Proposal (390) to South American Classification Committee

Recognize Scytalopus infasciatus as a species separate from Scytalopus griseicollis

Effect of Proposal: A Yes vote on this proposal would result in splitting Scytalopus infasciatus from S. griseicollis. A No vote is recommended.

Discussion:

The Pale-bellied (or Matorral or Rufous-rumped) Tapaculo S. griseicollis (Lafresnaye, 1840) and Colombian (or Cundinamarca) Tapaculo S. infasciatus Chapman, 1915 are both recorded from the Eastern Andes of Colombia. Both have rather light gray plumage compared to congeners and occur generally at high elevations. Zimmer (1939) treated S. infasciatus as a synonym of S. griseicollis and was followed by Peters (1951). It may have been better in retrospect if subsequent authors had left matters there. However, S. infasciatus was tentatively ranked as a species by Krabbe & Schulenberg (1997) and followed by, among others, Asociación Bogotana de Ornitología (2000) and Gill & Wright (2006). Krabbe & Schulenberg (1997) noted that comparison of material from the Eastern Andes with the type of infasciatus would be necessary before its status could be fully resolved. Perhaps having done so, these same authors later (2003) treated S. infasciatus as a subspecies of S. griseicollis, but restricted the former to a single site and noted that the two taxa might be synonymous. The current baseline reflects this treatment: S. infasciatus is not recognised.

Donegan & Avendaño-C. (2008) studied plumage, biometrics and voice of northern Andean Scytalopus in connection with the description of various undescribed taxa and the naming of one of them. Species and subspecies limits in various northern Andean forms were also considered. The methods and species limit models used were similar to those applied by Isler et al. to assess antbird species limits. We inspected photographs of the type specimens and series of specimens and sound recordings taken from the "infasciatus" type locality. No character, whether vocal or morphological, that might define S. infasciatus was found in this study. Notably, although other authors have speculated as to characters that might define infasciatus, a difference in the strength of vent barring was the only character considered diagnostic in Chapman's description of S. infasciatus. We found considerable individual variation in the strength of vent barring in all three subspecies of S. griseicollis (the nominate, newly described gilesi and an undescribed subspecies from the northern Cordillera Oriental). A discussion for the rationale for not recognising infasciatus is set out on pages 32-33 of the relevant paper.

I recommend a "No" vote, i.e. not to recognise S. infasciatus, as recommended by Krabbe & Schulenberg (2003) and Donegan & Avendaño-C. (2008).

Reference:

Donegan, T.M. & Avendaño-C., J.E. 2008. Notes on Tapaculos (Passeriformes: Rhinocryptidae) of the Eastern Andes of Colombia and Venezuelan Andes, with a new subspecies of Scytalopus griseicollis from Colombia. Ornitología Colombiana 6: 24-65. http://www.ornitologiacolombiana.org/oc6/doneganyavendano.pdf

Other references are cited in the above.

Jorge Enrique Avendaño C., February 2009

Comments from Stiles: “NO to continuing to recognize S. infasciatus as a distinct species (or a distinct taxon at any level). [I also endorse their suggestion of Pale-bellied Tapaculo as the most appropriate English name, as it is the most nearly distinctive plumage feature of the species (insofar as any grey tapaculo has distinctive features) ... and various tapaculos have rufous rumps.]”

Comments solicited from Niels Krabbe: “I would vote no to treating infasciatus as a valid taxon and apologize for questioning Zimmers synonomizing it with griseicollis. I have personal experience with neither griseicollis nor "infasciatus" and am the first to recognize that plumage characters are of little value in the genus. Gary Stiles originally suggested to me that two taxa were present in the range of griseicollis, and differences in some recordings from higher and lower elevation seemed to support this. Gary has now thrown in his towel and I do too. The great material in recordings at hand today bridges the gap between the recordings originally at my disposal.”

Comments from Cadena: “NO. The analyses reported by Donegan and Avendaño are convincing. I would add that I have sequenced mtDNA for several "griseicollis type" birds and there is no indication of the existence of two distinct lineages in the Cundinamarca area.”

Comments from Nores: “NO. El análisis aportado por Donegan y Avendaño parece ser lo suficientemente documentado como para no aceptar esta especie. Los datos agregados por Cadena, refuerzan esta idea. De todos modos, llama la atención en esta propuesta que se señala que tanto griseicollis como infasciatus tienen un plumaje gris claro, siendo que infasciatus es de color gris oscuro (ver HBW).”

Comments from Zimmer: “NO, for reasons stated in the proposal and by others.”

Comments from Jaramillo: “NO – For clear reasons in proposal, also personal comm. from Daniel in the voting comments regarding genetic data.”

Additional comment from Jorge Avendaño: “As noted by Krabbe and Stiles, there are indeed two species with different songs within the range of S. griseicollis.  However, the other species is S. spillmanni (see recordings on xeno-canto and discussion in Donegan & Avendano 2008).  The S. infasciatus type specimen is of a particular plumage within the range of variation shown by S. griseicollis."