Plectostoma austeni (Smith, 1894)
From the observation at Benuk area, Plectostoma austeni can sometime be found together with P. wallacei busauense at the same limestone hill. However, these two species occupy different part of the same limestone hill where Plectostoma austeni was found in the dark caves, and crevice but P. wallacei busauense which observed living outside the caves and holes.