Cretalamna Bryanti: New Dinosaur-Era Shark, Ancestor to Fierce and Ancient Megalodon, Discovered in Alabama

A megalodon tooth (center) and three bryant shark teeth (right.) McWane Science Center

Imagine a great white shark as long as a bowling lane, with teeth that could grow up to the size of your hand. Does this sound like the monster in a B-movie? Well, yes, megalodon is the star of several low-budget thrillers, but it was also a real animal. From 23 million to 2.6 million years ago, the largest shark that ever lived ruled the warm waters of the world.

Now, scientists have discovered a dinosaur-era shark that may have been an even earlier ancestor of megalodon, illustrating the evolution of one of the most fearsome creatures to swim the seas.

Paleontologists have been collecting fossilized ancient shark teeth in Alabama for decades. After nearly 50 years, the collection was large enough to enable paleontologists to name and describe a new species: Cretalamna bryanti, or the bryant shark.

Researchers from the University of Alabama and the McWane Science Center, also in Alabama, identified 33 teeth belonging to this species. The teeth described in their study and formal description of the animal, published in the journal PeerJ, were found between 1980 and 2011 in the Black Belt region of Alabama. This 240-mile region reaches from the northwest corner of the state into the center and provides a snapshot of the Upper Cretaceous period, which stretched from 100.5 to 66 million years ago, that is "nearly perfect," the study authors write. The bryant shark lived about 83 million years ago and gave rise to a variety of ancient shark species, including megalodon.

Paleontologists almost never find shark fossils that represent anything other than the teeth of the animals. That's because sharks have bones only in their mouths; their "skeletons" are made of cartilage, a soft tissue that rarely leaves fossil remains. Modern sharks give us the best clues about how their extinct ancestors may have looked, which is why artists and filmmakers often portray megalodon as a great white shark, but scaled up.

The bryant shark was an early member of a group of "mega-tooth" sharks, most of which went extinct at the same time as the non-bird dinosaurs 66 million years ago. The teeth on this shark were much smaller than those of megalodon; the biggest bryant shark tooth discovered so far is only an inch long. That also means that its body probably was about 15 feet long.

Over time, study co-author Jun Ebersole, director of collections at McWane Science Center, told LiveScience, sharks in the megalodon line, "grow to enormous sizes." This new study adds to our understanding of the ancient, giant creatures that once swam the saltwater seas of what is now Alabama.

The researchers named the shark after football player Paul "Bear" Bryant, who coached the University of Alabama's football team for 25 years.