Fossil vertebrate remains from Kut Island (Gulf of Thailand, Early Cretaceous)

The Mesozoic vertebrate fauna from Kut Island includes hybodont sharks (Hybodus sp., Isanodus paladeji, a new species of Heteroptychodus), actinopterygians (Semionotiformes indet., Lepidotes sp.), indeterminate turtles, goniopholidid crocodiles, cf. Theriosuchus sp. and theropod dinosaurs. The new hybodont species is also present in the Sao Khua Formation and maybe also in the Phu Kradung Formation on the Khorat Plateau in northeastern Thailand. The occurrence of both I. paladeji and the new hybodont, together with heavily ornamented Semionotiformes teeth strongly suggest that this fauna is of the same age as the Sao Khua Formation one. Deposits from Kut Island are therefore younger than usually considered, and not older than Berriasian.