page_title: Cetiosauriscus
section_title: Misassigned species
hierarchical_section_title: Cetiosauriscus / History of discovery / Misassigned species
caption_attribution_description: English: Text-fig. 47.—Cetiosaurus leedsi.—Right humerus, anterior aspect, and (A) transverse section showing internal cavity. c, internal core of rock representing a cavity; d., deltoid crest; h., thickened head. About 1/13 nat. size. Text-fig. 48.—Cetiosaurus leedsi.—Upper portion of right radius (r.) and ulna (u.), anterior aspect; and (A) upper articular end of the same. About 1/13 nat. size.
context_page_description: Cetiosauriscus is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian in what is now England. A herbivore, Cetiosauriscus had—for sauropod standards—a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about 15 m long and between 4 and 10 t in weight.
  The only known fossil that was later named Cetiosauriscus includes most of the rear half of a skeleton as well as a hindlimb. Found in Cambridgeshire in the 1890s, it was described by Arthur Smith Woodward in 1905 as a new specimen of the species Cetiosaurus leedsi. This was changed in 1927, when Friedrich von Huene found NHMUK R3078 and the C. leedsi type specimen to be too different from Cetiosaurus, warranting its own genus, which he named Cetiosauriscus, meaning "Cetiosaurus-like". Cetiosauriscus leedsi was referred to the sauropod family Diplodocidae because of similarities in the tail and foot, and had the dubious or intermediate species "Cetiosauriscus" greppini, "C." longus, and "C." glymptonensis assigned to it.
context_section_description: Huene (1927) assigned "Ornithopsis" greppini, which he had named in 1922, to the genus Cetiosauriscus. The known material, discovered in Late Jurassic (Kimmeridgian) deposits in the Reuchenette Formation of Switzerland, includes dorsal and caudal vertebrae, forelimb bones and a hindlimb and partial pes, from at least two individuals. The 53 cm (21 in) long humerus was built like Cetiosauriscus stewarti (C. leedsi of von Huene's 1927 usage), and the two species were originally distinguished from Cetiosaurus by having shorter dorsal vertebrae, a shorter forelimb, and a longer lower leg. The similarities like the anatomy of the caudal vertebrae were suggested by Christian Meyer and Basil Thüring in 2003 to support referral of greppini to Cetiosauriscus. However, Weishampel et al. (2004) and Whitlock (2011) considered "Cetiosauriscus" greppini to be Eusauropoda incertae sedis, while Hofer (2005) and Schwarz et al. (2007) concluded that "Cetiosauriscus" greppini represents an unnamed genus of basal eusauropod. "Ornithopsis" greppini was finally named as the new genus Amanzia in 2020. 
  The species Cetiosaurus longus, named in 1842 by Owen, was referred to the genus Cetiosauriscus without comment by sauropod palaeontologist John Stanton McIntosh in 1990. Material the species was named for included a dorsal and caudal vertebrae from the Portland Stone of Garsington, Oxfordshire, two other caudal vertebrae from the same deposit of nearby Thame, and a single vertebra and some metatarsals originally named Cetiosaurus epioolithicus (an invalid nomen nudum), although the material from Garsington has been lost since its description. One of the vertebrae (OUMNH J13871) may instead be a cervical, as it has one mildly convex and one concave articular face. Characterised as having uniquely elongate vertebral centra (body of the vertebra), C. longus is not a diagnostic taxon. As it lacks any diagnostic features of Cetiosauriscus, the species should be referred to by its original designation, Cetiosaurus longus.
  Cetiosaurus glymptonensis, named on the basis of nine middle-distal caudal centra from the Forest Marble Formation of Oxfordshire, England, was referred to Cetiosauriscus by McIntosh in 1990. These caudal vertebrae were considered to be more elongate than those of Cetiosaurus oxoniensis, but caudal length proportions vary significantly throughout the tail and in different taxa, Apatosaurus, Diplodocus and Cetiosauriscus having similarly elongate caudal vertebrae. The more anterior caudals have a large ridge two-thirds up the centrum and a smaller ridge one-third up. These ridges are similar to the middle caudals of Cetiosauriscus, but are absent in caudals of the same size and proportions, and because of this difference the species was concluded to be separate from Cetiosauriscus by Upchurch and Martin in 2003. "Cetiosaurus" glymptonensis is considered to be Eusauropoda incertae sedis by Upchurch and Martin (2003), Weishampel and colleagues (2004) and Whitlock (2011), and is in need of a new genus name because it has a single diagnostic feature, the lateral ridges.
  In 1980, Charig described a specimen of indeterminate diplodocid from the Early Cretaceous of England, and re-examined the holotype of Cetiosauriscus leedsii to compare its characteristics. In this publication he confirmed that the ilium of the holotype of C. leedsi, NHMUK R1988, was too incomplete to be compared to the also incomplete ilium of the referred specimen NHMUK R3078. Because of the lack of overlap the referral of NHMUK R3078 to Cetiosauriscus leedsii was no longer verifiable, so Charig named the new species Cetiosauriscus stewarti for NHMUK R3078. The specific name was chosen to honour Sir Ronald Stewart, the chairman of the London Brick Company that owned the clay pit the fossils had been found in. Furthermore, Charig considered Cetiosauriscus leedsii and Cetiosauriscus greppini to be dubious taxa, making C. stewarti the only valid species within Cetiosauriscus. Because of the invalidity of the type species C. leedsii, Charig made a petition to the Internatio
caption: Forelimb of Cetiosauriscus in front and top views
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