Oceanotitan
From Latin 'oceanus' meaning 'ocean', because the fossil was found at the base of a coastal cliff overlooking the Atlantic Ocean, combined with 'Titan' from Greek mythology meaning 'giant'.
Oceanotitan is a genus of sauropod dinosaur known from the Upper Jurassic (latest Kimmeridgian stage, about 149 million years ago) Lourinhã Formation of Portugal. It is represented by a single specimen consisting of several tail vertebrae and appendicular bones. It contains one species, Oceanotitan dantasi. Oceanotitan is classified as possibly one of the earliest members of the Somphospondyli, a group of sauropods that includes the titanosaurs.
Under dispute
Oceanotitan is a macronarian whose placement varies between analyses. Its describers recovered it as the earliest-branching somphospondylan on one matrix and in a polytomy at the base of Titanosauriformes on another (Mocho and colleagues, 2019); Mocho and colleagues (2023) recover it outside Titanosauriformes, as the sister of Aragosaurus, under implied weights, and Mannion and Carvalho (2026) regard it as a non-titanosauriform macronarian.
Diagnosis
- Sagittal groove on dorsal surface of anterior-most caudal vertebral neural spines
- Lateral depressions on distal tips of anterior to middle caudal neural spines, dorsally connected posteriorly
- Anterior caudal vertebrae with medial accessory articulation on prezygapophysis
- Transverse furrow on chevron articulations
- Circular, rough tuberosity on medial surface of scapula
- Elliptical concavity on ventral face of scapular blade near acromion
- Ischium shorter than pubis
- Robust fourth trochanter on midline of femoral posterior face
- Distal condyles of femur expanded onto anterior portion of shaft
- Rectangular morphology of fibular proximal end
Species
Oceanotitan dantasi Mocho et al., 2019
Type species
Named for Portuguese paleontologist Pedro Dantas, who was a major contributor to Portuguese vertebrate paleontology towards the end of the 20th century.
- Holotype
- SHN 181 , Sociedade de Historia Natural
- Material
- Partial skeleton including eight anterior caudal vertebrae, caudal neural arch fragments, anterior chevron, right scapula, right coracoid, ilium fragment, two pubes, two ischia, right femur, tibia, fibula, and astragalus
- Horizon
- Praia da Amoreira-Porto Novo Member, Lourinhã Formation, Kimmeridgian, Late Jurassic , 154.8–149.2 million years ago
- Locality
- cliffs north of Praia de Valmitão, Lisbon, Portugal
References
-
Mocho, P.; Royo-Torres, R.; Ortega, F. (2019). A new macronarian sauropod from the Upper Jurassic of Portugal. Journal of Vertebrate Paleontology 39(1): e1578782. Informa UK Limited. doi:10.1080/02724634.2019.1578782
Named Oceanotitan and recovered it as the earliest somphospondylan on one matrix and at the base of Titanosauriformes on another.
mocho2019a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the body length, mass, and hip height estimates.
jones2026b -
Mocho, P.; Escaso, F.; Gasulla, J. M.; Galobart, À.; Poza, B.; Santos-Cubedo, A.; Sanz, J. L.; Ortega, F. (2023). New sauropod dinosaur from the Lower Cretaceous of Morella (Spain) provides new insights on the evolutionary history of Iberian somphospondylan titanosauriforms. Zoological Journal of the Linnean Society 201(1): 214-268. Oxford University Press (OUP). doi:10.1093/zoolinnean/zlad124
Recovered Oceanotitan outside Titanosauriformes, as the sister of Aragosaurus, under implied weights.
mocho2023a -
Mannion, P. D.; Carvalho, I. S. (2026). Re-evaluation of the Early Cretaceous titanosauriform sauropod dinosaur Triunfosaurus leonardii from the Triunfo Basin, Brazil: implications for the initial radiations of Somphospondyli and Titanosauria. Zoological Journal of the Linnean Society 207(1). Oxford University Press (OUP). doi:10.1093/zoolinnean/zlag073
Regards Oceanotitan as a non-titanosauriform macronarian.
mannion2026a