Arambourgiania

Arambourgiania (meaning "Camille Arambourg's") is a genus of pterosaur, an extinct group of flying reptiles, that inhabited Jordan during the Maastrichtian age of the Cretaceous period, around 72 to 66 million years ago. Additional fossil remains from the United States and Morocco have also been found, but their assignment to Arambourgiania is only tentative. The holotype (name-bearing) specimen was discovered in 1943 by a railway worker near Russeifa, Jordan. After examination of the specimen by paleontologist Camille Arambourg, he described it as belonging to a new genus and species in 1959, Titanopteryx philadelphiae. The generic name means "titan wing", as the fossil was initially misidentified as a wing metacarpal (it would be later identified as a cervical (neck) vertebra), while the specific name refers to the ancient name of Amman (the capital of Jordan), Philadelphia. The genus name "Titanopteryx" would later be problematic, as it had already been taken by a fly. Because of this, paleontologist Lev Nessov in 1989 renamed the genus to Arambourgiania, in honor of Arambourg. Since 1943, additional isolated remains including vertebrae, wing bones, and hindlimb bones have been assigned to the genus.

Due to the fragmentary nature of the Arambourgiania fossils, there is little direct information about its anatomy. Its cervical vertebrae are extremely elongated, with the holotype vertebra measuring 77–78 cm (2 ft 6.31 in – 2 ft 6.71 in) in length. Based on the complete neck of its relative Quetzalcoatlus, Arambourgiania had a total neck length of 3 m (9 ft 10 in), longer than those of giraffes. Its vertebrae were also more lightly built and weakly muscled than those of its robust, short-necked relative Hatzegopteryx. Arambourgiania is one of the largest flying animals ever discovered. Initial wingspan estimates ranged from 11 to 13 m (36 to 43 ft), which would have made it the largest known pterosaur. However, given the fragmentary remains, more recent research has suggested wingspans anywhere between 8 to 10 m (26 to 33 ft), which would still place the genus among the largest known flying animals.

Arambourgiania is a member of the family Azhdarchidae, which includes some of the largest known pterosaurs. Azhdarchids are thought to have had a terrestrial stalker lifestyle, similar to that of extant storks, though some studies have pointed out that azhdarchids are frequently found in marine deposits. This includes Arambourgiania, whose fossils are exclusively known from oceanic or coastal localities, indicating that azhdarchids may have consumed aquatic prey as well. The bones of Arambourgiania are extremely hollow and lightly built with adaptations for soaring. One of the closest relatives of Arambourgiania is Quetzalcoatlus, as multiple studies have found both pterosaurs to be grouped together within Quetzalcoatlinae. In Jordan, Arambourgiania fossils are known from the Ruseifa Formation which had deep marine environment that was deposited during the Maastrichtian. At this time, Jordan was submerged under the Tethys Sea and had a diverse composition of marine life, including mosasaurids, elasmosaurids, bony fish, and selachians. Arambourgiania is one of two pterosaurs known from Jordan, the other being Inabtanin.