Reconsideration of the phylogenetic relationships of the enigmatic Bornean Bristlehead (Pityriasis gymnocephala).

Of the myriad birds with uncertain phylogenetic aYnities and convoluted taxonomic histories, perhaps none rivals the Bornean Bristlehead (Pityriasis gymnocephala) for the sheer number of families to which it has been allied and the resulting confusion as to its biogeographic history. The sole member of the genus is endemic to Borneo, where it is an uncommon resident of lowland and hill forests (Colenutt, 2002; Sheldon et al., 2001). It is seldom seen in the Weld, and long absences from suitable habitat punctuated by brief appearances of vociferous Xocks suggest that the species is highly nomadic (Witt and Sheldon, 1994). It is a relatively large passerine with a heavy, hooked bill. The plumage is mostly black, but with red and yellow feathers around the head and thighs. Plumage of the neck and head is coarse and stiV, giving rise to the English name, and it has been of particular interest to feather anatomists because of its unusual structure (Prum and Brush, 2002). The Bristlehead’s odd appearance and uncertain relationships led Mayr and Amadon (1951) to describe it as “one of the strangest members of all the Oscines.” Ahlquist et al. (1984) provided a thorough chronology of the various taxonomic assignations for Pityriasis, which we brieXy recount. Early taxonomic treatments placed Pityriasis closest to the genera Cracticus and Gymnorhina (Gadow, 1883; Temminck, 1835), similarly sized and heavy-mandibled genera from Australia and New Guinea. The Wrst dissenting view arose by the end of that century when Shelford (1899) suggested that it had aYnities to Eulabes (DGracula) and thus was a starling (Sturnidae). Confusion