The unidentified species from Mount Lumarku was formally described as N. hurrelliana in 2003 by Martin Cheek and Anthony Lamb. Its natural range is now known to cover northern Sarawak, Brunei, and southwestern Sabah, although it has not been recorded from Kalimantan. If N. mollis and N. hurrelliana were shown to be conspecific, the latter would become a heterotypic synonym of the former.