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Geosternbergia (Pteranodon sternbergi)

Pteranodon sternbergi is an extinct species of the pteranodontid pterodactyloid pterosaur genus Pteranodon from the Late Cretaceous geological period of North America. P. sternbergi was among the largest pterosaurs, with a wingspan of up to 6 metres (20 ft) in males. It has been argued that P. sternbergi should be classified in a separate genus, Geosternbergia, but this has not been followed by most other researchers.

Pteranodon sternbergi was among the largest pterosaurs, with the wingspan of most adults ranging between 3 and 6 meters (9.8 and 19.7 ft). No complete skulls of adult males have been found, but a nearly complete lower jaw has been estimated at 1.25 meters (4.1 ft) long.[7] While most specimens are found crushed, enough fossils exist to put together a detailed description of the animal. P. sternbergi differs from its close relative Pteranodon longiceps mainly due to its earlier time period and broader, more upright crest.[5]

The upright cranial crest of P. sternbergi is its distinctive characteristic. These crests consisted of skull bones (frontals) projecting upward and backward from the skull. The size and shape of these crests varied due to a number of factors, including age, sex, and species. Male P. sternbergi, the older species of the two described to date, had a larger vertical crest with a broad forward projection, while G. maiseyi had a short, rounded vertical crest and was generally smaller.[4] Females of both species were smaller and bore small, rounded crests.[3] The crests were probably mainly display structures, though they may have had other functions as well.[8]

Unlike the earlier pterosaurs, such as the rhamphorhynchids and the pterodactylids, P. sternbergi had a toothless beak that was made of solid, bony margins that projected from the base of the jaws, similar to modern-day birds. The structure of the beaks were long, slender, and ended in thin, sharp points. Its maxilla was also found to be longer than the mandible, and was curved upward.