Another one of the very rare species of the middle Eocene teeth (lower Bartonian - 40 mya) from Tushbair, W. Kazakhstan. The Trigonotodus represents the earliest occurrence of the Thresher sharks and is most likely the ancestor of the extinct Giant Thresher shark. Note the characteristic extra wide root. These are great examples of a rare early Thresher. These teeth are tough to locate! These new teeth are the first to come out of the Tushbair site for 5 years.