Proposal (914) to South American Classification Committee

Recognize the genus Sakesphoroides for "Sakesphorus” cristatus

Effect on SACC: This proposal would transfer “Sakesphorus” cristatus from its current placement in Sakesphorus to Sakesphoroides, an available genus for this monotypic species.

Background: SACC currently classifies three species in the genus Sakesphorus (S. canadensis, S. luctuosus, and S. cristatus). Until recently, the genus Sakesphorus included six species, but Brumfield and Edwards (2007) showed that three species (Sakesphorus melanonotus, S. melanothorax, and S. bernardi) are members of the genus Thamnophilus and did not provide sufficient information to establish the phylogenetic placement of S. cristatus. Grantsau (2010) erected the new monotypic genus Sakesphoroides for S. cristatus based on the absence of a pronounced bill hook and that toes 3 and 4 are fused up to the second phalange. Currently, the phylogenetic placement of S. cristatus remains unresolved and has never been tested using robust DNA data.

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 Sakesphorus, as currently defined, is not monophyletic because S. cristatus is sister of a clade formed by Herpsilochmus and Dysithamnus, and that the clade formed by S. canadensis (type species) and S. luctuosus is sister to the genus Thamnophilus. Because the phenotypic distinctiveness of S. cristatus, Dysithamnus, and Herpsilochmus argues against merging them into a single genus, Bravo et al. (2021) supported the recognition of the genus Sakesphoroides.

Recommendation: I recommend a “YES” vote to recognize the genus Sakesphoroides for “Sakesphorus” cristatus.

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.

Brumfield, R. T., and S. V. Edwards (2007). Evolution into and out of the Andes: A Bayesian analysis of historical diversification in Thamnophilus antshrikes. Evolution 61:346–367.

Grantsau, R. (2010). Guia completo para identificação das aves do Brasil. 2 vol. Ed. Vento Verde, São Carlos, Brazil.

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.

Gustavo A. Bravo, July 2021

Comments from Remsen: “YES. Solid genetic data require a new genus for cristatus, and as outlined in Bravo et al., inclusion of cristatus + Herpsilochmus + Dysithamnus 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. Kudos to R. Grantsau for noting the subtle but distinctive morphological characters that correspond to a generic boundary.”

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

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

Comments from Zimmer: “YES, for reasons clearly laid out in the Proposal, and based upon genetic data from Brumfield and Edwards (2007), new data from Harvey et al. 2020, the phylogenomic analysis of Bravo et al. (2021) and on the morphological detective work of Grantsau (2010). I would strongly agree with Bravo et al (2021) that the alternative treatment — merging cristatus and the other members of its clade, Dysithamnus and Herpsilochmus, into a single genus – would result in a genus that would be so phenotypically heterogeneous as to be uninformative from anything other than a genetic perspective.”

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

Comments from Stiles: “YES, given solid genetic evidence and morphological differences.”

Comments from Pacheco: “YES. The results by Bravo and colleagues abundantly support the proposed treatment. Grantsau was perceptive in realizing the generic value of the morphological details found.”

Comments from Jaramillo: “YES. Due to reasons laid out in the proposal, molecular data, in conjunction with morphological information. Single species genera are always a tad difficult, but in this case the argument is healthy for classifying this species as such.”

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