preceded by the Latin prefix lepto
-, meaning 'thin', 'fine', or 'slender', and according to Hartman (1945: 22) it refers to the expanded dorsal lobes of the atokous parapodia: "The phrase 'branchiis superioribus corporis medii et posterioris permagnis' refers to the very greatly expanded dorsal lobe ot atokous parapodia (Plate 3, Fig. 5), for which the generic name was coined."
Not stated by the author. The name is composed by the generic name