A 20-foot-long crocodile with three sets of fangs -- like wild boar tusks -- roamed parts of northern Africa millions of years ago, researchers reported Thursday.

While this fearsome creature hunted meat, not far away another newly found type of croc with a wide, flat snout like a pancake was fishing for food.

WATCH VIDEO: Slow motion reveals exactly how a crocodile's strong bite works.

And a smaller, 3-foot-long relative with buckteeth was chomping plants and grubs in the same region.

The three new species, along with new examples of two previously known ancient crocodiles, were detailed Thursday by researchers Paul Sereno of the University of Chicago and Hans Larsson of McGill University in Montreal. They spoke at a news conference organized by the National Geographic Society, which sponsored the research.

"These species open a window on a croc world completely foreign to what was living on northern continents," Sereno said of the unusual animals that lived 100 million years ago on the southern continent known as Gondwana.

Hans Dieter Sues of the Smithsonian Institution's National Museum of Natural History said the discovery revises the ideas of what crocodile-type reptiles were like.

"It's a joy for anyone who is interested in ancient life to see," said Sues, an editor at ZooKeys, which published the findings.

The researchers suggest that these crocs could gallop across the landscape chasing prey and yet dive into water and swim.

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