Elasmosauridae

This plesiosaur named Coralliusaurus (meaning coral lizard) is an aquatic species that lives in shallow water. The feeler-like structures on its back and chin are colored to resemble coral, hence the name. These Plesiosaurs are seen when the main characters cross the sea to reach South America (which is where the portal volcano is)

This is a very large Plesiosaur, being a similar size to Thalassomedon.

Do we have any evidence of Elasmosaurs hunting mosasaurs? Everyone knows mosasaurs hunted Elasmosaurs, but did it go the other way around sometimes?