Carinacanthus ("keeled spine") is an extinct genus of small freshwater hybodont shark that inhabited eastern North America during the Triassic period.

[1][2] It contains a single species, C. jepseni from the Late Triassic (Norian)-aged Lockatong Formation of Pennsylvania, USA.

[1][4][5] It is a very rare taxon, with only two potential specimens known despite the well-studied nature of the Newark Supergroup deposits.

The type specimen consists of a poorly-preserved axial skeleton, only about 130 millimetres (5.1 in) in length, which is missing the head but allows most of the post-cranial anatomy to be known, including the position of its two large spines and the presence of a heterocercal tail.

[6][7] The fossil egg case taxon Chimaerotheca oakesi, described from the Triassic of Massachusetts and attributed to a chimaeroid, may be potentially referable to Carinacanthus, as one of the only other chondrichthyans known from the Newark Supergroup.