A pregnant megamouth shark found on a Philippines beach was the first ever seen — and it solved a long-standing mystery

• A megamouth washed up on a beach in the Philippines in November.
• The shark was found with a pup alongside her and six fetuses inside her body.

A dead 18-foot megamouth shark that washed up on the beach in the Philippines was pregnant, confirming for the first time that these mysterious creatures give birth to live young.

The shark was found in the municipality of Aurora on November 14 with one pup and six fetuses, according to New Scientist.

The specimen is the first record of a pregnant megamouth found in the world, according to a statement from the National Museum of the Philippines published on Facebook on Friday.

The discovery solves a long-standing mystery about whether these creatures are ovoviviparous, meaning they can lay eggs inside their bodies and give birth to live young.

This is similar to the megamouth's cousin, the whale shark, that gives birth to live young.

The pup found alongside the megamouth adult could have been recently birthed as the stress of capture or stranding can cause sharks to expel their pups or eggs, said AA Yaptinchay of Marine Wildlife Watch of the Philippines who oversaw the necropsy, per New Scientist.

The six megamouth fetuses were transported to the National Museum of the Philippines for further detailed examination, per the statement. Genetic testing could now reveal whether the fetuses have different fathers, New Scientist reported.

Megamouth sharks have been particularly elusive. First found in 1976, there have been under 300 sightings of the deep sea sharks since. Fewer than 150 specimens have ever been uncovered. They are the smallest of three species of filtering sharks.

Like their cousins the basking sharks, they feed on krill suspended in seawater, sieved through their oversized mouths.

While most specimens have been found near the Philippines and Taiwan, these sharks have been spotted around the world.

A study published earlier this year reported a sighting of two megamouths swimming side by side off the coast of California. They were likely engaging in some sort of pre-copulation ritual, the study authors said.