"Guizhouichthyosaurus" was one of the largest marine vertebrates of the time, whose only predators composed of large macro-predatory Ichthyosaurs (that of which preferred to hunt smaller ichthyosaurs).The rise of the shelled cephalopods (ammonites that survived the Permian-Triassic extinction event, along with the appearance of belemnites) gave ichthyosaurs an abundant food supply with little competition.