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Cedarosaurus

Tidwell et al., 1999 SEE-duh-ro-SAWR-us

From Cedar (referring to the Cedar Mountain Formation where it was discovered) + Greek sauros ('lizard'), meaning 'Cedar lizard'.

137.1–132.6 million years ago Valanginian, Early Cretaceous
Early Cretaceous stages

Cedarosaurus is a genus of nasal-crested macronarian sauropod dinosaur from the Early Cretaceous Period (Valanginian). The fossils were discovered in 1996 in eastern Utah within the rocks of the Yellow Cat Member of the Cedar Mountain Formation. It was officially named and described by Tidwell, Carpenter and Brooks in 1999. It shows similarities to the brachiosaurid Eucamerotus from the Wessex Formation of southern England, as well as to Brachiosaurus from the Morrison Formation.

Diagnosis

  1. Anterior caudal vertebrae possess deeply concave anterior faces, lacking the posterior ball of titanosaurs; posterior faces of anterior caudal vertebrae are flat to concave.
  2. Anterior caudal vertebrae lack well-developed hyposphenes (only caudal 8 shows a small hyposphene).
  3. Mid-caudal vertebrae bear a sharp ridge extending axially along the sides of the neural arch.
  4. Deltopectoral crest of humerus placed closer to midshaft than in Brachiosaurus, Pleurocoelus nanus, or SMU 61732; humerus proportionally more robust than Brachiosaurus.
  5. Radius slender with two ridges beginning at midshaft; distal end subrectangular and flat rather than oval as in Pleurocoelus.
  6. Ulna with prominent posterior condyle separated from the lateral wall by a distinct groove, contrasting with Pleurocoelus nanus and SMU 61732.

Species

Cedarosaurus weiskopfae Tidwell et al., 1999

Type species

Named for the late Carol Weiskopf, in recognition of hard work in the field and laboratory.

Holotype
DMNH 39045 , Denver Museum of Nature and Science
Material
Eight articulated dorsal vertebrae, 25 caudal vertebrae, several chevrons, proximal scapulae, coracoids, sternal plates, right humerus, radius and ulna, metacarpal IV, pubes, ischia, partial left femur, right femur, right tibia, three metatarsals, one phalanx, three unguals, ribs, and gastroliths.
Horizon
upper Yellow Cat Member, Cedar Mountain Formation, Valanginian, Early Cretaceous , 137.1–132.6 million years ago
Locality
Cedarosaurus Quarry, Utah, United States

References

  1. Tidwell, V.; Carpenter, K.; Brooks, W. (1999). New sauropod from the Lower Cretaceous of Utah, USA. Oryctos 2: 21-37. tidwell1999a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b