variabilis=latin for variable, as this species is morphologically and genetically changeable throughout its known range
Meyer-Wachsmuth, I.; Curini Galletti, M.; Jondelius, U. (2014). Hyper-Cryptic Marine Meiofauna: Species Complexes in Nemertodermatida. <em>PLoS ONE.</em> 9(9): e107688.