Platecarpus

The mid-sized platecarpuses are the most common type of mosasaur. They're typically 15 feet long, but larger specimens can grow up to 20 feet. The larger varieties sometimes eat Medium humanoids, but most stick to smaller fare.

The massive swimming reptiles called mosasaurs thrash their powerful tails to propel them after prey. Four articulated, webbed paddles let them precisely steer their paths, and their hinged jaws-much like a snake's-allow mosasaurs to swallow larger creatures than their size would indicate. A small set of secondary pterygoid jaws in their gullets pull in their meals for more efficient digestion. As air breathers, mosasaurs must stay near the surface of the water, competing for food with whales. This proximity to the surface means they often capsize small boats, feasting on the crew members who fall out.