Proposal (301) to South American Classification Committee

Elevate subspecies humaythae, brunneiceps, and rufifacies (within Schistocichla leucostigma) to species rank

Background: As already footnoted in the checklist "Ridgely & Tudor (1994) and Zimmer & Isler (2003) suggested that Schistocichla leucostigma may consist of more than one species. Braun et al. (2005) provided evidence that the Tepui taxon saturata deserves species rank. Current SACC Note states: "SACC proposal passed to treat saturata as a species. Isler et al. (2007) further showed that the taxa humaythae, brunneiceps, and rufifacies, currently treated as subspecies of P. leucostigma, also warrant species rank. Proposal badly needed." Well, here is the proposal then.

SACC currently lists the following Schistocichla species:

Schistocichla schistacea Slate-colored Antbird 

Schistocichla leucostigma Spot-winged Antbird 

Schistocichla saturata Roraiman Antbird

Schistocichla caurensis Caura Antbird

Isler et al. (2007) proposed recognizing seven Schistocichla species, and recommended English names. They stated, "the sequence is tentative pending genetic analysis." They present the species as Percnostola, although SACC treats them in the genus Schistocichla. Following the treatment of Isler et al. (2007) yields the following taxa:

Schistocichla schistacea Slate-colored Antbird 

Schistocichla leucostigma Spot-winged Antbird 

Schistocichla humaythae Humaita Antbird

Schistocichla brunneiceps Brownish-headed Antbird

Schistocichla rufifacies Rufous-faced Antbird

Schistocichla saturata Roraiman Antbird

Schistocichla caurensis Caura Antbird

Effect on South American CL: This change adds three species to the list.

Recommendation: Isler et al. (2007) stated that further molecular phylogeny work on this complex is forthcoming, but as in their analysis of Hypocnemis, I agree that this initial revision better reflects the taxonomic status of population in the complex than current classifications.  I recommend voting "Yes" to adopt the treatment of Isler et al. (2007), but hope SACC committee members with personal experience with these taxa take a critical look at the work of Isler et al. (2007) before agreeing. 

References:

Isler, M. L., P. R. Isler, B. M. Whitney, & K. J. Zimmer. 2007. Species limits in the "Schistocichla" complex of Percnostola antbirds (Passeriformes: Thamnophilidae). Wilson Journal of Ornithology 119:53-70.

Daniel Lebbin, August 2007

============================================================

Comments from Stotz: "YES. This basic story has been in the works for a while and based on voice seems clear."

Comments from Jaramillo: "YES - I will note that the proposal is a little sparse though, not summarizing methods or data even in a cursory way. The Isler et al 2007 paper seems solid though."

Comments from Stiles: "YES. As presented the proposal is definitely thin, but the Isler et al. paper looks solid. It would be helpful if proponents of such proposals set out the main arguments thereof instead of simply stating "there is a paper that proposes X taxonomic change or new species, so I propose it to SACC."

Comments from Robbins: "YES. Although the proposal is weak in providing background and details of the results, the Isler et al. (2007) paper convincingly presents data supporting the recognition of three additional species."

Comments from Nores: "NO. Yo creo que hay que tener en cuenta lo sugerido por Isler et al. (2007) cuando proponen reconocer siete especies de Schistocichla. "The sequence is tentative pending genetic analysis" Tanto para este caso, como para la propuesta 295, la decisión implica crear nuevas especies que a lo mejor no existen en la naturaleza, por eso habría que tener total seguridad. Aunque al revés es también posible, o sea que existan en la naturaleza y no estén reconocidas, yo prefiero no innovar hasta que no haya datos que lo confirmen definitivamente."

Comments from Zimmer: "YES. As one of the authors of the paper on which this proposal is based, I clearly vote YES, for reasons spelled out in Isler et al."

Comments from Cadena: "YES. The data and analyses appear solid. The comment by the authors that "The sequence is tentative pending genetic analysis" does not mean that they are uncertain about their delimitation of species. Rather, they are saying that the definitive position of these species in a linear sequence will need to await phylogenetic analyses based on molecular data to establish their evolutionary relationships (i.e. a phylogeny). How the different populations are related to each other will not change the picture of how many species should be recognize, so I believe we can act now on the basis of the careful analyses that Isler et al. (2007) have provided.”