Proposal (656) to South American Classification Committee
Revise the generic classification of 6 species of Hylophilus: (A) resurrect Pachysylvia and (B) recognize Tunchiornis
Effect on SACC: This proposal would (A) transfer 5 species of Hylophilus (decurtatus, hypoxanthus, muscicapinus, aurantiifrons, and semibrunneus) to the resurrected genus Pachysylvia, with a required change the ending of 4 of those specific epithets (to decurtata, hypoxantha, muscicapina, and semibrunnea) to agree in gender with Pachysylvia, and (B) transfer Hylophilus ochraceiceps to the newly described genus Tunchiornis.
Background: SACC Vireonidae footnote 11 currently reads as follows:
11. Genetic data indicate that Hylophilus is not monophyletic (Johnson et al. 1988) and that at least three separate genera are required (Slager et al. 2014). SACC proposal needed <wait follow-up taxonomic paper by Slager et al. > The name Pachysylvia was formerly (e.g., Ridgway 1904) used for Hylophilus.
Other lines of evidence besides phylogenetics also support the polyphyly of Hylophilus. As Slager and Klicka (2014) wrote, "[a]lthough Hylophilus species do share some common anatomical proportions and plumage features, some striking and concordant differences in habitat, voice, and iris color led Ridgely and Tudor (1989) to posit that the genus might contain sufficient diversity to warrant splitting into multiple genera." Ridgely and Tudor (1989) categorized Hylophilus into three groups: The pale-eyed "scrub" group, the dark-eyed "canopy" group, and the "understory" group (Hylophilus ochraceiceps).
Slager et al. (2014) produced a phylogeny of Vireonidae using mitochondrial (ND2) and nuclear (3 Z-linked loci) data that included 221 samples representing 46/52 currently recognized vireonid species and 14/15 species of Hylophilus. The phylogeny of Slager et al. (2014) showed that Hylophilus was polyphyletic, composed of 4 clades spread throughout Vireonidae. The four clades are shown in phylogenetic context in Figure 1 of Slager and Klicka (2014).
Analysis & Recommendation:
Hylophilus is clearly polyphyletic based on molecular data (Slager et al. 2014) and four genera are needed to reflect this diversity (Slager and Klicka 2014).
The first clade, containing Hylophilus sclateri, is addressed in a separate SACC proposal.
The second clade, containing the pale-eyed, scrub-dwelling species H. poicilotis, H. amaurocephalus, H. flavipes, H. olivaceus, H. semicinereus, H. thoracicus, H. pectoralis, and H. brunneiceps, can remain in the genus Hylophilus since the type species of Hylophilus is H. poicilotis. See paragraph 5 of Slager and Klicka (2014) for more discussion.
The third clade contains several canopy-dwelling species with dark irides and complex songs: H. decurtatus, H. aurantiifrons, H. hypoxanthus, H. muscicapinus, and H. semibrunneus. Because Hylophilus is in use for the "scrub" greenlets, these canopy species should be transferred to the resurrected genus Pachysylvia Bonaparte (type species = H. decurtatus), which has priority. See 6th paragraph of Slager and Klicka (2014) for more details. Since Pachysylvia is feminine, the specific epithets for decurtatus, hypoxanthus, muscicapinus, and semibrunneus should be changed to decurtata, hypoxantha, muscicapina, and semibrunnea, respectively.
The fourth clade, containing the forest interior understory-dwelling Hylophilus ochraceiceps, is sister to (Vireo + Hylophilus sclateri + Pachysylvia) and clearly needs its own genus. Slager and Klicka (2014) described Tunchiornis for this purpose. See Slager and Klicka (2014) paragraph 7 and page 2 for details.
A YES vote is recommended on both, i.e. (A) resurrect Pachysylvia, and (B) recognize Tunchiornis.
Ridgely, R.S. & Tudor, G. (1989) The Birds of South America. Vol. 1. The Oscine Passerines. University of Texas Press, Austin, Texas, 596 pp.
Slager, D.L., Battey, C.J., Bryson, R.W. Jr., Voelker, G., & Klicka J. (2014) A multilocus phylogeny of a major New World avian radiation: The Vireonidae. Molecular Phylogenetics and Evolution 80, 95-104.
Slager, D.L. & J. Klicka. (2014). Polyphyly of Hylophilus and a new genus for the Tawny-crowned Greenlet (Aves: Passeriformes: Vireonidae). Zootaxa 3884:194-196.
Dave Slager, November 2014
Comments from Stiles: “YES to A and B. The canopy greenlets form a coherent group, with Pachysylvia available as the genus name. Clearly ochraceiceps also requires its own genus given its remote phylogenetic position.”
Comments from Nores: “A-B: NO. I would include H. ochraceiceps, “canopy” Hylophilus, and Hylophilus sclateri within Vireo.”
Comments from Zimmer: “YES to A and B. The genetic data are clear that Hylophilus, as currently constituted, is polyphyletic. The proposed reclassification would appropriately recognize the two internally coherent groups of pale-eyed (scrub greenlets) versus dark-eyed (canopy greenlets) in separate genera (while employing historically used names), while placing the very different, polytypic ochraceiceps in its own, newly erected genus.”
Comments from Robbins: “YES to both. Genetic data make this a straightforward decision for erecting two genera for the clades that clearly are not monophyletic with true Hylophilus vireos.”
Comments from Areta: “YES to A and B. Taxon sampling is excellent, and the phylogenetic grouping of the Pachysylvia should be recognized at the genus level. I also agree in that the very distinctive and phylogenetically isolated ochraceiceps deserves to be in its own genus. Tunchiornis is a fine name.”