Tiamat
Named after Tiamat, the primordial sea goddess of Mesopotamian (Babylonian) mythology, reflecting the ancient and primordial nature of the dinosaur.
Early Cretaceous and Late Cretaceous stages
Tiamat is a genus of titanosaur sauropod dinosaur from the Late Cretaceous (Cenomanian) Açu Formation of Ceará State, northeastern Brazil. The type species is Tiamat valdecii, described in 2024.
Diagnosis
- Marked accessory tuberosity dorsoventrally developed above prezygapophyses in middle caudal vertebrae
- Deeply medioventral excavated articulation facets of prezygapophysis and post-zygapophysis
- Presence of hypantrum–hyposphene articulations throughout caudal vertebral series
- Short middle caudal centra with well-marked articular facets for haemal arch
- Rough structure on spinopostzygapophyseal lamina unique among titanosaurs
Species
Tiamat valdecii Pereira et al., 2024
Type species
Named in honor of Dr. Valdeci dos Santos Júnior, who discovered the type locality.
- Syntypes
- UFRJ-DG 527-R, UFRJ-DG 574-R, UFRJ-DG 591-R, UFRJ-DG 606-R, UFRJ-DG 635-R, UFRJ-DG 636-R, UFRJ-DG 638-R, UFRJ-DG 704-R , Universidade Federal do Rio de Janeiro, Departamento de Geologia
- Material
- Associated sequence of anterior to middle caudal vertebrae.
- Horizon
- Açu Formation, Albian–Cenomanian, Early Cretaceous–Late Cretaceous , 113.2–93.9 million years ago
- Locality
- Ceará, Brazil
References
- Pereira, P. V L. G. C.; Bandeira, K. L. N.; Vidal, L. S.; Ribeiro, T. B.; Candeiro, C. R. dos A.; Bergqvist, L. P. (2024). A new sauropod species from north-western Brazil: biomechanics and the radiation of Titanosauria (Sauropoda: Somphospondyli). Zoological Journal of the Linnean Society 202(4). Oxford University Press (OUP). doi:10.1093/zoolinnean/zlae054 pereira2024a
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Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the body length, mass, and hip height estimates.
jones2026b