Complex sentence: Edward Newton described it as a full species "Zosterops semiflava" in 1867, though subsequently it was considered a subspecies of the Chestnut-sided White-eye from Mayotte.
Split into simpler sentences: Edward Newton described it as full species "Zosterops semiflava" in 1867. But subsequently it was long regarded as subspecies of the Chestnut-sided White-eye from Mayotte.