The phylogenetic position of the Black‐collared Bulbul Neolestes torquatus

The Black-collared Bulbul Neolestes torquatus is a resident African passerine occupying the lightly wooded savannah of central Africa. It occurs from Gabon to central Angola, Congo and extends northwest to the D. R. Congo (Keith 2000). Its range almost entirely falls within the Western and Southern Congolian Forest Savanna Mosaic as delimited in WWF’s Terrestrial Ecoregions for Africa (Burgess et al. 2004). Its taxonomic affinities have been a matter of contention for more than a century (Dowsett et al. 1999). Neolestes has a striking plumage, with a grey forecrown and nape, a black mask across the eye curving around the white throat to connect with the wide black collar across the breast, hence its vernacular name. In general shape and plumage pattern, it strongly resembles malaconotid bush-shrikes (Malanonotidae) and was originally described as an aberrant Malaconotid by Cabanis (1875). Although Gadow (1883) remarked that Neolestes ‘does not appear to be a Bush-Shrike, but to be allied to the Bulbuls or Pycnonotidae’, an association with the Malaconotidae or an enlarged Laniidae held for more than half a century (e.g. Reichenow 1902–1903, Sharpe 1903, Sclater 1930). Chapin (1921) was the first to observe and study the species in the field during his expeditions to the Congo. In both behaviour and morphology Neolestes was considered by him to be placed among the bulbuls (Pycnonotidae). Although an affinity with bulbuls has been the prevailing opinion ever since (White 1962, Hall & Moreau 1970, Wolters 1982, Sibley & Monroe 1990, Keith 2000), a link to the bush-shrikes has never been completely discounted (Bannerman 1953). More recently, Olson (1989) examined a fluid-preserved specimen of Neolestes. He suggested that the species be placed incertae sedis near the helmet-shrikes (Prionopidae), due to Prionops and Neolestes sharing tufts of stiff, plush, chestnut feathers behind the ear. In a reappraisal of its phylogenetic position, Dowsett et al. (1999) re-evaluated the morphological and behavioural evidence for an association of Neolestes with bulbuls, bush-shrikes or helmet-shrikes, together with molecular data. Although some morphological characters were equivocal in placing Neolestes among the bulbuls, they clearly indicated that any association with bushor helmet-shrikes was unwarranted. In particular, Neolestes shares with bulbuls similarities in syrinx, carpometacarpus, humerus and various skull structures, juvenile plumage, nest structure, eggs, clutch size, diet and song (Dowsett et al. 1999). The molecular data were limited to a short cytochrome-b sequence from a dozen oscine passerines. Despite the limited sampling, Neolestes clustered basally in a monophyletic clade with the other two bulbuls included in that dataset and far away from Laniarius and Prionops. Weighing both morphological and molecular evidence, Dowsett et al. (1999) suggested that Neolestes should be included among the bulbuls. They also predicted that it would probably represent a basal clade, or even the sister taxon of the remaining bulbuls. Two recent papers (Moyle & Marks 2006, Johansson et al. 2007) conducted phylogenetic analyses of bulbul relationships using molecular data. Whereas Moyle and Marks (2006) studied the relationships at the family level, Johansson et al. (2007) focused their attention on the Afrotropical radiation. Neither of these studies included Neolestes, and thus its placement within the Pycnonotidae remains unanswered. In the present paper we use nuclear and mitochondrial sequences to clarify the phylogenetic position of Neolestes torquatus.