Coloborhynchus

Coloborhynchus is a genus in the pterosaur family Ornithocheiridae, and is known from the Lower Cretaceous of England (Valanginian age, 140-136 million years ago[1]), and depending on which species are included, possibly the Albian and Cenomanian ages (113-93.9 million years ago) as well. It is the largest known toothed pterosaur.[2]

Coloborhynchus
Temporal range: EarlyLate Cretaceous, 140–98 Ma
Coloborhynchus clavirostris
Holotype of C. clavirostris
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: Pterosauria
Suborder: Pterodactyloidea
Family: Ornithocheiridae
Subfamily: Ornithocheirinae
Genus: Coloborhynchus
Owen, 1874
Type species
Coloborhynchus clavirostris
Owen, 1874
Species
  • C. capito? (Seeley, 1869)
  • C. clavirostris Owen, 1874
  • C. fluviferox Jacobs et al., 2018
Synonyms

Ptenodactylus Seeley, 1869 (preoccupied)

Description

Coloborhynchus
Holotype jaw fragment of C. clavirostris in multiple views

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.[3]

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.

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.[3]

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.[3]

The possible species Coloborhynchus capito represents the second largest known ornithocheirid (after a Tropeognathus specimen), 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 10 cm tall and 5.6 cm wide, with teeth up to 1.3 cm 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 75 cm, leading to an estimated wingspan of 7 metres (23 ft).[4] 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.[5]

Classification and species

Ornithocheirus capito
Holotype and referred specimen of C. capito

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.[3]

Coloborhynchus piscator jconway
Restoration of the possible species C. piscator

This changed in 1994 when Yuong-Nam Lee named Coloborhynchus wadleighi for a snout found in 1992 in the Albian age Paw Paw Formation Texas. 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.[3]

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.[3]

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 assigned 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 (aka 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.[3]

Unwin (in 2001) also reassigned the two other species from the Cambridge Greensand to Coloborhycnhus: 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. claviraostris, 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).[3]

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]

Below is a cladogram showing the phylogenetic placement of this genus within Pteranodontia from Andres and Myers (2013).[6]

 Pteranodontia 
 Nyctosauridae 

Muzquizopteryx coahuilensis

"Nyctosaurus" lamegoi

Nyctosaurus gracilis

Alamodactylus byrdi

 Pteranodontoidea 

Pteranodon longiceps

Pteranodon sternbergi

 Istiodactylidae 

Longchengpterus zhaoi

Nurhachius ignaciobritoi

Liaoxipterus brachyognathus

Istiodactylus latidens

Istiodactylus sinensis

Lonchodectes compressirostris

Aetodactylus halli

Cearadactylus atrox

Brasileodactylus araripensis

Ludodactylus sibbicki

Ornithocheirae
 Anhangueridae 

Liaoningopterus gui

Anhanguera araripensis

Anhanguera blittersdorffi

Anhanguera piscator

Anhanguera santanae

 Ornithocheiridae 

Tropeognathus mesembrinus

Ornithocheirus simus

Coloborhynchus clavirostris

Coloborhynchus wadleighi

List of species and synonyms

Species which have been assigned to Coloborhynchus by various scientists since 2000 include:

Coloborhynchus spielbergi2
Skeletal cast of the possible species C. spielbergi
  • ?C. capito (Seeley 1869) = Pterodactylus capito Sauvage 1882 = Ornithocheirus capito Seeley 1870 = Ptenodactylus capito Seeley 1869
  • C. clavirostris Owen, 1874, the type species
  • ?C. sedgwicki (Owen 1874) = Ornithocheirus sedgwicki (Newton 1888) = Pterodactylus sedgwickii Owen 1859 [now classified as Camposipterus]
  • ?C. araripensis[7] (Wellnhofer 1985) = Santanadactylus araripensis Wellnhofer 1985 [also classified as Anhanguera]
  • ?C. robustus (Wellnhofer 1987) = Tropeognathus robustus Wellnhofer 1987 [also classified as Anhanguera]
  • ?C. ligabuei (Dalla Vecchia 1993) = Cearadactylus ligabuei Dalla Vecchia 1993 [also classified as Anhanguera or Cearadactylus]
  • ?C. wadleighi Lee 1994 [also classified as Uktenadactylus]
  • ?C. moroccensis (Mader & Kellner 1999) = Siroccopteryx moroccensis Mader & Kellner 1999
  • ?C. piscator[7] (Kellner & Tomida 2000) = Anhanguera piscator Kellner & Tomida 2000 [also classified as Anhanguera or C. robustus]
  • ?C. spielbergi[7] Veldmeijer 2003 [also classified as Anhanguera]
  • C. fluviferox Jacobs, Martill, Ibrahim & Longrich 2018[8]

Species assigned to Coloborhynchus in the past include:

  • C. cuvieri (Owen 1874) = Ornithocheirus sedgwicki (Newton 1888) = Pterodactylus cuvieri Bowerbank 1851 [now classified as Cimoliopterus]

Biology

Like most ornithocheirids, Coloborhynchus is traditionally thought to be an oceanic piscivore.

See also

References

  1. ^ a b c Rodrigues, T.; Kellner, A. (2013). "Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England". ZooKeys. 308: 1–112. doi:10.3897/zookeys.308.5559. PMC 3689139. PMID 23794925.
  2. ^ BBC Nature - 'Ugly' fossil is largest toothed pterosaur
  3. ^ a b c d e f g h Rodrigues, T. and Kellner, A.W.A. (2008). "Review of the pterodactyloid pterosaur Colobrohynchus." Pp. 219–228 in: Hone, D.W.E. and Buffetaut, E. (eds), Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zitteliana B, 28.
  4. ^ Martill, D.M. and Unwin, D.M. (2011). "The world's largest toothed pterosaur, NHMUK R481, an incomplete rostrum of Coloborhynchus capito (Seeley 1870) from the Cambridge Greensand of England." Cretaceous Research, (advance online publication). doi:10.1016/j.cretres.2011.09.003
  5. ^ Martill, David M. (2015), First occurrence of the pterosaur Coloborhynchus (Pterosauria, Ornithocheiridae) from the Wessex Formation (Lower Cretaceous) of the Isle of Wight, England., 126, 3, Proceedings of the Geologists' Association, pp. 377–380, archived from the original on 2016-10-26, retrieved 2016-10-26
  6. ^ Andres, B.; Myers, T. S. (2013). "Lone Star Pterosaurs". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103: 1. doi:10.1017/S1755691013000303.
  7. ^ a b c Veldmeijer, A.J. (2003). "Description of Coloborhynchus spielbergi sp. nov. (Pterodactyloidea) from the Albian (Lower Cretaceous) of Brazil". Scripta Geologica. 125: 35–139.
  8. ^ Jacobs, M.L., Martill, D.M., Ibrahim, N., Longrich, N., 2018, "A new species of Coloborhynchus (Pterosauria, Ornithocheiridae) from the mid-Cretaceous of North Africa", Cretaceous Research DOI: 10.1016/j.cretres.2018.10.018.

The Pterosaur Database (multiple species, scroll down)

Albian

The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma (million years ago). The Albian is preceded by the Aptian and followed by the Cenomanian.

Amblydectes

Amblydectes is known from fragments of jaw. It apparently had a jaw flattened towards the tip and triangular in cross-section. It has at times been synonymised with Coloborhynchus, Criorhynchus, Lonchodectes, or Ornithocheirus. A 2013 study found A. crassidens and A. eurygnathus to be nomina dubia, with A. platystomus possibly belonging to a separate, yet unnamed genus.

Anhanguera (pterosaur)

Anhanguera (meaning "old devil", Portuguese pronunciation) is a genus of pterodactyloid pterosaur known from the Early Cretaceous (Albian age, 112 Ma) Romualdo Formation of Brazil. This pterosaur is closely related to Ornithocheirus, and belongs in the family Ornithocheiridae within its own subfamily, Anhanguerinae.

Anhanguera araripensis

Anhanguera araripensis is a pterosaur species from the Albian-age Romualdo Member of the Early Cretaceous Santana Formation, of Barra do Jardim, Araripe Plateau, Ceará Province, Brazil. A. araripensis was named after the Araripe Plateau.

Anhanguera piscator

Anhanguera piscator (meaning "fishing old devil") is a species of pterosaur known from the Early Cretaceous (Albian age, 112Ma) Santana Formation of Brazil. This pterosaur is closely related to Ornithocheirus, and belongs in the family Ornithocheiridae within its own subfamily, Anhanguerinae. A. piscator has also been classified in the genus Coloborhynchus as Coloborhynchus piscator or as a synonym of Coloborhynchus robustus.

Anhanguera robustus

Anhanguera robustus is a large pterosaur species known from fossil remains dating to the Early Cretaceous Period of South America.

Brasileodactylus

Brasileodactylus a genus of pterosaur from the Aptian (Early Cretaceous), Lower Santana formation of Chapada do Araripe, Ceará, Brazil.

The genus was named by paleontologist Alexander Wilhelm Armin Kellner in 1984. The genus name means 'pterosaur (literally, [wing] "finger") from Brazil'. The type species is Brasileodactylus araripensis. The specific name refers to the Araripe Plateau. The holotype, MN 4804-V, is the front part of a mandible.

Later remains referred to Brasileodactylus include SMNS 55414, a mandible, and MN 4797–V, the front of a snout and mandible. More complete fossils are BSP 1991 I 27, a fragmentary skeleton, and AMNH 24444, a 429 mm (16.9 in) long skull, with mandible and proximal left wing. The last two specimens have been assigned to a Brasileodactylus sp. indet. by André Jacques Veldmeijer. However, some of the more complete specimens may belong to other pterosaurs, such as Barbosania.Kellner first assigned Brasileodactylus to the Ornithocheiridae. In 1991 he changed that to a more cautious Pterodactyloidea incertae sedis. In 2000 he affirmed a close affinity to the Anhangueridae. David Unwin in 2001 considered the form part of Anhanguera but later retracted. Eberhard Frey in 2003 thought it was a species of Coloborhynchus. In 2007 Unwin and David Martill suggested Ludodactylus was a junior synonym of Brasileodactylus.

Brasileodactylus was a medium sized pterosaur with a wingspan of approximately 4 m (13 ft). It had a long pointed snout and conical teeth that in the extreme front of the jaws were long, thin and forward pointing. Unlike some other Brazilian pterosaurs it had no crest on the snout or lower jaw but might have had one on the back of the skull.

Camposipterus

Camposipterus is a genus of pterodactyloid pterosaur from the Cretaceous of England.

Cimoliopterus

Cimoliopterus is a genus of pterodactyloid pterosaur from the Cretaceous of England, United Kingdom and Texas, United States.The type species, Cimoliopterus cuvieri, was previously considered parts of several different genera depending on author, but received its own genus in 2013.

Coloborhynchus spielbergi

Coloborhynchus spielbergi is a pterosaur species from the Albian-age Romualdo Member of the Lower Cretaceous Santana Formation, of Barra do Jardim, Araripe Plateau, Ceará Province, Brazil. C. spielbergi was named after the filmmaker Steven Spielberg.

Graphical timeline of pterosaurs

Timeline showing the development of the extinct reptilian order Pterosauria from its appearance in the late Triassic period to its demise at the end of the Cretaceous, together with an alphabetical listing of pterosaur species and their geological ages.

Kem Kem Beds

The Kem Kem Beds (also referred to by various names including the Continental Red Beds and Continental intercalaire) is a geological formation along the border between Morocco and Algeria in southeastern Morocco, whose strata date back to the Late Cretaceous.Dinosaur remains are among the fossils that have been recovered from the formation. Recent fossil evidence in the form of isolated large abelisaurid bones and comparisons with other similarly aged deposits elsewhere in Africa indicates that the fauna of the Kem Kem Beds (specifically in regard to the numerous predatory theropod dinosaurs) may have been mixed together due to the harsh and changing geology of the region when in reality they would likely have preferred separate habitats and likely would be separated by millions of years.

Lonchodectes

Lonchodectes (meaning "lance biter") was a genus of lonchodectid pterosaur from several formations dating to the Turonian (Late Cretaceous) 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.

Ornithocheiridae

Ornithocheiridae is a group of pterosaurs within the suborder Pterodactyloidea. They were among the last pterosaurs to possess teeth.

Ornithocheirus

Ornithocheirus (from Ancient Greek "ὄρνις", meaning bird, and "χεῖρ", meaning hand) is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the UK.

Several species have been referred to the genus, most of which are now considered as dubious species, or members of different genera, and the genus is now often considered to include only the type species, Ornithocheirus simus. Species have been referred to Ornithocheirus from the mid-Cretaceous period of both Europe and South America, but O. simus is known only from the UK. Because O. simus was originally named based on poorly preserved fossil material, the genus Ornithocheirus has suffered enduring problems of zoological nomenclature.

Fossil remains of Ornithocheirus have been recovered mainly from the Cambridge Greensand of England, dating to the beginning of the Albian stage of the early Cretaceous period, about 110 million years ago. Additional fossils from the Santana Formation of Brazil are sometimes classified as species of Ornithocheirus, but have also been placed in their own genera, most notably Tropeognathus.

Phylogeny of pterosaurs

This phylogeny of pterosaurs entails the various phylogenetic trees used to classify pterosaurs throughout the years and varying views of these animals. Pterosaur phylogeny is currently highly contested and several hypotheses are presented below.

Siroccopteryx

Siroccopteryx is an extinct genus of pterodactyloid pterosaur, known from middle Cretaceous (between the Albian and Cenomanian stages, about 105 million years ago) sediments in Morocco. Some researchers, such as David Unwin, consider the genus a junior synonym of Coloborhynchus.

Tropeognathus

Tropeognathus is a genus of large pterosaurs from the late Early Cretaceous of South America. It was a member of the Ornithocheiridae (alternately Anhangueridae), a group of pterosaurs known for their keel-tipped snouts, and was closely related to species of the genus Anhanguera. The type and only species is Tropeognathus mesembrinus; a second species, Tropeognathus robustus, is now considered to belong to Anhanguera. Fossils of Tropeognathus have been recovered from the fossiliferous Romualdo Formation of the Araripe Basin in northeastern Brazil.

Uktenadactylus

Uktenadactylus is a genus of pterodactyloid pterosaurs from the Lower Cretaceous Paw Paw Formation of Texas.

In 1994 Yuong Nam-Lee named a new species within the genus Coloborhynchus: Coloborhynchus wadleighi, based on a partial snout found in 1992 in Albian layers in Tarrant County, holotype SMU 73058 (Shuler Museum of Paleontology, Southern Methodist University at Dallas). The specific name honours the collector of the fossil, Chris Wadleigh. The reference of the species to the genus Coloborhynchus was based on the fact that both C. wadleighi and the type species of Coloborhynchus, Coloborhynchus clavirostris, share the trait of having three pairs of teeth laterally placed within a broad snout tip. This would distinguish both from the species Criorhynchus simus and justify a revival of the genus Coloborhynchus that since an analysis by Reginald Walter Hooley in 1914 had generally been considered identical to the genus Criorhynchus or the genus the latter had again been sunk into, Ornithocheirus.As a result of the reappearance of the concept European workers referred many species discovered in South-America to Coloborhynchus, a practice rejected by most South-American researchers. In 2009 a study by the Brazilian paleontologists Taissa Rodrigues and Alexander Kellner concluded that Coloborhynchus comprised only a single species, its type species C. clavirostris. Accordingly, in the same publication they created a new genus for C. wadleighi: Uktenadactylus. The genus name is derived from Uktena, a giant horned snake from the mythology of the Cherokee and Greek daktylos, "finger", a common element in the names of pterosaurs since Pterodactylus, referring to their typical wing finger.The fossil has a length of about fifteen centimetres and consists of the front end of the skull, containing the premaxilla and a small part of the maxilla. On top the base of a crest is present, gradually curving upwards and ending at a height of 7.5 centimetres, having attained at that point a thickness of four millimetres. The snout broadens towards the front. On the left side eight tooth sockets or alveoli are visible, on the right side six. The first pair of teeth was located in the flat tip of the snout, pointing forwards. The alveoli at first increase in size from the tip towards the back, the third pair being the largest with a diameter of 17.6/17.7 millimetres. The fourth pair is much smaller; to the back gradually the tooth sockets again increase in size. Thus a "prey grab" is formed. According to Rodrigues and Kellner the species has two unique traits: the presence of an oval depression above and in between the first pair of teeth and of a ventral medial depression between the second pair of teeth, a circular hollow positioned on the lower edge of the snout tip that Lee had interpreted as a possible pneumatic foramen.

Rodrigues and Kellner base the distinction between Uktenadactylus and Coloborhynchus clavirostris on several stratigraphical, methodological and phylogenetic considerations. There is a possible age difference of perhaps over thirty million years between the Berriasian-Valanginian British and the younger Albian-Cenomanian American form. Because both taxa are based on very limited remains, that however, even within these limits are clearly distinguishable on the species level, they reject a rash assumption of generic identity. Also the uncertain affinity with the closely related form Siroccopteryx would make such an assumption problematical. Rodrigues and Kellner identify only one shared derived trait for Uktenadactylus and Coloborhynchus clavirostris: an extreme enlargement of the second and third pairs of teeth. Differences between the taxa include the more forward position of the crest with C. clavirostris, beginning at the very tip of the snout; a deeper palatal groove and shallow grooves running parallel to the ridge of the front part of the palate; a depression located below the first alveoli and a more lateral position of the second, third and fourth tooth pairs whereas the fifth and sixth pair are to the contrary much closer to the midline of the skull. Both forms share some derived traits with Siroccopteryx: the second and third teeth pairs are larger than the fourth; the tip of the snout is flat causing the "prey grab" to be rectangular in cross-section and a similar thickness of the crest. The authors conclude from this that the three taxa likely formed an, as yet unnamed, clade together within the Anhangueridae.

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