As I understand this paper, there were three possible populations (sub-species?) of Denisovans by 50kya:
D1) Homo denisova altaiensis (Siberia, Tibet and probably elsewhere in continental East Asia)
D2) Homo denisova luzonensis (South East Asia west of the Wallace Line)
D3) Homo denisova floresiensis (Sahul and South East Asia east of the Wallace Line)