Diagram of the different size estimates of Kronosaurus queenslandicus. File:Kronosaurus scale.svg    Though there are several uncertanties about Kronosaurus queenslandicus, it can be made certain that it was a very effective predator.  Kronosaurus was a carnivore that preyed on numerous marine animals.  These marine animals ranged from different types of sea turtles, reptiles, ammonites, smaller fish and larger fish.  Because Kronosaurus had an extremely large jaw with incredibly strong teeth, it was able to crush through shells and other hard objects (Renneboog, 2011)Kronosaurus could have easily bitten through the shells of the Red Rock Crab and the Moreton Bay Bug.  It was thought to have preyed on other marine animals such as the long-necked plesiosaurs.  Kronosaurus was so large and so powerful that it had little, if any, competition for food.  An example could be the Ichthyosaur.  Due to sheer size of Kronosaurus, it is thought to have possibly eaten almost anything smaller than it.  This could have included the giant squid and ElasmosauridaeThis includes other plesiosarus and pliosaurs.  The relationships that Kronosaurus had are still being debated.  This doesn't only include Kronosaurus, but pliosaurs in general.