Kingdom Animalia Class Chondrichthyes Superorder Selachimorpha | Phylum Chordata Subclass Elasmobranchii Order Lamniformes | |
Similar Isurus hastalis, Hemipristis serra, Cosmopolitodus, Isurus, Hemipristis | ||
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 to 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 2.0 in (5.0 cm), and are often found in the Temblor Formation of Bakersfield, California.
Description
Isurus planus teeth are similar to those of other mako sharks, especially the extinct species Isurus hastalis and Isurus desori. Adult upper teeth are generally 2-4 cm long with an unserrated cutting edge and no lateral cusplets. True to its name, each tooth is "hooked", the point of which is shifted away from the middle axis, in the direction of the corners of the mouth. In this, the teeth of I. planus and I. desori differ from I. hastalis. I. desori teeth are much more heterodonic than I. planus and their roots are more uneven in thickness and shape. The lower teeth of this species are much straighter.