Pteranodon

Pteranodon (/təˈrænədɒn/; from Ancient Greek pteron 'wing', an- 'without', and odon 'tooth') is a genus of pterosaur that included some of the largest known flying reptiles, with P. longiceps having a wingspan of over 6 m (20 ft). They lived during the late Cretaceous geological period of North America in present-day Kansas, Nebraska, Wyoming, South Dakota and Alabama. More fossil specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons.

When the first fossils of Pteranodon were found, they were assigned to toothed pterosaur genera, such as Ornithocheirus and Pterodactylus. In 1876, Othniel Charles Marsh recognised it as a genus of its own, making particular note of its complete lack of teeth, which at the time was unique among pterosaurs.

Pteranodon is part of the family Pteranodontidae, part of the clade Pteranodontia, which also includes nyctosaurids. Two distinct morphs of Pteranodon specimen have been found, that are thought to represent males and females. Male and female Pteranodon differed in size and crest shape. Males attained wingspans of 5.6–7.6 m (18–25 ft); females were smaller, averaging 3.8 m (12 ft).

Discovery and history

Pteranodon was the first pterosaur found outside of Europe. Its fossils were first discovered by Othniel Charles Marsh in 1870 or 1871 in the Late Cretaceous Smoky Hill Chalk deposits of western Kansas. These fossils included partial wing bones and a tooth from a prehistoric fish, which Marsh initially thought belonged to the pterosaur. He named the find Pterodactylus oweni but later renamed it Pterodactylus occidentalis after realizing the name was already used.

The first Pteranodon skull was found in 1876 by Samuel Wendell Williston along the Smoky Hill River in Wallace County, Kansas, USA. This skull showed that these pterosaurs were different from European species because they had no teeth and had bony crests. Marsh recognized this major difference and created the name Pteranodon, meaning "wing without tooth," in 1876. He reclassified all the North American species under this new name.

Description

Adult male Pteranodons were among the largest pterosaurs and the largest flying animals known until the late 20th century. An average adult male had a wingspan of about 5.6 m (18 ft), while females were smaller, averaging 3.8 m (12 ft). One large specimen named Pteranodon longiceps had a wingspan of over 6 m (20 ft).

Pteranodons had toothless beaks, unlike earlier pterosaurs. Their beaks were long and ended in sharp points. The most noticeable feature was the cranial crest on top of their skulls. Males had large, narrow crests, while females had smaller, rounded crests. These crests were likely used for display.

Paleobiology

Pteranodon likely flew similarly to a modern-day albatross, using a flight pattern called "dynamic soaring" to travel long distances without flapping its wings. It could also flap its wings for short bursts of speed. Pteranodon probably took off by leaping into the air using its strong forelimbs.

The diet of Pteranodon mainly consisted of fish. They likely caught fish by dipping their long beaks into the water while swimming, rather than while flying. The large crest on its skull was probably used for display, especially during mating, as it varied greatly in size and shape between males and females. Larger Pteranodon specimens had bigger crests, which helped them show off to potential mates.

Paleoecology

Main articles: Niobrara Formation and Western Interior Seaway

Pteranodon fossils have been found in places like the Smoky Hill Chalk and the Pierre Shale Formation. During the time Pteranodon lived, this area was covered by a big inland sea called the Western Interior Seaway. These rock layers stretch from Kansas in the United States up to Manitoba in Canada, but Pteranodon fossils are only found as far north as South Dakota.

Pteranodon shared the skies with other flying reptiles like Nyctosaurus and birds such as Ichthyornis. The oceans below were full of sea life, including ammonites, squid, sea turtles, plesiosaurs like Elasmosaurus and Styxosaurus, and large marine reptiles called mosasaurs. Some of these sea creatures may have eaten Pteranodon.

Classification

Pteranodon fossils come mainly from the Niobrara Formation in the central United States. They lived during the Santonian stage of the Cretaceous period, around 88 to 78 million years ago. Scientists have found about 1,200 fossils of Pteranodon, many with well-preserved skulls and skeletons.

Researchers generally agree there are two species of Pteranodon: Pteranodon longiceps and Pteranodon sternbergi. The main difference between them is the shape of the crest on the heads of adult males. Because skull fossils are rare, scientists often use the rock layer where a fossil is found to help identify the species. P. sternbergi had an upright crest and is older, while P. longiceps lived later.