A new discovery of fossilized footprints of tetrapods — the earliest known vertebrates with four limbs instead of fins — is changing what scientists thought about the timing of the transition from swimming to walking vertebrates.

Whether dinosaurs were warm-blooded or cold-blooded has been a long-standing question, but new research on the biomechanics of two-legged dinosaurs adds more weight to the case for warm-bloodedness.

Paleontological finds provide evidence both for and against dinosaurian ancestry — and many evolutionary puzzles remain: How did hands become wings? Did any dinosaurs have feathers? How did birds’ unusual, highly flight-specific respiratory systems evolve? Each new dinosaur discovery seems to muddy the picture further.

Last spring, researchers claimed they had found the common ancestor of monkeys and apes, dubbed Darwinius. The discovery of another, very similar, primate fossil provides more evidence that Darwinius was no missing link after all.

A new suite of studies of a hominid fossil that pre-dates Lucy by more than a million years is challenging some thinking about the human family tree — and suggest that the last common ancestor of chimpanzees and humans was not very chimp-like at all.

Tyrannosaurus rex was one of the most efficient predators to ever walk on Earth, apparently uniquely designed to swiftly run down and kill prey. But scientists have discovered a fossil that closely resembles the powerful predator — a smaller, "mini-me" version of the T. rex that lived 60 million years earlier.

Meet ART Evolved, where lifelong dinosaur enthusiasts share two things: a fascination with dinosaurs — usually going back to early childhood — and an inclination to daydream about how to visually resurrect these and other ancient creatures, complete with skin colors, feathers and movements.

Scientists unveiled a 47 million-year-old primate fossil Tuesday that they say may be the common ancestor of monkeys, apes and humans. But does the find really live up to all the publicity?

The discovery of collagen in the fossilized bones of a hadrosaur adds new evidence that soft tissues can be recovered from fossils that are tens of millions of years old.

A newly discovered web-footed mammal may shed new light on the land-to-sea animal evolutionary theory.

Fragments of a tiny skeleton, including a skull, found on the Indonesian island of Flores in the 1990s sparked an ongoing debate: was the meter-tall skeleton a deformed modern human, or an entirely new species? "Alien from Earth" offers a compelling primer on the debate.

The lambeosaur was a puzzle of a dinosaur: an odd-looking duck-billed creature with a curious hollow crest on its head. The crest concealed complex nasal airways whose function has been a mystery — until now.

Those who study coprolites — fossilized feces — get names like Doyenne of Doo-Doo, Professor Poop or Doctor of Dung. They give talks loaded with puns and double-entendres. They don’t get taken seriously by their colleagues. But coprolites add biological information not available from any other source.