None. Elasmosaurus was a herbivore. It probably was part of the diet of the more famous Permian finback, Dimetrodon
I made a stupid mistake...it all comes of not reading the question and my answer a bit more carefully.
Elasmosaurus was a plesiosaur which, while not a dinosaur, did live in Mesozoic seas as a contemporary, and preyed mainly on fish, I expect. I quite mindlessly confused Elasmosaurus with EDAPHOSAURUS. Edaphosaurus was a synapsid reptile that lived in the late Paleozoic (late Pennsylvanian to the end of the Permian) and was indeed an herbivorous animal, probably a part of the menu of its contemporary, Dimetrodon. Both of these reptiles are considered 'mammal-like' reptiles and were dominant, in terms of numbers, many millions of years before the dinosaurs came onto the scene.
They were obliterated in a mass extinction that was more catastrophic and sweeping than the one that brought the age of dinosaurs to an end.
If the Loch Ness Monster does exist, it would be a predator. The Loch Ness Monster is believed to be a surviving plesiosaur, a carnivorous aquatic reptile.
The plesiosaur ate mostly fish and plants
The Plesiosaur. Some people believe that the Loch Ness is a Plesiosaur.
There are no modern equivalents of Liopleurodon. Liopleurodon was a 50 foot long, short necked plesiosaur (pliosaur) and an apex predator. They lived during the Jurassic, about 162 - 150 million years ago.
It was not a dinosaur, but a plesiosaur and the longest plesiosaur. It could grow upto 15 m long.
The plesiosaur or the mosasaurid.
what other dinosaurs eat
nothing they are too big
they ate fish.
Plesiosaur
a pleasant one xx
An Archaeopteryx may have been able to fly, but a plesiosaur is a swimming reptile, and it doesn't fly. Archaeopteryx could not fly is was too heavey and its wings were way too short to support flight and as for the plesiosaur as the previous person mentioned it was a swimming reptile