Thrinacodus is an extinct genus of basal elasmobranch, found worldwide from the Late Devonian-Lower Carboniferous.

The type species is Thrinacodus nanus.

T. gracia, originally placed in the separate genus Thrinacoselache from the Serpukhovian-aged Bear Gulch Limestone, of what is now Montana, is known from full body impressions, showing a long, slender eel-like body up to a metre in length, with an elongate rostrum.

[2][3][4] Stomach contents of T. gracia include remains of crustaceans and small chondrichthyan fish (Harpagofututor and Falcatus).

This article about a prehistoric cartilaginous fish is a stub.