Proposal (#375) to South American Classification Committee
Transfer Automolus roraimae to Syndactyla
Effect on South American CL: This proposal would transfer one species (Automolus roraimae) to another genus, Syndactyla.
Background: This species was described in Philydor but transferred early to Automolus. Ridgely & Tudor (1994) suggested that it might be a Philydor after all, whereas Kratter and Parker (1997) suggested that it was closer to Syndactyla; in fact, their morphometric data showed that roraimae was closer to Syndactyla rufosuperciliata than to the Automolus species analyzed. The upturned mandible of Simoxenops and Syndactyla is also found in roraimae. See Zimmer et al. (2008) for summary.
New information: Zimmer et al. (2008) presented several lines of evidence that roraimae should be placed in Syndactyla.
1. Voice: Zimmer et al. (2008) presented data on the loudsongs of all species of Syndactyla, Simoxenops, Automolus, and Anabazenops, and 8 species of Philydor. The loudsong of roraimae ("a slow, harsh rattle that peaks in amplitude in mid-song and accelerates at the end") is more similar to those of Syndactyla and Simoxenops than to any other genera, including both genera in which it has been placed.
2. Syringeal morphology: Zimmer et al. (2008) compared the syrinx of roraimae to those of Automolus (5), Philydor (4), Anabacerthia (1), Syndactyla (3), plus Hyloctistes, Berlepschia, and Thripadectes (1). The syrinx of roraimae most closely resembled that of 3 of the species of Syndactyla.
3. Foraging behavior: Zimmer et al. (2008) noted that the foraging behavior or roraimae was similar to that of Syndactyla and unlike the dead-leaf-searching specializations shown in Automolus and Philydor.
Analysis: All available phenotypic data point towards roraimae being a member of Syndactyla/Simoxenops rather than Automolus, Philydor, or any other genus. In addition to the evidence presented by Zimmer et al. (2008), I also add that neither Automolus or Philydor has any species with similar distribution patterns to roraimae, namely a tiny range with a foothill component, and most species are found in lowland tropical forest; in contrast, no species of Syndactyla/Simoxenops has a lowland forest distribution, except for ucayalae, which is restricted to bamboo and has a patchy distribution. Thus, biogeographically roraimae is a better fit for Syndactyla/Simoxenops. Robbins and Zimmer (2005) previously recommended merger of Simoxenops into Syndactyla on the basis of voice, behavior, morphology, and plumage. We have not addressed that in a proposal (in part because the Brumfield lab is actively working on a gene-based phylogeny). Zimmer et al. (2008) could not predict whether roraimae was closer to Simoxenops or Syndactyla, but because they are congeneric, they did not hesitate to propose including roraimae into Syndactyla sensu lato.
Recommendation: Transfer of roraimae to Syndactyla is supported by all available data, and I see no reason not to recommend a YES on this one. The only question is whether it might be closer to Simoxenops, but how long we maintain that genus as separate is uncertain.
ROBBINS, M. B., AND K. J. ZIMMER. 2005. Taxonomy, vocalisations and natural history of Philydor dimidiatum (Furnariidae), with comments on the systematics of Syndactyla and Simoxenops. Bulletin British Ornith. Club 125: 212-228.
ZIMMER, K. J., M. B. ROBBINS, AND C. KOPUCHIAN. 2008. Taxonomy, vocalisations, syringeal morphology and natural history of Automolus roraimae (Furnariidae). Bulletin British Ornithologists Club 128: 187-206.
Van Remsen, October 2008
Comments from Nores: "YES. Aunque esto implica que la característica morfológica principal del género Syndactyla: ser mayormente rayado, ya no tendría importancia. De todos modos, eso ya fue cuestionado con la inclusión de Philydor dimidiatus en Syndactyla. Es evidente que para aclarar definitivamente la relación entre las especies de estos géneros falta un análisis molecular."
Comments from Zimmer: "YES. As lead author of the paper on which this proposal is based, I obviously vote YES, for reasons stated in the paper."
Comments from Stiles: "YES. Consistent with available evidence on all fronts."
Comments from Pacheco: "YES. A partir dos múltiplos dados fornecidos pelos autores, a manutenćčo de roraimae em Automolus é inconsistente com as evidźncias atuais. Ainda que a transferźncia para o gźnero Syndactyla possa ser revista no futuro, eu sou de opiničo que ela parece ser neste momento uma solućčo aceitável.”