Azhdarchoidea

Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea.

Azhdarchoidea
Temporal range:
Late Jurassic - Late Cretaceous, 150–66 Ma
Quetzalcoatlus 1
Reconstructed skeleton of Quetzalcoatlus northropi
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: Pterosauria
Suborder: Pterodactyloidea
Clade: Ornithocheiroidea
Clade: Azhdarchoidea
Nesov, 1984
Subgroups
Synonyms

Tapejaroidea
Unwin, 2003

Classification

Azhdarchoidea was given a phylogenetic definition by David Unwin in 2003. Unwin defined the group as the most recent common ancestor of Quetzalcoatlus and Tapejara, and all its descendants.[1]

There have been several competing views of azhdarchoid relationships. The first, presented by Felipe Pinheiro and colleagues in 2011, considered the tapejarids to be a monophyletic clade including the thalassodromids and chaoyangopterids.[2] The second, found by Naish & Martill 2006 as well as Lu et al. 2008, considered the traditional "tapejarids" to be a paraphyletic grade of primitive azhdarchoids. with true tapejarids most basal, and the thalassodromids and chaoyangopterids being successively more closely related to azhdarchids.[3] More recent and larger studies

All azhdarchoids which are part of the clade formed by Quetzalcoatlus and Tupuxuara are included in the group Neoazhdarchia ("new azhdarchids") as defined by Unwin in 2003. In 2003 Unwin also defined the clade Tapejaroidea, which he defined as the most recent common ancestor and all descendants of Tapejara, Quetzalcoatlus, and Dsungaripterus.[1]

There are competing theories of azhdarchoid phylogeny. Below is a cladogram showing the results of a phylogenetic analysis presented by Andres, Clark & Xu, 2014. This study found the a grouping of tapejarids at the base of the clade, with thalassodromids more closely related to azhdarchids and chaoyangopterids, as well as dsungaripterids.[4]

 Azhdarchoidea 

TapejaromorphaBakonydraco1DB

 Neoazhdarchia 
Dsungaripteromorpha

Thalassodromidae

Dsungaripteridae

Neopterodactyloidea

Chaoyangopteridae

AzhdarchidaeQuetzalcoatlus07

The result of another analysis, by Vidovic and Martill, is shown below. They found tapejarids (including chaoyangopterines) to be the closest relatives of azhdarchids, followed by thalassodromids (represented by Tupuxuara) and then by dsungaripterids, making Azhdarchoidea itself a small subgroup of dsungaripteroids.[5]

Dsungaripteroidea

Germanodactylus cristatus

Tapejaroidea

Dsungaripterus weii

Neoazhdarchia

TupuxuaraTupux longDB2

Azhdarchoidea
Tapejaromorpha

Shenzhoupterus

TapejaridaeBakonydraco1DB

AzhdarchidaeQuetzalcoatlus07

References

  1. ^ a b Unwin, D. M., (2003). "On the phylogeny and evolutionary history of pterosaurs." Pp. 139-190. in Buffetaut, E. & Mazin, J.-M., (eds.) (2003). Evolution and Palaeobiology of Pterosaurs. Geological Society of London, Special Publications 217, London, 1-347.
  2. ^ Pinheiro, F.L., Fortier, D.C., Schultz, C.L., De Andrade, J.A.F.G. and Bantim, R.A.M. (in press). "New information on Tupandactylus imperator, with comments on the relationships of Tapejaridae (Pterosauria)." Acta Palaeontologica Polonica, in press, available online 03 Jan 2011. doi:10.4202/app.2010.0057
  3. ^ Lü, J.; Unwin, D.M.; Xu, L.; Zhang, X. (2008). "A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution". Naturwissenschaften. 95 (9): 891–897. doi:10.1007/s00114-008-0397-5. PMID 18509616.
  4. ^ Andres, B.; Clark, J.; Xu, X. (2014). "The Earliest Pterodactyloid and the Origin of the Group". Current Biology. 24 (9): 1011–6. doi:10.1016/j.cub.2014.03.030. PMID 24768054.
  5. ^ Vidovic, S. U.; Martill, D. M. (2014). "Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: The Problem of Cryptic Pterosaur Taxa in Early Ontogeny". PLoS ONE. 9 (10): e110646. doi:10.1371/journal.pone.0110646. PMC 4206445. PMID 25337830.
1880 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1880.

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.

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.

Chaoyangopteridae

The Chaoyangopteridae are a family of pterosaurs within the Azhdarchoidea.

The clade Chaoyangopteridae was first defined in 2008 by Lü Junchang and David Unwin as: "Chaoyangopterus, Shenzhoupterus, their most recent common ancestor and all taxa more closely related to this clade than to Tapejara, Tupuxuara or Quetzalcoatlus". Based on neck and limb proportions, it has been suggested they occupied a similar ecological niche to that of azhdarchid pterosaurs, though it is possible they were more specialised as several genera occur in Liaoning, while azhdarchids usually occur by one genus in a specific location. The Chaoyangopteridae are mostly known from Asia, though the possible member Lacusovagus occurs in South America and there are possible fossil remains from Africa. Microtuban may extend the clade's existence into the early Late Cretaceous.Chaoyangopterids are distinguished from other pterosaurs by several traits of the nasoantorbital fenestra, a large hole on the side of the snout formed by the assimilation of the nares (nostril holes) into the antorbital fenestra. In members of this family, the nasoantorbital fenestra is massive, with the rear edge extending as far back as the braincase and jaw joint. The front edge is formed by a rod of bone known as the premaxillary bar, which is unusually slender in members of this family.Like their azhdarchid relatives, chaoyangopterids were terrestrial foragers.

Chaoyangopterus

Chaoyangopterus is a genus of azhdarchoid pterodactyloid pterosaur known from a partial skeleton found in Liaoning, China. It was found in rocks of the Aptian-age Lower Cretaceous Jiufotang Formation of Dapingfang, Chaoyang.

The genus was named and described in 2003 by Wang Xiaolin and Zhou Zhonghe. The type species is Chaoyangopterus zhangi. The genus name is derived from Chaoyang and a Latinised Greek pteron, "wing". The specific name honours journalist Zhang Wanlian for his efforts in protecting fossil sites.

The genus is based on holotype IVPP V13397, which includes the front of the skull, the lower jaws, the neck vertebrae, the shoulder and pelvic girdles, and the limbs. The skull is about 270 millimeters long (10.6 inches) and toothless, and its wingspan is estimated to have been around 1.85 meters (6.07 feet). Wang and Zhou concluded that it compared most closely to Nyctosaurus and classified it as a nyctosaurid, although they found that its shin was proportionally longer compared to the femur and humerus in Chaoyangopterus, that their animal had relatively shorter wings and longer legs than Nyctosaurus, and that it still had four fingers.The classification of Chaoyangopterus has since become unsettled, with subsequent reviewers disagreeing with the nyctosaurid assessment. David Unwin, in a popular work, included it without comment with the tapejarid family of azhdarchoid pterosaurs, known for their large head crests. A detailed phylogenetic analysis of Liaoning pterosaurs published by Lü Junchang and Ji Qiang in 2006 found it instead to be a basal azhdarchoid of no particular familial affiliation. However, subsequent analysis by Lu and Unwin found that within the Azhdarchoidea it formed a clade with several other forms such as Jidapterus and Shenzhoupterus, which they named Chaoyangopteridae.Wang and Zhou, however, stated in 2006 that Chaoyangopterus was a member of the Pteranodontidae and that Jidapterus, Eoazhdarcho and Eopteranodon are subjective junior synonyms of the former. This interpretation was not supported by a 2017 redescription of Jidapterus, which was able to reliably distinguish all of these genera.

Dsungaripteridae

Dsungaripteridae is a group of pterosaurs within the suborder Pterodactyloidea.

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.

Linlongopterus

Linlongopterus is a genus of pteranodontoid pterodactyloid pterosaur from the Early Cretaceous of China. It is known from a partial skull and mandible first named and described in 2015 by Rodrigues et al.. The only known specimen was found in the Jiufotang Formation of the Liaoning Province or China, and lived around 120 million years ago. The full binomial of the taxon is Linlongopterus jennyae, with the generic name translating from the Chinese "forest" (lin) and "dragon" (long), and the Greek "wing" (pteros), while the species name honours Elfriede Kellner, nicknamed Jenny, a supporter of paleontology. The proper word for wing in ancient Greek is however pteron (πτερόν).Linlongopterus was placed in a phylogenetic analysis to determine its relationships. The taxon was located within Dsungaripteroidea (sensu Kellner), which included Azhdarchoidea, Dsungaripteridae, and Pteranodontoidea, all of which were mostly dissolved due to the few remains known from Linlongopterus. Based on the teeth presence and anatomy, Linlongopterus was excluded from Azhdarchoidea and Dsungaripteridae, which are toothless and have very specialized teeth respectively. As such, Linlongopterus was placed within Pteranodontoidea. Within Pteranodontoidea, pteranodontids have no teeth, and istiodactylids have triangular teeth, different from the elongate teeth of Linlongopterus. The taxon does not have the crests on its jaws, which excludes it from derived Anhangueridae, leaving a position basal within Anhangueria most likely.

Lonchodectidae

Lonchodectidae is a group of pterosaurs within the clade Pterodactyloidea. It has variously been considered to be within Ctenochasmatoidea, Azhdarchoidea and Pteranodontia. They are notable for their high, conical tooth sockets.

Ornithocheiroidea

Ornithocheiroidea is a group of pterosaurs within the extinct suborder Pterodactyloidea.

Ornithostoma

Ornithostoma (meaning "bird mouth") is a genus of pterodactyloid pterosaurs.

In 1869, Harry Govier Seeley, cataloguing the fossils of the Sedgwick Museum at Cambridge, referred three snout fragments of toothless pterosaur specimens from the Lower Cretaceous Albian Cambridge Greensand of England to Ornithocheirus simus. These fragments had in 1859 been described by Richard Owen and referred to Pterodactylus sedgwickii and Pterodactylus fittoni. By 1871 Seeley had realised Ornithocheirus simus was a toothed form, different from the fragments. Therefore, he provisionally named them as a separate genus Ornithostoma, the name derived from Greek ὄρνις, ornis, "bird", and στόμα, stoma, "mouth". Seeley as yet provided no specific name. In 1891 however, he named the type species Ornithostoma sedgwicki Seeley 1891, apart from the snout fragments also referring to pelvis elements, claiming it was identical to Pteranodon and had priority. On that occasion he also selected a genolectotype from the three fragments, the holotype of the type species: specimen CAMSM B.54485.Samuel Wendell Williston in 1893 independently also considered Ornithostoma a synonym of Pteranodon ingens. He therefore renamed Pteranodon species: Ornithostoma ingens (Marsh 1872) Williston 1893 = Pteranodon ingens (= P. longiceps) and Ornithostoma harpyia (Cope 1872) = P. longiceps. Williston also created a special family and subfamily for Ornithostoma: the Ornithostomatidae and the Ornithostomatinae. Today, these concepts are no longer used. Williston indicated O. ingens as the type species, not knowing one had already been designated. However, Richard Lydekker denied the identity in 1904 and, also unaware of Seeley's earlier species name, created a purported (third) type species O. seeleyi.In 1914, Reginald Walter Hooley reviewed the material. He, incorrectly, claimed the pelvis elements were misidentified parts of the notarium of the shoulder girdel and referred several additional specimens to Ornithostoma, among them a skull fragment featuring a crest base, specimen CAMSM B.54406, and postcranial fragments such as vertebrae and limbs.In a 1994 paper, S. Christopher Bennett like Lydekker considered Ornithostoma to be distinct from Pteranodon, mainly because of the lower edge ridges of the jaw. He also concluded that it was a nomen dubium. This in 2001 was rejected however, by David Unwin who thought Ornithostoma to be a valid genus belonging to the Pteranodontidae, but limited the referable material to the original three fragments, including perhaps CAMSM B.54406. Hooley's postcranial fragments he referred to Lonchodectes. In 2012, Alexander O. Averianov again recombined the holotype with CAMSM B.54406 and selected postcrania, the combination showing traits that indicated a position in the Azhdarchoidea, representing an animal similar in some ways to Tapejara.The holotype specimen is a snout fragment with a length of about five centimetres or two inches. It represents a triangular cross-section of the snout, about an inch high. There is no crest and the jaws are toothless but featuring low protruding rims. The fragment is tapering towards the front, the upper edge inclining under an angle of 12°, indicating the snout tip was located about ten centimetres to the front of the breakage forming the anterior edge of the fragment.There has also been an Ornithostoma species based on a find from Russia. In 1914 Nikolai Nikolaevich Bogolubov named a single large vertebra found near Petrovsk Ornithostoma orientalis. The name was emended to O. orientale by George Olshevsky in 1991 because stoma is neuter. It has been renamed Bogolubovia orientalis (Nesov & Yarkov 1989) and been transferred from the Pteranodontidae to the Azhdarchidae.

Phylogeny of pterosaurs

This phylogeny of pterosaurs entails the various phylogenetic trees used to classify pterosaurs throughout the years and varying views of these animals. Pterosaur phylogeny is currently highly contested and several hypotheses are presented below.

Pteranodontia

Pteranodontia is an extinct group of ornithocheiroid pterosaurs that lived from the Early Cretaceous to the Late Cretaceous (middle Barremian to middle Campanian stages) of Asia, Europe, North America and South America.

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 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, 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.

Tapejaridae

Tapejaridae (meaning "the old beings") are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, Hungary, Morocco, Spain and China, where the most primitive genera are found, indicating that the family has an Asian origin.

Tapejaromorpha

Tapejaromorpha is a group of pterosaurs within the suborder Pterodactyloidea.

The Tapejaromorpha was defined in 2014 by Andres and colleagues. They made Tapejaromorpha the most inclusive clade containing Tapejara but not Quetzalcoatlus. Martill and Naish had previously proposed this same definition for Tapejaridae, but did not formalize it. Andres and colleagues instead defined Tapejaridae more narrowly, as the clade Tapejara + Sinopterus.

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.

Vectidraco

Vectidraco (meaning "dragon from the Isle of Wight"), is a genus of azhdarchoid pterosaur from the Lower Cretaceous of England.

In November 2008, Daisy Morris of Whitwell, Isle of Wight, a four-year-old avid natural history collector, discovered some small bones in a rock below the cliff face of Atherfield Point at the southwest coast of Wight. Her parents carefully collected all additional rocks with fossils in them that they could find at the site. In April 2009, Daisy's discovery was authenticated by palaeontologist Martin Simpson, from the University of Southampton. The Morris family donated the specimen to the Natural History Museum.

A scientific paper was published in 2013 about the find in the electronic journal PLoS ONE, titled A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy, Diversity and Phylogeny. In it Darren Naish, Martin Simpson, and Gareth Dyke described and named the type species Vectidraco daisymorrisae. The generic name is derived from the Latin Vectis, the Roman name of the island now known as the Isle of Wight, and dracō, meaning "dragon". The specific name honours the discoverer Daisy Morris. A children's book has also been written by Simpson about Daisy Morris's discovery, called Daisy and the Isle of Wight Dragon.The only known specimen, holotype NHMUK PV R36621, was uncovered in the Chale Clay Member of the Atherfield Clay Formation of the Lower Greensand Group, a clay layer of the Deshayesites forbesi zone, Deshayesites fittoni subzone, dating from the early Aptian, with an age of 124 million years. It consists of the left side of a pelvis, the right ischium, the rear dorsal vertebra and the first three sacral vertebrae, of a subadult or adult individual.Vectidraco is a relatively small pterosaur. The pelvis is four centimetres long as preserved. Vectidraco's wingspan was estimated at seventy-five centimetres, its total body length at thirty-five centimetres. In view of its affinities, the describing authors assumed it was a toothless form, featuring a crest on its snout.Several unique derived traits, autapomorphies, were established. The hip joint is bordered at its top rear corner by a triangular depression. This depression is overhung by a ridge running downwards to the rear. The front blade of the ilium features an undivided roughly oval depression at its front inner side, below a convex surface. Furthermore a unique combination of traits is present in that the elongated rear blade of the ilium is T-shaped, terminating in a wide expansion also projecting upwards, that is longer than the shaft of the rear blade itself.

Damage to the ilium shows the presence of camellate bone, internal air chambers. Also all the preserved vertebrae are pneumatised.Vectidraco was assigned to the Azhdarchoidea, in a basal position. If correct, this would make it one of the smallest azhdarchoids known.

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