What is "diabolepis"

Diabolepis (or Diabolichthys) is an extinct genus of very primitive lungfish which lived about 400 million years ago, in the Early Devonian period of South China. Diabolepis is the most basal known dipnoan.

A rather small fish, the fossil has risen to prominence as it has four nares like most fish, while modern lungfish have only two, the hindmost pair having moved on to the palate serving as choanae. This proved that the internal nares of lungfish had evolved independently of those in tetrapods. This has made the internal nares a case of parallel evolution rather than an homology between lungfish and tetrapods.