Wintonotitan, meaning “Winton titan,” is a genus of titanosauriform dinosaur from the late Albian age of the of the Early Cretaceous Period. It was discovered 37 miles northwest of Winton, Australia — for which its named. The type specimen is known from partial postcranial remains. A second specimen was found consisting of isolated tail vertebrae. Both specimens were collected from the lower part of the Winton Formation.
The fossils that were first found in 1974 by paleontologist Keith Watts. The fossils were originally assigned to Austrosaurus, which was the only named Australian Cretaceous sauropod genus. It was catalogued as QMF 7292. However, it was reassigned as the type specimen of Wintonotitan in 2009 by Scott Hocknull and colleagues. The type species being W. wattsi, honoring the discoverer. Further analysis revealed Wintonotitan to be a primitive titanosauriform sauropod.
Wintonotitan was found in sandstone interpreted as a point bar of a river. Also found at the site were fish fossils, a theropod tooth, and a variety of plant fossils. The Winton Formation had a faunal assemblage including bivalves, gastropods, insects, the lungfish Metaceratodus, turtles, the crocodilian Isisfordia, pterosaurs, and several types of dinosaurs, such as the theropod Australovenator, the sauropod Diamantinasaurus, and unnamed ankylosaurians and hypsilophodonts.
Like other sauropods, Wintonotitan would have been a large quadrupedal herbivore.