These are Sharpteeth that live in the water. They have been seen in some movies such as the 5th and 9th movies. Most are unable to go onto land, though some, such as Nothosaurus, have been seen on land.
It's unknown if friendly Swimmers like Elsie and Mo would be considered Swimming Sharpteeth because they do not attack dinosaurs, though they are carnivores. They have only been called Swimmers (though some speculate that plesiosaurs would be called "Swimming Longnecks").
- Frank Welker (IV,V,IX)