Proposal (958) to South American Classification Committee

Treat Serpophaga munda as a subspecies of S. subcristata

Our current SACC notes relevant to the issue are as follows:

"18. Serpophaga munda is often considered a subspecies (e.g., Zimmer 1955, Traylor 1977<?>, 1979a, Straneck 1993) or morph (Short 1975) of S. subcristata, but see Olrog (1963) and Herzog (2001).

“19. ‘Serpophaga griseiceps,’ known from four specimens from Bolivia, was formerly considered a valid species (e.g., Zimmer 1955, Meyer de Schauensee 1966, 1970). Traylor (1979) treated S. griseiceps as a synonym of S. munda; rationale, however, was not published. Straneck (1993) resurrected S. griseiceps as a valid species, but see Herzog & Barnett (2004), who concluded that "griseiceps" most likely represents the juvenal plumage of S. munda. See Hybrids and Dubious Taxa. Straneck (2007) described a new species, Serpophaga griseicapilla, for the taxon previously suspected to be S. "griseiceps." SACC proposal passed to recognize griseicapilla. SACC proposal to change English name did not pass."

Based on our extensive experience with both taxa, vocalizations of subcristata and munda are one and the same across their repertoires, and they respond readily to playback. Both forms meet in central Argentina, and seem to intermix freely, based on the intermediate aspect of numerous specimens (Bó 1969). Herzog´s (2001) criticism of Straneck´s (1993) appears to be exaggerated, and although Straneck´s work is far from flawless and based on relatively small sample sizes, he got it right where it mattered: the vocalizations are identical, and they respond readily to each other´s voices. There is this Xeno-Canto article by Niels Krabbe (2015) which supersedes and confirms Straneck´s take on the issue of species limits. We treated subcristata and munda as conspecific in our field guide (Pearman & Areta 2020), and in a recent note in Neotropical Birding that also provides a useful reference to evaluate this case (Pearman & Areta 2021). There is not a hint of evidence supporting that these two taxa are different species, and this was adequately treated by the late Roberto Straneck in 1993. We recommend that munda continues to be recognized, but as a subspecies of subcristata.

Areta and colleagues are currently working on an article on a phylogeny of Serpophaga, in which they also discuss the taxonomy of munda and the relationship with the cryptic griseicapilla (Herzog & Mazar-Barnett 2004, Straneck 2007). The preliminary mtDNA results are identical (ND2) or consistent with (COI) the tree by Harvey et al. (2020), and also in agreement with data in Rheindt et al. (2008).

Harvey et al 2020 tree:

References:

Bó, N. (1969) Acerca de la afinidad de dos formas geográficas de Serpophaga. Neotrópica 15: 54–58.

Herzog, S. K. (2001) A re-evaluation of Straneck’s (1993) data on the taxonomic status of Serpophaga subcristata and S. munda (Passeriformes: Tyrannidae): conspecifics or semispecies? Bull. Brit. Ornithol. Club 121: 273–277.

Herzog, S. K. & Mazar-Barnett, J. (2004) On the validity and confused identity of Serpophaga griseiceps Berlioz 1959 (Tyrannidae). Auk 121: 415–421.

Krabbe, N.K. (2015) Serpophaga [subcristata] vocalizations. Accessed from https://www.xeno- canto.org/article/189 on 20 November 2020.

Pearman, M. & Areta, J. I. (2020) Birds of Argentina and the South-west Atlantic. London: Christopher Helm.

Pearman, M. & J.I. Areta. 2021. Field identification of some look-alike Serpophaga tyrannulets and Plain Inezia from Argentina. Neotropical Birding 28:28-33.

Rheindt, F. E., Norman, J. A. & Christidis, L. (2008) Phylogenetic relationships of tyrant-flycatchers (Aves: Tyrannidae), with an emphasis on the elaeniine assemblage. Mol. Phyl. & Evol. 46: 88–101.

Straneck, R. (1993) Aportes para la unificación de Serpophaga subcristata y Serpophaga munda , y
la revalidación de Serpophaga griseiceps (Aves: Tyrannidae). Rev. del Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Zoología 16: 51–63.

Straneck, R. (2007) Una nueva especie de Serpophaga (Aves: Tyrannidae). Rev. FAVE – Ciencias Veterinarias 6: 31–42.

J. I. Areta & Mark Pearman, February 2023

Comments from Stiles: “YES, for all the reasons in the proposal.”

Comments from Lane: “YES to considering S. munda conspecific with subcristata. This complex has been rather confusing to me for years, and I think that the nearly complete overlap of voices of these two taxa has been at the core of that confusion, so I find it particularly satisfying to remove that issue by lumping them!”

Comments from Claramunt: “YES. Basically, the only difference between S. subcristata and munda is the coloration of the underparts (yellow versus white). I agree that this seems to be variation within a single species. It remains to be seen whether the difference is even genetic or environmentally induced (scarcity of carotenoids in the diet?) associated with the aridity along the Andean forelands.”

Comments from Stiles: “YES to lump munda and subcristata; clearly they are conspecific (and distinct from griseiceps, which is not sister to these).”

Comments from Niels Krabbe (who has Pacheco’s vote): “YES, for all the reasons given in the proposal and in my XC article (https://xeno-canto.org/article/189): S. subcristata and S. munda have similar vocalizations and mitochondrial DNA, and seem to interbreed wherever they meet. Additionally, the suture zone is broad and the (limited) material gives no firm indication of parental types dominating.”

Comments from Zimmer: “YES for all of the reasons laid out in the Proposal. Like Dan, I’ve always found the identification of these birds in extreme S Brazil to be problematic, precisely because the voices are identical to those of subcristata, and, accordingly, because white-bellied birds always responded to playback of subcristata. To make matters worse, subcristata in worn plumage, become grayer (less olive) dorsally, and whiter (less yellow) ventrally, making them difficult to separate from austral migrant munda by any criteria!”

Comments from Remsen: “YES. There are no data that support treating munda at the rank of species.”

Comments from Bonaccorso: “YES. The available evidence points towards maintaining Serpophaga munda as a subspecies of S. subcristata.”

Comments from Robbins: “YES for treating munda as a subspecies subcristata based on comments in the proposal as well as listening to online vocalizations.”