Pelagornis sandersi is an extinct seabird with the distinction of having one of the largest known avian wingspans. It is described from one well-preserved specimen composed of the complete skull, right wing and leg bones, unearthed in 1983 by Charleston Museum curator Albert Sanders in Bed 2 of the Chandler Bridge Formation near Charleston Airport (Charleston, South Carolina). This fossil bed exists where the land was covered by ocean at the time of this birds existance in the late Oligocene, ~25–28 million years ago. After its discovery the specimen remained in a museum drawer for many years until it was identified and described as a new species in July 2014 and named for Sanders (Ksepka 2014).
Ksepka (2014) conservatively estimates the wingspan of this mammoth seabird at about 6.4 meters (21 feet), rivaling the size of the previous avian wingspan record-holder (extinct South American condor Argentavis magnificens). It is far larger than the extant albatrosses that are today’s largest fliers, e.g. the wandering albatross Diomedea exulans, which has a wingspan up to 11.5 feet (3.5 meters; NESCent 2014; Vergano 2014).
Even with paper-thin bones perforated with air pockets, P. sandersi is estimated to have reached a weight of about 21.8 kg (48 pounds), too heavy to easily take off from the ground or water. Computer simulations performed by Ksepka (2014) using the fossil data indicate that P. sandersi may have waited for gusts or run into headwinds in order to get aloft; once in the air its long slender wings gave it high lift-to-drag ratios making it an efficient glider able to use currents rising from the ocean surface to soar at low altitude for long distances without flapping its wings. Like other known representatives in its family, the Pelagornithidae (known as the pseudotooth birds) it has tooth-like projections on its beak, useful for snapping up small fish, eels and squid from below the water surface, and perhaps catching other birds while in flight (Ksepka 2014; NESCent 2014; Vergano 2014).
The Pelagornithidae family has previously been considered most closely related to albatrosses, petrels, sheerwaters or pelicans, orders Procellariiformes and Pelecaniformes, but more recent analyses place it with land and water fowl, orders Galloanserae and Anseriformes (Howard 1957; Olsen 1985; Harrison and Walker 1976; Bourdon 2005; Mayr 2011; as cited in Ksepka 2014).
