Proposal (915) to South American Classification Committee

Recognize the genus Radinopsyche for "Herpsilochmus” sellowi

Effect on SACC: This proposal would transfer “Herpsilochmus” sellowi from its current placement in Herpsilochmus to Radinopsyche, the genus newly described for this monotypic species.

Background: SACC currently classifies 17 species in the genus Herpsilochmus (18 when the split of H. rufimarginatus into H. frater and H. rufimarginatus is implemented). Taxonomic membership of the genus has been universally accepted because these birds form a cohesive morphological, ecological, and behavioral group. Recent taxonomic changes within Herpsilochmus have resulted from descriptions of new taxa and reassessments of species limits.

The most phenotypically distinct species in the genus is the Brazilian endemic H. sellowi due to its voice—both songs and calls—and remarkably narrow bill, tarsi, and rectrices. Although specimens of H. sellowi had been identified as Herpsilochmus pileatus (Davis and O’Neill 1986 and older literature), Whitney et al. (2000) showed that those specimens represented an unnamed species morphologically and vocally diagnosable from all other members of the genus. In describing H. sellowi as a new species, they regarded it as “a highly distinctive species, both morphologically and vocally” and pointed out that “a reasonable argument could be made for its generic separation.” However, they stopped short of describing a monotypic genus pending phylogenetic evidence for the degree of relationship between H. sellowi and the name-bearing type species of the genus, H. pileatus.

New information: Using DNA sequences from the mitochondrion, nuclear exons, and ultraconserved elements (Harvey et al. 2020), phylogenomic analyses by Bravo et al (2021) show that the genus Herpsilochmus is not monophyletic because H. sellowi is sister of the monotypic species Biatas nigropectus, and that all other species in Herpsilochmus belong in a clade with Dysithamnus. Because the phenotypic distinctiveness of H. sellowi and B. nigropectus argues against merging them into a single genus and because no generic name is available for H. sellowi, Bravo et al. (2021) described the monotypic genus Radinopsyche for H. sellowi.

Recommendation: I recommend a “YES” vote to recognize the recently described genus Radinopscyhe for “Herpsilochmus” sellowi.

References:

Bravo, G. A., B. M. Whitney, R. Belmonte-Lopes, M. R. Bornschein, N. Aristizábal, R. Beco, J. Battilana, L. N. Naka, A. Aleixo, M. R. Pie, et al. (2021). Phylogenomic analyses reveal non-monophyly of the antbird genera Herpsilochmus and Sakesphorus (Thamnophilidae), with description of a new genus for Herpsilochmus sellowi. Ornithology 138:1–16.

Davis, T. J., and J. P. O’Neill (1986). A new species of antwren (Formicariidae: Herpsilochmus) from Peru, with comments on the systematics of other members of the genus. The Wilson Bulletin 98:337–352.

Harvey, M.G., G.A. Bravo, S. Claramunt, A. M. Cuervo, G. E. Derryberry, J. Battilana, G. F. Seeholzer, J.S. McKay, B.C. O’Meara, B.C. Faircloth, et al. (2020). The evolution of a tropical biodiversity hotspot. Science 370:1343–1348.

Whitney, B. M., J. F. Pacheco, D. R. C. Buzzetti, and R. Parrini (2000). Systematic revision and biogeography of the Herpsilochmus pileatus complex, with description of a new species from northeastern Brazil. The Auk 117:869–891.

Gustavo A. Bravo, July 2021

Comments from Remsen: “YES. Solid genetic data require a new genus for sellowi, and as outlined in Bravo et al., inclusion of sellowi in Biatas is not really a viable option by conventional standards of delimitation of genera. Further, as noted by Bravo et al., the antiquity of this lineage (stem age 8.4 my) is consistent with ages of lineages ranked as genera in antbirds.

”The full story of Radinopsyche sellowi merits a popular article. This taxon went from completely unrecognized to a monotypic genus thanks to the sleuthing by Bret Whitney and colleagues and the confirmation from modern genetic data. What a lesson!”

Comments from Areta: “YES [for reasons outlined in the proposal].”

Comments from Lane: “YES [for reasons outlined in the proposal].”

Comments from Zimmer: “YES. Genetic data showing that sellowi does not belong in the morphologically (plumage) similar (but vocally and structurally different) Herpsilochmus, but is, instead, sister to the very different Biatas nigropectus, appear rock solid, which necessitates removing sellowi from Herpsilochmus. The only other alternative to erecting a new genus for sellowi, would be its merger into currently monotypic Biatas, which would result in a phenotypically absurd pairing.”

Comments from Robbins: “YES based on the recent genetic data.”

Comments from Stiles: “YES, given genetic evidence and the great morphological difference from Biatas.”

Comments from Pacheco: “YES - I agree with Kevin that it would be phenotypically absurd to bring sellowi and Biatas together. Erecting a new genus is the most appropriate measure to express the results found in the analysis.”

Comments from Jaramillo: “YES . The molecular, vocal and morphological data support a single species genus for sellowi. Not having seen it live, in photos it looks remarkably like a gnatcatcher, perhaps due to the described narrow rectrices. In any case, while the plumage pattern may not be unique, the structure and shape of the bird actually seems quite unique.”

Comments from Bonaccorso: “YES [for reasons outlined in the proposal].”

Comments from Claramunt: “YES. Interesting that it was already noted as highly distinct.”