Researchers have discovered an ancient species of large predatory fish that lived in North American waterways 375 million years ago.

The ancient fish, named Laccognathus embryi, prowled ancient North American waterways during the Devonian Period, before backboned animals existed on land, according to scientists at the Academy of Natural Sciences in Philadelphia.

The new fish species was described in the Journal of Vertebrate Paleontology.

The Laccognathus embryi may have grown about 5 or 6 feet long, had a wide head with small eyes and robust jaws lined with large piercing teeth. The fish, whose closest living relative is the lungfish, had thick, quarter-size scales and a wide mouth--sort of like a modern-day grouper.

I wouldn't want to be wading or swimming in waters where this animal lurked, said Ted Daeschler, co-author of the paper and a vertebrate zoologist at the Academy of Natural Sciences. Clearly, these Late Devonian ecosystems were vicious places, and Laccognathus [meaning pitted jaw] filled the niche of a large, bottom-dwelling, sit-and-wait predator with a powerful bite.

The Devonian Period, from 415 million to 360 million years ago, was part of the Paleozoic era and known as the Age of Fishes due to the variety of fish that existed during that time, according to National Geographic.

The Devonian was a fish-eats-fish kind of world, Daeschler said. There was a real arms race going. If you [were a smaller fish and] didn't have good armor on your body, you were very vulnerable.

In the same arctic site in 2004 Tiktaalik roseae, a fossil creature that lived during the same period as L. embryo, was discovered. Tiktaalik roseae is considered to be a crucial link between fish and early limbed animals.

The fossil remains of the new species were found at the same site as Tiktaalik, on Ellesmere Island in the remote Nunavut Territory of Arctic Canada.

The kind of fish - Laccognathus - was previously only known from Eastern Europe. The discovery of Laccognathus embry extends the geographic range of Laccognathus to North America and confirms direct connection of the North American and European landmasses during the Devonian Period.

This study is the culmination of a lot of work in the field, in the fossil lab, and in the office, said lead author Jason Downs, an Academy research associate and a visiting professor at Swarthmore College.

The scientists who made the discovery were from the Academy of Natural Sciences in Philadelphia, Harvard University, and the University of Chicago. Research funding came from the National Science Foundation and the National Geographic Society.