Fossils

The creatures had heads like crocodiles and tails like fish.

They predate mammals, dinosaurs, and even fish.

This was from long before the dinosaurs.

These rocks formed at the bottom of ancient lake beds between three and four billion years ago, when the Martian surface was abundant in water and its climate was warmer.

The asteroid and its after-effects ushered in a great extinction event that wiped out some three quarters of all plant and animal life, including dinosaurs and most birds.

Around 550 million to 540 million years ago, there was a remarkable explosion in the diversity and complexity of animal life on Earth.

Researchers say the fossil underscores how little we know about these mysterious ancient beasts.

The fossil is from one of the most successful species to have lived on Earth.

Scientists now believe humans stalked and then confronted a giant ground sloth thousands of years ago in New Mexico.

"There's always something new being discovered, Velez-Juarbe said. "The discoveries are coming faster than we can include them in our own work."

Focusing too much on your looks? That's what sent these species over the edge.

The ancestors of modern humans once had a very pronounced ridge on their brow, however, over time, our foreheads gradually became smoother and the eyebrows more visible and versatile.

The fossil is 25,000 years older than traditional theories would expect.

Rot happens.

Kerygmachela kierkegaardi is a distant relative of today's spiders, butterflies and lobsters.

The 4.5-pound reptile didn't let size stop it from spreading across Pangea.

The dents could have been left by life long ago, says one scientist.

Not all animals take the time to parent their young, especially if they have hundreds per clutch of eggs. But it looks like this invertebrate did.

The fossil is 127 million years old.

It was almost made into jewelry.

This may be the densest deposit of Triassic-era fossils ever discovered in the United States.

The creature fills the gap between ancient tailed arachnids and true spiders.

This is the first time Candelarhynchus padillai has ever been seen in tropical South America.

The definition of a 'modern' human just became more contentious.

This makes 11 total Archaeopteryx specimens.

The human jawbone, which still has teeth, is between 175,000 and 200,000 years old.

You can almost taste the regret.

The palace is constructed from oolitic limestone, a material that contains 200-million-year-old microbes.

This is the oldest example of iridescence in a dinosaur.

The bat's teeth and bones were three times the size of today's average bat.