In the heart of the desert, scientists unearth an ancient inland ocean full of sea monsters. Opal fossils of some of these beasts paint a colorful picture of the exotic seascape, where long-necked plesiosaurs snacked on shelled creatures that grew as large as truck tires. The most fearsome was Kronosaurus, with a skull twice as long as T. rex.
Apparently, the platypus ended up inheriting the lot.