Acanthorhachis is an enigmatic extinct genus of chondrichthyan from the Carboniferous period.

This is due to the spine-like dermal denticles and their subsidiary spines, which coated the exterior of the animal.

The authors who erected this genus suggested the common name "The Spiny Spined Shark."

Acanthorhachis was first described from the Westphalian-aged lower coal measures of Yorkshire, England.

[2] It occurs rarely in Viséan-aged Eyam Limestone of Derbyshire, England.