A new species of Biemna Gray, 1867 (Demospongiae, Poecilosclerida) from the north coast of Brazil.

Biemna spinomicroxea sp. nov. is described from the coast of Amapa State, Brazil. It differs from all other Biemna species in lacking smooth sigmas. The spiculation consist of oxea megascleres, spined small sigmas and microxeas. A key to the tropical West Atlantic species of Biemna is provided.