They weren't exactly there when it happened, so scientists were excited when they uncovered the birthing mystery of mighty mosasaurs, gigantic marine lizards that once roamed the ancient oceans.

That's at least according to new findings published in the journal Palaeontology, which details how researchers at Yale University and the University of Toronto have discovered a new birth story for these long-extinct creatures.

Thanks to recently identified specimens at the Yale Peabody Museum of Natural History, paleontologists now believe that mighty mosasaurs - which could grow up to 50 feet long - gave birth to their young in the open ocean, not on or near shore.

For years, it has been debated how these giant lizards gave birth, and now it appears that scientists have finally found their answer.

"Mosasaurs are among the best-studied groups of Mesozoic vertebrate animals, but evidence regarding how they were born and what baby mosasaur ecology was like has historically been elusive," researcher Daniel Field, the study's lead author, said in a statement.

The findings answer long-held questions about the initial environment of an iconic predator that lived during the time of the dinosaurs. Mosasaurs populated most waters of the Earth before their extinction 65 million years ago.

So why has the birthing process of mosasaurs eluded scientists for so long? Well, part of the answer may be due to the fact that while these young mosasaur specimens have been in the Yale Peabody Museum's extensive collections for some time, they suffered from a case of mistaken identity.

"These specimens were collected over 100 years ago," Field said. "They had previously been thought to belong to ancient marine birds."

But after observing a variety of jaw and teeth features that are only found in mosasaurs, they realized their mistake.

"Really, the only bird-like feature of the specimens is their small size," researcher Aaron LeBlanc concluded. "Contrary to classic theories, these findings suggest that mosasaurs did not lay eggs on beaches and that newborn mosasaurs likely did not live in sheltered nearshore nurseries."

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