This species is represented in the Oriental Region by the subspecies mui which was described on the basis of one specimen from the island of Timor in Indonesia by Mason et al. (1984). Since it is quite different in appearance, it may best be treated as a separate species. Further research is needed.
Note also that it has been suggested, e.g. by Payne (2005) that another Oriental taxon, the Kai Coucal Centropus spilopterus, should best be treated as a subspecies of C. phasianinus. Refs:
Mason, I.J., McKean, J.L. and Dudzinski, M.L. (1984)
Geographical variation in the Pheasant Coucal Centropus phasianinus (Latham) and a description of a new subspecies from Timor. Emu 84: 1-15.
Payne, R.B. The Cuckoos (2005) Oxford University Press.