Coloborhynchus is a genus of pterodactyloidpterosaur belonging to the family Anhangueridae, though it has also been recovered as a member of the Ornithocheiridae in some studies. Coloborhynchus is known from the Lower Cretaceous of England (Valanginian age, 140 to 136 million years ago),[1] and depending on which species are included, possibly the Albian and Cenomanian ages (113 to 93.9 million years ago) as well. Coloborhynchus was once thought to be the largest known toothed pterosaur,[2] however, a specimen of the closely related Tropeognathus is now thought to have had a larger wingspan.[3]
Like many ornithocheiroid pterosaurs named during the 19th century, Coloborhynchus has a highly convoluted history of classification. Over the years numerous species have been assigned to it, and often, species have been shuffled between Coloborhynchus and related genera by various researchers.
In 1874 Richard Owen, rejecting the creation by Harry Govier Seeley of the genus Ornithocheirus, named a species Coloborhynchus clavirostris based on holotype BMNH 1822, a partial snout from the Hastings Beds of the Wealden Group of East Sussex, England. The genus name means "maimed beak", a reference to the damaged and eroded condition of the fossil; the specific name means "key snout", referring to its form in cross-section. Owen also reclassified Ornithocheirus cuvieri and O. sedgwickii as species within the genus Coloborhycnhus, though he did not designate any of these three as the type species. Owen considered the defining trait of the genus to be the location of the front tooth pairs high on the side of the upper jaws. However, in 1913 Reginald Walter Hooley concluded that this location was an artefact of the erosion and that the genus was indistinguishable from Criorhynchus simus, the second genus and species Owen erected in 1874. Hooley also ignored Owen's reassignment of the two former Ornithocheirus species, leaving them in that genus. In 1967, Kuhn agreed with Hooley that Coloborhynchus clavirostris was a synonym of Criorhynchus simus. Furthermore, Kuhn was the first to formally designate C. clavirostris as the type species of the genus, rather than one of the Ornithocheirus species. Most later researchers followed these opinions, regarding Coloborhynchus as invalid relative to Criorhynchus.[4][5]
This changed in 1994 when Yuong-Nam Lee named Coloborhynchus wadleighi for a snout found in 1992 in the Albian age Paw Paw FormationTexas. The revival of the genus meant that of several related species, then assigned to other genera, had to be re-evaluated to determine whether or not they actually belonged to Coloborhynchus. In 2008, Taissa Rodrigues and Alexander Kellner re-formulated the key features of Coloborhynchus, again based mainly on the unique positions of the tooth sockets. Rodrigues and Kellner argued that Lee's C. wadleighi, which possessed some differences in the skull and teeth from C. clavirostris, and from an earlier time period, belonged in its own genus, which they named Uktenadactylus.[4]
A partial lower jaw originally named Tropeognathus robustus from the Romualdo Member of the Santana Formation in Brazil was assigned to Coloborhynchus in 2001 by Fastnacht, as Coloborhynchus robustus. In 2002, David Unwin supported this position, and also synonymized the more well-known species Anhanguera piscator with C. robustus. Rodrigues and Kellner disagreed with this classification, however, noting that both did not possess the unique straightened crest beginning at the snout tip, or sideways pointed teeth, of C. clavirostris. Instead, Rodrigues and Kellner regarded both Anhanguera robustus and Anhanguera piscator as valid species of Anhanguera.[4]
Another Brazilian species from the Romualdo Member was named Coloborhynchus spielbergi by Veldmeijer in 2003. It shares one or two characters in common with C. clavirostris (such as a flattened upper surface of the snout), though Rodrigues and Kellner regarded them as dubious, and noted that they are also present in other genera. Kellner recombined it as Anhanguera spielbergi in 2006. Similarly, Kellner excluded C. araripensis (formerly assigned to the genus Santanadactylus from the genus, based on lack of comparable diagnostic features. Unwin, in 2001, assigned the species Siroccopteryx moroccensis to Coloborhynchus, based on its similarity to C. wadleighi (type species of Uktenadactylus). Kellner, who regarded Uktenadactylus as a distinct genus in 2008, also regarded Siroccopteryx as distinct, and noted that like the other species assigned to Coloborhynchus, lacked its unique characteristics of the tooth row, a position also supported by Fastnacht in 2001.[4]
In 2001, Unwin also reassigned the two other species from the Cambridge Greensand to Coloborhynchus: C. capito and C. sedgwickii, the second of which being one of the original members of the genus according to Richard Owen in 1874. According to Kellner, C. capito is too incomplete to fully compare to C. clavirostris, and its precise classification is open to debate. He noted that C. sedgwicki does not possess the unique features of C. clavirostris (in fact it lacks a crest altogether), and may instead belong to the same genus as "Ornithocheirus" compressirostris (=Lonchodectes).[4]
In 2013, Rodrigues and Kellner considered Coloborhynchus to be monotypic, containing only C. clavirostris, and placed most other species in other genera, or declared them nomina dubia.[1] In 2018, Jacobs et al. named a new species of Coloborhynchus, C. fluviferox from the Ifezouane Formation of the Kem Kem Group of Morocco based on a partial snout, and also tentatively referred another specimen from the same locality to a different, unnamed species.[6] A 2020 review of Coloborhynchinae by Holgado and Pêgas moved both C. capito and C. fluviferox to a new genus, Nicorhynchus, and also referred the unnamed Ifezouane Formation coloborhynchine to N. fluviferox.[7] However, a 2023 review of Kem Kem pterosaurs found the traits that distinguish Nicorhynchus from Coloborhynchus to be subtle enough to justify their synonymy, stating that the material was damaged and fragmentary enough to support this.[8]
List of species and synonyms
Holotype and referred specimen of the possible species C. capito
Species which have been assigned to Coloborhynchus by various scientists over the years include:
C. capito (Seeley, 1870) = Ornithocheirus capito Seeley, 1870 = "Ptenodactylus capito" Seeley, 1869 [now classified as Nicorhynchus]
C. fluviferox Jacobs, Martill, Ibrahim & Longrich, 2018[6][now classified as Nicorhynchus]
Description
1914 illustration of the C. clavirostris holotype with dotted lines reconstructing worn away jaw margin
The type specimen of Coloborhynchus is known only from a partial upper jaw. Therefore, according to Rodrigues and Kellner's 2008 re-evaluation on Coloborhynchus clavirostris, it can only be differentiated from its relatives based on its unique combination of tooth socket positions. In Coloborhynchus, the two front teeth pointed forward and were higher on the jaw than the other teeth, while the next three pairs of teeth pointed to the sides. The final two (preserved) pairs of teeth pointed downward. Finally, a unique oval depression was located below the first pair of teeth.[4]
Like the related Anhanguera and Uktenadactylus, the tip of the snout flared out into a wider rosette, in contrast to the narrow posterior jaws. However, whereas the rosettes of species typically assigned to Anhanguera were rounded and spoon-shaped, those of Coloborhynchus were robust and box-shaped.[6]
Also like its close relatives, Coloborhynchus had a keel-shaped crest on the front of its jaws, though it was broad and thinned from base to top, rather than the uniformly thin crests of its relatives. This kind of thickened crest is also seen in Siroccopteryx moroccensis, which may be its closest relative or a member of the same genus. It also had a straight, rather than curved, front margin, unlike its relatives, and begins at the tip of the snout, rather than further back as in other species.[4]
A second specimen showing all of these same unique features was reported to Brazilian paleontologist Alexander Kellner by Darren Naish in 2007, and likely represents a second specimen of C. clavirostris, though it has not yet been described.[4]
The possible species Coloborhynchus capito represents the second largest known ornithocheirid (after a Tropeognathus specimen),[3] and indeed the largest toothed pterosaur known. A referred specimen from the Cambridge Greensand of England described in 2011 consists of a very large upper jaw tip which displays the tooth characteristics that distinguish C. capito from other species. The jaw tip is nearly 10cm tall and 5.6cm wide, with teeth up to 1.3cm in base diameter. If the proportions of this specimen were consistent with other known species of Coloborhynchus, the total skull length could have been up to 75cm, leading to an estimated wingspan of 7 metres (23ft).[11] However, this species may belong to a different genus.[1]
A rostrum fragment diagnostic to Coloborhynchus sp. is known from the Wessex Formation of England.[12]
Classification
A topology made by Andres and Myers in 2013 placed the species Coloborhynchus clavirostris and C. wadleighi (now generally considered as Uktenadactylus) within the family Ornithocheiridae as sister taxa to Ornithocheirus simus, and the family itself is placed within the more inclusive clade Ornithocheirae.[13] Later, in 2019, Pentland et al. recovered a similar result to the one by Andres and Myers in 2013 where Coloborhynchus is the sister taxon of Ornithocheirus. Their cladogram is shown on the left.[14] In 2018, Jacobs et al. also recovered a similar cladogram compared to Andres and Myers (2013), where both Coloborhynchus and Siroccopteryx were assigned to the Ornithocheiridae, however, unlike the study made by Andres and Myers, they used the name Uktenadactylus wadleighi to refer to C. wadleighi in their analysis. They published their conclusion in 2019.[6] However, many subsequent analyses made in 2019 and 2020 have recovered Coloborhynchus within the family Anhangueridae, more specifically within the subfamily Coloborhynchinae.[15][16][17] The cladogram on the left shows a phylogenetic analysis made by Borja Holgado and Rodrigo Pêgas in 2020.[7]
C. clavirostris holotype with interpretative line drawings
Similar to most anhanguerids, Coloborhynchus is traditionally thought to be an oceanic piscivore.[18] However one study found it among the carnivorous pterosaur taxa, as opposed to several other piscivore and insectivore species.[19]
Cearadactylus is a genus of large anhanguerid pterodactyloid pterosaur from the Romualdo Formation of Brazil, South America. Fossil remains of Cearadactylus dated back to the Albian stage of the Early Cretaceous period, about 112 million years ago. The only known species is C. atrox, described and named in 1985 by Giuseppe Leonardi and Guido Borgomanero. The name refers to the Brazilian state Ceará, and combines this with Greek daktylos, "finger", a reference to the wing finger of pterosaurs. The Latin atrox means "frightful", a reference to the fearsome dentition of the species.
Ornithocheirus is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the United Kingdom and possibly Morocco.
Tropeognathus is a genus of large pterosaurs from the late Early Cretaceous of South America. This genus is considered to be a member of the family Anhangueridae, however, several studies have also recovered it within another family called Ornithocheiridae. Both of these families are diverse groups of pterosaurs known for their keel-tipped snouts and large size. Tropeognathus is regarded as the largest pterosaur found in the Southern Hemisphere, only rivaled by the huge azhdarchids. The type and only species is Tropeognathus mesembrinus. Fossil remains of Tropeognathus have been recovered from the Romualdo Formation, which is a Lagerstätte located in the Santana Group of the Araripe Basin in northeastern Brazil.
Anhanguera is a genus of pterodactyloid pterosaur known from the Early Cretaceous Romualdo Formation of Brazil and the Late Cretaceous Kem Kem Group of Morocco. This pterosaur is closely related to Ornithocheirus, but belongs in the family Anhangueridae. The generic name comes from the Tupi words añanga, meaning "spirit protector of the animals" + wera "bygone".
Araripesaurus is a genus a pterosaur belonging to the suborder Pterodactyloidea, it was discovered in the Romualdo Formation of the Santana Group in northeastern Brazil, which dates back to the Aptian and Albian of the Early Cretaceous. The type species is A. castilhoi.
Siroccopteryx is an extinct genus of anhanguerid pterodactyloid pterosaur which lived in Morocco during the Cenomanian stage of the Late Cretaceous. Some researchers, such as David M. Unwin, consider the genus a junior synonym of Coloborhynchus.
Lonchodectes was a genus of lonchodectid pterosaur from several formations dating to the Turonian of England, mostly in the area around Kent. The species belonging to it had been assigned to Ornithocheirus until David Unwin's work of the 1990s and 2000s. Several potential species are known; most are based on scrappy remains, and have gone through several other generic assignments. The genus is part of the complex taxonomy issues surrounding Early Cretaceous pterosaurs from Brazil and England, such as Amblydectes, Anhanguera, Coloborhynchus, and Ornithocheirus.
Lonchodectidae or Lonchodraconidae is a group of pterosaurs within the clade Pterodactyloidea. It has variously been considered to be within Ctenochasmatoidea, Azhdarchoidea and Pteranodontoidea. They are notable for their high, conical tooth sockets and raised alveolar margins.
Ornithocheiridae is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the Early to Late Cretaceous periods, around 140 to 90 million years ago.
Uktenadactylus is a genus of anhanguerid pterodactyloid pterosaurs from the Lower Cretaceous Paw Paw Formation of Texas, United States and the Wessex Formation on the Isle of Wight, England. Fossil remains of Uktenadactylus dated back to the Early Cretaceous period, from about 125 to 100 million years ago.
Ornithocheirae is an extinct clade of pteranodontoid pterosaurs from the Early Cretaceous to the Late Cretaceous of Asia, Europe, North America and South America. It was named by Harry Seeley in 1870 as a family that contains Ornithocheirus and its relatives. The name was emended to Ornithocheiridae, to match the requirements of the ICZN Code that a family-ranked clade should end with an -idae suffix. Brian Andres (2010) in his review of pterosaur phylogeny, defined the name Ornithocheirae phylogenetically, as a node-based taxon consisting of the last common ancestor of Anhanguera and Ornithocheirus and all its descendants. Thus Ornithocheirae is defined to include two families, the Anhangueridae and the Ornithocheiridae, following the opinion of Alexander Kellner and Andres that these families should not be synonymized based on their original phylogenetical definitions. However, subsequent studies in 2019 have found Ornithocheirae to be a more inclusive group containing both Anhangueria and Targaryendraconia.
Cimoliopterus is a genus of pterosaur that lived during the Late Cretaceous in what is now England and the United States. The first known specimen, consisting of the front part of a snout including part of a crest, was discovered in the Grey Chalk Subgroup of Kent, England, and described as the new species Pterodactylus cuvieri in 1851. The specific name cuvieri honoured the palaeontologist George Cuvier, and the genus Pterodactylus was then used for many pterosaurs of species that are no longer thought to be closely related. It was among the first pterosaurs to be depicted as sculptures, in Crystal Palace Park in the 1850s. The species was subsequently assigned to various other genera, including Ornithocheirus and Anhanguera. In 2013, the species was moved to a new genus, as Cimoliopterus cuvieri; the generic name Cimoliopterus is derived from the Greek words for "chalk" and "wing". Other specimens and species have also been assigned to or synonymised with the species with various levels of certainty. In 2015, a snout discovered in the Britton Formation of Texas, US, was named as a new species in the genus, C. dunni; the specific name honours its collector, Brent Dunn.
Lonchodraco is a genus of lonchodraconid pterodactyloid pterosaur from the Late Cretaceous of southern England. The genus includes species that were previously assigned to other genera.
Camposipterus is a genus of pterodactyloid pterosaur from the Early Cretaceous of England. Fossil remains of Camposipterus dated back to the Early Cretaceous, about 112 million years ago.
Anhangueria is a group of pterosaurs belonging to the clade Pteranodontoidea. Fossil remains of this group date back from the Early to Late Cretaceous periods, around 140 to 92.5 million years ago. Anhangueria was named by paleontologists Taissa Rodrigues and Alexander Kellner in a review of Ornithocheirus species in 2013, they defined the clade as a branch-based taxon consisting of all pteranodontoids more closely related to Anhanguera blittersdorffi than to Istiodactylus latidens and Cimoliopterus cuvieri.
Maaradactylus is a genus of anhanguerid pterodactyloid pterosaur known from the Lower Cretaceous period of the Romualdo Formation of northeastern Brazil.
Ornithocheiromorpha is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early to Late Cretaceous periods, around 140 to 92.5 million years ago. Ornithocheiromorphs were discovered worldwide except Antarctica, though most genera were recovered in Europe, Asia and South America. They were the most diverse and successful pterosaurs during the Early Cretaceous, but throughout the Late Cretaceous they were replaced by pteranodontians and azhdarchoids. The Ornithocheiromorpha was defined in 2014 by Andres and colleagues, and they made Ornithocheiromorpha the most inclusive clade containing Ornithocheirus, but not Pteranodon.
Serradraco is a genus of Early Cretaceous pterodactyloid pterosaur from the Valanginian aged Tunbridge Wells Sand Formation in England. Named by Rigal et al. in 2018 with the description of a second specimen, it contains a single species, S. sagittirostris, which was formerly considered a species of Lonchodectes, L. sagittirostris. In 2020, Averianov suggested it did not belong in Lonchodectidae.
Nicorhynchus is a genus of anhanguerid pterosaur from the Cretaceous period. It contains two species, the type species, N. capito, from the Cambridge Greensand of England, and N. fluviferox from the Kem Kem Group of Morocco. These species were previously assigned to Coloborhynchus.
Akharhynchus is an extinct genus of tropeognathine pteranodontoid pterosaurs possibly from the Cretaceous Kem Kem Group of Morocco. The genus contains a single species, A. martilli, known from a small fragment of the premaxillae.
↑ Martill, David M.; Unwin, David M. (April 2012). "The world's largest toothed pterosaur, NHMUK R481, an incomplete rostrum of Coloborhynchus capito (Seeley, 1870) from the Cambridge Greensand of England". Cretaceous Research. 34: 1–9. doi:10.1016/j.cretres.2011.09.003.
↑ Andres, Brian; Myers, Timothy S. (September 2012). "Lone Star Pterosaurs". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103 (3–4): 383–398. doi:10.1017/S1755691013000303. S2CID84617119.
↑ Borja Holgado, Rodrigo V. Pêgas, José Ignacio Canudo, Josep Fortuny, Taissa Rodrigues, Julio Company & Alexander W.A. Kellner, 2019, "On a new crested pterodactyloid from the Early Cretaceous of the Iberian Peninsula and the radiation of the clade Anhangueria", Scientific Reports9: 4940 doi:10.1038/s41598-019-41280-4
↑ Pêgas, Rodrigo V.; Holgado, Borja; Leal, Maria Eduarda C. (2021). "On Targaryendraco wiedenrothi gen. nov. (Pterodactyloidea, Pteranodontoidea, Lanceodontia) and recognition of a new cosmopolitan lineage of Cretaceous toothed pterodactyloids". Historical Biology. 33 (8): 1266–1280. doi:10.1080/08912963.2019.1690482. S2CID209595986.
↑ Myers, Timothy S. (2017). "Diet of ornithocheiroid pterosaurs inferred from stable carbon isotope analysis of tooth enamel". Abstracts with Programs. GSA Annual Meeting in Seattle, Washington, USA. Vol.49. Geological Society of America. p.305496. doi:10.1130/abs/2017AM-305496.
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