Scientists have finally identified a new species of megamouth shark that prowled the oceans about 23 million years ago, nearly 50 years after the first teeth were discovered and then forgotten.
The ancient shark likely prowled both deep and shallow waters for plankton and fish, using its massive mouth to filter food.
"It was a species that was known to be a new species for a long time," said study co-author Kenshu Shimada, a paleobiologist at DePaul University in Chicago. "But no one had taken a serious look at it," said Shimada, who described the new species here at the 73rd annual meeting of the Society for Vertebrate Paleontology. (8 Weird Facts About Sharks)
Scientists first found shark teeth from the species in the 1960s, but at the time, there were no similar living creatures, so scientists didn't quite know what to make of the find. Over time, researchers turned up hundreds of similar teeth along the coast of California and Oregon. All the specimens were tossed in a drawer and forgotten in the collections of the Los Angeles County Museum and a few other California museums.
Then in 1976, scientists discovered the modern megamouth shark, dubbed Megachasma pelagios, which feeds exclusively on shrimplike creatures called plankton. The sharks use their mammoth mouths to engulf plankton-filled water, forcing the water through gills equipped with a filtering apparatus called gill rakers, which direct plankton into the digestive track.
The monster beast is also a vertical migrator, meaning the shark lurks in the deep ocean during the day, but comes up to the shallow surface waters chasing plankton swarms at night, Shimada said.
Revisiting a shark
When Shimada came across the shark teeth at the Los Angeles County Museum, he was told that other scientists were studying them. But it turned out those scientists weren't actively working on the species.
Shimada contacted those scientists, Douglas Long of the California Academy of Sciences and Bruce Welton of the New Mexico Museum of Natural History, and persuaded them to take a second look with him.