Kryptodrakon Temporal range: Late Jurassic, | |
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Life restoration | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | † Pterosauria |
Suborder: | † Pterodactyloidea |
Genus: | † Kryptodrakon Andres, Clark & Xu, 2014 |
Type species | |
†Kryptodrakon progenitor Andres, Clark & Xu, 2014 |
Kryptodrakon is an extinct genus of pterodactyloid pterosaur from the Middle to Late Jurassic with an age of approximately 162.7 million years. [1] It is known from a single type species, Kryptodrakon progenitor. The age of its fossil remains made Kryptodrakon the basalmost and oldest pterodactyloid known to date. [1] [2]
In 2001, pterosaur bones were discovered in Xinjiang by Chris Sloan. The bones were first identified as those of a theropod; paleontologist James Clark later recognized their pterosaurian nature. [3]
In 2014, Brian Andres, Clark and Xu Xing named and described the type species Kryptodrakon progenitor. The generic name means hidden dragon from Greek κρυπτός, kryptos (hidden), and δράκων, drakon (dragon). The name alludes to the film Crouching Tiger, Hidden Dragon, which included some scenes filmed near the type locality. The specific name progenitor means ancestor or founder of a family in Latin, and refers to the animal's status as the most basal member of the Pterodactyloidea. [1]
The holotype, IVPP V18184, was uncovered in a layer of the Shishugou Formation dating from the Callovian–Oxfordian and having a minimum age of 161 million years. It consists of a partial skeleton lacking the skull. It contains fragments of both wings including the right fourth metacarpal, parts of the shoulder girdle and the second sacral vertebra. The bones were not articulated but were discovered in a small area of 30 square centimeters (4.7 sq in), at a considerable distance from other fossil remains, and thus likely represent a single individual. The bones were largely preserved three-dimensionally, without strong compression. The holotype probably was an adult individual. [1]
Kryptodrakon has an estimated wingspan of 1.47 meters (4.8 ft). Its fourth metacarpal is relatively slender and elongated, a strong indication that Kryptodrakon is a pterodactyloid. The fourth metacarpal has a minimum length of 72.2 centimeters (2.37 ft), while the humerus has an estimated length of between 75 centimeters (2.46 ft) and 86 centimeters (2.82 ft). These relative proportions are within the range of pterodactyloids. The radius shows an autapomorphy: it possesses an extra lump on the front outer lower side. The skeleton shows no signs of pneumatization. [1]
The main author performed a cladistic analysis, the most extensive ever published about the Pterosauria and providing clade definitions for most pterosaur groups previously undefined. The analysis showed that Kryptodrakon is the sister species of all other known Pterodactyloidea, together forming the Lophocratia, and thus the basalmost pterodactyloid known, if Pterodactyloidea is defined sensu Padian 2004 as containing those species possessing a metacarpal with at least 80% of the length of the humerus, homologous to Pterodactylus . The species is about five million years older than the oldest pterodactyloids previously discovered. A supposedly older pterodactyloid, a partial jaw referred to the group Ctenochasmatidae, had been described from the Middle Jurassic of the UK. [4] However, this specimen probably represents a teleosaurid stem-crocodilian instead of a pterosaur. [1]
Below is a cladogram showing the results of a phylogenetic analysis presented by Longrich, Martill, and Andres, 2018. [5]
Caelidracones |
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Kryptodrakon lived in a terrestrial or in-land habitat, far from the coast. Andres and colleagues saw this as an indication that the Pterodactyloidea had a terrestrial origin. The relatively short wings of Kryptodrakon confirm this hypothesis, as long-winged species of modern birds and long-winged pterosaurs tend to live at the coast and short-winged species tend to inhabit forests, as was shown by a study published as part of the describing article. [1]
Germanodactylus is a genus of germanodactylid pterodactyloid pterosaur from Upper Jurassic-age rocks of Germany, including the Solnhofen Limestone. Its specimens were long thought to pertain to Pterodactylus. The head crest of Germanodactylus is a distinctive feature.
Arambourgiania is an extinct genus of azhdarchid pterosaur from the Late Cretaceous period of Jordan, and possibly the United States. Arambourgiania was among the largest members of its family, the Azhdarchidae, and it is also one of the largest flying animals ever known. The incomplete left ulna of the "Sidi Chennane azhdarchid" from Morocco may have also belonged to Arambourgiania.
Montanazhdarcho is a genus of azhdarchoid pterosaur from the Late Cretaceous period of what is now the state of Montana, United States. Montanazhdarcho is known from only one species, M. minor.
Pterodactyloidea is one of the two traditional suborders of pterosaurs, and contains the most derived members of this group of flying reptiles. They appeared during the middle Jurassic Period, and differ from the basal rhamphorhynchoids by their short tails and long wing metacarpals. 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.
Gallodactylidae is a group of pterosaurs within the suborder Pterodactyloidea. Gallodactylids differed from other related pterosaurs in several distinct features, including fewer than 50 teeth present only in the jaw tips, and rounded crests present on the rear portion of the skull and jaws but not near the ends of their snouts. At least some species possessed jaw flanges, possibly used to bissect hard-shelled prey.
Bennettazhia is a genus of tapejaromorph pterosaur which lived during the Albian stage of the Early Cretaceous from what is now the Hudspeth Formation of the state of Oregon in the United States. Although originally identified as a species of the pteranodontoid pterosaur Pteranodon, Bennettazhia is now thought to have been a different animal. The type and only species is B. oregonensis.
Siroccopteryx is an extinct genus of anhanguerid pterodactyloid pterosaur, known from middle Cretaceous sediments in modern-day Morocco. Some researchers, such as David M. Unwin, consider the genus a junior synonym of Coloborhynchus.
Eoazhdarcho is a genus of azhdarchoid pterodactyloid pterosaur named in 2005 by Chinese paleontologists Lü Junchang and Ji Qiang. The type and only known species is Eoazhdarcho liaoxiensis. The fossil was found in the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China.
Muzquizopteryx is a genus of nyctosaurid pterodactyloid pterosaur from the Late Cretaceous period of what is now Coahuila, Mexico.
Kepodactylus is an extinct genus of ctenochasmatid pterodactyloid pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Colorado, United States.
Elanodactylus is a genus of ctenochasmatid pterodactyloid pterosaur from the Early Cretaceous period of what is now the Yixian Formation of Liaoning, China.
Monofenestrata is an unranked group of pterosaurs that includes the family Wukongopteridae and the suborder Pterodactyloidea.
Germanodactylidae is a controversial group of pterosaurs within the suborder Pterodactyloidea. It was first named by Yang Zhongjian in 1964, and given a formal phylogenetic definition in 2014 by Brian Andres, James Clark, and Xu Xing. They defined it as the least inclusive clade containing Germanodactylus cristatus and Normannognathus wellnhoferi, which they considered to be close relatives at the time. However, more recent studies by the same researchers have found that these pterosaurs may be only distantly related.
Eupterodactyloidea is an extinct group of pterodactyloid pterosaurs that existed from the latest Late Jurassic to the latest Late Cretaceous periods. Eupterodactyloids lived on all continents except Antarctica.
Alamodactylus is an extinct genus of nyctosaurid pteranodontoid pterosaur known from the Late Cretaceous of Texas, southern United States. It contains a single species, Alamodactylus byrdi.
Maaradactylus is a genus of anhanguerid pterodactyloid pterosaur known from the Lower Cretaceous period of the Romualdo Formation of northeastern Brazil.
Tethydraco is a genus of pterodactyloid pterosaur that lived during the Late Cretaceous period of what is now the area of present Morocco, about 66 million years ago. Tethydraco was originally assigned to the family Pteranodontidae. Some researchers argued that subsequently described material suggests that it may have been an azhdarchid, and possibly synonymous with Phosphatodraco, though this has been disputed. The type and only species is T. regalis.
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Barbaridactylus is a nyctosaurid pterosaur from the Ouled Abdoun Basin of Morocco, a basin that dates back to the Maastrichtian stage of the Late Cretaceous. It was published in 2018 by paleontologists Nicholas R. Longrich, David M. Martill, and Brian Andres. In the same publication, two other pterosaurs from the same basin were described: Alcione and Simurghia. The type and only species is B. grandis.
Simurghia is a genus of pterosaur from the Ouled Abdoun Basin of Morocco, a basin that dates to the Maastrichtian stage of the Late Cretaceous period, about 66 million years ago. It was published in 2018 by paleontologists Nicholas R. Longrich, David M. Martill, and Brian Andres, along with two other pterosaurs from the same basin: Alcione and Barbaridactylus. The type and only species is S. robusta.