This shark is only found in Pacific Ocean deposits and appears to be an offshoot of Cosmopolitodus hastalis with which it is found. Compared with hastalis, upper C. planus, teeth tend to be slightly narrower and possess a more hooked blade. Lower teeth are virtually indistinguishable from those of hastalis. For information on the genus see — Cosmopolitodus.

Fig. 1 & 2   Cosmopolitodus planus Upper anterior & lateral and lower anterior tooth. Lingual (left) and labial views of specimens. Note: lower tooth could be C. hastalis instead. Largest tooth 51mm slant height. Image by Bill Heim © 1998