Ornithopsis (meaning "bird-likeness") was a medium-sized Early Cretaceous sauropod dinosaur, from England. It has been considered a synonym of the wastebasket taxon Pelorosaurus, but recent research suggests that this is not as clear-cut as supposed. While Pelorosaurus is synonymous with several species of Ornithopsis, other genera are also considered synonyms, and the type species is since the nineties often seen as valid.
The type species, Ornithopsis hulkei, was named and described by Harry Govier Seeley in 1870. The type consisted of two dorsal vertebrae: BMNH R2239 found in East Sussex and BMNH R28632 found on Wight in the Wessex Formation dating from the Barremian. The genus name is derived from Greek ὄρνις (ornis), "bird", en ὄψις (opsis), "face" or "likeness", a reference to the fact that Seeley considered the animal to be an intermediate form bridging the gap between pterosaurs, birds and dinosaurs. The specific name honours John Whitaker Hulke.
Seeley's creation of the genus was, however, not accepted by Richard Owen, who rejected the evolutionary interpretation of the material. Disregarding priority, he therefore in 1875 split it, naming the one vertebra, BMNH R2239, that he had in 1841 described as the quadrate of Iguanodon, Bothriospondylus magnus, the other, BMNH R28632, Bothriospondylus elongatus.
As a result of the split both vertebrae now went their separate nomenclatural way. BMNH R2239 was in 1876 by Owen made the type of Chondrosteosaurus magnus; was in 1889 by Richard Lydekker included in Pelorosaurus hulkei, in 1893 referred by him to Oplosaurus (spelled as "Hoplosaurus") and was in 2005 referred by Sebastian Apesteguía to Eucamerotus.
BMNH R28632 was in 1882 by Hulke referred to Ornithopsis eucamerotus. However, in 1995 William Blows made it the lectotype of Ornithopis hulkei. This invalidated Pelorosaurus hulkei, apart from the fact that Blows considered any identity with Pelorosaurus impossible to prove as its holotype consists of a humerus. Blows also excluded BMNH R2239 from Ornithopsis as being of a clearly different type.
In 1882 Hulke named a Ornithopsis eucamerotus based on BMNH R97, a set of pelvis bones found by William D. Fox. Blows in 1995 removed O. eucamerotus from Ornithopisis, classifying it as Brachiosauridae incertae sedis.
In 1887 a third species nova was created for Ornithopsis when Hulke named Ornithopsis leedsii based on BMNH R1984-1988, partial remains of a pelvis found by Alfred Nicholson Leeds near Petersborough. This species would be renamed Cetiosaurus leedsi and later Cetiosauriscus leedsii, both today seen as incorrect identifications.
It also happened that already existing species were renamed into species of Ornithopsis. In 1888 Lydekker renamed "Ischyrosaurus" manseli Hulke 1874 (BMNH 41626) into a Ornithopsis manseli and Cetiosaurus humerocristatus Hulke 1874 (BMNH 44635) into a Ornithopsis humerocristatus. Friedrich von Huene in 1922 renamed Bothriospondylus suffossus into a Ornithopsis suffossa and Cetiosaurus greppini into a Ornithopsis greppini. In 1929 he renamed Pelorosaurus conybearei into Ornithopsis conybeari, which however violates the priority of the earlier named Pelorosaurus. All these names are today considered nomina vana, failed new names, or incorrect identifications.
Other remains have been referred to Ornithopsis hulkei; today this is only the case for the badly eroded type specimen, of which basically only the centrum remains lacking the neural spine. The vertebra is heavily pneumatised, filled with large cavities, camellae. It is narrow, tall, has a ridge on the underside, is opisthocoelous and has a posteriorly placed deep subtriangular pleurocoel over two thirds of its length. These features are compatible with a placement within the Titanosauriformes, perhaps more precisely the Brachiosauridae.
Read more about Ornithopsis: Species