Von Koenigswald (1949 p. 110) established the name Pithecanthropus dubius to accommodate the 1939 mandibular fragment from Sangiran (Sangiran 5). Von Koenigwald wrote, "A third type, called Pithecanthropus dubius v. K. (because of his doubtful position) is represented by a jaw-fragment, found at Sangiran in 1939, the symphysis of which is different from Meganthropus (to which this jaw was originally attributed) as well as from Pithecanthropus B. The teeth show a specialized pattern."
Campbell (1965) lists this name as available and valid as does Groves (1989)
