Long before T. rex, the Earth was dominated by super-carnivores stranger and more terrifying than anything dreamed up by ...

They lived during the late Permian period, roughly 260 to 252 million years ago. These creatures were more closely related to mammals than to reptiles, making them distant cousins to us.

Still recovering from the intense volcanic activity that triggered the era, Earth's oceans were warm in the aftermath of the end-Permian extinction and oxygen-drained.

Therapsids, the ancient relatives of mammals, once roamed Earth in great numbers during the middle to late Permian period. These land-dwelling creatures would later evolve into mammals, but their ...

The Permian extinction, on the other hand, unfolded over hundreds of thousands of years, he explains. More like this: • The 120-year search for the purpose of T. rex's puny arms ...

Earth’s largest mass extinction eliminated a lot of marine species. But it didn’t eliminate them all. According to a study in Science Advances, warm, oxygen-depleted waters may have helped select ...