Open Paleo

Andesaurus

Calvo & Bonaparte, 1991 AN-duh-SOR-uhs /ˌændəˈsɔːrəs/

Named for the Andes mountain range, near where the fossils were found in South America, combined with Greek 'sauros' meaning 'lizard', meaning 'Andes lizard'.

100.5–93.9 million years ago Cenomanian, Late Cretaceous
Late Cretaceous stages

Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, it would have had a small head on the end of a long neck and an equally long tail.

Diagnosis

  1. Posterior dorsal vertebrae with hyposphene-hypantrum articulations, absent in other titanosaurids
  2. Neural arch of dorsal vertebrae proportionately taller than in other titanosaurs, representing three-quarters the height of the vertebra
  3. Prespinal lamina wide and bifurcate in its inferior portion
  4. Amphiplatyan (platycoelous) caudal vertebrae throughout the available series, with no indication of procoely
  5. Caudal neural spine laminar with axially extensive base; neural arch placed on the centroanterior portion of the centrum
  6. Pubis with markedly wide proximolateral process and pubic foramen located far from the lateral border

Species

Andesaurus delgadoi Calvo & Bonaparte, 1991

Type species

Named for Alejandro Delgado, the person who found the fossils of Andesaurus.

Holotype
MUCPv 132 , Universidad Nacional del Comahue
Material
Four articulated posterior dorsal vertebrae, 27 articulated caudal vertebrae, nearly complete left and incomplete right ischium, nearly complete left pubis, incomplete right humerus and femur, and various incomplete ribs
Horizon
lower Candeleros Formation, Cenomanian, Late Cretaceous , 100.5–93.9 million years ago
Locality
El Chocón, 5 km southeast, Neuquén, Argentina

References

  1. Calvo, J. O.; Bonaparte, J. F. (1991). Andesaurus delgadoi gen. et sp. nov. (Saurischia-Sauropoda), dinosaurio Titanosauridae de la Formacion Rio Limay (Albiano-Cenomaniano), Neuquén, Argentina [Andesaurus delgadoi gen. et sp. nov. (Saurischia-Sauropoda), a titnosaurid dinosaur from Rio Limay Formation (Albian-Cenomanian), Neuquén, Argentina]. Ameghiniana 28(3-4): 303-310. calvo1991a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026b