Cetiosauriscus
From Greek 'ketos' meaning 'sea monster' or 'whale', 'sauros' meaning 'lizard', and '-iskos' meaning 'resembling', meaning 'resembling Cetiosaurus' (the whale lizard).
Cetiosauriscus is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian (Middle Jurassic Period) in what is now England. A herbivore, Cetiosauriscus had — by sauropod standards — a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about 15 m (49 ft) long and between 4 and 10 t (3.9 and 9.8 long tons; 4.4 and 11.0 short tons) in weight.
Under dispute
Long allied with diplodocoids, Cetiosauriscus is no longer regarded as a member of Diplodocoidea. Tschopp and colleagues (2015) recovered it outside Neosauropoda as a non-neosauropod eusauropod (near Omeisaurus) under implied weighting, though within Diplodocimorpha under equal weighting; Moore and colleagues (2020, 2023) recover it as a non-neosauropod eusauropod near Omeisaurus in most of their analyses. Its precise position among eusauropods is unresolved.
Diagnosis
- Extraordinarily short presacral and anterior caudal vertebrae
- Posterior dorsal vertebrae with deep but circumferentially small pleurocoels
- Fused neural spines on the middle sacral vertebrae
- Broad, steeply inclined neural spines proportional to centrum length
- Low, elongate ilium, lower than in Cetiosaurus, with a slender femur
- Short humerus (about 0.69 of femoral length) with a proportionally long forearm, the radius lacking the proximal "Cetiosaurus beak"
Species
Cetiosauriscus stewarti Charig, 1980
Type species
Named for Sir Ronald Stewart, the chairman of the London Brick Company that owned the clay pit where the fossils were found.
- Holotype
- NHMUK PV R 3078 , Natural History Museum
- Material
- A partial skeleton: fragmentary dorsals and sacrals, a long caudal series with chevrons (the diplodocid-like tail), the right scapulocoracoid and forelimb, both ilia, and the left hind limb.
- Horizon
- Peterborough Member, Oxford Clay Formation, Callovian, Middle Jurassic , 165.3–161.5 million years ago
- Locality
- Peterborough brick-pit, City of Peterborough, United Kingdom
Notable specimens
-
NHMUK PV R 1967
Natural History Museum pathology
A distal caudal tail tip from a different individual, once referred to Cetiosauriscus. Across ten biconvex vertebrae it shows injury at two points, with breakage that later healed, identified as the same form of pathology seen in the tail of Diplodocus.
ICZN cases
-
Type species Ruled
Designated Cetiosauriscus stewarti as the type species under the plenary power, replacing the original type C. leedsi (poor material).
Application: Charig (1993) Opinion: International Commission on Zoological Nomenclature (1995)
References
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Woodward, A. S. (1905). On parts of the skeleton of Cetiosaurus leedsi, a sauropodous dinosaur from the Oxford Clay of Peterborough. Proceedings of the Zoological Society of London 1(January–April): 232-243.
Original description of the holotype skeleton (R3078), as Cetiosaurus leedsi; made the holotype of C. stewarti by Charig (1980).
woodward1905a -
Huene, F. V. (1927). Sichtung der Grundlagen der jetzigen Kenntnis der Sauropoden [Sorting through the basis of the current knowledge of sauropods]. Eclogae Geologicae Helvetiae 20: 444-470.
Erects the genus Cetiosauriscus, originally with C. leedsi as the type species.
huene1927c -
Huene, F. V. (1927). Short review of the present knowledge of the Sauropoda. Memoirs of the Queensland Museum 9(1): 121-126.
Concise diagnosis of the genus in the "Short review of the present knowledge of the Sauropoda".
huene1927b -
Charig, A. J. (1980). A diplodocid sauropod from the Lower Cretaceous of England. Aspects of Vertebrate History: Essays in Honor of Edwin Harris Colbert (Jacobs, L. L., ed.) 231-244. Museum of Northern Arizona Press.
Describes Cetiosauriscus stewarti, later designated the type species of Cetiosauriscus by ICZN Opinion 1801 (1995).
charig1980a -
Charig, A. J. (1993). Case 2876. Cetiosauriscus von Huene, 1927 (Reptilia, Sauropodomorpha): designation of C. stewarti Charig, 1980 as the type species. Bulletin of Zoological Nomenclature 50(4): 282-283. doi:10.5962/bhl.part.1874
Petition to the ICZN to designate C. stewarti as the type species of Cetiosauriscus.
charig1993a -
International Commission on Zoological Nomenclature (1995). Opinion 1801. Cetiosauriscus Huene, 1927 (Reptilia, Sauropodomorpha): Cetiosauriscus stewarti Charig, 1980 designated as type species. Bulletin of Zoological Nomenclature 52: 113.
Designated C. stewarti Charig, 1980 as the type species of Cetiosauriscus, replacing the original type C. leedsi.
iczn1995a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the hip height estimate.
jones2026b -
Moore, A. J.; Upchurch, P.; Barrett, P. M.; Clark, J. M.; Xu, X. (2020). Osteology of Klamelisaurus gobiensis (Dinosauria, Eusauropoda) and the evolutionary history of Middle-Late Jurassic Chinese sauropods. Journal of Systematic Palaeontology 18(16): 1299-1393. doi:10.1080/14772019.2020.1759706
Source of the non-neosauropod eusauropod placement (near Omeisaurus), followed by later work.
moore2020a -
Tschopp, E.; Mateus, O.; Benson, R. B. J. (2015). A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3: e857. PeerJ. doi:10.7717/peerj.857
Recovered Cetiosauriscus as a non-neosauropod eusauropod near Omeisaurus under implied weighting, though within Diplodocimorpha under equal weighting.
tschopp2015a -
Moore, A. J.; Barrett, P. M.; Upchurch, P.; Liao, C. C.; Ye, Y.; Hao, B.; Xu, X. (2023). Re-assessment of the Late Jurassic eusauropod Mamenchisaurus sinocanadorum Russell and Zheng, 1993, and the evolution of exceptionally long necks in mamenchisaurids. Journal of Systematic Palaeontology 21(1). doi:10.1080/14772019.2023.2171818
Echoes the non-neosauropod eusauropod (near Omeisaurus) reading of Moore and colleagues (2020) without independently re-analyzing Cetiosauriscus.
moore2023a