mammoths." "Predators like saber toothed cats and dire wolves would attack the helpless animals, only to be trapped themselves." "In the case of the Gobi dinosaurs, the quickmud would have been equally fatal." "Once the first animal got trapped, then they became active predator traps." "Here is what might have happened on that distant day, nearly 100 million years before T-Rex ruled the world." "The Gobi was a primordial Eden, where swift and deadly raptors darted about in search of prey... among them, Guanlong, the crested dragon, lion of the Jurassic." "This place is lush enough to support the first true giants... like Mamenchisaurus, with its nine-meters neck." "These are beyond the appetite of even voracious Guanlong." "The smaller creatures, like Yin long, are fair game." "But something is going very wrong." "Nearby a mountain is spewing its flaming guts into the sky... hurling ash miles into the air, in all directions." "Ash rains down into the marsh, creating sticky pits." "Dinosaurs blunder into the sucking mud." "The ravenous Guanlong is not one to turn down an easy meal." "The trapped dinosaurs have no chance." "Another, bigger Guanlong, drawn by the shrieks of the dying, joins in the slaughter." "The smaller Guanlong begins to struggle against the mud, in vain." "The larger, not above cannibalism, turns on it." "In the thrashing, the adult crushes the adolescents neck." "But it, too, is doomed." "Like the smaller Guanlong, and the other dinos before it, it will die in the muck." "And time stops... freezing a stunning tableau of dinosaur death, a Jurassic Pompeii, for 160 million years." "Premature deaths for Guanlong and the other creatures, but tremendous luck for the humans who will come along eons later to find this buried treasure." "So what?" "Why is this stuff so important?" "You actually start seeing evidence for things that were happening on an hourly, daily, weekly or monthly basis, that's really giving you some spectacular insights into life in the past." "Just as the ancestors of humans, like Lucy, tell us so much about ourselves, the first ancient tyrannosaur, Guanlong, fills in a long-empty gap in the record of the great meat eaters." "I liken Guanlong to the discovery of Lucy." "Guanlong is a very important specimen because it provides a snapshot of what that ancestor looked like." "And the same goes for the other new species, like Yin long, that will become the great Triceratops." "A primitive ornithopod that will became the great duck-bills of the Cretaceous." "And Junggarsuchus, whose giant descendants would lurk in water to ambush unsuspecting prey." "They're going to fit very neatly into this blank spot we've always had, the Middle Jurassic." "And what about that larger question:" "how did dinosaurs grow gigantic and come to dominate the planet?" "Guanlong and the Gobi dinos are filling in missing pieces of this story as well." "Many prey animals of this time were getting bigger and some predators appeared to follow suit." "It seems the great evolutionary arms race had begun." "In the end, it's the remarkable slice of time captured in the sands of the Gobi that sticks in the memory:" "The stunning panorama of creatures frozen in the last moments of life and death... and opening a remarkable window on their once lost world." "It's kind of like Pompeii." "It's like you catch these animals just, you know, in time doing something..." "It really sort of provides a snapshot of the events that unfolded over a very short period of time." "This is the real Jurassic Park."