Sometime in the neighborhood of 23 million years ago, the megamouth shark swam the oceans. Thought to be extinct, scientists recently identified a new species of megamouth shark by teeth found around 50 years ago. Confused? So were the scientists!

The teeth baffled scientists in the 1960s because they didn’t know of any species they could have come from. The limited knowledge and technology available to identify the source of the teeth was just too limited. Without any idea of what they had, they put the teeth in storage in the Los Angeles County Museum. Basically, they put them away for a rainy day and hoped that sometime, someone would figure out their origins.

The Modern Megamouth Shark was discovered in 1976. This shark, as you can imagine by the name, has a huge mouth and feeds on small fish and plankton. It swims along with its mouth open and uses filters in its gills to collect the plankton for ingestion. The modern megamouth (megachasma pelagios) stays in deep waters during the day and swims to shallow, plankton filled waters to feed at night.

Paleobiologist Kenshu Shimada, a paleobiologist from DePaul University in Chicago, found the mystery teeth from the 1960s at the Los Angeles County Museum. No one was studying them or working on identifying the species. Shimada asked two other scientists, Douglas Long from the California Academy of Sciences and Bruce Welton from the New Mexico Museum of Natural History to look at the teeth with him to see if they related to the megamouth shark.

The three scientists realized that the teeth appeared to be related to the Modern Megamouth, but the teeth were longer and sharper. There were enough similarities for the scientists to clearly link the teeth to the genus Megachasma, but then they needed to apply the latest in technology and their combined experience to put together the rest of the picture. The ancient teeth also suggested that this ancestor of the megamouth probably had a wider variety of sea life in its diet with the sharpness of the teeth. It likely added some kinds of fish to its menu in addition to the plankton. They also concluded that the prehistoric shark was approximately 20 – 27 feet long with a longer, narrower snout than their modern relative.

The teeth were found in both deep and shallow waters, suggesting migration to find food. The evolutionary process that brought about the wider, flatter mouth; the move to shallower water thus changing the diet; the change in tooth shape; and filter feeding is unknown. The new species does not have a name as of yet, just the genus. All of the findings will be available in an upcoming issue of the Journal of Vertebrate Paleontology.

It is truly amazing how teeth that could not be attributed to any species in 1960 have been classified with today’s knowledge and technology. That a team today can not only determine the genus, but many of the physical characteristics beyond the teeth is nothing short of astounding.