Opisthocoelicaudia
- Pronunciation: o-piss-tho-SEE-luh-caw-dee-uh
- Translation: Behind Hollow Tail
- Order: Saurischia
- Suborder: Sauropodomorpha
- Infraorder: Sauropoda
- Family: Camarasauridae
- Height: 16 feet (4.9 meters)
- Length: 40 feet (12.2 meters)
- Period: Late Cretaceous
- Description: Herbivore, Quadrupedal
- Notes: Opisthocoelicaudia was found in the Gobi desert in a remarkable state of preservation. A mid-sized sauropod, it hadforelegs and hind legs of nearly equal length and a short tail.