Diabolepis is an extinct genus of very primitive marine lungfish which lived during the Early Devonian period.

It contains a single species, D. speratus of Yunnan, China, from the mid-late Lochkovian of the Xitun Formation.

It is the only member of the family Diabolepididae and the order Diabolepidiformes[3], although neither of these parent taxa have been officially described, despite their names being in scientific usage.

This has made the internal nares a case of parallel evolution rather than a homology between lungfish and tetrapods.

There can only be a narrow space between nostril and mouth, and an interrupted canal has been scored for Diabolepis.