Barosaurus: a long-necked Jurassic sauropod

Physical characteristics

Barosaurus had an exceptionally long neck compared with many other sauropods; vertebrae in the neck were elongated to give great reach while keeping a relatively slender overall profile. Compared with its close relative Diplodocus, Barosaurus is usually reconstructed as having a longer neck and a shorter tail, with a lighter, more gracile skeleton rather than the robust build seen in some other genera. Its limb bones were columnar and adapted to support a massive body weight, but the bones and overall proportions suggest a more lightly built frame than that of Apatosaurus or the larger forms sometimes called Brontosaurus.

Skeleton, skulls and reconstructions

Skulls of diplodocids are seldom preserved, and to date no undisputed Barosaurus skull has been found. Because of this gap, restorations of Barosaurus skulls are usually modeled on better-known relatives, most commonly Diplodocus. The neck was made up of many elongate vertebrae with air-filled cavities that reduced weight — a common sauropod feature — and the tail was comparatively shorter than in some related genera. Museums mountings and scientific reconstructions vary in neck posture and feeding height because those behaviors remain debated.

Discovery and fossil record

The genus was named by Marsh in 1890 and is best represented by material from the Morrison Formation of western North America. Isolated remains and fragmentary material attributed to Barosaurus or very similar animals have also been reported from parts of East Africa; those records are sometimes subject to re-evaluation, so researchers treat African attributions with caution. For regional occurrence summaries see the North American lists at western North America and discussions of African finds at East Africa.

Ecology and behavior

As a high-browser, Barosaurus likely fed on foliage well above the reach of most other herbivores, stripping leaves or fronds from tall conifers and other Jurassic plants. Its neck gave it a wide feeding envelope without moving the whole body, and it may have been able to raise its head still higher by rearing or by elevating the anterior portion of the trunk — behaviors inferred but not proven. These feeding adaptations allowed diplodocids like Barosaurus to occupy ecological niches distinct from more heavily built sauropods.

Notable facts and distinctions

• Named by O. C. Marsh in 1890 — the name means "heavy lizard"; see the original naming context at naming.
• Often compared to Diplodocus for its close relationship; distinguished by proportionally longer neck and lighter skeleton.
• Fossil material primarily from the Morrison Formation, with additional attributed remains reported from East Africa and extensive collections in western North America.
• Reconstruction uncertainty: no confirmed skull and differing opinions on neck posture and feeding height; further research continues to refine these aspects (summary).

For further reading and specimen data consult regional and taxonomic resources listed at Late Jurassic resources, museum catalogs at North American collections and comparative diplodocid reviews at Apatosaurus comparisons and Brontosaurus context.