Do you have information about Kronosaurus?

Kronosaurus was a short-necked late Cretaceous plesiOSaur. PlesiOSaurs are marine reptiles, and Kronosaurus - a meat-eating pliOSaur - was, as far as is known, the largest marine reptile that ever lived. One fossil indicates it was 42 ft. (12.8 m) in length when alive, with a skull that was 9 feet (more than 2.5 meters) long. It was a Mesozoic marine reptile, but it was not a dinosaur. There were no marine dinosaurs.

I made (above para) a minor error of omission and one of commission. Kronosaurs belong to a group of short-necked plesiOSaurs called pliOSaurs and are related to today's Varanid (monitor) lizards -- in other Words, they were enormous marine lizards. I should probably have mentioned that.

My error of commission involved the size. The maximum length of the Kronosaurs may have been ''only'' 30 feet instead of the 42 feet (4.8 metres) suggested in the earlier paragraph. As an aside, it's also worth mentioning that since these reptiles were enormous lizards, they were not water-breathers. Like today's dolphins and whales, they had to surface periodically to breathe.