The phylogeny of Anurognathidae is disputed. Both Alexander Kellner and David Unwin in 2003 defined the group as a node clade: the last common ancestor of Anurognathus and Batrachognathus and all its descendants. Some analyses, such as that of Kellner (2003), place them as the most basal group in the pterosaur tree.[12] Unwin also recovered the group as very basal, falling between Dimorphodontidae and Compylognathoididae.[12] However, anurognathids have some characteristics in common with the derivedPterodactyloidea, such as short and fused tail bones. More recent analyses, which include more fossils and taxa, support this observation and recover the group as substantially more derived than previously thought, but still basal to pterodactyloids. In 2010 an analysis by Brian Andres indicated the Anurognathidae and Pterodactyloidea were sister taxa. This conformed better to the fossil record because no early anurognathids were known at the time, and being the basalmost pterosaur clade would require a ghost lineage of over sixty million years.[13] However, the reassignment of "Dimorphodonweintraubi" to a basal position within Anurognathidae helps fill this gap and suggests this group appeared earlier than previously thought, possibly in the Early Jurassic Period.[14][15] Depending on where Anurognathidae falls within the Pterosauria, the existence of "Dimorphodonweintraubi" may have important implications for the timing of the evolution of major pterosaur clades, making further study of this specimen critical for pterosaur research.[15] In 2022, a phylogenetic analysis accompanying the description of Cascocauda recovered Anurognathidae as a sister clade to Breviquartossa.[16]
Lifestyle
Anurognathids are widely believed to have been nocturnal or crepuscular akin to bats. The fact that many anurognathids have large eye sockets supports the theory of operating in low-light environments. Anurognathid teeth suggest they were largely insectivorous, though some may have had more prey choices, such as Batrachognathus and Jeholopterus, which have been hypothesized to have been piscivorous.[17] At least some, such as Vesperopterylus, were arboreal, with claws suited for gripping tree branches.[4]
Feathers
A 2018 study of the remains of two small Jurassic-age pterosaurs from Inner Mongolia, China, named as the genus Cascocauda in 2022,[16] found that pterosaurs had a wide array of pycnofiber shapes and structures, as opposed to the homogeneous structures that had generally been assumed to cover them. Some of these had frayed ends, very similar in structure to four different feather types known from birds or other dinosaurs but almost never known from pterosaurs prior to the study, suggesting homology.[18][19] A response to this study was published in 2020, where it was suggested that the structures seen on the anurognathids were actually a result of the decomposition of aktinofibrils: a type of fibre used to strengthen and stiffen the wing.[20] However, in a response to this, the authors of the 2018 paper point to the fact that the presence of the structures extend past the patagium, and the presence of both aktinofibrils and filaments on Jeholopterus ningchengensis[21] and Sordes pilosus.[22] The various forms of filament structure present on the anurognathids in the 2018 study would also require a form of decomposition that would cause the different 'filament' forms seen. They therefore conclude that the most parsimonious interpretation of the structures is that they are filamentous proto-feathers.[23] But Liliana D’Alba points out that the description of the preserved integumentary structures on the two anurogmathid specimens is still based upon gross morphology. She also points out that Pterorhynchus was described to have feathers to support the claim that feathers had a common origin with Ornithodirans but was argued against by several authors. The only method to assure if it was homologous to feathers is to use a scanning electron microscope.[24]
1 2 Lü, J.; Meng, Q.; Wang, B.; Liu, D.; Shen, C.; Zhang, Y. (2017). "Short note on a new anurognathid pterosaur with evidence of perching behaviour from Jianchang of Liaoning Province, China". In Hone, D.W.E.; Witton, M.P.; Martill, D.M. (eds.). New Perspectives on Pterosaur Palaeobiology(PDF). Geological Society, London, Special Publications. Vol.455. London: The Geological Society of London. pp.95–104. doi:10.1144/SP455.16. S2CID219196969.
↑ Sprague, M. & McLain, M. A. (2018). Resolving the Mesadactylus Complex of Dry Mesa Quarry, Morrison Formation, Colorado. Journal of Vertebrate Paleontology, Program and Abstracts, 2018, p. 220.
↑ Unwin, D. M. & Bakhurina, N. N. (2000): Pterosaurs from Russia, Middle Asia and Mongolia. – In: M. J. Benton, M. A. Shishkin, D. M. Unwin & E. N. Kurochin (Eds), The age of dinosaurs in Russia and Mongolia; Cambridge (Cambridge University Press), 420–433.
↑ So, K. S.; Kim, P. H.; Won, C. G. (2024). "First Articulated Rhamphorhynchoid Pterosaur from the Early Cretaceous of the Democratic People's Republic of Korea". Paleontological Journal. 57 (1 supplement): S90–S94. doi:10.1134/S003103012360018X.
↑ Yang, Zixiao; Jiang, Baoyu; McNamara, Maria E.; Kearns, Stuart L.; Pittman, Michael; Kaye, Thomas G.; Orr, Patrick J.; Xu, Xing; Benton, Michael J. (December 2020). "Reply to: No protofeathers on pterosaurs". Nature Ecology & Evolution. 4 (12): 1592–1593. doi:10.1038/s41559-020-01309-8. hdl:10468/11874. PMID32989267. S2CID222163211.
Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous. Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger.
Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant birds from other living groups.
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.
Jeholopterus was a small anurognathid pterosaur known from the Middle to Late Jurassic Daohugou Beds of the Tiaojishan Formation of Inner Mongolia, China, and possibly the Early Cretaceous Sinuiju Formation of North Korea.
Anurognathus is an extinct genus of small pterosaur from the Late Jurassic Altmühltal Formation of Germany.
Azhdarchidae 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. Azhdarchids are mainly known for including some of the largest flying animals discovered, but smaller cat-size members have also been found. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the Azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and Titanopteryx. 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 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.
Batrachognathus is an extinct genus of anurognathid pterosaur from the Late Jurassic Karabastau Formation of the central Asian republic of Kazakhstan. The genus was named in 1948 by the Russian paleontologist Anatoly Nicolaevich Ryabinin. The type species is Batrachognathus volans. The genus name is derived from Greek batrakhos, "frog" and gnathos, "jaw", in reference to the short wide head. The specific epithet means "flying" in Latin.
The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represents an evolutionary grade of primitive members of flying reptiles. This suborder is paraphyletic unlike the Pterodactyloidea, which arose from within the Rhamphorhynchoidea as opposed to a more distant common ancestor. Because it is not a completely natural grouping, Rhamphorhynchoidea is not used as a formal group in most scientific literature, though some pterosaur scientists continue to use it as an informal grouping in popular works, such as The Pterosaurs: From Deep Time by David Unwin, and in some formal studies. Rhamphorhynchoids were the first pterosaurs to have appeared, in the late Triassic Period. Unlike their descendants, the pterodactyloids, most rhamphorhynchoids had teeth and long tails, and most species lacked a bony crest, though several are known to have crests formed from soft tissue like keratin. They were generally small, with wingspans rarely exceeding 2.5 meters, though one specimen alluded to by Alexander Stoyanow would be among the largest pterosaurs of all time with a wingspan of 10 meters, comparable to the largest azhdarchids. However, this alleged giant Jurassic pterosaur specimen is not recorded anywhere outside the original Time article. Nearly all rhamphorhynchoids had become extinct by the end of the Jurassic Period, though some anurognathids persisted to the early Cretaceous. The family Wukongopteridae, which shows a mix of rhamphorhynchoid and pterodactyloid features, is known from the Daohugou Beds which are most commonly dated to the Jurassic, but a few studies give a Cretaceous date. Furthermore, remains of a non-pterodactyloid from the Candeleros Formation extend the presence of basal pterosaurs into at least the early Late Cretaceous.
Dendrorhynchoides was a genus of anurognathid pterosaur containing only the holotype species D. curvidentatus that is known from the Middle Jurassic Tiaojishan Formation of Qinglong, northern Hebei Province, China.
Pterorhynchus is an extinct genus of pterosaur from the mid-Jurassic aged Daohugou Formation of Inner Mongolia, China.
Pterosaurs included the largest flying animals ever to have lived. They are a clade of prehistoric archosaurian reptiles closely related to dinosaurs. Species among pterosaurs occupied several types of environments, which ranged from aquatic to forested. Below are the lists that comprise the smallest and the largest pterosaurs known as of 2022.
The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period. It is known for its exceptionally preserved fossils, including those of plants, insects and vertebrates. It is made up mainly of pyroclastic rock interspersed with basic volcanic and sedimentary rocks. Previously, the Tiaojishan Formation was grouped together with the underlying Haifanggou Formation as a single "Lanqi Formation." The Tiaojishan Formation forms a key part of the Yanliao Biota assemblage, alongside the Haifanggou Formation.
The Caelidracones is a group of pterosaurs.
Novialoidea is an extinct clade of macronychopteran pterosaurs that lived from the latest Early Jurassic to the latest Late Cretaceous, their fossils having been found on all continents except Antarctica.
This timeline of pterosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of pterosaurs, the famed flying reptiles of the Mesozoic era. Although pterosaurs went extinct millions of years before humans evolved, humans have coexisted with pterosaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about thunderbirds told by the Native Americans of the modern Western United States may have been influenced by observations of Pteranodon fossils. These thunderbirds were said to have warred with water monsters, which agrees well with the co-occurrence of Pteranodon and the ancient marine reptiles of the seaway over which it flew.
Vesperopterylus is a genus of anurognathid pterosaur from the Early Cretaceous Jiufotang Formation of China, the geologically youngest member of its group. Notably, Vesperopterylus appears to have a reversed first toe, which would have been suited for gripping; it was likely arboreal, climbing or clinging to tree branches with curved, sharp claws. It also has a relatively short tail, in contrast with its tailless (Jeholopterus) and long-tailed (Dendrorhynchoides) relatives. It was first described and named by Lü Junchang et al. While the original spelling of the name was Versperopterylus, this was a typo, and was emended by the authors in accordance with the International Code of Zoological Nomenclature.
Luopterus is an extinct genus of anurognathid pterosaur containing only the holotype species L. mutoudengensis that is known from the Middle Jurassic Tiaojishan Formation of Qinglong, northern Hebei Province, China. It was originally named as a species of Dendrorhynchoides in 2012 but it was moved to the genus Luopterus in 2020. Luopterus was originally thought to be from the Early Cretaceous, with a wingspan that is about 40 centimeters (16 in), making it one of the smallest known pterosaurs.
Cascocauda is an extinct genus of anurognathid pterosaur from the Late–Middle Jurassic Tiaojishan Formation of Hebei Province, China. The genus contains a single species, C. rong, known from a complete skeleton belonging to a juvenile individual preserved with extensive soft-tissues, including wing membranes and a dense covering of pycnofibres. Some of these pycnofibres appear to be branched, resembling the feathers of maniraptoran theropod dinosaurs, and suggesting that pterosaur pycnofibres may be closely related to feathers in dinosaurs.
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