Paleontology

Ask a third grader what happened to the dinosaurs and she will tell you that an asteroid killed them all. Many adults even know what caused the demise of the dinosaurs: A massive bolide crashed into the Yucatán Peninsula in Mexico about 65 million years ago, setting in motion a series of environmental changes that killed off 60 percent of life on Earth. But if you ask people about the origin of dinosaurs 165 million years earlier, you get blank looks. Even many paleontologists have little to say about the subject.

The debate over when our ancestors first used stone tools is not over just yet. In August, researchers had reported finding scratch marks on two 3.4-million-year-old animal bones that they said were made by Australopithecus afarensis — the ancestor made famous by Lucy — scraping meat off the bones with sharp-edged stones. If true, that would push tool use back to 800,000 years earlier than previously thought.

Triceratops and its cousin Torosaurus are not hard to tell apart. Both horned dinosaurs had a giant bony frill that rose up behind the head, but Torosaurus’ frill was much longer and was adorned with giant holes that were covered by a thin layer of protein called keratin. Yet Triceratops and Torosaurus may have been more alike than scientists realized: New research suggests that the two animals were actually the same species, with Torosaurus being the adult version of Triceratops.

The only monkeys you’ll find on the islands of the Caribbean today were brought there (intentionally or not) by people. But just a few thousand years ago, thriving populations of primates existed across the Caribbean. The discovery of exceptionally well-preserved monkey bones in the Dominican Republic is helping researchers better understand the evolutionary history of these now-extinct primates.

The revolution started with a bang in 1980. For some, this revolution became a religion, even an orthodoxy. The true believers became proselytes and began to see signs supporting their viewpoint everywhere. But each time the proselytes claimed to have found yet another example in support of their “religion,” naysayers and doubters emerged. Two sides formed, each loudly castigating and questioning their opponents.

This back-and-forth ideological debate describes both the historical and still-ongoing struggle over a purported cause of mass extinctions: the meteor impact theory.

Modern birds range across the color spectrum from brilliant blue to Big Bird yellow to vibrant vermillion, so it stands to reason that feathered dinosaurs shared these colorful traits. And in fact, few paleontologists have doubted that dinosaurs were multihued beasts. But until a couple of recent finds in China, they had no real evidence. Two new studies detail the findings, which researchers say also resolve the debate over whether birds descended from dinosaurs.

About 18 million years earlier than they were thought to exist, tetrapods — vertebrates with four limbs instead of fins — walked in what is today Poland. A new study published in Nature describes tracks belonging to a tetrapod in a Polish tidal flat, dating to the Middle Devonian period, about 395 million years ago. The discovery may prompt scientists to completely reassess the environment, origins and timing of early tetrapods.

Whether dinosaurs were warm-blooded or cold-blooded has been a long-standing question in paleobiology. Now, new research on how two-legged dinosaurs walked and ran adds new evidence to the argument for warm-bloodedness, and suggests that even the earliest dinosaurs may have been warm-blooded.

In 1861, German paleontologist Christian Erich Hermann von Mayer excavated the fine-grained limestone layers of a quarry near Solnhofen, Germany. The 150-million-year-old limestone had already proven promising for finding fossils: A year earlier, von Mayer had found the imprint of a single feather preserved in the rock. But this time, he discovered something more spectacular: an entire skeleton of what appeared to be an ancient bird.

Blogging on EARTH

Darwinius — the purported primate “missing link” that made headlines last spring — is back, sort of. Scientists have now found a close cousin of the primate — and they say the new fossil is no more a missing link than Darwinius was.

The Tyrannosaurus rex — arguably the most famous dinosaur of all time — was also one of the most efficient predators to ever walk on Earth. With its powerful jaws, large eyes, strong hind limbs and even tiny arms, the T. rex was uniquely designed to swiftly run down and dispatch prey. But on Wednesday, scientists announced that those characteristic T. rex features were not as unique as once thought: A new fossil find shows that 60 million years earlier, a T.

Lillian the Albertosaur strolls through the halls of the American Museum of Natural History in New York City, glancing sideways at the skeletal model of a T. rex. She’s much prettier than the skeleton, from her textured brown skin, adorned with bright purple spots, to her slightly superior smirk. Neither dinosaur is actually alive: One is a fossil, and the other is a computer graphic superimposed on a photograph of the actual museum. But somehow, Lillian does liven the place up.

What the planet’s past mass extinctions tell us about the future of life on Earth

The crash-landing of a 10-kilometer-wide asteroid 65 million years ago made for a very bad day for dinosaurs — or one very lucky day for mammals.

About 505 million years ago, the continent that would become North America straddled the equator. With no terrestrial plants or animals, the land was a barren landscape. The warm, shallow sea bordering the continent, however, hosted a carbonated reef teeming with a diverse array of organisms, most of which were relatively small bottom-dwellers. Periodically, the animals would get washed over the reef and deposited at its base, where their bodies accumulated in the muddy sediments. Today, these creatures are beautifully preserved in the Burgess Shale.

A squirrel-sized primate that lived 47 million years ago in the rainforests of Europe may be the common ancestor of monkeys, apes and humans, according to scientists who announced the discovery of the “missing link” fossil yesterday at a press conference. The well-preserved fossil has been at the center of a whirlwind PR blitz, including a History Channel documentary airing next week and an upcoming book — yet some scientists say the bones don’t live up to the hype.

A two-year-old debate is back in the flesh — literally.

Molecular paleontologist Mary Schweitzer of North Carolina State University in Raleigh and colleagues presented evidence this week in Science that they had successfully recovered and identified collagen, a type of protein, from the femur of an 80-million-year-old hadrosaur, a duck-billed dinosaur.

A newly discovered web-footed mammal may be a “missing link” between land-based and marine pinnipeds, a group that includes seals, walruses and sea lions. The find, occurring on the 150th anniversary of Charles Darwin’s "On the Origin of Species," may shed new light on the land-to-sea animal evolutionary theory.

Or so a new fossil discovery might indicate.

March 1, 1872

Edward Drinker Cope stood before a smoke-filled audience at the American Philosophical Society in Philadelphia, Pa., on March 1, 1872. One of the nation’s leading paleontologists, Cope would present his latest fossil find: an extinct flying reptile he designated Ornithochirus. Certainly the piece would be recognized as a major contribution to the scientific understanding of ancient life. More importantly, Cope thought, he would receive credit as its discoverer.

For many years, local legend on the Indonesian island of Flores told of an elflike creature with large feet and a voracious appetite that lived alongside humans. Flores was already a mythical sort of place, featuring (now-extinct) dwarf elephants, Komodo dragons and giant rats the size of rabbits.