Quetzalcoatlus - Discovery and Species

Discovery and Species

The first Quetzalcoatlus fossils were discovered in Texas, from the Maastrichtian Javelina Formation at Big Bend National Park (dated to around 68 million years ago) in 1971 by a geology graduate student from the University of Texas at Austin's Jackson School of Geosciences, Douglas A. Lawson. The specimen consisted of a partial wing (in pterosaurs composed of the forearms and elongated fourth finger), from an individual later estimated at over 10 m (33 ft) in wingspan. Lawson discovered a second site of the same age, about forty kilometers from the first, where between 1972 and 1974 he and Professor Wann Langston Jr. of the Texas Memorial Museum unearthed three fragmentary skeletons of much smaller individuals. Lawson in 1975 announced the find in an article in Science. That same year, in a subsequent letter to the same journal, he made the original large specimen, TMM 41450-3, the holotype of a new genus and species, Quetzalcoatlus northropi. The genus name refers to the Aztec feathered serpent god Quetzalcoatl. The specific name honors John Knudsen Northrop, the founder of Northrop, who was interested in large tailless flying wing aircraft designs resembling Quetzalcoatlus. At first it was assumed that the smaller specimens were juvenile or subadult forms of the larger type. Later, when more remains were found, it was realized they could have been a separate species. This possible second species from Texas was provisionally referred to as a Quetzalcoatlus sp. by Alexander Kellner and Langston in 1996, indicating that its status was too uncertain to give it a full new species name. The smaller specimens are more complete than the Q. northropi holotype, and include four partial skulls, though they are much less massive, with an estimated wingspan of 5.5 meters (18 ft).

The holotype specimen of Q. northropi has yet to be properly described and diagnosed. Where the known remains overlap, it has been considered by Mark Witton and colleagues (2010) to be indistinguishable from its Romanian contemporary Hatzegopteryx. If Q. northropi is complete enough to be distinguished from other pterosaurs (i.e., if it is not a nomen dubium), Hatzegopteryx may represent the same animal. It is likely that huge pterosaurs such as Q. northropi would have had very large, transcontinental ranges, making its presence in both North America and Europe unsurprising. Mark Witton et al. pointed out that the skull material of Hatzegopteryx and Q. sp. differ enough that they cannot be regarded as the same animal, making it likely that Q. sp., if not identical to Quetzalcoatlus northropi, represents a distinct genus.

An azhdarchid neck vertebra, discovered in 2002 from the Maastrichtian age Hell Creek Formation, may also belong to Quetzalcoatlus. The specimen (BMR P2002.2) was recovered accidentally when it was included in a field jacket prepared to transport part of a tyrannosaur specimen. Despite this association with the remains of a large carnivorous dinosaur, the vertebra shows no evidence that it was chewed on by the dinosaur. The bone came from an individual azhdarchid pterosaur estimated to have had a wingspan of 5 - 5.5m (16.5 – 18 ft).