The long-dead 25-million year old seabird boasted a wingspan 21 feet wide, with even one of its wings dwarfing a California condor or a royal albatross.
This latest addition to the fossil vaults is detailed for the first time in the Proceedings of the National Academy of Science (PNAS) and was ironically discovered just outside of an airport in Charleston, South Carolina.
"It's kind of amusing," study author Daniel Ksepka told National Geographic. "A giant bird lands at an airport 25 million years too soon... Maybe he should have just waited and landed on the new runway."
According to Ksepka the fossil of this massive sea bird, the Pelagornis sandersi, rivals that of the largest bird fossil known to man - the Argentavis magnificens, a 6-million year old condor with a 23 foot wingspan.
In his study of the Pelagornis sandersi remains, Ksepka aimed to determine how such a massive creature could have flown. One thing he concluded is that it was likely a very graceful flier despite its behemoth wingspan, with a light build that likely allowed it to glide for long distances - a likely far better flier overall than the Argentavis magnificens.
For this massive bird, the challenge wasn't actually flying, Ksepka concluded. It was take-off.
"I think they just waited on the beach for a strong wind to carry them aloft," the researcher explained.
This means the birds were likely restricted to living in coastal regions with strong and predictable winds.
According to Ksepka, this analysis and study was long overdue. After the ancient seabird fossils were discovered during runway construction 31 years ago, they were stored in a drawer at the Charleston Museum in South Carolina until the right expert for the job came along.
The study was published in PNAS on July 7.