Proposal
(329) to South American
Classification Committee
Recognize Scytalopus
diamantinensis (Diamantina Tapaculo) as a valid species
Effect on South American CL: This proposal would add a
recently described species to our main list.
Bornschein, Maurício, Belmonte-Lopes, Mata and Bonatto (2007)
recently described a new species of tapaculo, Scytalopus diamantinensis (Diamantina
Tapaculo) from Bahia, Brazil. The new species is known exclusively from the
Chapada Diamantina geomorphological unit between 850 and1600m (8 localities
with vouchers), mainly its eastern slopes. The new species is a member of the
taxonomically complex S. speluncae group (see Mauricio 2006),
within which it is most closely related to S. novacapitalis, S.
pachecoi, and Scytalopus sp. nov. from the southern Espinhaço Range.
(A nomenclatorial controversy exists here. This taxon was treated as the
genuine S. speluncae by Raposo et al. 2006, but not by
Bornschein et al. 2007).S. diamantinensis is diagnosable by
vocal, plumage, and molecular characters from all other Brazilian taxa.
Although its song differs little from those of the closely related species, its
calls are notably distinct.
The Scytalopus populations occupying the Chapada
Diamantina (Bahia) was regarded as representing the same taxon found in the
southern part of Serra do Espinhaço (Minas Gerais) by Raposo et al.
2006, based on 4 specimens. However, recognition of the population of Diamantina
as a distinct taxon by Bornschein and colleagues is supported by analysis of 5
specimens (5 males, 1 female, all with tissue samples examined) and 369 samples
of voices of at least 18 individuals, as well as the examination of a much
larger series of the related taxa.
The authors believe that S. diamantinensis, S. pachecoi,
and Scytalopus sp. nov. would probably be lumped into a single
polytypic biological species. Therefore, they recognized all four allopatric
taxa with accelerating songs as distinct (at least) phylogenetic species.
Furthermore, the mean differences in songs and consistent differences in calls
in this clade are strongly correlated not only with clear genetic distinctions,
but also with plumage differences.
Recommendation: I recommend a "YES" vote on
accepting this tapaculo as a new (indeed biological) species to our list, based
mainly on the genetic distinctions found among the related taxa. A member of
this group (S. pachecoi) is already treated as valid by SACC (see
Proposal #196).
Literature Cited:
BORNSCHEIN,
M. R., G. N. MAURÍCIO, R. BELMONTE-LOPES, H. MATA AND S. L. BONATTO. 2007.
Diamantina Tapaculo, a new Scytalopus endemic to the Chapada
Diamantina, northeastern Brazil (Passeriformes: Rhinocryptidae). Rev. Bras.
Orn. 15(2): 151-174.
RAPOSO, M.
A., R. STOPIGLIA, V. LOSKOT AND G. M. KIRWAN. 2006. The correct use of the name
Scytalopus speluncae (Ménétriés [sic], 1835), and the description of a new
species of Brazilian tapaculo (Aves: Passeriformes: Rhinocryptidae). Zootaxa
1271: 37-56.
José
Fernando Pacheco, Jan. 2008
________________________________________________________________________________________________________
Comments from Thomas Donegan: "The proposal to recognize Scytalopus diamantinensis (Diamantina
Tapaculo) at first may appear a difficult one to accept. Species rank was
assigned to S. diamantinensis in the description with reference to
diagnosable calls (scolds) and immature plumage under a PSC concept.
However, only mean differences in songs exist. Songs are generally
considered of primary importance in differentiating species in this
genus. Krabbe & Schulenberg (1997, 2003)'s taxonomy for Scytalopus
(on which the SACC sequence is based) treated taxa with diagnosable calls, but not
songs, as (BSC) subspecies. I am not sure which species concept SACC employs. However, a
"No" vote would plausibly leave S. pachecoi as the only
biological species level taxon of this three-taxon group.
"No published example (of which I am aware)
exists of two Scytalopus species on the SACC list which vary diagnosably
in their calls but not in their songs. However, if reference can be made
to soon-to-be-published work, a "Yes" vote is likely to prove to be
the better long-term decision. S.
griseicollis and S. spillmanni replace one another sympatrically
(actually in elevational parapatry and at distances of 10 m horizontally
/ 2 m vertically) at montane forest-paramo ecotones in the East Andes of
Colombia. Jorge Avendaño and I have an MS in review that
shows these species to differ diagnosably (per the Isler diagnosability
test for antbird songs, but for fewer variables) in their calls (scolds) and
plumage but not in their songs - the same scenario presented by S.
diamantinensis/pachecoi. Although
results of the East Andes study are not published yet - expected for Spring
2008 - they will bolster the case for recognition of S. diamantinensis,
the undescribed Brazilian taxon and possibly some other Scytalopus populations
as species under biological species concepts."
Comments from Stiles: "A tentative YES. Clearly
this group of closely related forms is at least in the process of speciating
and given the consistency of morphological, genetic and vocal differences among
them is probably best united at the superspecies level rather than at the
species level. Convergence in songs to reinforce interspecific territoriality
among ecologically similar forms with parapatric distributions is not unknown
and probably applies to the case mentioned by Thomas. The present case is
rather one of limited divergence rather than convergence, but one could
envision selection favoring conservatism in long-distance vocalizations like
song in the absence of contact zones, while being relaxed regarding call notes
which in any case tend to be more graded, close-range signals."
Comments from Robbins: "NO. Until the Donegan paper
is published and available for review, I vote "no" for recognizing
this taxon as a species."
Comments from Stotz: "NO. Given that Krabbe and Schulenberg
is in my view the current state of the art on Scytalopus taxonomy,
and the authors conclude that based on those criteria, this taxon would be
considered part of a polytypic species and that the genetic details for this
taxon, including the relationships among the various taxa of Brazilian
tapaculos, are still to be published, I think it is premature to recognize this
as a distinct species."
Comments from Nores: "NO. Teniendo en cuenta que no hay diferencias en coloración de los adultos,
ni tampoco en el canto (sólo en los llamados), me parece que es más probable
que sea solo una subespecie que difiere en tamaño."
Comment from Niels Krabbe: "I would vote no. One cannot use a phylogenetic species
concept for some species and a biological species concept for others. No matter
what the genetic distance, similar songs suggest they would interbreed if in
contact.
"There are already at least two similar
cases, where a population with a distinctive homologous call is not given
biological species rank.
"These include S. spillmanni from
the Western Andes of Colombia (see p. 44 in Krabbe et al. 2006, Orn Col. 4:
37-48), and Scytalopus canus opacus from southern Ecuador (see
p. 72 in Krabbe and Schulenberg 1997, Orn. Monogr. 48).
"Genetically these two cases differ,
the spillmanni from the West Andes of Colombia are almost
identical to populations in the Central Andes of Colombia and Ecuador, whereas
south Ecuador opacus differs from more northerly populations by about as
much as diamantinensis does from its closest relatives.
"One may speculate what happens if two
populations with different calls meet. One call might disappear, or both calls
might remain as alternate calls (intermediate calls seem unlikely). I know of
at least one case (a Scytalopus from Apurimac) of a form with two
different calls that I suspect could have such an origin."
Comments from Jaramillo: "NO - I will await genetic
data to see what is upheld and rejected then. Since our recognized taxa
in Scytalopus are largely based on the work of Schulenberg and
Krabbe, it seems logical to apply their criteria to this taxon. It appears that
under their criteria they would not consider this a species."
Comments from Nacho Areta: ""I think that the main problem is that there is a new
question regarding the functions of voices in the Scytalopus that needs
to be answered. We know, largely thanks to the work by Krabbe et Schulenberg,
that different songs indicate phylogenetic and biological species in Scytalopus.
But we do not know with the same degree of certainty what the
phylogenetic/biological meaning of differences in calls could be. For example,
are calls more important than song in maintaining pair-bonds? What if female
choice is based on calls and not in songs? Another case of similar/identical
songs but (apparently) differing calls and certainly differing phenotypes was
presented by Chendo Fraga and I in the last NOC in Venezuela comparing the true
Scytalopus magellanicus and a population living in Mendoza and
Chile. This population is so different from nominate magellanicus that
it was considered to be fuscus by some previous authors. I think
that we should strive to understand the biological meaning of the calls to make
a valid taxonomic judgment on this proposal. It is not only a matter of
comparing how different the voices of are, but of what are the effects of these
differences for real/potential interbreeding of the forms."
Comments from Cadena: "YES. This is a hard one for
the reasons pointed out by several committee members, but I think that Nacho
has made a good point: we simply don't know what is the function of calls in
mate choice in Scytalopus. This doesn't mean that calls are not
important and only songs are. Calls might even be crucial, as it seems to be
the case with the two Hypocnemis ex. Cantator that are sympatric
in Amazonian Peru, whose songs are remarkably similar but they retain their
integrity as separate species, possibly because their calls differ. Also, as
noted by Bornschein et al., it is important to realize that variation in songs
among species of Scytalopus that are already recognized by SACC and
other authorities as distinct (e.g. S. iraiensis and S.
speluncae) is minor, and the only substantial vocal differences between
such taxa are in their calls. Thus, I would argue that the status
quo in this group is based on criteria that are not as stringent as the
ones that are now being applied for this particular taxon. Because S.
diamantinensis is diagnosable based on plumage and calls, and because
it is genetically distinct (Alvaro, the paper describing it already has
molecular data), I think that in the context of how Brazilian species in this
group have been delimited and accepted by SACC in the recent past, the data are
most consistent with the idea that S. diamantinensis should be
considered a separate species."
Additional comment from T. Donegan: "The paper referred to above has now been published.
http://www.ornitologiacolombiana.org/oc6/doneganyavendano.pdf ."
Comments from Schulenberg: "YES, largely for the
reasons outlined by Daniel. I recognize that this may cause some
inconsistencies, if Andean taxa are defined more on the basis of songs than of
calls. But, inconsistencies happen. These may reflect differences in the
biology of Brazilian vs. Andean Scytalopus (i.e., differences in
the "significance" of different vocalizations), or the
inconsistencies may suggest that perhaps we should revisit the Andean taxa with
calls as well as songs in mind. The much greater amount of genetic information on
Scytalopus that is emerging also will be shining some light on the
issue. As Daniel mentioned, the genetic data from Brazil already point to
species status for these taxa."
Comments from Remsen: "NO. Diamantinensis is
clearly a valid, diagnosable taxon, by three suites of characters. The question
is at what rank? Plumage differences define other Scytalopus taxa
recognized as subspecies, so this is of no help. No diagnosable differences in
song are known, so that points towards subspecies rank to be consistent with
Krabbe-Schulenberg scheme for Andean taxa. The differences in calls are of
interest and merit further study. If differences in call notes are found to be
associated with cessation in gene flow, then I will change my vote. To be
consistent with my vote, I also consider other members of this Brazilian group
that we currently treat as species to better fit the rank of subspecies.
[Someone who knows more about this group should consider a proposal for
change.]
"Concerning 'genetic differences' --- of course they differ
genetically. If we assume that plumage and calls have a genetic basis, then we
know they differ genetically even if we can't measure the genes responsible for
the differences. Genetic differences per se do not count for anything in
evaluating taxon rank of allopatric populations. Yes, genetic differences
between parapatric and sympatric taxa are obviously critical to assessing gene
flow, but when comparing allopatric populations, I think they are next to
useless. Any two populations isolated for a certain number of generations are
going to begin accumulating genetic differences. We can often detect this in
the pitiful number of fast-evolving genes that we can sample (relative to the
25,000 or so genes out there in the bird genome), but using this as any sort of
yardstick lacks conceptual or (so far) empirical underpinnings. North American
wood-warblers, flycatchers, and others with clear plumage pattern or vocal
differences and widespread syntopy are sometimes barely distinguishable
genetically, but "our" ongoing work at LSU reveals tropical species
with up to 10% sequence divergence (mtDNA) for which there are no detectable
phenotypic differences. Thus, the data themselves on genetic divergence and
speciation show nearly as large a range as we can measure between congeners --
they range from near 0% to more than 10%. Even restricting the comparisons to
sedentary, tropical congeners (as in Scytalopus) will likely reveal a
wide range of degrees of genetic divergence. Why? The latter depends not only
on time-since-separation, but also on initial population size and structure,
subsequent bottlenecks, effective population size, etc. Pending further
empirical data, I think it is safe to say that the correlation between degree of
divergence in, say, mtDNA sequences and "speciation" remains unknown
at best, and that use of comparative % sequence divergence data provides little
crucial information, despite its quantitative and 'modern' appeal. Part of that
appeal is due to misinterpretation of the term "genetic distance",
which implies to many that we've measure some genome-wide difference when in
fact, the typical "genetic distance" involves differences in 1-2
mitochondrial genes, not the genome."
Comments from Zimmer: "YES. I have been delinquent
in voting or commenting on this proposal until now, and although the proposal
has already been rejected, I would like to weigh in. The debate surrounding
this proposal has expanded to call into question the rank of the other taxa in
the complex, and, as much as anything, I'd like to comment on this. The
conflicting views expressed by others have made some excellent points. In
particular, I find myself agreeing with much of what Van had to say about the
use of genetic differences in determining species limits among allopatric
populations, and about the general misinterpretation of the term "genetic
distance". I also think that Daniel and Tom have made some valid points
regarding our lack of understanding of the relative importance of calls versus
songs as to how they function in mate choice.
"Let me just summarize my understanding of the Brazilian Scytalopus
situation as it applies to this present debate. Historically, the Brazilian
taxa have been considered to break down into two distinct groups:
1) indigoticus/psychopompus, with distinctly white ventral
regions, rufous flanks, blue-gray upperparts and similar songs (a distinctly
"froggy" trill) that are completely different from any vocalizations
found among taxa in the other group (and which I won't further consider in the
present discussion); and 2) the so-called speluncae group, comprised of
several basically gray taxa whose songs consist largely of a lengthy,
repetitious series of similar notes. More recent workers (e.g. Maurício 2005, Bornschein
et al. 2007) have demonstrated that the speluncae group itself
breaks down into two distinct subgroups: 1) consisting of three taxa (speluncae
[which consists of a larger northern form with faster-paced songs, and a
smaller southern form with slower-paced songs, the two of which, arguably,
represent distinct taxa], iraiensis, and an-as-yet-unnamed taxon from
the Serra da Ouricana, Serra das Lontras and surrounding highlands of SE-SC
Bahia = species novum #1) in which the adult males are fairly uniformly dark
gray and lack rufous-and-black barring on the flanks and vent, and, in which
the songs consist of the aforementioned repetitious series of single notes
without any differentiated accelerated trill at the end; and 2) a group
consisting of four taxa (novacapitalis, pachecoi, diamantinensis, and
an-as-yet-unnamed population from the southern part of the Espinhaço Range in
Minas Gerais = species novum #2) that are generally paler gray than the speluncae/iraiensis
subgroup (particularly on the median underparts) with rufous flanks/vent that
are more or less barred, even in adult males, and, in which exists a
distinctive song type with a differentiated ending that accelerates into a
trill (this song type possibly given only or mostly by females of the various
taxa, but which nonetheless is completely unknown from the speluncae/iraiensis
subgroup).
"[TIME OUT: The foregoing discussion does not reflect
an-as-yet-unresolved nomenclatural controversy within this group. Raposo et al.
(2006) consider that the name speluncae has been historically
misapplied to the dark gray birds of the Serra do Mar. Their examination of
photographs of the holotype of speluncae (as well as of the type
description and accompanying plate, in conjunction with the peculiar type
locality (which is outside the current known range of the dark gray
coastal-range birds) have led them to conclude that the holotype of speluncae is
actually one of the paler-breasted, rufous-flanked birds of the southern
Espinhaço range (treated by Maurício 2005, Bornschein et al. 2007 and other
authors as "Scytalopus sp. novum"), and that therefore,
the epithet speluncae is referable only to birds of the Espinhaço range,
including birds from the northern part of the range in Bahia, subsequently recognized
by Bornschein et al. 2007 as diamantinensis. Concomitantly, Raposo et
al. (2006) concluded that the uniformly dark gray populations of the Serra do
Mar (= speluncae by all other authors) lacked a name, and
redescribed that population as Scytalopus notorius. These conclusions
have been refuted by Bornschein et al. (2007), and the debate rages on. In the
interest of not making this discussion any more complicated than it already is,
I am not going to deal with this nomenclatural issue further, and will continue
to use the nomenclature advocated by Bornschein et al. (2007), which coincides
with current SACC taxonomy.]
"The immediate issue at hand is whether or not to treat the
newly described (Bornschein et al. 2007) diamantinensis as a
distinct species (as advocated by the authors), or as a subspecies of speluncae.
The proposed new species (diamantinensis) is diagnosable from all other
Brazilian taxa by some combination of morphological and/or vocal characters, as
well as by genetic characters. Bornschein et al. (2007), in a phylogenetic
analysis in which all known species of Brazilian Scytalopus were
represented, consistently recovered (with high statistical support) a
monophyletic group formed by diamantinensis, novacapitalis, pachecoi, and
Scytalopus sp. nov. #2 (southern Espinhaço Range in Minas Gerais).
Within this clade, diamantinensis was distinct from other taxa, but
closest to novacapitalis (observed sequence divergence of 3.5%),
followed by species novum (4.5%) and pachecoi (5.0%). Trouble arises
when one considers the morphological and vocal distinctions. Although readily
distinguishable morphologically from both novacapitalis and sp. novum #2
(both of which are distinctly paler on the median underparts), diamantinensis is
indistinguishable from pachecoi in both its adult male and adult female
plumages. There are apparently some diagnostic mensural differences (several
characters for females; only bill depth and culmen length for males). Immature
males of the two taxa are separable on the basis of differing barring patterns
on the upper wing coverts. Vocal differences are also far from clear-cut. Diamantinensis
has 2 distinct calls that are not found in any other taxa in the larger speluncae
group, but the songs, while differing diagnosably (no overlap) in two
characters from songs of novacapitalis, are apparently not diagnosably
different from songs of either pachecoi or sp. novum #2 (Songs of diamantinensis
do differ on average in several characters from songs of pachecoi and species
novum #2, but there is overlap in all characters.)
"SACC debate to this point has generally centered on whether diamantinensis
meets the criteria of differentiation established for biological species of
Andean-distributed Scytalopus by the seminal Krabbe & Schulenberg
(1997) paper, the authors of which recognized taxa as distinct at the species
level only when their songs differed diagnosably. Advocates for using the
Krabbe & Schulenberg criteria have voted against species-ranking for diamantinensis
on the basis that its songs are not diagnosably different from those of pachecoi
or species novum. Note that in the original proposal, Fernando states: The
authors believe that S. diamantinensis, S. pachecoi, and Scytalopus sp.
nov. would probably be lumped into a single polytypic biological species.
Therefore, they recognized all four allopatric taxa with accelerating songs as
distinct (at least) phylogenetic species.
"I think it is important to clarify that the authors did not
state that they did not believe that the taxa involved did not represent
biological species, but, rather, that they would not be accepted as biological
species if held to the same criteria advocated by Krabbe & Schulenberg
(1997).
"Based on the foregoing question, Van raised the logical next
question, which goes beyond species status for diamantinensis, and
questions whether the other Brazilian taxa under discussion merit species
status or whether they should just be recognized at the subspecific
level. Something that has not been made clear in the various
discussions is that while many of these taxa are allopatrically distributed,
some of the taxa occur syntopically at multiple sites. Maurício
(2005), in his formal description of pachecoi, listed and mapped
multiple localities in the Planalto Meridional of northeastern Rio Grande do
Sul (primarily in the vicinity of Cambará do Sul) and in adjacent Santa
Catarina in which both pachecoi and the southern form of speluncae
occurred syntopically. He reported strong interspecific segregation in these
areas, with speluncae being generally confined to steep slopes,
surrounded by territories of pachecoi (in at least one case, pairs of
the two forms were only 10-20 m apart). Subsequently, scattered territories of iraiensis
have also been discovered in marshes within the highlands of the region, with
the result that in the Cambará do Sul/Itaimbezinho & Aparados da Serra
region, pachecoi, speluncae, and iraiensis can all be found
within a few kms of one another (Indeed, we have seen and tape recorded all
three taxa within a few kms of one another in this region.). Within these three
sympatric taxa, adults (but not immatures or subadults) of pachecoi are
distinctive in having paler gray underparts with consistently rufous &
black-barred flanks/vent, and in having the accelerated song type with a
terminal trill, as well as in having some diagnostic calls. The taxa speluncae
and iraiensis differ more subtly from one another in morphological
characters, and their songs are very similar, but they do differ diagnosably in
their calls (iraiensis has a monosyllabic or bisyllabic call that
Maurício termed "very distinct" from calls of all other members of
the speluncae group). All three sympatrically occurring taxa (pachecoi,
speluncae, iraiensis) exhibit ecological differences in terms of
microhabitats occupied.
"Given that pachecoi, speluncae and iraiensis pass
the test of sympatry, it would seem that their treatment as separate biological
species is secure. The molecular analysis of Bornschein et al. (2007)
establishes the monophyly of pachecoi, novacapitalis,
diamantinensis, and species novum #2 as a clade distinct from speluncae,
iraiensis and species novum # 1. So the issue then becomes
whether pachecoi, diamantinensis, and sp. novum #2 should be
considered separate species, or merely subspecies of novacapitalis,
which has priority. As reiterated above, diamantinensis differs
diagnosably (no overlap) in two characters of its song from novacapitalis
(along with possessing 2 diagnostic call types and differing in plumage
characters), and so, would seem to fit the Krabbe/Schulenberg criteria for
recognition as separate species. Songs of pachecoi and novacapitalis
also seem to differ diagnosably from one another in pace, frequency and note
length (Table 2, Maurício 2005); pachecoi has a unique call not found in
novacapitalis; and the two forms differ in plumage characters. So,
again, these two taxa would seem to meet the Krabbe/Schulenberg criteria for recognition
as separate species.
"The remaining pairwise comparisons to consider are diamantinensis
versus pachecoi, and each of those forms relative to species novum #2.
To reiterate, diamantinensis differs diagnosably in plumage characters
from species novum #2, but is indistinguishable from pachecoi (except
for immature males, which can be diagnosed on plumage characters). Since
species novum #2 hasn't been formally described (except by Raposo et al. 2006),
the SACC does not recognize it at any level, so it would seem that for the time
being it is a moot point as to whether or not it is distinct from diamantinensis
[The known ranges of the two forms are separated by more than 500 km; they
occupy different habitats, with diamantinensis being strictly a
forest bird and species novum #2 being found in both forest and non-forest
habitats, but more often in campo rupestre; they differ diagnosably in
plumage characters; they differ diagnosably in at least one call type; and the
observed sequence divergence in mitochondrial DNA was 4.5%] or pachecoi.
The diagnosability of diamantinensis relative to pachecoi rests
on non-overlapping differences in wing covert pattern of immature males,
diagnostic differences in calls, diagnostic differences in pace of the
transitional segment of the accelerating song type, and in the 5.0%
mitochondrial DNA sequence divergence (Bornschein et al. 2007).
"I would submit that the sum of the distinctions between diamantinensis,
pachecoi and species novum #2, although perhaps not meeting the
Krabbe/Schulenberg criteria for biological species, are, in fact, consistent
with separate species status. They are as different from one another (differing
ecologically, morphologically, and in calls, but with overlapping song
characters) as are speluncae and iraiensis, two taxa in the same
genus that despite subtle morphological differences and overlapping song
parameters, exist sympatrically while maintaining their genetic integrity. The
yardstick supplied by the speluncae/iraiensis example would seem to
answer the question of whether diagnostic differences in calls can be as
important as diagnostic differences in songs when it comes to mate choice and
pre-mating barriers to reproduction. As pointed out by Daniel, differences in
calls have been shown to be more important than songs in sorting out the
species-limits in the Hypocnemis cantator group of antbirds. Isler
et al. showed that the taxa peruviana and collinsi/subflava,
although not differing diagnosably in song characters, did have distinctly
different call types, and mated assortatively in areas of syntopy. Conversely,
within the Schistocichla group of antbirds, calls did not vary
appreciably between taxa, whereas songs did. I realize that we are talking
about two different genera, but the point remains the same - different vocal
characters may have different relative importance from one group of birds to
the next.
"As Van points out, the sequence divergences reported by
Bornschein et al. 2007 do not prove anything in and of themselves, but they are
least consistent. Given the geographic distances involved (500+ km) between the
nearest known inter-taxon populations in the diamantinensis/novacapitalis/pachecoi/species
novum #2 clade, combined with the sedentary nature of Scytalopus in
general, it would seem pretty clear that these taxa are on independent
evolutionary trajectories. The only taxon in the greater speluncae/novacapitalis
group that I don't have personal field experience with (including the two
undescribed forms) is diamantinensis, so I can't speak for how different
it is from "species novum #2", but the remaining members of the group
all seem like pretty different critters to me, at least relatively speaking
(given the general conservative nature of plumage and vocal differences within
the genus as a whole). So, my vote would be YES on Proposal #329,
and I would urge "no" voters to reconsider. I would also vote against
any proposal to demote any of the Brazilian Scytalopus currently
recognized in our list as distinct species to subspecies status."
Additional comments solicited from Niels Krabbe: "Kevin makes a fine summary of the Brazilian forms of Scytalopus (and
points out that the authors of diamantinensis considered it a
phylogenetic, but not a biological species).
"To sum up: The core issue is whether sp. nov.
#2 (Espinhaço range) and diamantinensis are the same biological species
despite diamantinensis being closer related to novacapitalis than
to sp. nov. #2. Following the song criterion, they are.
"Kevin brings forward two new arguments:
habitat and geographical distance.
"As for habitat, I cannot help but think of
Scytalopus latrans. Eastern and western forms in Ecuador and Colombia
occupy distinct habitats (western birds semi-humid to humid, including heavily
disturbed, forest in a broad elevational range, eastern birds humid-wet, more
pristine forest in a narrow elevational belt. The two have rather different
songs; their calls vary a lot, but can sound fairly similar. They would qualify
for being two species, were it not for the form subcinereus in southwestern
Ecuador and northwestern Peru. Subcinereus occupies an exceptional
wide range of habitats, from humid to dry forest, and appears to grade into
both the eastern and western forms. Genetically, birds from the core area of subcinereus are
closest to the eastern form.
"500 km may sound like a lot of
geographical distance between diamantinensis and sp.nov."2, but
both are in the same mountain range (Espinhaço), so it might not take a big
climatic change to bring them into contact again.
"So my vote remains NO."
Additional comments by Remsen: "YES, based mainly on
Kevin's comments."
Additional comments by Robbins: "YES, based on
Kevin's comments."