It's time for some deep water terror! I'm working on Livyatan, the first book in the Periled Waters series. Livyatan  melvillei is an extinct genus of highly predatory sperm whale. It once lived alongside Megalodon and died out about five-million years ago. But... are we positive it no longer exists. Man has only explored up to ten percent of the ocean and 0.001% of the deep ocean seafloor.