In 1997, Matthew Jebb and Martin Cheek published their monograph A skeletal revision of Nepenthes (Nepenthaceae), in which they referred to N. dubia specimens from Mount Talang (Kurata s.n. SING) and the mountains of the Tjampo region near Payakumbuh (Meijer 6949 L). The latter specimen is the holotype of N. tenuis, which Jebb and Cheek treated in synonymy with N. dubia.