Ornithocheirus Temporal range: Late Cretaceous, 110 Ma |
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Holotype of O. simus, CAMSM B54428, and referred specimen CAMSM B54552 | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | †Pterosauria |
Suborder: | †Pterodactyloidea |
Family: | †Ornithocheiridae |
Subfamily: |
†Ornithocheirinae Seeley, 1870 |
Genus: |
†Ornithocheirus Seeley, 1869 |
Type species | |
†Pterodactylus simus Owen, 1861 |
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Species | |
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Synonyms | |
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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 late 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.
O. simus is only known from fragmentary jaw tips. It bore a distinctive convex "keeled" crest on its snout.Ornithocheirus had relatively narrow jaw tips compared to Anhanguera and Coloborhynchus, which had prominently-expanded rosettes of teeth. Also unlike related pterosaurs, the teeth of Ornithocheirus were mostly vertical, rather than set at an outward-pointing angle.
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 fossilised. 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.