Open Paleo

Eustreptospondylus

Walker, 1964 yoo-STREPT-o-spon-DY-luhs /juːˌstrɛptoʊspɒnˈdaɪləs/

From Ancient Greek eu- (well) + streptos (twisted) + spondylos (vertebra): 'well-twisted vertebra', referring to the morphology of its vertebrae.

165.3–161.5 million years ago Callovian, Middle Jurassic
Middle Jurassic stages

Eustreptospondylus is an extinct genus of megalosaurid theropod dinosaur from the Callovian and Oxfordian stages of the Jurassic period (some time between 166 and 154 million years ago) in southern England, at a time when Europe was a series of scattered islands due to tectonic movement that raised the sea-bed and flooded the lowland.

Under dispute

Eustreptospondylus oxoniensis is a basal megalosaurid whose exact position is unresolved. Carrano and colleagues (2012) and Benson (2010) recover it as the basalmost megalosaurid outside the two subfamilies, Rauhut and colleagues (2016) place it in the megalosaurid subfamily they call Eustreptospondylinae, while Sadleir and colleagues (2008) recovered it as the sister of Spinosauridae, with weak support. Proposed synonymies with Magnosaurus and Streptospondylus have been rejected.

Diagnosis

  1. Shallow lachrymal fenestra incorporating a second, smaller foramen within the main excavation.
  2. Squamosal with a hypertrophied ventral flange that overhangs the infratemporal fenestra in lateral view, partially obscuring its posterodorsal corner.
  3. Ventral midline keels absent from the centra of the cervical, cervicodorsal, and dorsal vertebrae.
  4. Marked depression on the anterior part of the ventral surface of cervical vertebra 10.
  5. Excavation along the posterior surface of the ventral process of the postorbital, forming a shallow fossa around the anterior margin of the infratemporal fenestra (distinguishing it from all other spinosauroids).

Species

Eustreptospondylus oxoniensis Walker, 1964

Type species

Named for Oxford, England (Latin 'Oxonia'), the city near which the holotype skeleton was discovered.

Holotype
OUMNH PAL-J.013558 , Oxford University Museum of Natural History
Material
Juvenile partial skull and postcranial skeleton: premaxillae, maxillae, frontals, dentaries, postorbitals, a partial braincase, the axial column from cervical 2 to caudal 5 (plus isolated posterior caudals), right scapula and humerus, much of the pelvis, both hindlimbs, and partial pedes.
Horizon
Stewartby Member, Oxford Clay Formation, Callovian, Middle Jurassic , 165.3–161.5 million years ago
Locality
Webb's Pit, Summertown, Oxfordshire, United Kingdom

References

  1. Walker, A. D. (1964). Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 248: 53-134. doi:10.1098/rstb.1964.0009

    Gives the holotype's locality as the "Summertown brick pit, Wolvercot, near Oxford".

    walker1964a
  2. Sadleir, R.; Barrett, P. M.; Powell, H. P. (2008). The anatomy and systematics of Eustreptospondylus oxoniensis, a theropod dinosaur from the Middle Jurassic of Oxfordshire, England. Monographs of the Palaeontographical Society 160(627): 1-82. Palaeontographical Society.

    Redescribes the holotype OUMNH PAL-J.013558, with an emended diagnosis; resolves Eustreptospondylus as a basal spinosauroid and interprets the holotype as a juvenile.

    sadleir2008a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c
  4. Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2): 211-300. Informa UK Limited. doi:10.1080/14772019.2011.630927

    Recovered Eustreptospondylus as the basalmost megalosaurid outside its two subfamilies.

    carrano2012a
  5. Benson, R. B. J. (2010). A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society 158(4): 882-935. Oxford University Press (OUP). doi:10.1111/j.1096-3642.2009.00569.x

    Recovered it as the basalmost megalosaurid outside the two subfamilies

    benson2010c
  6. Rauhut, O. M.; Hübner, T.; Lanser, K. (2016). A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic. Palaeontologia Electronica 19(2): 26A. Coquina Press. doi:10.26879/654

    Wiehenvenator description placed it in the megalosaurid subfamily Eustreptospondylinae

    rauhut2016a