Kronosaurus is a type of Swimming Sharptooth. At the very beginning of The Land Before Time IV: Journey Through the Mists, during the Narrator's Introduction, a Kronosaurus can be seen jumping out of the water. Kronosaurus has not been seen since, although Liopleurodon, a similar species of Pliosaur, later appeared, in The Land Before Time IX: Journey to Big Water. However, it is alternatively believed to be a Mosasaurus.