WASHINGTON — History's largest flying sea bird, a gull-like creature that glided over ancient oceans on a wingspan of more than 18 feet, has been identified in a fossil dug out of a South Carolina rock formation.
Scientists at the Smithsonian Institution and at the Charleston Museum in Charleston, S.C., said last week that the fossil has been identified as a member of the extinct bird family called pseudodontorn, or bony-toothed birds.
Storrs L. Olson of the Smithsonian said the bird lived about 30 million years ago.
The fossil was discovered in 1984 during construction at the Charleston Airport after scientists chipped away hardened sand and silt from a 4-by-5-foot stone block.
Olson said the recovered fossil includes "most of the major bones" of the skeleton, including the skull, lower jaw, one leg and most of one wing.
He said the bird may have weighed nearly 90 pounds and probably spent most of its life riding wind currents on its 18-foot wingspan. The largest living sea bird is the wandering albatross, which weighs 20 pounds and has a wingspan of 11 feet.
The pseudodontorn is second in size only to a fossil vulture-like bird from Argentina that had a wingspan of 20 feet to 25 feet.
Olson said an examination of the skeleton shows that the pseudodontorn lacked the ability to sustain flight on muscle alone and, thus, must have depended upon winds to soar. He said the bird's upper arm bone could not rotate to achieve the flapping motion that allows most birds to fly.
"It couldn't have had much of a rotary motion at all," Olson said. "All this bird could do is hold its wings out."
The bird's jaw, he said, is lined with a bony structure that resembles teeth, but lacks the dentine and enamel of real teeth.
"They look like teeth and functioned like teeth but were really bone," he said. He said the bird probably lived on squid or fish that it scooped from the ocean and tore apart with its beak.
Olson said the pseudodontorn's jaw was hinged in the middle, which probably allowed the bird to create a pouch to hold fish or food for its young.
The family of pseudodontorn birds first appeared 50 million years ago and survived about 45 million years. The pseudodontorn family is part of a larger group of birds that includes the present-day pelican.