5 39;5.5 Feet In Meters

[Sabel Kantah]

Qnorthropi is considered problematic since it has yet to be properly described and diagnosed. Mark Witton et al. (2010) note the holotype is undiagnostic in every capacity, complicating azhdarchid taxonomy. Witton et al. (2010) suggest a general anatomy to be nearly identical to other large azhdarchids, overlapping some with Hatzegopteryx. If Quetzalcoatlus can be differentiated and remains valid, Hatzegopteryx may be considered a European variant. They also note the skull of the latter and Q. sp. differentiate enough to be distinct, but significance for this may not be determined since other problematic relationships exist. However, these can be resolved if Q. northropi is seen as valid and Q. sp. are investigated. Another factor is that azhdarchids were capable of long-distance flights, leading some continents to likely share and interchange genera.

BMR P2002.2, an azhdarchid neck vertebrae discovered in 2002 from the Hell Creek Formation, was accidentally recovered in a field jacket containing partial Tyrannosaurus remains was used for transport. Though associated with a large theropod, it shows no evidence of chewing. This pterosaur would have had a wingspan of 5-5.5 meters (16-18 feet) and was assigned Q. sp..

Quetzalcoatlus was one of the largest pterosaurs, reaching a wingspan as large as a small plane. Quetzalcoatlus was most likely a scavenger, eating small animals whole and eating carcasses. Unlike popular adaptations of the animal, Quetzalcoatlus was unable to lift or carry animals with its hindlimbs. Quetzalcoatlus' neck was considerably long, towering over its body and limbs. Its head bears a thin crest, which may have been coloured bright colours in life. Its eyes sat on the side of its head an had nostrils that sat high-up its rostrum. Its neck was stiffened through large muscles. It beak is very pointed, and the underside of its lower jaw bears a knob that functioned as an anchor to a soft tissue pouch in life. Old reconstructions sported a blunter beak, possibly because remains once attributed to Quetzalcoatlus actually belonged to a tapejarid close in form to Tupuxuara. The exact size of the head crest in life is unknown. Q. lawsoni has a wingspan of 4.5 meters, considerably smaller than Q. nothropi.

Many different ideas have been suggesting in terms of Quetzalcoatlus' feeding patterns. Due to the sheer vastness of the holotypes locality and the lack of bodies of water, the idea of a piscivorous diet was rejected. Quetzalcoatlus was then theorized to have fed like a marabou stork (an occasional scavenger, also a land-bound predator), but since its fossils have been found entangled with Alamosaurus, the idea was rejected. It was noted that the downturned beak of Quetzalcoatlus would leave a 5 centimeter, 2 inch gap when closed, a function which is unlike the hooked bills of scavenging birds. The same team proposed that the vertebrae and toothless beak were adapted to skimming.

Until 2007, the idea was challenged when another research team concluded that, for large airborne animals, skimming took too much energy to be a viable feeding method. In 2008, Mark Witton and Darren Naish noted that most azhdarchids are found in inland formations, and added on that the features present in Quetzalcoatlus were not compatible with other extant skimmers. They concluded that Quetzalcoatlus was a terrestrial-stalking hunter/scavenger. Like storks, they likely snatched small animals on land and in shallow streams. Quetzalcoatlus additionally has forelimb-hindlimb proportions suited towards terrestrial striding.

Witton and Naish (2015) suggest that Quetzalcoatlus had flexibility in the neck that allowed reach to the ground, a reclined occipital face that angled the head towards the ground, a long neck that makes easier access to the ground, increased stride in all limbs and weight bearing adaptations in the hands; these would have allowed Quetzalcoatlus to hunt prey with ease.

The Quetzalcoatlus monograph published in 2021 notes that the terrestrial ground stalking hypothesis has fared well in light of recent data. Noting that it lived in an environment with shallow bodies of water, so Quetzalcoatlus may have also fed there. However, Naish, suspects that the lack of terrestrial adaptations in Quetzalcoatlus suggest it only hunted on land.

Quetzalcoatlus used its limbs to vault off of a high surface. This speed and the lift of its large wings gave the animal the ability to glide into the air. Models of Quetzalcoatlus have been made, and put on autopilot in a controlled simulation. They were able to fly with a combination of soaring and flapping. Though some sources have claimed Quetzalcoatlus to be flightless, the general consensus as of now is that Quetzalcoatlus would have been capable of flight as well as terrestrial stalking. Quetzalcoatlus was able to fly at about 130 km/h from 7-10 days at an altitude of about 4600 meters (15,000 feet). It was suggested further, by another team, that Quetzalcoatlus was able to fly from 13,000-19,000 kilometers (8000-12,000 miles). However, these estimates were based on relatively old size models, and Quetzalcoatlus differed from what they based their studies from. The newest study concludes that Quetzalcoatlus, and other large pterosaurs, used short bursts of speed to transition to thermal soaring.

Quetzalcoatlus may have stopped by in the Hell Creek formation with another unknown azhdarchid. The animal likely swooped down from the skies when it spotted small animals, or an abandoned carcass. Once Quetzalcoatlus was done on the ground, it would vault into the sky with its forelimbs, and quickly open its wings to take off. Quetzacoatlus was built for long-time flying. Though it lived in certain geographic regions, it may have occasionally landed in unfamiliar territories and surrounding rock formations.

Styracosaurus (/stɪˌrkəˈsɔːrəs/ sti-RAK-ə-SOR-əs; meaning "spiked lizard" from the Ancient Greek styrax/στύραξ "spike at the butt-end of a spear-shaft" and sauros/σαῦρος "lizard")[1] is an extinct genus of herbivorous ceratopsian dinosaur from the Late Cretaceous (Campanian stage) of North America. It had four to six long parietal spikes extending from its neck frill, a smaller jugal horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to 60 centimeters (2 feet) long and 15 centimeters (6 inches) wide. The function or functions of the horns and frills have been debated for many years.

Barnum Brown and crew, working for the American Museum of Natural History in New York, collected a nearly complete articulated skeleton with a partial skull in 1915. These fossils were also found in the Dinosaur Park Formation, near Steveville, Alberta. Brown and Erich Maren Schlaikjer compared the finds, and, though they allowed that both specimens were from the same general locality and geological formation, they considered the specimen sufficiently distinct from the holotype to warrant erecting a new species, and described the fossils as Styracosaurus parksi, named in honor of William Parks.[6] Among the differences between the specimens cited by Brown and Schlaikjer were a cheekbone quite different from that of S. albertensis, and smaller tail vertebrae. S. parksi also had a more robust jaw, a shorter dentary, and the frill differed in shape from that of the type species.[6] However, much of the skull consisted of plaster reconstruction, and the original 1937 paper did not illustrate the actual skull bones.[4] It is now accepted as a specimen of S. albertensis.[5][7]

In the summer of 2006, Darren Tanke of the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta relocated the long lost S. parksi site.[5] Pieces of the skull, evidently abandoned by the 1915 crew, were found in the quarry. These were collected and it is hoped more pieces will be found, perhaps enough to warrant a redescription of the skull and test whether S. albertensis and S. parksi are the same. The Tyrrell Museum has also collected several partial Styracosaurus skulls.[8] At least one confirmed bone bed (bonebed 42) in Dinosaur Provincial Park has also been explored (other proposed Styracosaurus bone beds instead have fossils from a mix of animals, and nondiagnostic ceratopsian remains). Bonebed 42 is known to contain numerous pieces of skulls such as horncores, jaws and frill pieces.[5]

Several other species which were assigned to Styracosaurus have since been assigned to other genera. S. sphenocerus, described by Edward Drinker Cope in 1890 as a species of Monoclonius and based on a nasal bone with a broken Styracosaurus-like straight nose horn, was attributed to Styracosaurus in 1915.[9] "S. makeli", mentioned informally by amateur paleontologists Stephen and Sylvia Czerkas in 1990 in a caption to an illustration, is an early name for Einiosaurus.[10] "S. borealis" is an early informal name for S. parksi.[11]

A species, Styracosaurus ovatus, from the Two Medicine Formation of Montana, was described by Gilmore in 1930, named for a partial parietal under the accession number USNM 11869. Unlike S. albertensis, the longest parietal spikes converge towards their tips, instead of projecting parallel behind the frill. There also may only have been two sets of spikes on each side of the frill, instead of three. As estimated from the preserved material, the spikes are much shorter than in S. albertensis, with the longest only 295 millimeters (11.6 inches) long.[12] An additional specimen from the Two Medicine Formation was referred to Styracosaurus ovatus in 2010 by Andrew McDonald and John Horner, having been found earlier in 1986 but not described until that year. Known from a premaxilla, the nasal bones and their horncore, a postorbital bone and a parietal, the specimen Museum of the Rockies 492 was considered to share the medially-converging parietal spikes with the only other specimen of S. ovatus, the holotype. Following this additional material, the species was added to a phylogenetic analysis where it was found to group not with Styracosaurus albertensis, but in a clade including Pachyrhinosaurus, Einiosaurus and Achelousaurus, and therefore McDonald and Horner gave the species the new genus name Rubeosaurus.[13] Another specimen, the partial immature skull USNM 14768, which was earlier referred to the undiagnostic genus Brachyceratops, was also referred to Rubeosaurus ovatus by McDonald and colleagues in 2011. While the medial spikes of USNM 14768 were too incomplete to show if it shared the convergence seen in other R. ovatus specimens, it was considered to be the same species as it was also found in the older deposits of the Two Medicine Formation, and had a unique combination of parietal features only shared completely with the other specimens of the species.[14]

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