| Diet | Herbivore |
| Height | 4m |
| Length | 20m |
| Weight | 15 tonnes |
| Environment | Land |
| Era | Jurassic |
| Period | Late Jurassic |
| Type | Sauropod |
| Location | North America |
Eobrontosaurus was a massive sauropod dinosaur that roamed the ancient landscapes of North America during the Late Jurassic period, approximately 155 to 149 million years ago. Originally described as a distinct genus by renowned palaeontologist Robert T. Bakker in 1998, this colossal herbivore has since been reclassified by most scientists as belonging to the well-known genus Camarasaurus, specifically as Camarasaurus grandis.
This enormous sauropod measured around 20 metres in length and stood approximately 4 metres tall at the hip, weighing an estimated 15 tonnes. Like other sauropods, it possessed the characteristic long neck and tail, massive body, and pillar-like legs that supported its tremendous bulk. Its fossils were discovered in the famous Morrison Formation of Wyoming, a geological treasure trove that has yielded numerous Late Jurassic dinosaur specimens.
As a herbivore, this sauropod would have spent much of its time feeding on the abundant plant life of the Late Jurassic period, using its long neck to reach vegetation that other dinosaurs couldn't access. The climate during this time was warm and humid, supporting lush forests of conifers, ferns, and cycads that provided ample food for these gentle giants.
Despite its original classification as a separate genus, the reassessment of Eobrontosaurus demonstrates how palaeontology continues to evolve as new discoveries are made and existing specimens are re-examined with fresh perspectives and improved techniques.
Eobrontosaurus was characterised by its massive size, extremely long neck and tail, and robust limb bones typical of large sauropods. The specimen showed features that were later determined to fall within the natural variation seen in Camarasaurus grandis.
Like other large sauropods, Eobrontosaurus likely lived in herds for protection against predators such as Allosaurus. It would have been a slow-moving browser, using its tremendous reach to feed on high vegetation whilst remaining relatively stationary.
Eobrontosaurus was first described by Robert T. Bakker in 1998. The original fossils were discovered at Morrison Formation, Wyoming, USA.
