"Ths group of animals comprises a complex of disparate groups including the dolphin/shark-like ichthyosaurs, manatee-like placodonts, long- and short-necked plesiosaurs, the mososaur lizards, marine turtles, and crocodilians. Sea reptile paleontology is a very active field in terms of new discoveries and research, so the guide is highly topical. For example, it is becoming increasingly apparent that the long-standing assumption that prehistoric oceanic reptiles had low metabolic rates, like reptiles, is incorrect. Instead, it is now thought that many of these beasts were endothermic, and that this evolutionary adaptation was far more widespread than formerly realized. Preserved soft tissues are showing that most mososaurs were not snake-like undulating swimmers but were compact-bodied, deep tailed and swift swimmers (as shown by the attached skeletals that show the development of tail fins over time). Studies of bone microstructure are revealing how some sea reptiles dove deep enough to be victims of the bends. Gigantic forms as big as whales have been uncovered. There are about 350 named sea reptile species. About 250 will be accurately illustrated"-- Provided by publisher.