![]() ![]() Possible causes of their demise include changes in climate that affected wind speeds over the seas, a change in the availability of preferred foods, or some combination of the two.Albatrosses are some of the largest and most impressive birds in all the animal kingdom. More mysterious, Ksepka says, is why members of this group died out. sandersi and its close relatives-which lived from 55 million years ago until about 3 million years ago-thrived worldwide. The ability to soar long distances and forage for food with a minimum of effort might help explain how P. Habib explains that it would have been able to cross broad stretches of ocean by taking advantage of thermals (rising columns of air created over warmer-than-normal patches of ocean) to gain altitude, then gliding until it reached the next thermal. If its winding flight paths were straightened out and then measured, "it would have been a champion," he suggests. ![]() ![]() sandersi's body plan was well adapted to long-range flight, says Michael Habib, a vertebrate paleontologist at the University of Southern California in Los Angeles. Using the broad range of size and wingspan estimates to assess flight performance, rather than a single combination, "is a refreshing change from the speculations that sometimes characterize sensational finds of fossils representing truly gigantic extinct animals," says Adam Smith, an evolutionary biologist at the North Carolina Museum of Natural Sciences in Raleigh. The bird's flight performance "is pretty much what you'd expect for a creature with that wingspan," he notes. sandersi "was a superalbatross," he adds. Ksepka's new analysis is "a solid piece of work," says Mark Witton, a paleobiologist at the University of Portsmouth in the United Kingdom. On average, Ksepka says, for every 1 meter the bird dropped while gliding, it could have moved forward 22 m. sandersi outperformed a frigatebird and a vulture (two types of bird known for their soaring ability) and typically bested the gray-headed albatross, Diomedea chrysostoma. For most combinations of body weight and wing proportions that he analyzed, P. sandersi, allowed Ksepka to estimate the gliding performance of the bird. That range, combined with the probable range of wingspans for P. sandersi's hind limbs suggest that the bird weighed between about 22 and 40 kilograms. Proportions of the weight-bearing bones in P. Previously, scientists had suggested that pelagornithids, as the birds are known, were related to pelicans and albatrosses, but recent studies hint that the group is more closely related to ducks, geese, and swans. These giant seabirds-all of them extinct and all the size of today's albatrosses or larger-ranged worldwide, because their fossils have been found on all continents. The new species, dubbed Pelagornis sandersi, is one of a handful within the genus Pelagornis-which means "bird of the open sea" in ancient Greek. ![]() In comparison, the largest wild-caught specimens of today's wandering albatross, Diomedea exulans, have a wingspan of only 3.5 m. Add wingtip feathers and the width of the body, and the bird's total wingspan was likely 6.4 m but possibly larger, Ksepka reports online today in the Proceedings of the National Academy of Sciences. He extrapolated, based on the skeletal proportions of this species' close relatives, that each wing would have measured almost 2.5 meters. Ksepka's analyses hint that the bone, if complete, would have been about 94 cm long. The largest bone of the bunch was an 81-centimeter-long fragment of humerus, which in humans stretches from shoulder to elbow. (The 3-decade delay in describing the species stems, in part, from the time needed to tease the delicate fossils from the rock.) Ksepka was invited to check out the specimen, part of the collection at the Charleston Museum, when he worked at North Carolina State University in Raleigh. The fossils had been entombed in rocks laid down as seafloor sediments sometime between 25 million and 28 million years ago, says Daniel Ksepka, a vertebrate paleontologist who is now at the Bruce Museum in Greenwich, Connecticut. Like modern-day albatrosses, the newly described species would have been a soaring champ.įragmentary fossils of the new species-bones from a fairly complete skull, as well as some from one wing and leg-were discovered in 1983, when excavations began for a new terminal at Charleston International Airport. The animal measured 6.4 meters from wingtip to wingtip, about the length of a 10-passenger limousine and approaching twice the size of the wandering albatross, today's wingspan record-holder. Fossils unearthed at a construction project in South Carolina belong to a bird with the largest wingspan ever known, according to a new study. ![]()
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