Abstract
An isolated first costal turtle plate from the Early Cretaceous of Kut Island, Gulf of Thailand, is reported and assigned to Trionychoidae gen. et sp. indet. The morphology of the plate and comparison with turtle assemblages of the Khorat Group support the correlation of the vertebratesbearing beds of Kut Island with the Sao Khua Formation, as already suggested by the studies on sharks and dinosaurs.