Remains of taxa that can be confidently assigned to Istiodactylidae have been found in the UK and China, in rocks dating from the Early Cretaceous period (Barremian to Aptian stage). Arbour and Currie (2011) described Canadian Gwawinapterus beardi as a member of Istiodactylidae living in the late Cretaceous (upper Campanian stage); however, Witton (2012) suggested the tooth replacement pattern in this animal does not match that of pterosaurs, suggesting that the species might be non-pterosaurian. Additional research suggested that the species was in fact a fish. The earliest known species might be Archaeoistiodactylus linglongtaensis, from the Middle Jurassic of China; however, it also has been suggested that the holotype specimen of this species might actually be a poorly preserved specimen of Darwinopterus. Hongshanopterus, a supposed istiodactylid from China, has been reclassified as a non-istiodactylid member of Ornithocheiroidea of uncertain phylogenetic placement by Witton (2012).
Istiodactylids were medium sized pterosaurs with flat, rounded jaws similar to that of a duck. They had small teeth lining their jaws, however.
|Life restoration of Istiodactylus latidens feeding on a stegosaur corpse.|
Howse, Milner & Martill, 2001
Unlike most ornithocheiroids, istiodactylids bear physiologies suited to a terrestrial life and many of their fossils have been found in freshwater-deposits. Istiodactylids are considered to be pterosaurian equivalents to vultures: acting as the clean-up crew in their native locations. Whether or not istiodactylids could swim like most water-loving pterosaurs remains a mystery.
Alamodactylus is an extinct genus of non-pteranodontoid pteranodontian known from the Late Cretaceous of Texas, southern United States. It contains a single species, Alamodactylus byrdi.Anurognathus
Anurognathus is a genus of small pterosaur that lived during the late Jurassic Period (Tithonian stage). Anurognathus was first named and described by Ludwig Döderlein in 1923. The type species is Anurognathus ammoni. The genus name Anurognathus is derived from the Greek αν/an- ("without"), оυρα/oura ("tail"), and γναθος/gnathos ("jaw") in reference to its unusually small tail relative to other "rhamphorhynchoid" (i.e. basal) pterosaurs. The specific name ammoni honours the Bavarian geologist Ludwig von Ammon, from whose collection Döderlein had acquired the fossil in 1922.Archaeoistiodactylus
Archaeoistiodactylus is an extinct genus of pterosaur from the Middle Jurassic of China.Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch (or Lower Cretaceous series). It is preceded by the Hauterivian and followed by the Aptian stage.Cuspicephalus
Cuspicephalus is an extinct genus of monofenestratan pterosaur known from Dorset in England.Guidraco
Guidraco (Chin. gui (鬼) "malicious ghost" + Lat. draco "dragon") is an extinct genus of toothed pterodactyloid pterosaur known from the Early Cretaceous of Liaoning Province, northeast China.Gwawinapterus
Gwawinapterus is a genus of Mesozoic fish known from a single fossil specimen, representing the single species Gwawinapterus beardi, from the late Cretaceous period of British Columbia, Canada. While initially described as a very late-surviving member of the pterosaur (flying reptile) group Istiodactylidae, further examination has cast doubt on the identification of the specimen as a pterosaur, and research published in 2012 identified the remains as having come from a saurodontid fish.Hongshanopterus
Hongshanopterus is a genus of istiodactylid ornithocheiroid pterodactyloid pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, China.The type species Hongshanopterus lacustris was in 2008 named and described by Wang Xiaolin, Diogenes de Almeida Campos, Zhou Zhonghe and Alexander Wilhelm Armin Kellner. The generic name combines a reference to the Hongshan culture in Lioaning with a Latinised Greek pteron, "wing". The specific name means "of the lake" in Latin, referring to the lake deposits the fossil was found in, at Dapinfang.Hongshanopterus is based on the holotype IVPP V14582, found in a layer of the Jiufotang Formation dating from the Aptian, It consists of a skull and five neck vertebrae of a single subadult individual.The wingspan of Hongshanopterus was estimated at 1.8 to 1.9 meters. It possessed a relatively high number of teeth, about thirty-six for both upper jaws combined. The teeth were robust and had triangular crowns which were flattened from mouth side to "lip" side, like those of other istiodactylids. The pterygoid bone had a ridge at the underside, pointing obliquely to the front and the outside.Hongshanopterus was in 2008 placed in the Istiodactylidae, in a basal position. It was less derived than other istiodactylids by having a tooth row that extended beyond the first third of the skull, and by having some teeth that were directed backwards.Istiodactylus
Istiodactylus is a genus of pterosaur that lived during the Early Cretaceous period, about 120 million years ago. The first fossil was discovered on the English Isle of Wight in 1887, and in 1901 became the holotype specimen of a new species, O. latidens (Latin for "wide tooth"), in the genus Ornithodesmus. This species was moved to its own genus, Istiodactylus, in 2001; this name is Greek for "sail finger". More specimens were described in 1913, and Istiodactylus was the only pterosaur known from three-dimensionally preserved fossils for much of the 20th century. In 2006, a species from China, I. sinensis, was assigned to Istiodactylus, but it has since been found to belong to a different genus.
Istiodactylus was a large pterosaur; estimates of its wingspan range from 4.3 to 5 metres (14 to 16 ft). Its skull was about 45 centimetres (18 in) long, and was relatively short and broad for a pterosaur. The front of the snout was low and blunt, and bore a semicircle of 48 teeth. The triangular teeth were closely spaced, interlocked, and formed a "razor-edged" outline. The lower jaw also had a tooth-like projection that occluded with the teeth. The skull had a very large naso-antorbital opening (which combined the antorbital fenestra and the opening for the bony nostril) and a slender eye socket. Some of the vertebrae were fused into a notarium, to which the shoulder blades connected. It had very large forelimbs, with a wing-membrane distended by a long wing-finger, but the hindlimbs were very short.
Until the 21st century, Istiodactylus was the only known pterosaur of its kind, and was placed in its own family, Istiodactylidae, within the group Ornithocheiroidea. Istiodactylus differed from other istiodactylids in having a proportionally shorter skull. The distinctive teeth of Istiodactylus indicate that it was a scavenger that may have used its teeth to sever morsels from large carcasses in the manner of a cookie cutter. The wings of Istiodactylus may have been adapted for soaring, which would have helped it find carcasses before terrestrial carnivores. Istiodactylus is known from the Wessex Formation and the younger Vectis Formation, which represent river and coastal environments that were shared with various pterosaurs, dinosaurs, and other animals.Liaoxipterus
Liaoxipterus is a genus of pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The type species is Liaoxipterus brachyognathus. The genus name is derived from the discovery locality Liaoxi and a Latinised Greek pteron, "wing". The specific name is derived from Greek brachys, "short" and gnathos, "jaw".Longchengpterus
Longchengpterus was a genus of istiodactylid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus was named in 2006 by Wang Li, Li Li, Duan Ye and Cheng Shao-li. The genus name is derived from the old name of Chaoyang City, Longcheng, and a Latinised Greek pteron, "wing". The specific name honours Zhao Dayu, the president of Shenyang Normal University and a contributor to the founding of the Western Liaoning Institute of Mesozoic Paleontology.Moganopterus
Moganopterus is an extinct genus of boreopterid pterosaur from the Early Cretaceous of western Liaoning Province, China.Monofenestrata
The Monofenestrata are an unranked group of pterosaurs that includes the family Wukongopteridae and the suborder Pterodactyloidea.The clade Monofenestrata was in 2009/2010 defined as the group consisting of Pterodactylus and all species sharing with Pterodactylus the synapomorphy, shared derived trait, of an external nostril confluent with the antorbital fenestra, the major skull opening on the side of the snout. The name is derived from Greek monos, "single", and Latin fenestra, "window". The concept was inspired by the discovery of Darwinopterus, a species combining a pterodactyloid-type skull with a more basal build of the remainder of the body. The Darwinoptera, a primitive subgroup of monofenestratans showing this transitional anatomy, was also named for Darwinopterus and defined as all descendants of its common ancestor with Pterorhynchus.The earliest known monofenestrate fossils have been found in the Stonesfield Slate formation of the United Kingdom, which dates to the Bathonian stage of the Middle Jurassic, dated to about 166 million years ago. Identified elements include cervical vertebrae, fourth metacarpals and a possible pterodactyloid synsacrum. Below is a cladogram showing the results of a phylogenetic analysis presented by Andres, Clark & Xu, 2014. This study found the two traditional groupings of ctenochasmatoids and kin as an early branching group, with all other pterodactyloids grouped into the Eupterodactyloidea.Nurhachius
Nurhachius is a genus of istiodactylid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China.
The genus was named in 2005 by Wang Xiaolin, Alexander Kellner, Zhou Zhonghe and Diogenes de Almeida Campos. The type species is Nurhachius ignaciobritoi. The genus name refers to Nurhaci, the first khan of the Qing Dynasty, whose original power base encompassed the region where the fossil was found. The specific name honours the late Brazilian paleontologist Ignácio Aureliano Machado Brito, who pioneered the study of pterosaurs in his country.Ornithocheiromorpha
Ornithocheiromorpha is a group of pterosaurs within the suborder Pterodactyloidea.
The Ornithocheiromorpha was defined in 2014 by Andres and colleagues. They made Ornithocheiromorpha the most inclusive clade containing Ornithocheirus but not Pteranodon.Pteranodontoidea
Pteranodontoidea is an extinct clade of ornithocheiroid pterosaurs from the Early Cretaceous to the Late Cretaceous (middle Barremian to middle Campanian stages) of Asia, Europe, North America and South America. It was named by Alexander Wilhelm Armin Kellner in 1996. In 2003, Kellner defined the clade as a node-based taxon consisting of the last common ancestor of Anhanguera, Pteranodon and all its descendants. Ornithocheiroidea is sometimes considered to be the senior synonym of Pteranodontoidea, however its depends on it definition. Ornithocheiroidea was originally defined as an apomorphy-based taxon by Christopher Bennett in 1994. Later, Kellner (2003) redefined it to represent the node of Anhanguera, Pteranodon, Quetzalcoatlus and Dsungaripterus. Later, David Unwin (2003) suggested a different definition, the node that contains Pteranodon longiceps and Istiodactylus latidens, thus making Pteranodontoidea a junior synonym of Ornithocheiroidea. Brian Andres (2008, 2010, 2014) in his analyses, converts Ornithocheiroidea using the definition of Kellner (2003) to avoid this synonymy.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.Wukongopteridae
The Wukongopteridae are a group of basal pterosaurs, found in China and the UK. It contains seven species in five genera, all dated to the middle Jurassic period,The Wukongopteridae were first named by Wang et al. in 2009, not yet giving an exact definition. The clade Wukongopteridae was first defined by Wang et al. in 2010 as "the most recent common ancestor of Wukongopterus lii and Kunpengopterus sinensis, and all of its descendants".Wukongopterus
Wukongopterus is a genus of basal pterosaur, found in Liaoning, China, from the Daohugou Beds, of the Middle or Late Jurassic. It was unusual for having both an elongate neck and a long tail.
The genus was described and named in 2009 by Wang Xiaolin, Alexander Kellner, Jiang Shunxing and Meng Xi. The genus name is derived from Sun Wukong, the Monkey King, the main hero of the Chinese classic novel Journey to the West, and a Latinised Greek pteron, "wing". The specific name honours Li Yutong, senior preparator of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP).The genus is based on holotype IVPP V15113, a nearly complete but compressed skeleton lacking the back and middle of the skull. The type individual appears to have broken its shin during life. Its wingspan is estimated at 730 millimetres (29 in). Wukongopterus also may have had an uropatagium, a membrane between the hind legs.