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Red-billed Tyrannulet Zimmerius cinereicapilla

  • Order: Passeriformes
  • Family: Tyrannidae
  • Monotypic
  • Authors: Thomas S. Schulenberg


Geographic Variation

Zimmerius cinereicapilla is monotypic.

Related Species

Described as Phyllomyias cinereicapilla Cabanis 1873; type locality Monterico, Ayacucho, Peru

Hellmayr (1927) considered cinereicapilla to be a subspecies of Zimmerius gracilipes (Slender-footed Tyrannulet), but the status of cinereicapilla as a distinct species no longer is in doubt (see Similar Species).

For most of the 20th century, cinereicapilla was classified in the genus Tyranniscus (e.g Hellmayr 1927, Meyer de Schauensee 1966), which included all species currently assigned to Zimmerius, as well as three species now placed in Phyllomyias: nigrocapillus (Black-capped Tyrannulet), uropygialis (Tawny-rumped Tyrannulet), and cinereiceps (Ashy-headed Tyrannulet). Zimmer (1955) pointed out that the last three species differed from other species of "Tyranniscus" by having wing bars (rather than pale edgings to the wing coverts). Ames (1971) discovered that a significant difference in syringeal morphology between the two groups. Based on this information, Traylor (1977) merged nigrocapillus, uropygialis, and cinerceiceps into Phyllomyias. As nigrocapillus was the type species for Tyranniscus, this left the remaining species of "Tyranniscus" without a genus. Consequently, Traylor proposed a new genus, Zimmerius, for these species, including cinereicapilla. The name Zimmerius honors John T. Zimmer, who published dozens of papers on South American birds, especially of the birds of Peru. Phylogenetic analysis of syringeal and skull morphology (Lanyon 1988) and of DNA sequence data (Ohlson et al. 2008, Tello et al. 2009) confirms that Zimmerius is quite distinct from all Phyllomyias, although the DNA data also suggest that Phyllomyias sensu Traylor is not a monophyletic genus.

Zimmerius cinereicapilla may be sister to Zimmerius villarejoi (Mishana Tyrannulet) (Rheindt et al. 2013), although that study did not include a recently described tyrannulet (Zimmerius chicomendesi, Chico's Tyrannulet; Whitney et al. 2013) that may belong to this same group.

Recommended Citation

Schulenberg, T. S. (2015). Red-billed Tyrannulet (Zimmerius cinereicapilla), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.