Cetiosaurus ( meaning 'whale lizard', from the Greek / meaning 'sea monster' (later, 'whale') and / meaning 'lizard'), is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Period, living about 171 to 165 million years ago during the Bajocian and Bathonian ages in what is now Britain and probably France.
Cetiosaurus was named in 1842, making it the first sauropod from which bones were described and is the most complete sauropod found in England. It was so named because its describer, Sir Richard Owen, supposed it was a marine creature, initially an extremely large crocodile, and did not recognise it for a land-dwelling dinosaur. Because of the early description many species would be named in the genus, eventually eighteen of them. Most of these have now been placed in other genera or are understood to be dubious names, based on poor fossil material. The last is true also of the original type species, Cetiosaurus medius, and so C. oxoniensis was officially made the new type species in 2014. C. oxoniensis is based on three more-or-less-complete specimens, discovered from 1868 onwards. Together they contain most of the bones, with the exception of the skull. Cetiosaurus was a quadrupedal, long-necked, small-headed herbivore. It had a shorter tail and neck than most sauropods. The forelimbs on the other hand, were relatively long. It is estimated to have been about long and to have weighed roughly .
Discovery and species
Initial finds
Cetiosaurus is, with the exception of the tooth genus Cardiodon, the first sauropod to be discovered and named as well as being the best known sauropod from England."Cetiosaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs. Publications International, LTD. p. 65. . Numerous species have been assigned to Cetiosaurus over the years belonging to several different groups of sauropod dinosaurs. The genus thus functioned as a typical "wastebasket taxon". Fossilized remains once assigned to Cetiosaurus have mainly been found in England but also in France, Switzerland and Morocco.
The first fossils, vertebrae and limb elements, were discovered near Chipping Norton, Oxfordshire in the early nineteenth century and were reported upon by collector John Kingdon in a letter read on 3 June 1825 to the Geological Society; they were seen as possibly belonging to a whale or crocodile. In 1841 biologist, comparative anatomist and palaeontologist Sir Richard Owen, named these as the genus Cetiosaurus, the year before he coined the term Dinosauria. Owen initially did not recognise Cetiosaurus for a dinosaur but considered it a gigantic sea-dwelling reptile. This was reflected by the name, derived from Greek κήτειος, kèteios, "sea-monster".Owen, R., 1841, "A description of a portion of the skeleton of the Cetiosaurus, a gigantic extinct saurian reptile occurring in the oolitic formations of different portions of England", Proceedings of the Geological Society of London 3: 457–462 In 1842 Owen named two species in the genus: Cetiosaurus hypoolithicus and Cetiosaurus epioolithicus. The specific names reflected whether the finds had been made below (hypo) or above (epi) the so-called oolithic layers. The first species was based on the material of Kingdon; the latter on vertebrae and metacarpals found at White Nab in Yorkshire.Owen, R., 1842, "Second rapport sur les reptiles fossiles de la Grande-Bretagne", L’Institut, Journal général des Sociétés et Travaux Scientifique de la France et de l’Étranger 10: 11–13 The publication did not contain a sufficient description and the species are often considered nomina nuda. The same year in a subsequent publication Owen named four additional Cetiosaurus species: Cetiosaurus brevis, "the short one"; Cetiosaurus brachyurus, "the short-tailed"; Cetiosaurus medius, "the medium-sized", and Cetiosaurus longus, "the long one". Owen had abandoned the two earlier names, as shown by the fact that their fossils were referred to several of the new species. These again were each mostly based on disparate material, from often geographically widely separated sites.Owen, R., 1842, "Report on British Fossil reptiles, Pt. II". Reports of the British Association for the Advancement of Science 11: 60–204
As became apparent in 1849, some of these bones were not sauropod in nature at all but of Iguanodontidae. That year Alexander Melville, in a misguided attempt to clear matters up, named the authentic sauropod material of C. brevis as Cetiosaurus conybeari but thereby merely created a junior objective synonym of the former name.Melville, A.G., 1849, "Notes on the vertebral column of Iguanodon", Philosophical Transactions of the Royal Society of London 139: 285–300 In 1842, Owen noted a partial skeleton of a sauropod dinosaur consisting of "five vertebrae, a scapula, coracoid, sternal plate, and portions of limb bone", found in rock exposed by railway construction near Blisworth, Northamptonshire, which he attributed to the species Cetiosaurus medius.101 However this specimen was lost by 1871, as in a book by Professor John Phillips published that year he was unable to locate the specimen. It has been suggested that two tail vertebrae mentioned by Richard Lydekker in 1888 as being the collection of the Natural History Museum in London, which were catalogued as BMNH R16090 and R160901, and recorded as having been purchased from Blisworth by the museum in 1843, originate from the Blisworth skeleton. However in a 2003 paper on the taxonomy of Cetiosaurus, neither of the two vertebrae were able to be located in the museum's collections by the paper's authors.
Cetiosaurus oxoniensis
In March 1868, workers near Bletchingdon discovered a sauropod right femur. Between March 1869 and June 1870 Professor John Phillips, further investigating the site, in a layer dating from the Bathonian uncovered three skeletons and additional bone material. In 1871 based on these he named two species: Cetiosaurus oxoniensis (originally spelled Ceteosaurus Oxoniensis) and Cetiosaurus glymptonensis. "Oxoniensis" refers to Oxford, "glymptonensis" to Glympton.J. Phillips. 1871. Geology of Oxford and the Valley of the Thames. Clarendon Press, Oxford 523 pp Already in 1870 Thomas Huxley had published a letter by Phillips in which the latter named a Cetiosaurus giganteus based on specimen OUMNH J13617, a left femur earlier found at Bletchingdon; as the letter did not contain a description, this is a nomen nudum.
A century later, a new C. oxoniensis specimen (LCM G468.1968), subsequently named by the local media, the "Rutland Dinosaur", was unknowingly excavated on 19 June 1968 in the form of several tons of discarded siderite ironstone from a clay-pit near Great Casterton, Rutland, which was subsequently deduced to be from the base of the Rutland Formation dating to the Bajocian. The excavator driver recognised what he correctly thought might be bone fragments amidst the pile of broken blocks and consequently the ironstone was removed to Leicester Museum and Art Gallery and placed in store. No preparatory work on the material was possible until after September 1968 due to a museum staff vacancy, but by the end of that year a probable sauropod dinosaur identity had been established on the basis of several complete cervical vertebrae having been recovered from matrix. It was not until late 1970 however that a provisional identification of C. oxoniensis was published by curator Michael Jones following examination and corroboration by Prof. J S McIntosh of the Peabody Museum of Natural History Yale UniversityJones, M. D. 1970. Cetiosaurus oxoniensis, a middle Jurassic sauropod from Rutland, England. Transactions of the Leicester Literary & Philosophical Society, 64, 144-150.
This determination was based on six cervical, two dorsal and three anterior caudal vertebrae, several chevrons and whilst still embedded in matrix, numerous rib fragments, and indications of parts of the pectoral and pelvic girdles and limb bones. It is one of the most complete specimens of a dinosaur ever found in the UK. Most of the best preserved vertebrae were displayed in a new geology gallery at Leicester Museum and Art Gallery in 1975. This included a visual representation of Cetiosaurus within its Jurassic environment, supported by other fossil material from the collections. With preparation of the most significant and well preserved components completed, no further work on the remainder or any possibility of a full reconstruction was feasible until the 1980s, culminating in the largely replica model first displayed in 1985 at Leicester Museum and Art Gallery. A comprehensive published review of all the prepared skeletal components followed in 2002 Upchurch & Martin 2002 The Rutland Cetiosaurus: the anatomy and relationships of a Middle Jurassic British sauropod dinosaur. Journal of Palaeontology, 45, issue 6, pages 1049–1074
The specimen on display at Leicester Museum and Art Gallery is 15 m (49 ft) in length and has fourteen cervical vertebrae, ten dorsals, five sacrals and about fifty caudals.11 Only the more structurally sound parts of the dinosaur are on display, with the more-fragile parts in store. Much of what can be seen in the display is a representation (replica), and not the entire dinosaur.
Other species In 1874, John Whitaker Hulke named Cetiosaurus humerocristatus, "with a crested humerus", based on specimen BMNH 44635, a humerus found that year at Sandsfoot near Weymouth in Dorset.Hulke, J.W., 1874, "Note on a very large saurian limb-bone adapted for progression upon land, from the Kimmeridge clay of Weymouth, Dorset", Quarterly Journal of the Geological Society of London 30(1–4): 16–17 In 2010, this was made a separate genus Duriatitan.Barrett, P.M., Benson, R.B.J. & Upchurch, P., 2010, "Dinosaurs of Dorset: Part II, the sauropod dinosaurs (Saurischia, Sauropoda) with additional comments on the theropods", Proceedings of the Dorset Natural History and Archaeological Society 131: 113–126 This today is often considered a nomen dubium.
Ornithopsis leedsii was named in 1887 by John Hulke for a pelvis, vertebrae and ribs collected by Alfred Nicholson Leeds, an English farmer and amateur fossil collector who throughout his life compiled numerous collections of fossils from the Oxford Clay. It was described in more detail by Seeley in 1889, where he considered Ornithopsis hulkei (which had been described by Harry Seeley in 1870 based on vertebrae from the Early Cretaceous Wessex Formation of the Isle of Wight in southern England), C. oxoniensis and O. leedsii to all be in the same genus, bearing the name Cetiosaurus. But naturalist Richard Lydekker discussed with Seeley, before the publication of Seeley's 1889 paper, that Cetiosaurus and Ornithopsis were not the same taxon. Lydekker suggested that Wealden fossils (including O. hulkei) belonged to Ornithopsis and the Jurassic remains (including O. leedsii and C. oxoniensis) to Cetiosaurus. Lydekker in 1895 changed his mind and referred the species O. leedsii to Pelorosaurus (known already from the species P. brevis, once named Cetiosaurus brevis)—as P. leedsi—and referred the genus to Atlantosauridae. Arthur Smith Woodward supported Seeley's classification scheme in 1905, placing C. leedsi in Cetiosaurus, including within C. leedsi a partial sauropod skeleton collected from the Oxford Clay of Peterborough, England. In 1927, Friedrich von Huene assigned C. leedsi to the separate genus Cetiosauriscus. The holotype material of "C." leedsi, NHMUK R1988, consisting of a left and right ischium, is today considered indeterminate eusauropod remains, rendering the species a nomen dubium, while the sauropod skeleton described by Woodward from Peterborough in 1905 is now assigned to the valid separate species Cetiosauriscus stewarti.