Isanosaurus

Isanosaurus is an extinct genus of sauropod dinosaur from the Early Jurassic in Thailand. Isanosaurus was originally thought to have lived during the Late Triassic, which would make it one of the oldest known sauropods, but other authors questioned this age estimate, suggesting that the genus lived during the Jurassic period. In 2026, U-Pb zircon dating confidently supported that the rock layers bearing the fossils of Isanosaurus were deposited during the Sinemurian-Pliensbachian stage of the Early Jurassic. The genus contains a single species, Isanosaurus attavipachi. Its exact relationships to other early sauropods remain unresolved due to the fragmentary known remains.