Pteranodon
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| Pteranodon Fossil range: Mid-Late Cretaceous |
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Pteranodon (pronounced /tɨˈrænədɒn/; from Greek πτερ- "wing" and αν-οδων "toothless"), from the Late Cretaceous (Coniacian-Campanian, 89.3-70.6 million years ago) of North America (Kansas, Alabama, Nebraska, Wyoming, and South Dakota) was one of the largest pterosaur genera, with a wingspan of up to 9 m (30 ft).
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[edit] Description
Unlike earlier pterosaurs such as Rhamphorhynchus and Pterodactylus, Pteranodon had toothless beaks, like modern birds.
Pteranodon fossils have been generally found in the Cretaceous chalk beds of Kansas. These chalk beds were deposited at the bottom of what was once an epicontinental seaway on what is now the North American continent. The first Pteranodon skull was found on May 2, 1876, in the Smoky Hill River in Wallace County, Kansas, USA, by S. W. Williston, a fossil collector working for Othniel Marsh. The Niobrara Formation is possibly the most famous unit here, and other fossils found in this formation include those of sea turtles, mosasaurs, and early birds.[1]
Pteranodon were reptiles, but not dinosaurs. By definition, all dinosaurs were diapsid reptiles with an upright stance, and consist of the group containing saurischians and ornithischians. While the advanced pterodactyloid pterosaurs (like Pteranodon) had a semi-upright stance, it evolved independently of the upright stance in dinosaurs, and pterosaurs lacked the distinctive adaptations in the hip associated with the dinosaurian posture. However, dinosaurs and pterosaurs may have been closely related, and most paleontologists place them together in the group Ornithodira, or "bird necks".
[edit] Discovery and species
A number of species of Pteranodon have been named, the most well-supported being the type species, P. longiceps. This was named by Othniel Charles Marsh in 1876, and had a wingspan of 7 m (23 ft).[2][3] Other species include the larger P. sternbergi, with a wingspan of 9 m (30 ft),[2] P. occidentalis, P. velox, P. umbrosus, P. harpyia, and P. comptus. Many are dubious and may be synonymous with the more well-known species. Marsh identified Pteranodon as "distinguished from all previously known genera of the order {pterosauria} by the entire absence of teeth." This meant that any toothless pterosaur jaw fragment, wherever it was found in the world, tended to be attributed to Pteranodon. Hence there came to be a plethora of species and a great deal of confusion. The name became a wastebasket taxon, rather like the dinosaur Megalosaurus, to label any pterosaur remains that could not be distinguished other than by the absence of teeth. Notable authors who have discussed the various aspects of Pteranodon include Bennett, Padian, Unwin, Kellner, and Wellnhofer. One species, P. orogensis is not actually a pteranodontid and has been renamed Bennettazhia oregonensis. Likewise, P. orientalis has been renamed Bogolubovia orientale (Nessov & Yarkov, 1989) and transferred to the Azhdarchidae.
[edit] Paleobiology
The diet of Pteranodon is known to have included fish; fossilized fish bones have been found in the stomach area of one Pteranodon, and a fossilized fish bolus has been found between the rami of another Pteranodon. Pteranodon's wing shape suggests that it would have flown rather like a modern-day albatross. This is a suggestion based on the fact that the Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and utilize a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping,[4] and without the aid of thermals (which do not occur over the open ocean the same way they do over land). However, other scientists have suggested that Pteranodon could flap their wings and fly with power. These two flight styles need not have been mutually exclusive in Pteranodon, or in pterosaurs in general. Recent wind tunnel tests on model pterosaur wings with the pteroid bone in an extended antero-ventral orientation supporting a large, highly cambered propatagium show that such a configuration enables the wing to develop up to 30% more lift, even at very high angles of attack. This anatomical feature, based on the pteroid bone - the bone unique to the pterosaur clade - may have enabled pterosaurs to be active, powered flyers in spite of the lack of other features associated with strong fliers. For example, pterosaurs usually had a small (relative to modern birds) sternum keel as an anchor point for the pectoralis muscle.
Pteranodon was notable for its skull crest. These may have been used as mating displays, or it might have acted as a rudder, or perhaps both; also, it may have acted as a counterweight to the large beak; the muscles required to keep it upright otherwise would probably have weighed more than the crest did.[citation needed] It has been suggested that males of the species bore larger crests, but with fossil animals it is often difficult to tell whether differences in crest shape reflect different sexes or different species.
Consensus regarding the terrestrial locomotion of Pteranodon (whether it was bipedal or quadrupedal) has historically been the subject of debate. Today, most pterosaur researchers agree that pterosaurs were quadrupedal, thanks largely to the discovery of several pterosaur trackways; however, some new research suggest it was bipedal [[1]]. The possibility of swimming has been discussed briefly in two papers (Bennett 2001 and Bramwell & Whitfield),[5] and has been studied in detail at Michigan State University (Smith , 2007) through the use of quantitative morphometrics and an extant phylogenetic bracket (a morphologically comparative technique invented by Larry Witmer).
[edit] In popular culture
- See also: Biological issues in Jurassic Park
In colloquial language, Pteranodon is often erroneously called the "pterodactyl." However, "pterodactyl" is not actually the name of a specific species; rather, it is a term for all short-tailed pterosaurs (the suborder Pterodactyloidea), which includes Pteranodon, Pterodactylus, and Quetzalcoatlus. This misuse is most likely due to Pteranodon's high profile in popular culture as the quintessential pterodactyloid. Pteranodon is also not the name of a specific species, it is the name of a genus.
Pteranodon was seen briefly at the end of the 1997 film The Lost World: Jurassic Park, and also appeared in its sequel, Jurassic Park III. The depiction in Jurassic Park III featured many inaccuracies, including toothed jaws, exaggerated strength and, presumably, aggression. (Pteranodon is thought to have eaten fish, and was incapable of grasping with its feet). In the novelization of the film, some of these inaccuracies were attributed to the genetic engineering process used to create the animals. More scientifically accurate Pteranodon appeared in the television programs Chased by Dinosaurs, Sea Monsters, and Primeval. A trained Pteranodon named Turu appears in the Jonny Quest series. Pteranodon appear in two Ray Harryhausen movies, The Valley of Gwangi and One Million Years B.C., as well as the pre-Harryhausen classic King Kong.
Petrie from The Land Before Time (series) is a Pteranodon.
[edit] References
- ^ Bennett SC. (2000) Inferring stratigraphic position of fossil vertebrates from the Niobrara Chalk of western Kansas. Current Research in Earth Sciences, Kansas Geological Survey Bulletin 244, Part 1, 26 p
- ^ a b Wellnhofer, Peter [1991] (1996). The Illustrated Encyclopedia of Pterosaurs. New York: Barnes and Noble Books, 139. ISBN 0-7607-0154-7.
- ^ Identified as P. ingens in Wellnhofer, 1991.
- ^ Padian K. (1983)A functional analysis of flying and walking in pterosaurs. Paleobiology 9(3):218-239
- ^ Bramwell CD & Whitfield GR (1974) "Biomechanics of Pteranodon", Phil. Trans. Roy. Soc. B. 267
Smith, Amy C. 2007. Pteranodont claw morphology and its implications for aquatic locomotion. Master's Thesis, Michigan State University.
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