Before the -saurs, giant fish named Big Mouth.

Did Super-Sized Animals Live Long Before Dinosaurs?

It's generally believed that Earth's earliest animals were not very big, but discovery of a huge new fish that lived around 423 million years ago has scientists rethinking what life was like close to 200 million years before the first dinosaurs emerged.

The fish, named Big Mouth Blunt Tooth (Megamastax amblyodus), is described in the latest issue of Scientific Reports. For its time, the toothy and lobe-finned fish was in the number one spot on the food chain.

"At 1 meter (3.3 feet) in length or greater, it was vastly larger than any other animal," lead author Brian Choo told Discovery News, adding that Big Mouth was "likely the earliest vertebrate (backboned) apex predator in the fossil record."

Read more about Big Mouth here