Lethenia is an extinct genus of mackerel shark from the Rupelian age of the Oligocene epoch.

[2] It is considered closely related to Isurolamna and sometimes included within it.

It differs in the morphology of its teeth, which are much more gracile than Isurolamna and has larger spacing between its crown and lateral cusps.

Lethenia is rare and only known from isolated teeth.

This article about a prehistoric shark is a stub.