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.
Literature Cited
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.
Giovanni N.
Maurício - Comitê Brasileiro de Registros Ornitológicos (CBRO)
December 2005
Also received:
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.
References:
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."