Elaphrosaurus

Elaphrosaurus was an unusual, fleet-footed theropod from the Late Jurassic Tendaguru beds of modern-day Tanzania. Reaching roughly six metres in length, it was remarkably slender, sporting an elongated neck, a shallow torso, and long, graceful hind legs built for sprinting across open ground. Although initially mistaken for an ornithomimosaur or ostrich dinosaur due to its proportions, anatomical details of the pelvis and limbs revealed it to be an early, highly specialised ceratosaur. The skull remains unknown, leaving its precise diet somewhat uncertain, though close relatives like Limusaurus suggest it may have been an omnivore or herbivore rather than a dedicated predator. Elaphrosaurus shared its coastal floodplain environment with famous giant sauropods, plated stegosaurs, and larger carnivores, relying on speed to evade danger.

Despite reaching over five metres in length, its slender limbs and hollow bones made it exceptionally lightweight and swift.

Where and when

Elaphrosaurus lived in the Late Jurassic, from 154.8 to 150 million years ago (Kimmeridgian-Tithonian age). Its remains come from Tanzania, in the Tendaguru Formation.

The numbers

Length 5.9 m (estimates run from 5.5 to 6.2 m). Mass about 260 kg. Hip height about 1.5 m. That is 3.5 human-lengths, or 0.53 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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