Isurus planus, also known as the Hook-tooth Mako or Hooked Mako, is an extinct mako shark that lived during the Miocene epoch from 23-5 million years ago. I. planus can only be found in marine deposits on the Pacific rim, especially the west coast of the United States. Teeth belonging to I. planus can reach lengths of two inches, and are often found in Bakersfield, California.