Red-billed Scythebill (Campylorhamphus trochilirostris) - HBW 8, p. 446

Taxonomy: Dendrocolaptes trochilirostris M. H. K. Lichtenstein, 1820, Brazil = Bahia, Brazil.
Suggested as sister-species of C. procurvoides, with relationships among some taxa in group unclear; specimens of latter’s SE Amazonian race multostriatus are intermediate between the two species, while its S races are vocally more similar to present species. Also close to C. falcularius, and sometimes regarded as forming a superspecies with it or even as conspecific. Assessment of geographic variation and separation from C. procurvoides both complicated by marked individual variation in general coloration and in extent and width of streaking above and below, but at least three geographically isolated groups evident: “venezuelensis group” (with brevipennis) in E Panama and N South America, “thoracicus group” (with zarumillanus) along Pacific coast of South America, and “trochilirostris group” (including remaining races) from Amazonia, Atlantic forest and dry interior of South America. In last-mentioned group, affinities of Amazonian races problematic; napensis morphologically closest to “thoracicus group” of Pacific coast, whereas notabilis, snethlageae and devius apparently closer to lafresnayanus of dry interior, which region also includes hellmayri and major; described races omissus (E Brazil) and guttistriatus (S Goiás, Brazil) both synonymized with major. Twelve subspecies recognized.