Fossil finds from the miniature to the monstrous
by Holly Hartman and Borgna Brunner
Recent years have been a news bonanza for dinosaur fans. With the discovery of fossils great and small, scientists have broken new ground in their quest to understand the amazing creatures that roamed our planet millions of years ago. And that won't be all?it's estimated that less than 1 percent of all dinosaur species have been discovered.
One scary crocodile
Length: 10?13 ft.
Scientists have found the fossil skull of a 135-million-year-old sea crocodile they've nicknamed "Godzilla." The fossil has been given the scientific name Dakosaurus andiniensis. This fearsome creature was very different from other crocodile species. Marine crocodiles have long snouts and many sharp teeth, but "Godzilla's" head and teeth looked more like T. rex's than his modern cousin's. This ancient crocodile also had flippers instead of legs and a tail like a fish's to propel it through the ocean.
The discovery was made in Patagonia, an area of Argentina that was once under the Pacific Ocean. Crocodiles today live in swamps and on river banks but "Godzilla" spent its whole life in the sea. At about 13 feet long, it wasn't the largest sea crocodile known but its fierce teeth indicate that it chomped chunks out of larger sea creatures rather than nibbling the small fish that other sea-living crocodiles ate.
"I'm sure it wasn't nice," said Diego Pol, a member of the research team. "A top predator role in the food chain."
Other "monsters" living in the seas around this time include the 75-foot-long ichthysaur and the long-necked plesiosaur that resembled the Loch Ness monster. When all these creatures died out with the dinosaurs, whales took their place in the oceans.
Maybe not so tough after all
Length: 30 feet
Paleontologist Jack Horner is challenging conventional notions of T. rex as a savage predator. Horner argues that T. rex was not a hunter but a scavenger, a creature that eats animals it finds already dead?usually the remains of what another animal has killed. Horner believes that T. rex was too slow, its forelegs were too short, and its eyes were too small to make it an effective predator. Most likely, Horner maintained, T. rex simply bullied or scared away carnivorous dinosaurs after they had killed their prey and then stole their food.
Horner is sorry his theory about T. rex has tarnished the image of the fierce king of the dinosaurs. "Almost every kid, almost everybody in the world, hates the idea of T. rex being a scavenger," said Horner. Jack Horner is one of the world's most famous paleontologists. He has made many dinosaur discoveries, including finding the first dinosaur eggs in the Americas, discovering and naming two species of dinosaurs, and serving as technical adviser to Stephen Spielberg on the movie Jurassic Park and Lost World. The paleontologist in Jurassic Park, Alan Grant, is believed to have been based on Jack Horner.
Feasted on friend and foe alike
Length: 30 feet
Scientists studying dinosaur bones found on the African island nation of Madagascar have discovered a dinosaur who wasn't just an ordinary carnivore?this creature was a cannibal! Scientists believe that the 65-million-year-old Majungatholus atopus, a two-legged dinosaur from the Cretaceous period, sometimes ate others of its own kind. Scientists drew this conclusion after examining the chewed and gnarled bones belonging to the Majungatholus. The distinct tooth marks on the bones perfectly matched the teeth of another Majungatholus skull found nearby, leading the scientists to conclude that the Majungatholus not only ate other dinosaurs, but feasted on members of its own species. Before drawing this conclusion, the scientists examined the jaws and teeth of other carnivorous dinosaurs living in Madagascar at the time. "With these other candidates eliminated, Majungatholus atopus stands accused of cannibalism and is presumed guilty until proven innocent, which, in my opinion, is unlikely to happen," said one of the scientists, David Krause. This is the first genuine evidence that a dinosaur species practiced cannibalism. According to the journal Nature, the Majungatholus is hardly the only cannibal in the animal kingdom. Today cannibalism is practiced by a variety of creatures, ranging from mice to lions.
A beautiful mix of dinosaur and bird
Scientists have uncovered the fossil of a new species of flying dinosaur in northeastern China thought to have existed 120 million years ago. The Chinese team that discovered the dinosaur has named it Microraptor gui in honor of Chinese paleontologist Gu Zhiwei. It is a predatory carnivore related to the Tyrannosaurus rex, though much smaller?from head to tail the tiny raptor measures just 30 inches.
Microraptor gui is the first dinosaur ever discovered to have four wings, and the fossil indicates that the dinosaur was covered with feathers. Scientists believe the creature may have lived in trees, perhaps gliding from branch to branch. Scientists hope this dinosaur may prove the link between dinosaurs and birds?some scientists have hypothesized that birds evolved directly from dinosaurs, but thus far there hasn't been enough evidence to prove this. "It is a beautiful mix of dinosaur and bird . . . It's so unique," commented Paleontogist Nick Czaplewski of the Sam Noble Oklahoma Museum of Natural History. "It's a very interesting critter no matter how it's classified."
The largest meat-eater
Weight: 18,000 pounds
Found in the desert of Patagonia, this creature is the largest meat-eater ever discovered. It is even longer than the 41-foot-long Gigantosaurus and the 40-foot-long Tyrannosaurus rex. This as-yet-unnamed giant probably looked a lot like T. rex but with a pointy, scissorslike jaw. "I think it would have been terrifying," said one of the excavators. A number of these massive meat-eaters?both adults and youngsters?were found together, possibly drowned. The grouping was a surprise to scientists who had thought that meat-eating dinosaurs traveled alone. They now wonder if the dangerous carnivores in fact hunted as a pack, ganging up on much larger plant-eaters.
Our Tiniest Ancestor
The smallest primate
Weight: 1/2 ounce
Its foot bones are the size of grains of rice, and it weighs less than a dozen paperclips. Yet the miniature "Dawn Monkey" could represent an evolutionary link between lower primates and higher primates, a group that includes apes and humans. The structure of its tiny ankle bones suggest that it could walk flat footed, using all four legs, like advanced primates. Unlike advanced primates, however, it probably "didn't have a lot of time to be social," guesses one scientist. That's because the little animal had to spend most of its time eating to feed its high-speed metabolism?when it wasn't trying to avoid being eaten by bigger creatures. The discovery of this specimen in Asia suggests that our earliest ancestors did not live in Africa alone, as previously thought.
A Giant Vegetarian
The longest of them all
Weight: 20,000 pounds
In a remote desert area of Argentina, a villager found the remains of what is believed to be the world's longest dinosaur. Like Brontosaurus and other plant-eating dinosaurs, this giant creature probably had a small head and a very long neck and tail. But it is at least 25 feet longer than Seismosaurus, which was previously believed to be the largest dinosaur. The lonely region where it was discovered has turned out to be a hotbed of dinosaur fossils. "In Patagonia, walking among the rocks is enough to discover fossils," says a researcher in the area. As they discover ever-larger dinosaurs, it gets harder for scientists to name each massive beast?unfortunately for this unnamed hulker, Gigantosaurus, Supersaurus, and Ultrasaurus are already taken.
Careful Feeding this Baby
The most complete young T. Rex
Weight: 1350 pounds
This baby Tyrannosaurus rex, a male, was probably one-quarter the size of its parents, and was still young enough that its spine was not fully developed. Like other youngsters, it had long, gangly legs. But even as a baby it had the bone-crushing jaws of an adult. This suggests that even though a Kid Rex would not have been strong enough to tackle large prey, it ate an adult diet supplied by its parents. This 66-million-year-old baby, nicknamed "Tinker," died with half a duck-billed Platypus in his belly. With a skeleton that could be 90 percent complete, researchers hope to gain new understanding of the T. rex's life cycle. "You're getting a window into the childhood of the world's favorite dinosaur," says one paleontologist. It wasn't an easy childhood?this youngster appears to have been chewed up by a larger dinosaur, perhaps a confused parent.
The earliest dinosaurs
Jawbones of the two oldest dinosaurs ever found were discovered by a boy on the African island of Madagascar. These prosauropods (early plant-eaters) are estimated to be 230 million years old. Because scientists know so little about that era?when not only dinosaurs but mammals developed?they hope the find will help them to unravel the mysteries of dinosaur evolution. The two plant-eaters are about the size of young cows and probably used their front legs to rummage through plants on the ground, though they could also run on all four legs. Over the next ten or so million years, these little creatures evolved into the huge sauropods we think of when we hear the word dinosaur. "How they got so big so fast is an interesting question," said a scientist working on the find.