Ornithocheirus

*Ornithocheirus simus*

Tim Bradley Artwork

***Ornithocheirus*** (from Greek "ορνις", meaning bird, and "χειρ", 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 late Cretaceous period, about 110 million years ago. Additional fossils from the Santana Formation of Brazil, dating to 112-108 million years ago, are sometimes classified as species of *Ornithocheirus*,[2] but have also been placed in their own genera, most notably *Tropeognathus*.

## Description

The original material of *Ornithocheirus simus*, recovered from England, indicates a mid-sized species with a wing span of 2.5 meters (8.2 feet). Referred specimens attributed to *Ornithocheirus simus* can reach 5 meters (16.5 feet).

*O. simus* bore a distinctive convex "keeled" crest on its snout. Unlike the related *Anhanguera* and *Coloborhynchus*, which had an expanded rosette of teeth at the jaw tips, *Ornithocheirus* species (including *O. simus*) had straight jaws that narrowed toward the tip. Also unlike related pterosaurs, the teeth of *Ornithocheirus* were mostly vertical, rather than set at an outward-pointing angle. They also had fewer teeth than related species.

The type specimen of *Ornithocheirus simus* is represented only by a broken piece of the upper jaw tip. While it does preserve several characteristic features of Ornithocheirus, it is nearly identical to comparable bones in *Tropeognathus mesembrinus*, making clear distinction between these two species impossible.

## Discovery and naming

During the 19th century, in England many fragmentary pterosaur fossils were found in the Cambridge Greensand, a layer from the early Cretaceous, that had originated as a sandy seabed. Decomposing pterosaur cadavers, floating on the sea surface, had gradually lost individual bones that sank to the bottom of the sea. Water currents then moved the bones around, eroding and polishing them, until they were at last covered by more sand and fossilized. Even the largest of these remains were damaged and difficult to interpret. They had been assigned to the genus *Pterodactylus*, as was common for any pterosaur species described in the early and middle 19th century.

Young researcher Harry Govier Seeley was commissioned to bring order to the pterosaur collection of the Sedgwick Museum in Cambridge. He soon concluded that it was best to create a new genus for the Cambridge Greensand material that he named *Ornithocheirus*, "bird hand", as he in this period still considered pterosaurs to be the direct ancestors of birds, and assumed the hand of the genus to represent a transitional stage in the evolution towards the bird hand. To distinguish the best pieces in the collection, and partly because they had already been described as species by other scientists, he in 1869 and 1870 each gave them a separate species name: *O. simus*, *O. woodwardi*, *O. oxyrhinus*, *O. carteri*, *O. platyrhinus*, *O. sedgwickii*, *O. crassidens*, *O. capito*, *O. eurygnathus*, *O. reedi*, *O. cuvieri*, *O. scaphorhynchus*, *O. brachyrhinus*, *O. colorhinus*, *O. dentatus*, *O. denticulatus*, *O. enchorhynchus*, *O. xyphorhynchus*, *O. fittoni*, *O. nasutus*, *O. polyodon*, *O. compressirostris*, *O. tenuirostris*, *O. machaerorhynchus*, *O. platystomus*, *O. microdon*, *O. oweni* and *O. huxleyi*, thus 28 in total. As yet Seeley did not designate a type species.

When Seeley published his conclusions in his 1870 book The Ornithosauria, this provoked a reaction by the leading British paleontologist of his day, Richard Owen. Owen was not an evolutionist and he therefore considered the name *Ornithocheirus* to be inappropriate; he also thought it was possible to distinguish two main types within the material, based on differences in snout form and tooth position — the best fossils consisted of jaw fragments. He in 1874 created two new genera: *Coloborhynchus* and *Criorhynchus*. *Coloborhynchus*, "maimed beak", comprised a new species, *Coloborhynchus clavirostris*, the type species, and two species reassigned from *Ornithocheirus*: *C. sedgwickii* and *C. cuvieri*. *Criorhynchus*, "ram beak", consisted entirely of former Ornithocheirus species: the type species *Criorhynchus simus* and furthermore *C. eurygnathus*, *C. capito*, *C. platystomus*, *C. crassidens* and *C. reedi*.

Seeley did not accept Owen's position. In 1881 he designated *O. simus* the type species of *Ornithocheirus* and named a new species *O. bunzeli*. In 1888 Edward Newton renamed several existing species names into: *Ornithocheirus clavirostris*, *O. daviesii*, *O. sagittirostris*, *O. validus* and *O. giganteus*; as new species he created: *O. clifti*, *O. diomedeus*, *O. nobilis* and *O. curtus*. Others had already named an *O. umbrosus*, *O. harpyia*, *O. macrorhinus* and *O. hilsensis* and would create an *O. hlavaci*, *O. wiedenrothi* and *O. mesembrinus*.

In 1914 Reginald Walter Hooley made a new attempt to structure the large number of species. Keeping the name Ornithocheirus, he added to it Owen's Criorhynchus, in which however *Coloborhynchus* was sunk, and to allow for a greater differentiation created two new genera, again based on jaw form: *Lonchodectes* and *Amblydectes*. *Lonchodectes*, "lance biter", comprised *L. compressirostris*, *L. giganteus* and *L. daviesii*. *Amblydectes*, "blunt biter", consisted of *A. platystomus*, *A. crassidens* and *A. eurygnathus*. However, Hooley's classification was rarely applied later in the century, when it became common to subsume all the poorly preserved and confusing material under the name *Ornithocheirus*. In 1978 Peter Wellnhofer, assuming no type species had been designated, made *Ornithocheirus compressirostris* the type.

From the seventies onwards many new pterosaur fossils were found in Brazil, from formations about the same age as the Cambridge Greensand, 110 million years old. Contrary to the English material, these new finds included some of the best preserved large pterosaur skeletons and several new genera names were given to them, such as *Anhanguera*. This situation caused a renewed interest in the *Ornithocheirus* material and the validity of the several names based on it, for it might be possible that it could by more detailed studies be established that the Brazilian pterosaurs were actually junior synonyms of the European types. Several European researchers concluded that this was indeed the case. Unwin revived *Coloborhynchus* and Michael Fastnacht *Criorhynchus*, each author ascribing Brazilian species to these genera. However, in 2000 Unwin stated that *Criorhynchus* could not be valid. Referring to Seeley's designation of 1881 he considered *Ornithocheirus simus*, holotype CAMSM B.54428, to be the type species. This also made it possible to revive Lonchodectes, using as type the former *O. compressirostris*, which then became *L. compressirostris*. This position has not universally been accepted. Brazilian workers also typically reject the identification of their genera with European types. Unwin, and this caused no controversy, reaffirmed that most *Ornithocheirus* species are *nomina dubia*, names that are invalid because the fossils they refer to lack sufficient diagnostic features.

As a result, though over forty species have been named in the genus *Ornithocheirus* over the years, not a single one of them, not even *O. simus*, is currently recognized as valid by all pterosaur researchers. Often, there is a total lack of consensus; e.g. *Tropeognathus mesembrinus* named by Peter Wellnhofer in 1987 has afterwards been considered *Ornithocheirus mesembrinus* by David Unwin in 2003 (making *Tropeognathus* a junior synonym), but as *Anhanguera mesembrinus* by Alexander Kellner in 1989, *Coloborhynchus mesembrinus* by André Veldmeijer in 1998 and *Criorhynchus mesembrinus* by Michael Fastnacht in 2001. Even earlier, in 2001, Unwin had referred the "*Tropeognathus*" material to O. simus in which he was followed by Veldmeijer; however the latter denied that *O. simus* is the type species in favor of *O. compressirostris* (alternately *Lonchodectes*), and used the names *Criorhynchus simus* and *Cr. mesembrinus*. Kellner in 2000 again recognized *Tropeognathus* as a valid genus.

### Formerly assigned species

In 2013, Rodrigues and Kellner found *Ornithocheirus* to contain only *O. simus* under the genus and either placed most other species in other genera or declared them nomina dubia. They also considered *O. platyrhinus* a junior synonym of *O. simus*.

**Species previously assigned to *Ornithocheirus*:**

* *O. compressirostris* (Hooley, 1914): reclassified as *Lonchodectes*
* *O. crassidens*: reclassified as *Amblydectes*
* *O. cuvieri* (Seeley, 1870) = *Pterodactylus cuvieri* [later reclassified as *Cimoliopterus*]
* *O. curtus* (Hooley, 1914) = *Pterodactylus curtus* Owen, 1874
* *O. giganteus*: now reclassified as *Lonchodraco*
* *O. hilsensis*: more likely a theropod dinosaur
* *O. mesembrinus*: *Tropeognathus mesembrinus*
* *O. nobilis:* later reclassified as *Pterodactylus nobilis*
* *O. sedgwicki:* *Pterodactylus sedgwickii* Owen 1859 [now classified as *Camposipterus*]
* *O. wiedenrothi*: now known as *Tergaryendraco*
* *Cimoliornis diomedeus:* likely closer related to Azhdarchoidea
* *Cretornis hlavatschi:* more so considered an azharchid
* *Palaeornis clifti:* confirmed to be a lonchodectid
* *O. buenzeli* (cited in the past as evidence of Late Cretaceous ornithocheirids) has since been reconsidered as an azdarchid.

*Cimoliornis diomedeus*, *Cretornis hlavatschi*, and *Palaeornis clifti*, originally misidentified as birds, have been assigned to *Ornithocheirus* in the past, but they are probably distinct genera instead, a position held by David Unwin. *Cimoliornis* may be closer to azhdarchoidea, *Cretornis* is likely an azhdarchid, and *Palaeornis* was shown to be a lonchodectid in 2009.[9] *O. buenzeli* (Bunzel 1871, often mis-spelled and mis-attributed as *O. bunzeli*, Seeley 1881), cited in the past as evidence of Late Cretaceous ornithocheirids,[10] has since been re-identified as a likely azhdarchid as well.

## Classification

Andres and Myers (2013) place it within Ornithocheiridae as more derived than *Tropeognathus* but more basal than *Coloborhynchus*, all within Ornithocheirae. However, Pêgas et al. (2019) suggest it is basal inside Ornithocheirae, placing similar taxa inside Anhangueridae:

## Appearance in other media

### *Jurassic Park*

* Ornithocheirus appeared in Jurassic World: The Game.