Azhdarchidae (from Persian word azhdar (اژدر), a serpentine creature equivalent to a dragon 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 included some of the largest-known flying animals of all time, but members no larger than a cat have also been found. Originally considered 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. By the time of the end-Cretaceous mass extinction, most pterosaur families except for the Azhdarchidae disappear from the fossil record, but recent studies indicate a wealth in pterosaurian faunas, including pteranodontids, nyctosaurids, tapejarids and several indeterminate forms. Some taxa like Navajodactylus, Bakonydraco and Montanazhdarcho were moved from Azhdarchidae to other clades.
|Reconstructed skeleton of Quetzalcoatlus northropi|
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: 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 the azhdarchid bauplan, the unusually 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 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), making it potentially the largest flying animal currently known to science.
Azhdarchids were originally classified as close relatives of Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to 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.
Alanqa is a genus of pterosaur from the Late Cretaceous Kem Kem Beds (which date to the late Albian or Cenomanian age) of southeastern Morocco.
The name Alanqa comes from the Arabic word العنقاء al-‘anqā’, for a Phoenix similar to the Simurgh of Persian mythology.Aralazhdarcho
Aralazhdarcho is a genus of azhdarchid pterosaur from the Santonian-early Campanian Late Cretaceous Bostobe Svita of Kazakhstan.
The genus was named in 2007 by Alexander Averianov. Already in 2004 the holotype had been described. The type species is Aralazhdarcho bostobensis. The genus name is derived from the Aral Sea and the related genus Azhdarcho. The specific name refers to the Bostobe Formation.
The genus is based on holotype ZIN PH, no. 9/43, consisting of the anterior end of a neck vertebra, probably the fifth or sixth. Several paratypes have also been referred: a jugal, a toothless lower jaw fragment, centra from vertebrae, the distal end of a scapula, the proximal end of a second phalanx of the left wing finger and the proximal end of a left femur, of which, however, the head has broken off. The remains were found at the Shakh-Shakh locality.
Aralazhdarcho was by Averianov assigned to the Azhdarchidae, in view of its lack of teeth and geological age. Averianov presumed it presented a more southern form as opposed to the contemporary related genus Bogolubovia that was found in adjoining more northern regions.Arambourgiania
Arambourgiania is a pterosaur from the Late Cretaceous (Maastrichtian) of Jordan and the United States. It was one of the largest members of this group.Argentinadraco
Argentinadraco (meaning "Argentina dragon") is an extinct genus of azhdarchoid pterosaur from the Late Cretaceous of Argentina. It contains a single species, A. barrealensis, named in 2017 by Alexander Kellner and Jorge Calvo. Argentinadraco is unusual for bearing a bottom jaw with a concave bottom edge, as well as a pair of ridges and depressions on the top surface. These features distinguish it from all other azhdarchoid groups, complicating its assignment, but it may belong to the Azhdarchidae. The ridges on the lower jaw may have been used to feed on small invertebrates in loose sediment within the system of lakes and rivers that it resided in.Azhdarcho
Azhdarcho is a genus of pterodactyloid pterosaur from the late Cretaceous Period of the Bissekty Formation (middle Turonian stage, about 92 million years ago) of Uzbekistan. It is known from fragmentary remains including the distinctive, elongated neck vertebrae that characterizes members of the family Azhdarchidae, which also includes such giant pterosaurs as Quetzalcoatlus. The name Azhdarcho comes from the Persian word azhdar (اژدر), a dragon-like creature in Persian mythology. The type species is Azhdarcho lancicollis. The specific epithet lancicollis is derived from the Latin words lancea (meaning "lance" or "spear") and collum ("neck").Azhdarchoidea
Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea.Bennettazhia
Bennettazhia is a genus of pterosaur (flying reptile).
In 1928 Charles Gilmore named a new species of Pteranodon: P. oregonensis. A humerus (holotype MPUC V.126713), two fused dorsal vertebrae and the broken-off end of some joint bone had been unearthed from the Lower Cretaceous (Albian) beds of the Hudspeth Formation in Wheeler County, in the state of Oregon, USA, to which the specific epithet refers. Gilmore noted similarities to Nyctosaurus though the specimens were larger.
In 1989 S. Christopher Bennett concluded that the remains might be those of a member of the Azhdarchidae instead of a pteranodontid. Russian paleontologist Lev Nesov therefore in 1991 named a new azhdarchid genus: Bennettazhia. The genus name honours Bennett and combines his name with Persian azhdarha, "dragon", a reference to Azhdarcho, the type genus of the Azhdarchidae. Bennett himself in 1994 changed his opinion and stated that it belonged to the Dsungaripteridae. Wellnhofer (1991), Peters (1997), Kellner (2003) and Unwin (2003) left it as belonging to the Pterodactyloidea incertae sedis.
In 2007 American biologist Michael Habib revealed the result of a study by CAT-scan of the type specimen. The humerus, 183 millimetres long, is uncrushed, which is uncommon for a pterosaur fossil and therefore offered a rare opportunity to investigate the bone structure. Apart from the thin bone wall, the humerus was filled with a spongy tissue consisting of trabeculae, very thin bone layers and struts, forming a light yet strong construction. Habib inferred that such strength would have allowed even very large pterosaurs to launch themselves from the ground using their forelimbs. The same investigation made a better classification possible. The humerus has an elongated deltopectoral crest that is unwarped. Both dsungaripterids and azhdarchoids show this feature, but only the latter group is typified by such a very thin outer bone wall. Habib concluded that Bennetazhia was a member of the Azhdarchoidea, a more encompassing group than the Azhdarchidae.Bogolubovia
Bogolubovia is a genus of pterosaur from the Upper Cretaceous (early Campanian) Rybushka Formation of Petrovsk, Saratov Oblast, Russia. It is named for Nikolai Nikolaevich Bogolubov, the palaeontologist who discovered the remains in 1914. It was in 1991 assigned to the Azhdarchidae. Wellnhofer (1991) however, retained it in the Pteranodontidae. Bogolubov had initially assigned the specimen, consisting of a single partial large cervical vertebra, as a new species of Ornithostoma, O. orientalis. It was later reclassified as a species of Pteranodon, before being assigned its own genus by Lev Nesov and Alexander Yarkov in 1989. The holotype has probably been lost, but other partial remains have been referred to the genus.
Most modern paleontologists consider it a probable member of the family Azhdarchidae. It would have been a mid-sized member of this family, with an estimated wingspan of 3–4 meters (9.8–13 feet) suggested by the holotype; a later found radius indicates a wingspan of 4.3 meters.Eoazhdarcho
Eoazhdarcho is a genus of azhdarchoid pterodactyloid pterosaur named in 2005 by Chinese paleontologists Lü Junchang and Ji Qiang. The type species is Eoazhdarcho liaoxiensis. The genus name combines a Greek eos, "dawn" with the name of the genus Azhdarcho, with the implication it was an early related form of the latter. The specific name refers to the ancient region Liaoxi.
The fossil was found in the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus is based on holotype GMN-03-11-02, a partial skeleton and lower jaw, and is distinguished from other pterosaurs by the proportions of its bones. The metacarpals are very elongated but the cervical vertebrae and hind limbs are not. It was relatively small by azhdarchoid standards, with a wingspan of about 1.6 meters (5.2 feet).
Its describers first assigned Eoazhdarcho to the Azhdarchidae in a basal position, and compared it to Azhdarcho. However, in 2006 they published a cladistic analysis, determining that several forms, among them Eoazhdarcho, were united in a natural group, a separate clade that could be set apart from a Azhdarchidae proper. In 2008 that clade was by Lü, Unwin and colleagues named the Chaoyangopteridae — the sister group of the Azhdarchidae within a much larger Azhdarchoidea — with Eoazhdarcho as one of the members.Eopteranodon
Eopteranodon (meaning "dawn Pteranodon (toothless wing)") is a genus of azhdarchoid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Yixian Formation of Beipaio City, Liaoning, China. The genus was in 2005 named by Lü Junchang and Zhang Xingliao. The type species is Eopteranodon lii.
It is based on the type specimen or holotype BPV-078, an incomplete skeleton and skull. Its skull, including a large crest, was toothless and similar to that of Pteranodon. The skull lacks the point of the snout but it was in life less than 200 millimeters long (7.9 inches), and the animal had a wingspan of about 1.1 meters (3.6 feet). A second specimen, D2526, described in 2006, had a larger wingspan. Despite its similarities to Pteranodon, Eopteranodon was not placed into a family by its describers, who put it into the clade Pteranodontia as incertae sedis (uncertain position).Shortly thereafter, a phylogenetic study of all known Yixian pterosaurs by the same scientists found it to be close to the azhdarchoids, noted for the crested genera Tapejara and Tupuxuara, and the giant, long-necked Quetzalcoatlus. A further analysis of other recently discovered forms, in 2006 still considered basal to (having split off earlier than) azhdarchoids, helped the original authors, along with David Unwin, to place these species together with Eopteranodon in a new clade Chaoyangopteridae, the possible sister group of the Azhdarchidae. However, in 2017, it was considered a member of the Tapejaridae based on proportions of the crest on the lower jaw and the limbs.Kem Kem Beds
The Kem Kem Beds (also referred to by various names including the Continental Red Beds and Continental intercalaire) is a geological formation along the border between Morocco and Algeria in southeastern Morocco, whose strata date back to the Late Cretaceous.Dinosaur remains are among the fossils that have been recovered from the formation. Recent fossil evidence in the form of isolated large abelisaurid bones and comparisons with other similarly aged deposits elsewhere in Africa indicates that the fauna of the Kem Kem Beds (specifically in regard to the numerous predatory theropod dinosaurs) may have been mixed together due to the harsh and changing geology of the region when in reality they would likely have preferred separate habitats and likely would be separated by millions of years.Montanazhdarcho
Montanazhdarcho is a genus of azhdarchoid pterosaur from the late Cretaceous Period (Campanian stage) of North America, known from only one species, M. minor.
The genus was named in 1993 by Kevin Padian, Armand de Ricqlès, and Jack Horner, again published by the same authors in 1995 and fully described in 2002.
The type species is Montanazhdarcho minor. The genus name refers to Montana and to the related species Azhdarcho. The specific name means "the smaller one" in Latin, a reference to the relatively small size in comparison to closely related forms.
The holotype, MOR 691 (Museum of the Rockies), was found by Robert W. Harmon in Glacier County, in the territory of the Blackfoot, in sandstone of the Upper Two Medicine Formation, a layer about 74 million years old. The fossil is largely uncompressed and that of an adult exemplar, as established by a study of the bone by de Ricqlès. It consists of a partial left wing, lacking the outer three wing finger phalanges, a complete shoulder girdle, a crushed cervical vertebra and two fragments of the symphysis of the mandible. The jaws were edentulous, i.e.: they lacked teeth.
Montanazhdarcho was by the authors assigned to the Azhdarchidae, mainly based on the elongated form of the neck vertebra. Compared to other azhdarchids, it was small; the fragments of humerus, radius, and carpal suggest an animal with a 2.5 metre wingspan (eight feet). Its ulna was longer than the wing metacarpal, which is atypical for azhdarchids. Further phylogenetic studies have disagreed as to its phylogenetic position; while some have recovered it as an Azhdarchid, others have found it to be a non-Azhdarchid AzhdarchoidNavajodactylus
Navajodactylus (meaning "Navajo finger") is an extinct genus of pterosaur from Late Cretaceous (late Campanian stage) deposits of San Juan Basin, New Mexico and Alberta, Canada.
The holotype specimen was discovered and collected by oceanographer Arjan C. Boeré from the Kirtland Formation in 2002. Navajodactylus was first named by Robert M. Sullivan and Denver W. Fowler in 2011 and the type species is Navajodactylus boerei. The generic name honors the Navajo Nation, combining their name with a Greek δάκτυλος, daktylos, "finger". The specific name honors Arjan C. Boeré.Navajodactylus is based on the holotype SMP VP-1445, from the Hunter Wash Member of the Kirtland Formation, San Juan Basin, dating to the upper Campanian, about 75 million years old. It consists of three pieces of the first phalanx of the wing finger. The paratype is SMP VP-1853, an ulna fragment. Two other first phalanges were referred: TMP 72.1.1 and TMP 82.19.295, from the Dinosaur Park Formation of the Dinosaur Provincial Park, Alberta.Navajodactylus was a medium-sized pterosaur, with an estimated wingspan of 3.5 meters (11.5 ft). Its autapomorphies largely exist in the unique form of the process on the first wing phalanx for the extensor tendon.Navajodactylus was tentatively assigned to the Azhdarchidae, because of its geological age as it does not show any synapomorphies of the group. Indeed, it may not actually be an azhdarchid, as it lacks pneumacy in its forelimb elements, as opposed to the extensive pneumacy seen in azhdarchids.Pterodactyloidea
Pterodactyloidea (derived from the Greek words πτερόν (pterón, for usual ptéryx) "wing", and δάκτυλος (dáctylos) "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional suborders of pterosaurs ("wing lizards"), and contains the most derived members of this group of flying reptiles. They appeared during the middle Jurassic Period, and differ from the basal (though paraphyletic) rhamphorhynchoids by their short tails and long wing metacarpals (hand bones). The most advanced forms also lack teeth, and by the late Cretaceous, all known pterodactyloids were toothless. Many species had well developed crests on the skull, a form of display taken to extremes in giant-crested forms like Nyctosaurus and Tupandactylus. Pterodactyloids (specifically the family Azhdarchidae) were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles.
"Pterodactyl" is also a common term for pterodactyloid pterosaurs, though it can also be used to refer to Pterodactylus specifically or (incorrectly) to pterosaurs in general. Well-known examples of pterodactyloids include Pterodactylus, Dsungaripterus, Pteranodon, and Quetzalcoatlus.
In 2014, fossils from the Shishugou Formation of China were classified as the most basal pterodactyloid yet found, Kryptodrakon. At a minimum age of about 161 my, it is about 5 million years older than the oldest previously known confirmed specimens. Previously, a fossil jaw recovered from the Middle Jurassic Stonesfield Slate formation in the United Kingdom, was considered the oldest known. This specimen supposedly represented a member of the family Ctenochasmatidae, though further examination suggested it belonged to a teleosaurid stem-crocodilian instead of a pterosaur. O'Sullivan and Martill (2018) described a partial synsacrum from the Stonesfield Slate identified as possibly pterodactyloid based on the number of incorporated sacrals although they commented that the morphology was perhaps closer to that of wukongopterids. If correctly identified, it would be the oldest pterodactyloid fossil known.Quetzalcoatlus
Quetzalcoatlus northropi is a pterosaur known from the Late Cretaceous of North America (Maastrichtian stage) and one of the largest-known flying animals of all time. It is a member of the family Azhdarchidae, a family of advanced toothless pterosaurs with unusually long, stiffened necks. Its name comes from the Mesoamerican feathered serpent god, Quetzalcoatl.Radiodactylus
Radiodactylus is an extinct genus of non-azhdarchid azhdarchoid pterosaur known from the Early Cretaceous of Texas, southern United States. It contains a single species, Radiodactylus langstoni.Thalassodromidae
Thalassodromidae or Thalassodrominae (meaning "sea runners", due to previous misconceptions of skimming behaviour; they are now thought to be terrestrial predators) is a group of azhdarchoid pterosaurs from the early Cretaceous period of Brazil. They are considered either to be a distinct family within the clade Neoazdarchia, closely related to dsungaripterids or azhdarchids, or alternatively a subfamily of the family Tapejaridae.Tupuxuara
Tupuxuara is a genus of large, crested, toothless pterodactyloid pterosaur.Volgadraco
Volgadraco ("Volga River dragon") is a genus of azhdarchid pterodactyloid pterosaur from the Upper Cretaceous of European Russia. It is known from lower beak (holotype SGU, no. 46/104a) and postcranial fragments from the early Campanian-age Rybushka Formation of Saratov, Russia. The size of this animal, and the development of blood supply in the lower jaw, are intermediate between older Santonian or Turonian azhdarchids like Azhdarcho and Bakonydraco and later Maastrichtian azhdarchids like Quetzalcoatlus. Volgadraco was described in 2008 by Averianov, Arkhangelsky, and Pervushov. The type species is V. bogolubovi, the specific name honouring Russian paleontologist Nikolai Nikolaevich Bogolubov. The authors consider the earlier named genus Bogolubovia to be a nomen dubium that in fact might be identical to Volgadraco.