Cimoliopterus

Cimoliopterus Temporal range: Ma PreꞒ Ꞓ O S D C P T J K Pg N
Holotype snout tip of C. cuvieri shown from the right side and below
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Pterosauria
Suborder:	†Pterodactyloidea
Clade:	†Ornithocheiromorpha
Clade:	† Lanceodontia
Clade:	† Ornithocheiriformes
Genus:	†Cimoliopterus Rodrigues & Kellner, 2013
Type species
†Pterodactylus cuvieri Bowerbank, 1851
Species
†C. cuvieri (Bowerbank, 1851) †C. dunni Myers, 2015
Synonyms
Genus synonymy Lonchodectes? Hooley, 1914 Synonyms of C. cuvieri Pterodactylus cuvieri Bowerbank, 1851 Ornithocheirus cuvieri (Bowerbank, 1851) Seeley, 1870 Coloborhynchus cuvieri (Bowerbank, 1851) Owen, 1874 Anhanguera cuvieri (Bowerbank, 1851) Bakhurina & Unwin, 1995 Ornithocheirus brachyrhinus? Seeley, 1870 Ornithocheirus dentatus? Seeley, 1870 Ornithocheirus denticulatus? Seeley, 1870 Ornithocheirus enchorhynchus? Seeley, 1870 Ornithocheirus scaphorhynchus? Seeley, 1870 Lonchodectes scaphorhynchus? (Seeley, 1870) Hooley, 1914 Ornithocheirus xyphorhynchus? Seeley, 1870 Pterodactylus fittoni? Owen, 1859 Ornithocheirus fittoni? (Owen, 1859) Seeley, 1870 Anhanguera fittoni? (Owen, 1859) Unwin, 2001 Pterodactylus compressirostris? Owen, 1851 Ornithocheirus compressirostris? (Owen, 1851) Seeley, 1870 Lonchodectes compressirostris? (Owen, 1851) Hooley, 1914

Cimoliopterus is a

Lithograph showing the C. cuvieri holotype and its now lost teeth, as figured by Bowerbank in 1851

Wing-finger bone that Owen

assigned to then P. cuvieri in 1851

In 1922, the Austrian naturalist Gustav von Arthaber lamented that the scientific literature had accepted the many Ornithocheirus names that had only been mentioned in Seeley's catalogue for students. In his opinion names were of no use without an illustration of the specimens they were based on, or better still, a complete reconstruction of the relevant skeleton. For this reason, he provided a drawing of the skull of O. cuvieri (among other species), one of the few species for which the known jaw material proved its validity.^[21] In 1924, von Arthaber's interpretations were criticised by the Hungarian palaeontologist Franz Nopcsa von Felső-Szilvás, who found some of the skull reconstructions "worthless".^[22]

Von Arthaber's outdated 1919 skull reconstruction of C. cuvieri

The discovery of more complete fossils of related pterosaurs from Brazil, such as Anhanguera (to which C. cuvieri was once assigned, skull shown), made the appearance of fragmentary English species clearer.

O. cuvieri and many other English pterosaurs were kept in the genus Ornithocheirus for most of the 20th century.

In 2013, the Brazilian palaeontologist Taissa Rodrigues and Kellner reviewed the species that had so far been placed in the genus Ornithocheirus (which they restricted to its

Because the fossils are incomplete, the size of Cimoliopterus is difficult to estimate.^[31] Extrapolating from the remains of more complete pterosaur species, as well as various bones possibly belonging to C. cuvieri, Bowerbank estimated a wingspan of about 5.1 metres (16.6 ft) in 1851. This was larger than the estimates for the earlier named P. giganteus (now in the genus Lonchodraco), which he had considered "gigantic" for a pterosaur.^[5][33] Later the same year, Owen called C. cuvieri "truly gigantic", compared to P. giganteus, which he felt was therefore inaccurately named.^[34] In 2001, comparing the C. cuvieri holotype specimen with the more complete Anhanguera, Unwin estimated a wingspan of about 3.5 metres (11 ft). He estimated an assigned specimen, CAMSM B54.431, to have had a wingspan of up to 5 metres (16 ft).^[2] In 2013, this specimen—originally a syntype snout tip of Ornithocheirus colorhinus—was tentatively assigned instead to Camposipterus by Rodrigues and Kellner.^[10] Witton and Michel gave a 4 metres (13 ft) wingspan for C. cuvieri in 2023, but cautioned it was "rough" due to the poor fossils.^[9] In 2015, Myers stated the holotypes of C. cuvieri and C. dunni belonged to individuals of a similar size.^[7] C. dunni would have been mid-sized for a pterosaur, with a wingspan of about 1.8 metres (6 ft), according to a press release accompanying its description.^[32] In 2019, Pêgas and colleagues refrained from estimating wingspans for such species represented by too fragmentary material.^[31]

More completely known related genera were fairly large pterosaurs, with proportionally large skulls, long jaws and tooth-rows, and often with large, rounded crests at the front of the jaws. The teeth at the front of the jaws were large and recurved, and further back the teeth were smaller, slightly recurved, and well-spaced. Much of the skeleton would have been

The C. cuvieri holotype snout in right (with old museum label), left, bottom, and top views

The holotype of C. cuvieri is composed of the front 18 cm (7 in) of the snout, represented mainly by the premaxillae, including the premaxillary crest. Eleven tooth sockets are preserved on each side.^[5][10] The preserved part of the snout is narrow. C. cuvieri is distinct in that the premaxillary crest is placed hindward on the snout by the seventh socket pair, but before the nasoantorbital fenestra (a large opening in front of the eye that combined the antorbital fenestra with the bony nostril).^[10] C. cuvieri has a low snout compared to Ornithocheirus and also possesses a forward-facing first pair of tooth sockets, unlike that genus. Furthermore, C. cuvieri can be distinguished from the genus Anhanguera because it lacks an expansion at the front of the snout, a feature otherwise present in the family Anhangueridae. C. cuvieri also does not have its fourth and fifth pair of tooth sockets smaller than its third and sixth, which is a key feature of Anhanguera.^[7][10][31]

Bowerbank and Owen described and figured the now lost teeth found with the C. cuvieri holotype in 1851. The right of the two frontmost sockets contained a newly erupted (emerged through the gums) tooth, which protruded about one-third of an inch downwards and forwards at an oblique angle. The fifth socket on the right side and the eighth on the left contained budding teeth that did not protrude past the sockets, lying close to the inner walls of the sockets of the fully erupted teeth. The two fully developed displaced teeth were slightly curved, somewhat compressed, and their breadth gradually diminished from the open bases to their tips. The tips were broken off, revealing they were composed of compact, hard

Other pterosaur species have been considered similar to C. cuvieri, but most are too fragmentarily known to be unquestionably assigned to it or synonymised with it. For example, Pterodactylus fittoni shares with C. cuvieri a low snout tip, the lack of a front expansion at the end of the snout, a palate that is curved towards the back, as well as a palatal ridge extending hindward until the third pair of tooth sockets, though the latter feature is only shared with C. cuvieri if the first preserved pair of tooth sockets in P. fittoni is its second pair. The height of P. fittoni's snout can be differentiated from that of C. cuvieri, whose tip is also wider than high; the latter difference is possibly due to fracture, though, and the species cannot be unquestionably assigned. Another species, Ornithocheirus brachyrhinus, shares a number of features with C. cuvieri, including a curved palate, the front end being higher than wide, lack of a sideways expansion at the front of the snout and the lack of a crest at the front of the snout. The structure of O. brachyrhinus' snout tip fully resembles that of C. cuvieri, suggesting that O. brachyrhinus is assignable to this species. Even so, the holotype of O. brachyrhinus is fragmentary, and it is therefore impossible to conclude if it has a crest located towards the back, or if it has the size variation of tooth sockets that is distinct for C. cuvieri.[2]^[36]

Other species that have been considered synonyms of C. cuvieri, like O. dentatus and O. enchorhynchus, differ with the former having smaller tooth sockets that are placed closer together. The latter, while quite similar to C. cuvieri (sharing features including the lack of a hindward positioned crest, the palate curving towards the back, the first tooth pair facing forward, as well as the lack of a front expansion), is fragmentary like O. brachyrhinus, which makes it hard to compare to other pterosaurs. O. scaphorhynchus has also been tentatively synonymised with C. cuvieri, but the incompleteness of this species makes it difficult to assign it clearly to any genus. The margins of the tooth sockets in O. scaphorhynchus are poorly preserved, but it is dissimilar to the spacing pattern present in C. cuvieri.^[2][36]

Cimoliopterus dunni

The holotype snout of C. dunni is composed of the front 18.5 cm (7.3 in) of the snout, comprising the premaxilla and maxilla (including a largely intact premaxillary crest), broken off just behind the 13th pair of tooth sockets. The

The tip of the snout in C. dunni is blunt. It is distinct in that the front surface of the jaw faces forwards and downwards, forming a 45° angle relative to the front part of the palate. Viewing the front end of C. dunni's snout from below the palate, it expands as it goes further back to a maximum width of 1.6 centimetres (0.63 in) above the third pair of tooth sockets. It suddenly narrows to a minimum width of 1.5 centimetres (0.59 in) at the level of the fourth pair of sockets. The width of the snout continues increasing hindward until it reaches a maximum of 1.8 to 1.9 centimetres (0.71 to 0.75 in) at the broken part of the hind edge of the crest. An angle of 8° relative to the flat area of the rear part of the palate is presumed to be based on its front portion being reflected towards the back. An inflection point (the point where the surface changes) close to the level of the eighth tooth sockets can also be seen.^[7]

C. dunni is distinct from C. cuvieri in that the first pair of tooth sockets is directed more downward than forward. The spaces between the tooth sockets measure a maximum of 11.5 millimetres (0.45 in) toward the front, and a minimum of 1.6 millimetres (0.063 in) towards the back. Since only a small replacement tooth is preserved in C. dunni, the texture of its teeth is unknown. While the

In 1870, Seeley assigned P. cuvieri (under the name Ornithocheirus cuvieri in his classification) to a group named

margins of their tooth sockets rose above the palate.^[20]

21st century schemes

Holotype snout tips of P. fittoni, O.  brachyrhinus, and O. enchorhynchus; these dubious species are similar to C. cuvieri but too fragmentary to assign.

In 2001, Unwin considered A. cuvieri a member of Ornithocheiridae, along with many of the English and Brazilian Cretaceous species, and suggested that some pterosaur species from these countries belonged to the same genera, such as Anhanguera, Ornithocheirus and Coloborhynchus.

phylogenetic analysis (the study of the evolutionary development of a species or a group) conducted by Chinese palaeontologist Xiaolin Wang and colleagues, Cimoliopterus was found to have been closely related to the pterosaur Ikrandraco, which at the time, along with the pterosaurs belonging to the Anhangueria, were the only ones known to have had blade-like crests on their jaws.^[40]

Aerodraco sedgwickii

(right; A-D), and C. colorhinus (right; E-H, once considered a large specimen of C. cuvieri), related species described from fragmentary English specimens in the 19th century which were also moved to new genera in the 21st century.

In his description of C. dunni, Myers used a modified version of the data set of an older phylogenetic analysis that he conducted Brian Andres in 2013.

paraphyletic (unnatural) group according to Myers.^[7]

In 2018, a phylogenetic analysis conducted by Nicholas Longrich and colleagues also recovered Aetodactylus and Cimoliopterus as sister taxa, reinforcing their close relationship.[42] In 2019, the British palaeontologist Megan Jacobs and colleagues performed a phylogenetic analysis where they placed both C. cuvieri and C. dunni within the family Ornithocheiridae, as the sister taxon of Camposipterus nasutus. In turn, their clade forms a polytomy (an unresolved group) along with the species Camposipterus colorhinus and C. sedgwickii.^[38] This close relationship of C. cuvieri and Camposipterus was already recovered by Hooley in 1914 and by Unwin in 2001, though as species of Ornithocheirus and Anhanguera, respectively.^[2][20] Also in 2019, Borja Holgado and colleagues recovered a clade consisting of Cimoliopterus and the Anhangueria, this clade being defined by a palate that is deflected towards the back. Ornithocheirus was recovered as the sister taxon to this clade, and in turn, all of them were placed within the group Ornithocheirae.^[43]

Later in 2019, Pêgas and colleagues redescribed the species Ornithocheirus wiedenrothi as

Targaryendraconidae.^[31]

Holotype mandible fragments of Targaryendraco (top) and Aussiedraco (bottom, once assigned to A. ?cuvieri), two genera from the clade Targaryendraconia, of which Cimoliopterus is a possible member

Cladogram 1: Jacobs and colleagues, 2019. Ornithocheirae Anhangueridae Ornithocheiridae Coloborhynchus clavirostris Uktenadactylus wadleighi Coloborhynchus reedi Coloborhynchus capito Coloborhynchus fluviferox Coloborhynchus NHMUK R481 Siroccopteryx moroccensis Ornithocheirus simus Tropeognathus mesembrinus Camposipterus segwickii Camposipterus colorhinus Camposipterus nasutus Cimoliopterus cuvieri Cimoliopterus dunni

Cladogram 2: Pêgas and colleagues, 2019. Ornithocheirae Ornithocheirus simus Targaryendraconia Targaryendraconidae Aussiedraco molnari Barbosania gracilirostris Targaryendraco wiedenrothi Cimoliopteridae Aetodactylus halli Camposipterus nasutus Cimoliopterus cuvieri Cimoliopterus dunni Anhangueria Hamipteridae Hamipterus tianshanensis Iberodactylus andreui Anhangueridae Tropeognathus mesembrinus Coloborhynchinae Anhanguerinae

A 2022 phylogenetic analysis by Rudah Ruano C. Duque and colleagues also confirmed the validity of Cimoliopteridae.^[44]

Evolution

Unwin stated in 2001 that the Cambridge Greensand and what is now the Grey Chalk Subgroup provided some of the youngest records of ornithocheirids, with A. cuvieri being the youngest known member of the group.

palaeobiogeographical (geographical distribution of prehistoric animal groups) affinities by the mid-Cretaceous was also supported by other related pterosaurs identified in North America, Europe and northern Africa, such as Coloborhynchus and Uktenadactylus.^[7]

Myers elaborated in a press release that the population ancestral to C. dunni and C. cuvieri was able to move between North America and England until about 94 million years ago, as the similarity between the two species indicated that there had been little time between their divergence. As the Atlantic opened up the supercontinent

island-hopped between the land masses that emerged between. However, it still remained a mystery why no close ties had been identified between pterosaurs of North and South America, indicating there could have been a barrier to their dispersal.^[32]

In 2019, Pêgas and colleagues agreed with Rodrigues and Kellner that the crest of Cimoliopterus had evolved independently from those of anhanguerians, since closer related targaryendraconian taxa, such as Barbosania, Camposipterus, and Aetodactylus, did not possess crests. According to their analysis, since Cimoliopterus was more closely related to Targaryendraco (of

stratigraphic distribution.^[31] Witton and Michel noted in 2023 that Cimoliopterus has the disinction of being among the last toothed pterosaurs.^[9]

Palaeobiology

Feeding

In 1987, Wellnhofer stated that while the crests of pterosaurs such as Pteranodon and

hydrodynamic rather than aerodynamic function.^[23] In 1991, he elaborated they would have fished while flying just above the water, by thrusting the long head rapidly forward, dipping it in the water, and seizing prey with their pointed jaws.^[45]

André J. Veldmeijer and colleagues pointed out in 2006 that apart from ornithocheirids usually being found in deposits associated with water, their interlocking teeth also supported

piscivory (fish-eating), being built for spearing slippery prey rather than cutting or slashing. The long, curved front teeth would be suited for catching slippery prey such as fish, and the smaller teeth at the back of the jaws ensured food was held and transported down the throat. The frontal position of the eyes and some adaptations to the brain may have been related to accurately evaluating the position of a fish before entering the water. They also pointed out that the differences in crest position, size of the palatinal ridge, and the presence or absence of a front expansion of the jaw, made it hard to believe they all obtained food in the same way, but that this did not rule out some overlap.^[46]

stealing prey

from Lonchodectes

Veldmeijer and colleagues noted that since the bodies of these pterosaurs were small, they would not have had space for large fish, and such fish may also have altered their flight capability, as is the case for

sexual display. They were unable to determine what the consequences were of Anhanguera having a more hindward placed crest than Coloborhynchus and Ornithocheirus.^[46]

Witton stated in 2012 that ornithocheirids showed adaptations for feeding without landing, with teeth of varying size that protruded from the jaw from many angles. Only using the front teeth to grab prey helped distance the body from the water's surface, minimising the chance of crashing.

display structures, as the crests are thought to have been sexually dimorphic in some species.^[48] In 2022, Duque and colleagues reported a crestless Anhanguera specimen, which they argued was evidence for the crests being linked to growth development or sexual dimorphism.^[44]

Locomotion

Witton summarised ideas of ornithocheirid

seabirds, they were probably better adapted for oceanic soaring than soaring over terrestrial areas, which is supported by their fossils being found mainly in marine deposits. They were possibly able to take off from water, which would be helped by their small torsos and legs. Their terrestrial locomotion was probably limited by their short legs, and they may have been restricted to slower shuffling walks (so that the long forelimbs did not outpace the hindlimbs) and faster bounding, which indicates they may have spent limited time on the ground. As has been hypothesised for pterosaurs in general, they probably took flight by launching quadrupedally, and they were possibly able to swim fairly well to be able to take off from water surfaces.^[1]

In 2017, the British biologist Colin Palmer used

keratinous material (the same material in human hair and nails), and differed greatly from the membranes of bats.^[49]

Palaeoenvironment

Grey Chalk Subgroup

where C. cuvieri was found, 6 shows Texas, where C. dunni was found.

The holotype of C. cuvieri was found in Kent, England, collected in chalks and

hadrosauroid "Iguanodon" hilli.^[50]

The holotype of C. dunni was found in the Britton Formation of north-central Texas, which dates to the Cenomanian stage of the early Late Cretaceous. The formation is part of the Upper Cretaceous

faeces) attributed to fish are also known.^[52]

See also

• List of pterosaur genera
• Timeline of pterosaur research

References

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External links

Wikimedia Commons has media related to Cimoliopterus.

• Southern Methodist University – New toothy Texas pterosaur, with an English cousin – Timothy Myers talks about Cimoliopterus dunni