I edited and processed all three of the following screen captures from a video uploaded to YouTube on April 22, 2012, by "blackriverfossils." All fossils were collected from the middle Miocene Round Mountain Silt Member of the Temblor Formation, Sharktooth Hill Bone Bed, Kern County, California (approximately 16 to 15 million years old).

Top to bottom: Teeth from the extinct Mako shark, Isurus planus; second image--teeth from the extinct Mako shark, Isurus hastalis; bottom image--teeth from the extinct Tiger shark, Galeocerdo aduncus.