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Taxonomic status of Seismosaurus hallorum, a Late Jurassic sauropod dinosaur from New Mexico

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew B. Heckert Ph.D., Assistant Professor of Geology (Creator)
Appalachian State University (ASU )
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Abstract: The holotype of the Late Jurassic sauropod dinosaur Seismosaurus hallorum consists of part of the thoracic and caudal vertebrae, most of the sacrum and pelvis, some ribs and chevrons and an incomplete femur. Reexamination of the holotype indicates that Seismosaurus hallorum differs little from Diplodocus, and none of the morphological differences are significant enough to justify a separate genus. Particularly important to this conclusion has been careful re-examination and further preparation of the ischium of the S. hallorum holotype, which indicates that the distal, hook-like process originally described was actually the tip of a vertebral neural spine and sandstone matrix adhering to the ischium. We consider Seismosaurus to be a junior subjective synonym of Diplodocus. We suggest that Diplodocus hallorum is also a junior subjective synonym of D. longus, but a careful taxonomic revision of the species of Diplodocus is needed to verify this suggestion.

Additional Information

Lucas, S.G., Spielmann, J.A., Rinehart, L.F., Heckert, A.B., Herne, M.C., Hunt, A.P., Foster, J.R., and Sullivan, R.M., (2006) Taxonomic status of Seismosaurus hallorum, a Late Jurassic sauropod dinosaur from New Mexico. New Mexico Museum of Natural History and Science Bulletin, v. 36, p. 149-161. Archived in NC DOCKS with permission of the editor. The version of record is available at:
Language: English
Date: 2006