Pelagornis, the giants of the sky

James Gurney
James Gurney
The Pelagornis flew over the seas for over fifty million years. With their wingspan of more than 6 meters, how did these birds take off?

The scenic harbor of Charleston, South Carolina, harbors a wide variety of resident or passage birds, from pelicans to cormorants to gulls, herons and many passerines. But about 25 million years ago, giant birds reigned in the sky of this natural harbor. In 1983, when a new terminal was built at the local airport, a team of paleontologists led by Albert Sanders, then curator of the city museum, uncovered the fossil of a large bird. Unfortunately, as these researchers were confronted at the same time with many fossils, the remains in question found themselves left on shelves. Until recently, one of us, Daniel Ksepka, decides to re-examine this fossil and highlight what is extraordinary: it is the remains of the largest flying bird ever identified!

With its considerable span, it looks like a small plane, and the fact that it was discovered at an airport is tasty. In honor of his discoverer, Daniel Ksepka named his species Pelagornis sandersi, literally „Sanders Pelagic Bird“.

Daniel Ksepka then carried out research to understand how this bird could fly, the dimensions of which exceeded those that some specialists considered to be the best for a bird capable of flying. For his part, Michael Habib studied other giant fossil birds. All this work has led to a much more complete description of the pelagornithidae, the family to which P. sandersi belongs. In particular, it is now possible to speculate which flight styles these birds were likely to practice.

Pelagornithidae entered the fossil record in 1857, when Édouard Lartet described a humerus. This father of French prehistoric science thought he had identified a bone belonging to a very old albatross and named the corresponding species Pelagornis miocaenus, or „Miocene high seas bird“. This name little inspired does not detract from the spectacular character of the fossil, since the humerus in question measures nearly 60 centimeters long. This means that its owner had a size at least double that of a large albatross of today (average 3.1 meters). In Lartet’s time, such a scale was inconceivable. Unfortunately, on the basis of this unique humerus, the paleontologists of the nineteenth century were not in a position to determine to what this bird could have resembled.
A deep-sea bird

However, the idea that the humerus described by Lartet could originate from a species other than that of a large albatross was imposed a decade later in 1873 when Richard Owen described the skull of another Giant bird, found in England. His research clearly showed that the species from which this skull came-which he called Odontopteryx toliapica-could not belong to any of the modern bird groups. And the subsequent discovery of more complete specimens revealed that the bird of which Lartet had studied a humerus belonged to the same extinct group defined by the skull of Owen: that of the pelagornithidae.

Other discoveries were made during the next century. In 1910, a Brazilian sailor sold a pelagornithid skull to the University of Königsberg in Germany (now Kaliningrad, Russia). It was attributed to a new species: Pseudodontornis longirostris. Then its trace was lost during the allied bombing on the city in 1945.