Around 20 species belong to the family Ziphiidae, with several only having been discovered in the past couple of decades.    From Wordnik.com.  [UnderwaterTimes.com News of the Underwater World] Reference

"" The Anatomy and Systematics of Colepiocephale lambei (Dinosauria: Pachycephalosauridae), "" Diprotodontid Footprints from the Pliocene of Central Australia, "" Cranial Mechanics and Functional Interpretation of the Horned Carnivorous Dinosaur Carnotaurus sastrei, "and" A New Beaked Whale (Odontoceti, Ziphiidae) from the Middle Miocene of Peru. ".    From Wordnik.com.  [Stuff That Happened Yesterday®] Reference