Proposal (196) to South American Classification Committee
Recognize the newly proposed taxon Scytalopus pachecoi as a species
Maurício (2005) erected a new name, Scytalopus pachecoi, for some populations traditionally identified as S. speluncae in southern Brazil and Argentina. The three disjunct populations of the new species - one occupying southern Rio Grande do Sul (Brazil), another the Misiones Province in Argentina and adjacent Brazil and another one the highlands of northeastern Rio Grande do Sul and southeastern Santa Catarina states - differ in all plumages/ages from adult males of S. speluncae by having buff flanks conspicuously barred black and by having paler gray underparts; adult males of S. speluncae are dark gray overall, without barring on the flanks. All birds attributed to the new taxon have a slower paced song compared to S. speluncae: song pace of S. pachecoi = 2.01-3.36 notes/second; song pace of S. speluncae = 4.56 - 5.86 notes/s. The constancy of this pattern was supported by exhaustive sampling of specimens and vocalizations: all birds with slow-paced songs (i.e. S. pachecoi) collected (n = 25 specimens) or carefully observed in the field (n = 71) have conspicuously barred flanks and pale gray underparts, while birds with fast-paced songs (i.e. the traditional S. speluncae) were plain gray in adult male plumage (n = 11 collected, plus 10 observed). Females and younger males of both taxa were similar in plumage, although young S. speluncae generally have darker gray underparts than S. pachecoi. Scytalopus pachecoi is also diagnosed from S. speluncae by several other vocal differences. They have completely distinct short calls (semi-metallic and monosyllabic in S. pachecoi and bisyllabic and structurally less complex in S. speluncae) and alarm calls (call notes are very distinct in shape and frequency). Besides the above-mentioned characters, all three populations of S. pachecoi share a distinct song type, whose pace is greatly accelerated at the end of the song; among described taxa, this accelerating song is matched only by the same song type of S. novacapitalis of Central Brazil. The vocally well-known S. speluncae lacks this song type. Based on this shared character state, it was hypothesized by Maurício (2005) that S. pachecoi and S. novacapitalis are closely related; these two species also share the barred flanks in all plumages/ages.
It is important to note that S. pachecoi and S. speluncae are sympatric in the highlands of northeastern Rio Grande do Sul and southeastern Santa Catarina states, where they frequently occur in the same forest patch (Maurício 2005).
Recently, all Brazilian Scytalopus were the subject of genetic studies by Helena Mata and Sandro Bonatto at Pontifícia Universidade Católica do Rio Grande do Sul. These studies included all specimens collected for the study of Maurício (2005) and also several new samples. All mtDNA (ND2 sequences) phylogenies obtained by H. Mata revealed that S. pachecoi and S. novacapitalis (plus Scytalopus populations from the central Minas Gerais highlands, sometimes attributed to S. novacapitalis) form a strongly supported clade (100% bootstrap support), while S. speluncae is only distantly related. Genetic distances (Kimura 2-parameter) between S. pachecoi and the other Brazilian taxa were high: S. pachecoi vs. S. speluncae = 11.7 to 12.8%; S. pachecoi vs. S. novacapitalis = 4.5%; S. pachecoi vs. S. iraiensis = 11.4%; and S. pachecoi vs. S. indigoticus = 15%. Despite the comparatively low genetic distance between S. pachecoi and S. novacapitalis, these two taxa are fully diagnosable by voice (song and alarm call) and plumage (Maurício 2005).
All genetic data mentioned above were obtained from the M.Sc. thesis of Helena Mata, which was presented at the Pontifícia Universidade Católica do Rio Grande do Sul in early 2005. Part of this information was published as abstracts in several scientific meetings in Brazil in 2004 and 2005 and Krabbe et al. (2005), while describing S. rodriguezi, cites in a general way the sequences of the Brazilian taxa sent them by H. Mata and S. Bonatto.
Krabbe, N., P. Salaman, A. Cortés, A. Quevedo, L. A. Ortega, and C. D. Cadena. 2005. A new species of Scytalopus tapaculo from the upper Magdalena Valley, Colombia. Bulletin of the British Ornithologist's Club 125:93-108.
Maurício, G. N. 2005. Taxonomy of southern populations in the Scytalopus speluncae group, with description of a new species and remarks on the systematics and biogeography of the complex (Passeriformes: Rhinocryptidae). Ararajuba 13 (1): 7-28.
Maurício - Comitê Brasileiro de Registros Ornitológicos (CBRO)
Recognize Scytalopus pachecoi as a valid species
Effect on South American CL: This proposal would add a newly described species to the list.
Background: Mauricio (2005) described a new tapaculo from southern Brazil and Misiones, Argentina. It was formerly considered part of S. speluncae. It is known from 25 specimens, differs from S. speluncae vocally and in the presence of black and buff barring over the flanks in all ages (this is absent in adult male S. speluncae). Also by having paler gray under parts. It also differs consistently in plumage and vocalizations from all members of the S. speluncae complex. Even though there was no genetic data presented in the article and as vocalizations have been shown to be one of the keys to species limits in the genus, (see Krabbe & Schulenberg 1997,2003) I have no problem in recognizing this as a new species-level taxon.
Recommendation: Based on the vocal and genetic information, I believe this paper clearly documents a new species level taxon. I recommend a "yes" vote to add this newly described tapaculo to the South American list.
Mauricio, G.N. Taxonomy of southern populations in the Scytalopus speluncae group, with description of a new species and remarks on the systematics and biogeography of the complex (Passeriformes: Rhinocryptidae).
Krabbe, N., and T.S. Schulenberg. 1997. Species limits and natural history of Scytalopus tapaculos (Rhinocryptidae), with descriptions of the Ecuadorian taxa, including three new species. Pages 47-88 in Studies in Neotropical Ornithology Honoring Ted Parker (J.V. Remsen, Jr., Ed.) Ornithological Monographs no. 48.
Krabbe, N., and T.S. Schulenberg. 2003. Family Rhinocryptidae (tapaculos). Pages 748-787 in Handbook of the Birds of the World, Vol. 8: Broadbills to Tapaculos (J. del Hoyo, A. Elliott, and D. Christie, Eds.) Lynx Edicions, Barcelona, Spain.
Daniel Zimberlin, December 2005
Note from Remsen: Mauricio suggested the English name "Planalto Tapaculo" for S. pachecoi.
Comments from Remsen: "YES. Sympatry of pachecoi and speluncae demands species rank for pachecoi."
Comments from Robbins: "YES. As we all recognize, vocalizations are the key in species delineations in Scytalopus. Thus, the vocal data coupled with pachecoi being sympatric with speluncae leaves no doubt that pachecoi should be recognized as a species."
Comments from Zimmer: "YES, following the same reasoning as in Props #193 and #195. I recently spent some time studying S. pachecoi in the field, and it is actually fairly different (as tapaculos go) in plumage characters from S. speluncae, being considerably more pallid gray below, with buffy (not rusty) flanks that are distinctly barred even in adult males. Vocal differences are pronounced, and local sympatry (with speluncae) is the clincher."
Comments from Jaramillo: "YES - voice, plumage and sympatry -- what else could you ask for?"
Comments from Nores: "YES. Las evidencias de color, canto y genéticas muestran claramente que se trata de una buena especie, que increíblemente ha pasado desapercibida por casi dos siglos. Que hayan pasado desapercibidas las diferencias genéticas y de canto es aceptable, dado su reciente auge, pero que no hayan sido percibidas las diferencias en color, tan estudiadas por taxónomos clásicos, es sorprendente."
Comments from Pacheco: "YES. As evidências reunidas e apresentadas por Maurício são robustas e verificáveis."