Rufous-backed Honeyeater (Ptiloprora guisei) - HBW 13, p. 658

Taxonomy: Ptilotis (?) guisei De Vis, 1894, Mount Maneao, south-east New Guinea.
Formerly considered conspecific with P. erythropleura, P. mayri and P. perstriata, but the four differ in size, plumage (crown colour, dorsal coloration, colour of wing-covert edgings, distinctness of ventral spotting, flank colour) and iris colour. May form a superspecies with P. mayri, and often treated as conspecific with that species alone, but comparative studies indicate that the two are better considered separate species. Has sometimes been thought conspecific with P. perstriata, but the two occur sympatrically (with mutually exclusive altitudinal ranges) over at least 560 km in E New Guinea. Birds of Huon Peninsula intermediate between nominate and umbrosa, but closer to latter and generally included within it; populations of Adelbert Mts and Mt Bosavi likewise provisionally placed in umbrosa. W limits of nominate race uncertain; populations of Bismarck Range and Kubor Range placed in nominate, but may belong with umbrosa (or intergradient between the two races). Two subspecies recognized.