Judith Massare is a paleontologist specializing in Mesozoic marine reptile research.
In 1987, Massare published an analysis of plesiosaur feeding habits.
She concluded that the long-necked plesiosauroids ate soft prey.
Liopleurodon and its relatives, on the other hand, had teeth resembling those of killer whales and probably ate larger, bonier prey.
[1] The next year, Massare analyzed Mesozoic marine reptile swimming abilities and found that long-necked plesiosaurs would have been significantly slower than pliosaurs due to excess drag incurred from their large round bodies.