The plainchin dreamarm was first formally described in 1925 as Dolopichthys gracilispinis by the English ichthyologist Charles Tate Regan with its type locality given as the eastern Pacific Ocean off Panama at 6°40'N, 80°47'W from a depth of 1,750 m (5,740 ft).

[5] The 5th edition of Fishes of the World classifies this taxon in the family Oneirodidae in the suborder Ceratioidei of the anglerfish order Lophiiformes.

The metemorphosed adults are distinguished from other members of the Oneirodidae by the possession of a well-developed spine on the manbible and in having an elongated, thin lobe to the pectoral fin.

The illicium is longer than the bulb of the esca, the illicial pterygiophore is cylindrical along its whole length, emerging between the frontal bones on the snout with its anterior end just poking through te skin and its rear end hidden beneath the skin.

They have 6 teeth on the lower denticular bone and like the females they also have no dermal spinules in the skin.