Open Paleo

Atlantosaurus

Marsh, 1877 Nomen dubium

From Atlas, the Titan of Greek myth who bore the sky on his shoulders, and Greek 'sauros' ('lizard'), for the great size of the animal.

161.5–137.1 million years ago Oxfordian–Berriasian, Late Jurassic–Early Cretaceous
Late Jurassic and Early Cretaceous stages

Atlantosaurus is a dubious genus of sauropod dinosaur. It contains a single species, Atlantosaurus montanus, from the Late Jurassic upper Morrison Formation of Colorado, United States. Atlantosaurus was the first sauropod to be described during the infamous 19th century Bone Wars, during which scientific methodology suffered in favor of pursuit of academic acclaim.

Species

Atlantosaurus montanus (Marsh, 1877) Nomen dubium

Type species

First named as Titanosaurus montanus

From Latin 'montanus' ('of the mountains'), for the Rocky Mountain region where the type material was collected.

Holotype
YPM 1835 , Yale Peabody Museum of Natural History
Material
Partial sacrum, including the last two sacral vertebrae with their transverse processes, together with portions of the posterior limbs.
Horizon
Morrison Formation, Oxfordian–Berriasian, Late Jurassic–Early Cretaceous , 161.5–137.1 million years ago The age of the containing rock unit; no finer age has been published.
Locality
Lakes' Quarry 1, Morrison, Colorado, United States

Synonyms

  • Titanosaurus montanus preoccupied

    The original combination, published by Marsh in July 1877. The generic name was preoccupied by Titanosaurus Lydekker, 1877, and Marsh replaced it with Atlantosaurus later the same year.

References

  1. McIntosh, J. S.; Berman, D. S. (1975). Description of the palate and lower jaw of the sauropod dinosaur Diplodocus (Reptilia: Saurischia) with remarks on the nature of the skull of Apatosaurus. Journal of Paleontology 49(1): 187-199. Cambridge University Press (CUP).

    Places the type in Lakes' Quarry 1 at Morrison.

    mcintosh1975a
  2. Marsh, O. C. (1877). Notice of new dinosaurian reptiles from the Jurassic formation. American Journal of Science s3-14(84): 514-516. American Journal of Science (AJS). doi:10.2475/ajs.s3-14.84.514

    Replaces the preoccupied generic name Titanosaurus with Atlantosaurus, establishing the combination Atlantosaurus montanus.

    marsh1877c
  3. Marsh, O. C. (1877). Notice of a new and gigantic dinosaur, Titanosaurus. American Journal of Science s3-14(79): 87-88. American Journal of Science (AJS). doi:10.2475/ajs.s3-14.79.87

    Original description of the type species as Titanosaurus montanus, on a partial sacrum and portions of the posterior limbs.

    marsh1877b
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Gives the holotype as YPM 1835, a partial sacrum, and finds nothing uniquely identifiable about the specimen.

    jones2026b
  5. Upchurch, P.; Barrett, P. M.; Dodson, P. (2004). Sauropoda. The Dinosauria, Second Edition (Weishampel, D. B.; Dodson, P.; Osmólska, H., eds.) 259-322. University of California Press, Berkeley.

    Lists the type species among nomina dubia, with its material given as sacral centra.

    upchurch2004a
  6. Tschopp, E.; Mateus, O.; Benson, R. B. J. (2015). A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3: e857. PeerJ. doi:10.7717/peerj.857

    Recovers the holotype of the second species Atlantosaurus immanis as an indeterminate apatosaurine lacking autapomorphies, so a nomen dubium.

    tschopp2015a
  7. Olshevsky, G. (1991). A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2: 1-196.

    Treats the genus as a nomen dubium and records the preoccupation of Titanosaurus Marsh, 1877 that Atlantosaurus replaces.

    olshevsky1991a