Sinopterus Temporal range: Early Cretaceous, | |
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Fossil specimen of S. dongi, National Museum of Natural Science | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | † Pterosauria |
Suborder: | † Pterodactyloidea |
Family: | † Tapejaridae |
Subfamily: | † Sinopterinae |
Genus: | † Sinopterus Wang & Zhou, 2003 |
Type species | |
†Sinopterus dongi Wang & Zhou, 2003 | |
Synonyms | |
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Sinopterus (meaning "Chinese wing") is a genus of tapejarid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. It was first described and named by Wang Xiaolin and Zhou Zhonghe. Historically, there were multiple species attributed to the genus although only one is considered to be valid. Sinopterus is known for its proportionally large skull, which has a birdlike pointed beak, a long bony crest that starts with a tall premaxilla and goes back along the middle of the skull to form a point overhanging the rear of the skull, and its lack of teeth.
The type species, S. dongi, is based on IVPP V13363, an articulated, nearly complete skeleton. The skull of this individual was 17 centimeters (6.7 inches) long, and the wingspan was estimated to be 1.2 meters (3.9 feet). The authors suggested that it was an omnivore, and noted that it was the first record of a tapejarid outside of Brazil, and the earliest and most complete tapejarid. [1] The maximum adult wingspan of this pterosaur would have been 1.9 metres (6.2 ft), and an individual of this size would have weighed 2.87 kg (6.3 lb). [2]
Sinopterus is known from numerous specimens, some of which have been assigned to unique species and even different genera over the years. The type species, Sinopterus dongi, is known from one specimen described in 2003. A second specimen, BPV-077, was also described in 2003 by Li, Lü, and Zhang, who classified it in its own species, S. gui. It was said to differ from S. dongi mainly in its smaller size (only about half the size of S. dongi) and the presence of a notarium, [3] though this was later disproved. [4] Some later studies found S. gui to simply represent a younger specimen of S. dongi, [5] though one large analysis in 2014 found it to be a more primitive tapejarid. [6]
A third specimen was referred to Sinopterus in 2007, again classified as a new species, this time given the name S. jii. This species was first named by Lü & Yuan in 2005 as the type species of a new genus which they named Huaxiapterus. Two later studies in 2007 and 2011 both showed that H. jii was in fact more closely related to Sinopterus than to the two other species also assigned to Huaxiapterus, "H." corollatus and "H." benxiensis. Both groups of researchers concluded that Huaxiapterus jii should therefore be reclassified as Sinopterus jii, and that the other two species of "Huaxiapterus" require a new genus name. [4] [5] However, a more complete phylogenetic analysis suggested that Sinopterus may actually be an intermediate step in the grade between H. jii and the other two Huaxiapterus species, making Sinopterus paraphyletic if H. jii is included. [6]
In 2016, another species, S. lingyuanensis, was named. It purportedly differed from the other species in the proportions of its nasoantorbital fenestra, its rostral index, the relative sizes of its femur and tibia, and the relative sizes of the first and second wing digits. In the same paper describing this species, the species Huaxiapterus atavismus was also named. [7] However, Xinjun Zhang and colleagues in 2019 considered Huaxiapterus an invalid genus and therefore reassigned H. atavismus to Sinopterus, which created the new combination Sinopterus atavismus. [8]
A 2021 study by Darren Naish and colleagues of variation within pterosaur growth stages noted that numerous species had been classified as Sinopterus or "Huaxiapterus", most based only on a single specimen, and most differentiated from each other by features like wing proportions, skull length, and crest shape and size. Naish et al. pointed out that all of these features are known to be variable within a single species due to growth, and that there were unlikely to be such a high diversity of extremely similar species in the same ecosystem when their differences are more likely due to variation within a few species. They suggested that a larger study would be needed to untangle the question of how many species of Sinopterus-like pterosaurs actually existed in the Jiufotang ecosystem, and how they are related to each other. In a preliminary opinion, these scientists stated that there is likely only one valid species of Sinopterus, S. dongi, but that "Huaxiapterus" corollatus might be a valid second species based on unique wing and leg proportions. [2]
In 2023, Rodrigo V. Pêgas et al. reviewed the recent taxonomic histories of the tapejarids. In their article, they made S. gui and S. lingyuanensis synonymous with S. dongi. In addition, the genus Huaxiapterus was synonymized with Sinopterus as a result of H. jii and H. atavismus being reclassified as synonyms of S. dongi and "H." corollatus being reclassified to the new genus Huaxiadraco from which Huaxiapterus benxiensis became synonymous with. [9]
The cladogram below follows the 2014 analysis by Brian Andres and colleagues, showing the placement of two Sinopterus species ("S." gui and S. dongi) within the clade Tapejaromorpha. [6]
Tapejaromorpha |
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In 2019, a different analysis, this time by Alexander Kellner and colleagues, had recovered Sinopterus within the Tapejarinae, a subfamily within the larger group Tapejaridae, sister taxon to both Eopteranodon and Huaxiapterus. [10] The cladogram of their analysis is shown below:
Tapejaromorpha |
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Sinopterus is known from several specimens at various stages of growth, which has allowed scientists to study the changes these animals went through during their life histories.
At least one very small juvenile (possibly hatchling) specimen has been attributed to Sinopterus. This specimen was originally classified as a distinct genus in 2008, Nemicolopterus crypticus. The name Nemicolopterus comes from the Greek words "Nemos" meaning "forest", "ikolos" meaning "dweller", and the Latinised "pteron" meaning "wing". The specific name crypticus is derived from the Greek "kryptos", meaning "hidden". Thus "Nemicolopterus crypticus" means "Hidden flying forest dweller". The type specimen of N. crypticus, catalog number IVPP V-14377, is housed in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. The fossil was collected from the Jiufotang Formation, like all adult Sinopterus specimens. It was discovered in the Luzhhouou locality of Yaolugou Town, Jianchang County, Huludao City, western Liaoning Province in northeastern China. It has a wingspan of slightly under 25 centimeters (10 in), making it smaller than all but a few specimens of hatchling pterosaurs. [11] Wang et al. (2008), who originally described the specimen, concluded that it was immature, citing the amount of bone fusion and the ossification of the toes, gastralia, and sternum as indicating that it was a sub-adult rather than a hatchling. However, Darren Naish argued on his popular weblog that, due to the hypothesis that pterosaurs were highly precocial, bone fusion and ossification could have occurred very early in life, and that Nemicolopterus might in fact be a hatchling Sinopterus. [12] This identification was formally presented in 2021 study, which found that Nemicolopterus fit into a growth series as a young juvenile or hatchling Sinopterus hatchling. [2] An analysis of pterosaur relationships by Andres and colleagues in 2014 found the specimen in a sister group relationship with "Sinopterus" gui. [6]
Based on study of hatchling Sinopterus skeletons as well as comparison with hatchlings of other pterosaur species, Naish and colleagues (2021) found that the wing proportions and bone strength/flexibility of hatchlings were similar to adults, and concluded that Sinopterus was capable of powered flight very shortly after hatching. They found that while young juveniles would have been excellent gliders, they would not have been reliant on gliding alone as opposed to true flight. Juveniles also seem to have been more adapted to flight in closed environments, like dense forests, compared to adults. Juveniles therefore probably occupied different ecological niches than adults, transitioning between different niches as they grew. [2]
Tupuxuara is a genus of large, crested, and toothless pterodactyloid pterosaur from the Early Cretaceous period of what is now the Romualdo Formation of the Santana Group, Brazil, about 125 to 112 million years ago. Tupuxuara is a close relative of Thalassodromeus, and both form a group that is either called Thalassodrominae or Thalassodromidae.
Thalassodromeus is a genus of pterosaur that lived in what is now Brazil during the Early Cretaceous period, about a hundred million years ago. The original skull, discovered in 1983 in the Araripe Basin of northeastern Brazil, was collected in several pieces. In 2002, the skull was made the holotype specimen of Thalassodromeus sethi by palaeontologists Alexander Kellner and Diogenes de Almeida Campos. The generic name means "sea runner", and the specific name refers to the Egyptian god Seth due to its crest being supposedly reminiscent of Seth's crown. Other scholars have pointed out that the crest was instead similar to the crown of Amon. A jaw tip was assigned to T. sethi in 2005, became the basis of the new genus Banguela in 2015, and assigned back to Thalassodromeus as the species T. oberlii in 2018, though other researchers claim that Banguela is a valid genus. Another species was described in 2015 based on a supposed crest fragment, but this was later shown to be part of a turtle shell.
Tapejaridae are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, England, Hungary, Morocco, Spain, the United States, and China. The most primitive genera were found in China, indicating that the family has an Asian origin.
Eopteranodon is a genus of tapejarid pterosaur from the Aptian-age Lower Cretaceous Yixian Formation of Beipiao City, Liaoning, China. The genus was named in 2005 by paleontologists Lü Junchang and Zhang Xingliao. The type species is Eopteranodon lii.
Chaoyangopterus is a genus of chaoyangopterid pterosaur known from a partial skeleton found in Liaoning, China. Chaoyangopterus was found in rocks dating back to the Aptian-age Lower Cretaceous Jiufotang Formation of Dapingfang, Chaoyang.
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".
Jidapterus is a genus of chaoyangopterid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus was in 2003 named by Dong Zhiming, Sun Yue-Wu and Wu Shao-Yuan. The type species is Jidapterus edentus. The genus name is derived from Jílín Dàxué or "Jilin University" and a Latinized Greek pteron, "wing". The specific name means "toothless" in Latin.
Nurhachius is a genus of istiodactylid pterodactyloid pterosaur from the Barremian to Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. Its fossil remains date back about 120 million years ago.
Liaoningopterus, sometimes misspelled as "Liaoningopteryx", was a genus of anhanguerid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China.
The Jiufotang Formation is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms. It is a member of the Jehol group. The exact age of the Jiufotang has been debated for years, with estimates ranging from the Late Jurassic to the Early Cretaceous. New uranium-lead dates reveal the formation is deposited in the Aptian stage of the Early Cretaceous. Fossils of Microraptor and Jeholornis are from the Jiufotang.
Nemicolopterus is a dubious genus of tapejaromorph pterosaur, based on a very small specimen described as the smallest known "adult" pterosaur to date. It lived in the Jehol Biota 120 million years ago.
Shenzhoupterus is a genus of chaoyangopterid pterosaur from the Jiufotang Formation of modern-day Liaoning, China. Fossil remains of Shenzhoupterus date back to the Early Cretaceous period, approximately 120 million years ago.
Hongshanopterus is a genus of pterodactyloid pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, China.
Dsungaripteridae is a group of pterosaurs within the suborder Pterodactyloidea. They were robust pterosaurs with good terrestrial abilities and flight honed for inland settings, and were commonly interpreted as durophagous and possibly piscivorous pterosaurs. Fossils have been discovered from Early Cretaceous deposits in Asia, South America and possibly Europe based on a specimen found in Romania.
Chuanqilong is a monospecific genus of basal ankylosaurid dinosaur from the Liaoning Province, China that lived during the Early Cretaceous in what is now the Jiufotang Formation. The type and only species, Chuanqilong chaoyangensis, is known from a nearly complete skeleton with a skull of a juvenile individual. It was described in 2014 by Fenglu Han, Wenjie Zheng, Dongyu Hu, Xing Xu, and Paul M. Barrett. Chuanqilong shows many similarities with Liaoningosaurus and may represent a later ontogenetic stage of the taxon.
Ikrandraco is a genus of lonchodraconid pterodactyloid pterosaur known from the Lower Cretaceous Jiufotang Formation of northeastern China, and the Cambridge Greensand of England. It is notable for its unusual skull, which features a crest on the lower jaw.
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.
Forfexopterus is a genus of ctenochasmatid pterosaur from the Early Cretaceous Jiufotang Formation in China. It contains a single species, F. jeholensis, named from a mostly complete skeleton by Shunxing Jiang and colleagues in 2016. A second specimen, consisting of a wing, was described in 2020. While the first specimen is larger, it shows signs of being less mature than the second specimen, indicating that the developmental trajectories of Forfexopterus were variable. Like other ctenochasmatids, Forfexopterus had a long, low skull filled with many slender teeth; unlike other members of the group, however, it did not have a spatula-shaped snout tip or crests, and its teeth were more curved. A single characteristic distinguishes Forfexopterus from all other members of the wider group Archaeopterodactyloidea: of the four phalanx bones in its wing finger, the first was shorter than the second but longer than the third.
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).
Huaxiadraco is a genus of tapejarid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. It is the third valid genus of tapejarid from the Jehol Biota, after Sinopterus and Eopteranodon. It contains one species, Huaxiadraco corollatus, originally assigned to the defunct genus Huaxiapterus.