49-708: Quetzalcoatlus ( / k ɛ t s əl k oʊ ˈ æ t l ə s / ) is a genus of azhdarchid pterosaur known from the Late Cretaceous Maastrichtian age of North America. The first specimen, recovered in 1971 from the Javelina Formation , consists of several wing fragments. It was made the holotype of Quetzalcoatlus northropi in 1975 by Douglas Lawson and was named after the Aztec serpent god, Quetzalcōātl , and Jack Northrop , designer of tailless fixed-wing aircraft. The remains of
98-405: A body mass of 65 kg (143 lb). A complete skull of Quetzalcoatlus is not known, so reconstructions necessarily draw from eight specimens of Q. lawsoni that preserve skull elements. The skull of Q. lawsoni was about 94–96 cm (37–38 in) long. Like other azhdarchoids , Quetzalcoatlus had a long, toothless beak that was comprised largely of the premaxilla and maxilla . At
147-544: 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 4.5–5.5 m (15–18 ft). This species was named Q. lawsoni in 2021, in honor of the genus' original describer. An azhdarchid neck vertebra, discovered in 2002 from the Maastrichtian age Hell Creek Formation , may also belong to Quetzalcoatlus . The specimen, BMR P2002.2,
196-536: A letter to the same journal a few months later, in which he made the original specimen (TMM 41450-3) the holotype of a new genus and species, Quetzalcoatlus northropi . The genus name refers to the Aztec feathered serpent god, Quetzalcōātl . The specific name honors John Knudsen Northrop , the founder of Northrop Corporation , who drove the development of large tailless flying wing aircraft designs resembling Quetzalcoatlus . The holotype specimen of Q. northropi
245-589: A putative azhdarchiform . In 1975, Douglas Lawson compared the wing bones of Quetzalcoatlus northropi 's holotype to equivalent elements in Dsungaripterus and Pteranodon , and suggested that it represented an individual with a wingspan of around 15.5 m (51 ft), though presented alternative estimates of 11 m (36 ft) and 21 m (69 ft). Estimates put forward in subsequent years varied dramatically, ranging from 5.2–25.8 m (17–85 ft), owing to differences in methodology. From
294-817: A reduced fee. However, research articles published after 1997 are available for free (with online registration) one year after they are published i.e. delayed open access . Significant public-health related articles are also available for free, sometimes immediately after publication. AAAS members may also access the pre-1997 Science archives at the Science website, where it is called "Science Classic". Institutions can opt to add Science Classic to their subscriptions for an additional fee. Some older articles can also be accessed via JSTOR and ProQuest . The journal also participates in initiatives that provide free or low-cost access to readers in developing countries, including HINARI , OARE, AGORA , and Scidev.net . Other features of
343-459: A relatively light weight (about 70 kg (150 lb) in Chatterjee and Templin's case), and even then, struggled to explain how takeoff was achieved. Based on the work of Mark P. Witton and Michael Habib in 2010, it now seems likely that pterosaurs, especially larger taxa such as Quetzalcoatlus , launched quadrupedally, using the powerful muscles of their forelimbs to propel themselves off
392-651: A second Big Bend site around 40 km (25 mi) from the first. Field crews from the University of Texas, led by Wann Langston Jr. of the Texas Memorial Museum , investigated the site between 1972 and 1974, and unearthed three fragmentary skeletons of much smaller individuals. In 1975, Lawson announced the original find in an article in Science . At the time, a detailed description was underway, though this never saw publication. Instead, he published
441-417: A second species were found between 1972 and 1974, also by Lawson, around 40 km (25 mi) from the type of Q. northropi . In 2021, these remains were assigned the name Quetzalcoatlus lawsoni by Brian Andres and (posthumously) Wann Langston Jr . Quetzalcoatlus northropi has gained fame as a candidate for the largest flying animal ever discovered, though estimating its size has been difficult due to
490-644: A short, blunt beak, owing to the attribution of remains from Wellnhopterus , the beak is actually long and slender. The tip is not preserved, so it is not clear how the beak ends. The beak likely had a gape of around 52 degrees. Typically among azhdarchids, the nasoantorbital fenestra is very large, with more than 40% of its height being above the orbit . The orbit is small and obovate (an inverted egg shape). Quetzalcoatlus had nine elongated cervical vertebrae that were compressed dorsoventrally (up-and-down), and accordingly better suited to dorsoventral motion than lateral (side-to-side) motion. However, lateral motion
539-608: A similar size or body plan, and in consequence, published results vary widely. Crawford Greenewalt gave mass estimates of between 30–440 kg (66–970 lb) for Q. northropi , with the former figure assuming a small wingspan of 5.2 m (17 ft). A majority of estimates published since the 2000s have been substantially higher, around 200–250 kg (440–550 lb). In 2021, Kevin Padian and his colleagues estimated that Q. lawsoni would have weighed 20 kg (44 lb). In 2022, Gregory S. Paul estimated that Q. lawsoni had
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#1732790392113588-573: A specific field, Science and its rival Nature cover the full range of scientific disciplines . According to the Journal Citation Reports , Science ' s 2023 impact factor was 44.7. Studies of methodological quality and reliability have found that some high-prestige journals including Science "publish significantly substandard structures", and overall "reliability of published research works in several fields may be decreasing with increasing journal rank". Although it
637-536: A sub-family of Pteranodontidae , Nesov (1984) named the Azhdarchinae to include the pterosaurs Azhdarcho , Quetzalcoatlus , and Titanopteryx (now known as Arambourgiania ). They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. Previously it was thought that by the end of the Cretaceous, most pterosaur families except for
686-448: A terrestrial lifestyle. The humerus was short and robust, with considerable mobility, whereas the femur was more gracile. The wing finger may have been held between the body and proximal limb elements whilst on land. The first digit (digit I) is the smallest, and digit III is the biggest, with the exception of the wing finger. Like in all pterosaurs, forelimb musclature was extensive, and flapping power came from several muscle groups on
735-441: A very long neck and beak, shortened non-wing digits that were well adapted for terrestrial locomotion , and a very short tail. While historical interpretations of Quetzalcoatlus ' diet have ranged from scavenging to skim-feeding like the modern skimmer bird , it is likely that, like other large azhdarchids, Quetzalcoatlus northropi hunted small prey on the ground, similar to storks and ground hornbills . This has been dubbed
784-507: Is a cladogram showing the phylogenetic placement of Quetzalcoatlus within Azhdarchidae, from Andres (2021). Azhdarcho Albadraco Aerotitan Mistralazhdarcho Aralazhdarcho Phosphatodraco Eurazhdarcho Zhejiangopterus Cryodrakon Wellnhopterus Hatzegopteryx Arambourgiania Quetzalcoatlus lawsoni Quetzalcoatlus northropi Azhdarchidae Azhdarchidae (from
833-565: Is based in Washington, D.C., United States, with a second office in Cambridge , UK. The major focus of the journal is publishing important original scientific research and research reviews, but Science also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals , which focus on
882-786: Is currently unnamed, recently discovered in Transylvania , may be the largest representative of the family thus far discovered. This unnamed specimen (nicknamed " Dracula " by paleontologists), currently on display in the Altmühltal Dinosaur Museum in Bavaria is estimated to have a wingspan of 12–20 m (39–66 ft), although similarities to the contemporary azhdarchid Hatzegopteryx have also been noted. Azhdarchids were originally classified as close relatives of Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to
931-622: Is large compared to that of other specimens, with deep posterior (rear) emargination and no preserved symphisis . This suggests sexual dimorphism similar to that suggested for other monofenestratans (i.e. Darwinopterus , Anhanguera and Nyctosaurus ). Based on the limb morphology of Q. lawsoni , related azhdarchids such as Zhejiangopterus and other pterosaurs, Quetzalcoatlus was likely quadrupedal . Quetzalcoatlus and other azhdarchids have fore and hind limb proportions more similar to modern running ungulate mammals than to their smaller cousins, implying that they were uniquely suited to
980-537: Is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. Science
1029-664: Is the journal of the AAAS, membership in the AAAS is not required to publish in Science . Papers are accepted from authors around the world. Competition to publish in Science is very intense, as an article published in such a highly cited journal can lead to attention and career advancement for the authors. Fewer than 7% of articles submitted are accepted for publication. Science was founded by New York journalist John Michels in 1880 with financial support from Thomas Edison and later from Alexander Graham Bell . (Edison received favorable editorial treatment in return, without disclosure of
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#17327903921131078-686: The Persian word azhdar , اژدر , a dragon-like creature in Persian mythology ) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well (late Berriasian age, about 140 million years ago). Azhdarchids are mainly known for including some of the largest flying animals discovered, but smaller cat-size members have also been found. Originally considered
1127-409: The Q. northropi type material is of generalized enough morphology to be near identical to that of other giant azhdarchids, such as the overlapping elements of the contemporary Romanian giant azhdarchid Hatzegopteryx . Assuming that Q. northropi could be distinguished from other pterosaurs (i.e., if it was not a nomen dubium ), the possibility of it representing the same taxon as Hatzegopteryx
1176-549: The "blunt-beaked" forms with shorter and deeper bills and the "slender-beaked" forms with longer and thinner jaws. It had been suggested azhdarchids were skimmers, but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks and ground hornbills . Most large azhdarchids probably fed on small prey, including hatchling and small dinosaurs; in an unusual modification of
1225-536: The 1980s onwards, estimates were narrowed down to 11–12 m (36–39 ft). More recent estimates based on greater knowledge of azhdarchid proportions place its wingspan at 10–11 m (33–36 ft). Q. lawsoni , was estimated to have a wingspan of around 4.5 m (15 ft). In 2022, Gregory S. Paul estimated that Q. lawsoni had a wingspan of 5 m (16 ft) and a body length of 3.5 m (11 ft). Body mass estimates for giant azhdarchids are extremely problematic because no existing species shares
1274-516: The AAAS and executive publisher of Science , stated that the journal was becoming increasingly international: "[I]nternationally co-authored papers are now the norm—they represent almost 60 percent of the papers. In 1992, it was slightly less than 20 percent." The latest editions of the journal are available online, through the main journal website, only to subscribers, AAAS members, and for delivery to IP addresses at institutions that subscribe; students, K–12 teachers, and some others can subscribe at
1323-869: The Azhdarchidae disappeared from the fossil record, but recent studies indicate a wealth of pterosaurian fauna, including pteranodontids , nyctosaurids , tapejarids and several indeterminate forms. In several analyses, some taxa such as Navajodactylus , Bakonydraco and Montanazhdarcho were moved from Azhdarchidae to other clades. Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus . Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. There are two major types of azhdarchid morphologies:
1372-460: The University of California, Berkeley. The specimen he discovered 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 . In a thesis, Lawson gave the remains the provisional name of " Pteranodon gigas ", describing it as being "nearly twice as large as any previously described species of Pteranodon" . In 1972, Lawson discovered
1421-1004: The analysis Cretornis and Volgadraco were recovered as pteranodontians , Alanqa was recovered as a thalassodromine , and Montanazhdarcho was recovered just outside Azhdarchidae. The other most complete azhdarchid cladogram so far is that of Zhou et al. (2024): , based on Pêgas (2024): Keresdrakon Chaoyangopteridae Alanqidae Aralazhdarcho Eurazhdarcho Wellnhopterus Phosphatodraco Zhejiangopterus Mistralazhdarcho Aerotitan Azhdarcho Bayshin Tsav azhdarchid (MPC−Nd 100/303) Cryodrakon Albadraco Pui azhdarchid (LPB (FGGUB) R.2395) Hatzegopteryx Nipponopterus Burkhant azhdarchid (MPC−Nd 100/302) Arambourgiania Thanatosdrakon Quetzalcoatlus northropi Quetzalcoatlus lawsoni aff. Quetzalcoatlus sp. [REDACTED] [REDACTED] [REDACTED] Science (journal) Science
1470-506: The azhdarchid bodyplan, the robust Hatzegopteryx may have tackled larger prey as the apex predator in its ecosystem. In another departure from typical azhdarchid lifestyles, the jaw of Alanqa may possibly be an adaptation to crushing shellfish and other hard foodstuffs. Azhdarchids are generally medium- to large-sized pterosaurs, with the largest achieving wingspans of 10–12 metres (33–39 ft), but several small-sized species have recently been discovered. Another azhdarchid that
1519-469: The base of the beak, formed from the premaxilla, was a small crest. Though its exact form has yet, it is possible, based on what is preserved, that two distinct morphotypes exist: one with a humped premaxillary crest and a tall nasoantorbital fenestra (the opening combining the nasal and antorbital fenestra), and one with a more semicircular premaxillary crest and a shorter nasoantorbital fenestra. While early reconstructions of Quetzalcoatlus depicted it with
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1568-1105: The clade Azhdarchoidea was defined by David Unwin , and azhdarchids were determined to form a clade with Tapejaridae . Quetzalcoatlus now represents the type genus of the subfamily Quetzalcoatlinae, alongside other very large azhdarchids such as Arambourgiania and possibly Hatzegopteryx , as well as smaller taxa like Zhejiangopterus . Below is a cladogram showing the phylogenetic placement of Quetzalcoatlus within Neoazhdarchia from Andres and Myers (2013). Thalassodromeus sethi Tupuxuara leonardii Tupuxuara longicristatus Domeykodactylus ceciliae [REDACTED] Dsungaripterus weii Noripterus complicidens Noripterus parvus Eoazhdarcho liaoxiensis Shenzhoupterus chaoyangensis Chaoyangopterus zhangi Jidapterus edentus Radiodactylus langstoni Azhdarcho lancicollis TMM 42489 Zhejiangopterus linhaiensis Arambourgiania philadelphiae Quetzalcoatlus northropi [REDACTED] Quetzalcoatlus lawsoni Below
1617-599: The early part of the 20th century, important articles published in Science included papers on fruit fly genetics by Thomas Hunt Morgan , gravitational lensing by Albert Einstein , and spiral nebulae by Edwin Hubble . After Cattell died in 1944, the ownership of the journal was transferred to the AAAS. After Cattell's death in 1944, the journal lacked a consistent editorial presence until Graham DuShane became editor in 1956. In 1958, under DuShane's leadership, Science absorbed The Scientific Monthly , thus increasing
1666-596: The editor of Science in 2000. Biochemist Bruce Alberts took his place in March 2008. Geophysicist Marcia McNutt became editor-in-chief in June 2013. During her tenure the family of journals expanded to include Science Robotics and Science Immunology , and open access publishing with Science Advances . Jeremy M. Berg became editor-in-chief on July 1, 2016. Former Washington University in St. Louis Provost Holden Thorp
1715-447: The financial relationship, at a time when his reputation was suffering due to delays producing the promised commercially viable light bulb.) However, the journal never gained enough subscribers to succeed and ended publication in March 1882. Alexander Graham Bell and Gardiner Greene Hubbard bought the magazine rights and hired young entomologist Samuel H. Scudder to resurrect the journal one year later. They had some success while covering
1764-440: The fragmentary nature of its type specimen. Wingspan estimates over the years have ranged from 5.2–25.8 m (17–85 ft), though this has more recently been narrowed down to around 10–11 m (33–36 ft), based on extrapolations from more complete azhdarchids. The smaller and more complete Q. lawsoni had a wingspan of around 4.5 m (15 ft). Quetzalcoatlus ' proportions were typical of azhdarchids. It possessed
1813-607: The ground and into the air. 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 Douglas A. Lawson , who was then a geology graduate student from the Jackson School of Geosciences at the University of Texas, Austin. He would then go on to become a doctoral student at
1862-642: The journal's circulation by over 62% from 38,000 to more than 61,000. Physicist Philip Abelson , a co-discoverer of neptunium , served as editor from 1962 to 1984. Under Abelson the efficiency of the review process was improved and the publication practices were brought up to date. During this time, papers on the Apollo program missions and some of the earliest reports on AIDS were published. Biochemist Daniel E. Koshland Jr. served as editor from 1985 until 1995. From 1995 until 2000, neuroscientist Floyd E. Bloom held that position. Biologist Donald Kennedy became
1911-496: The meetings of prominent American scientific societies, including the AAAS. However, by 1894, Science was again in financial difficulty and was sold to psychologist James McKeen Cattell for $ 500 (equivalent to $ 17,610 in 2023). In an agreement worked out by Cattell and AAAS secretary Leland O. Howard , Science became the journal of the American Association for the Advancement of Science in 1900. During
1960-464: The subfamily Azhdarchinae within Pteranodontidae to comprise Azhdarcho , Quetzalcoatlus , and Titanopteryx . Unaware of the subfamily, in the same year, Kevin Padian erected the family Titanopterygiidae to accommodate Quetzalcoatlus and Titanopteryx . Two years later, in 1986, he synonymised the two taxa and elevated Azhdarchinae to family level, forming the family Azhdarchidae. In 2003,
2009-477: The terrestrial stalking model. Q. lawsoni , however, appears to have been associated with alkaline lakes , and a diet of small aquatic invertebrates has been suggested. Similarly, while Q. northropi seems to have been fairly solitary, Q. lawsoni appears to have been highly gregarious . For years it was uncertain how Quetzalcoatlus took off. Early models using a bipedal stance, such as that of Sankar Chatterjee and R.J. Templin in 2004, were heavily reliant on
Quetzalcoatlus - Misplaced Pages Continue
2058-640: The toothy ctenochasmatids (which include filter-feeders like Ctenochasma and Pterodaustro ). Currently it is widely agreed that azhdarchids were closely related to pterosaurs such as Tupuxuara and Tapejara . Classification after Unwin 2006, except where noted. One of the most complete cladograms of azhdarchids is presented by Andres (2021): Azhdarcho Albadraco Aerotitan Mistralazhdarcho Phosphatodraco Aralazhdarcho Eurazhdarcho Zhejiangopterus Wellnhopterus Cryodrakon Hatzegopteryx Arambourgiania Quetzalcoatlus [REDACTED] In
2107-629: The torso, forearm and manus . Terrestrial locomotion in Quetzalcoatlus likely involved a pacing gait, with both limbs on a given side of the body moving at the same time. The forelimbs were probably lifted off the ground first to avoid collision with the hindlimbs. When describing Quetzalcoatlus in 1975, Douglas Lawson and Crawford Greenewalt opted not to assign it to a clade more specific than Pterodactyloidea , though similarities to Titanopteryx (later Arambourgiania ) were noted earlier that year. In 1984, Lev Alexandrovich Nessov erected
2156-410: Was assumed that the smaller specimens of Quetzalcoatlus 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 Wann Langston Jr. in 1996, indicating that its status was too uncertain to give it
2205-581: Was named editor-in-chief on Monday, August 19, 2019. In February 2001, draft results of the human genome were simultaneously published by Nature and Science with Science publishing the Celera Genomics paper and Nature publishing the publicly funded Human Genome Project . In 2007, Science (together with Nature ) received the Prince of Asturias Award for Communications and Humanity. In 2015, Rush D. Holt Jr. , chief executive officer of
2254-404: Was not properly described and diagnosed until 2021, and until then, the status of the genus Quetzalcoatlus was noted as problematic. Mark Witton et al . noted that the holotype of Q. northropi represents elements which are typically considered undiagnostic to generic or specific level and that this complicates interpretations of azhdarchid taxonomy. For instance, Witton et al . suggested that
2303-611: Was noted. However, Witton et al . also noted that the skull material of Hatzegopteryx and then-unnamed Q. lawsoni differ enough that they cannot be regarded as the same taxon. These issues could only be resolved by Q. northropi being demonstrated as a valid taxon and its relationships with Q. lawsoni being investigated. An additional complication to these discussions is the likelihood that huge pterosaurs, such as Q. northropi , could have made transcontinental flights, suggesting that locations as disparate as North America and Europe could have shared giant azhdarchid species. Initially, it
2352-442: Was recovered accidentally when it was included in a field jacket prepared to transport part of a Tyrannosaurus rex specimen. Despite their association, the vertebra shows no evidence of scavenging. The bone came from an individual azhdarchid pterosaur estimated to have had a wingspan of 5–5.5 m (16–18 ft). However, while initially assigned to Quetzalcoatlus , Brian Andres and Wann Langston Jr (2021) regarded BMR P2002.2 as
2401-459: Was still extensive, and the neck and head could swing left and right about 180 degrees. The vertebrae at the base of the neck and the pectoral girdle are poorly preserved. The first four dorsal vertebrae are fused into a notarium . Most other dorsal vertebrae are absent, except for those integrated into the sacrum . Seven true sacral vertebrae are preserved. No caudal vertebrae are preserved. The pelvis of one Q. lawsoni specimen (TMM 41954-57)
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