According to the National Geographic article, "Sea Monster" Bones Reveal Ancient Shark Feeding Frenzy, recent analysis of the fossilized bones of a plesisaur indicated the presences of over 80 sharks teeth embedded in the bones. The teeth were identified as belonging to the extinct species Cretalamna appendiculata, which was believed to have reached 3m in length. The plesiosaur was considerably larger at approximately 7m in length.

Paleontologist, Kenshu Shimada, believes that the plesiosaur was likely dead on near death when the shark bites occurred, as he believes that the sharks would have been no match for a healthy plesiosaur. While all of the teeth found embedded in the bones are believed to have come from the same species, the varying size and shape of the teeth indicate that sharks of various ages were involved in the "attack". Shimada estimated that at least seven different sharks of varying ages attacked the plesiosaur. For more information, check out the entire articles at National Geographic.