Proposal (505) to South American
Classification Committee
Split Thrush-like
Manakin Schiffornis turdina into any of two to seven species
Background: In Proposal 327, S. turdina was proposed to be
split into five species, based on Nyári (2007). Although several
committee members voted in favour of this treatment (and all were
in favour of some splitting), the proposal was rejected, there has
been no follow up proposal, and S. turdina remains a single
species on the AOU-SACC list. A large number of archived and
published sound recordings are now available of greater turdina in
published recording compilations and online resources such as xeno-canto. Donegan et al. (2011) re-examined Nyári
(2007)’s recommendations for purposes of the Colombian checklist and recent
Spanish language field guide (McMullan et al. 2011) in light of the additional
sound recordings available today. Photographs of birds representing
the three different Colombian populations were also presented. This
proposal gives the AOU-SACC the opportunity to reconsider this over-lumped
group once again.
Summary
of Proposal:
Nyári (2007) presented molecular data and some sonograms, as discussed in
proposal 327. The present species ‘turdina’ is a complex
group obviously constituting several biological species, with several
distinctive vocal types and some instances of sympatry. Donegan et
al. (2011) studied geographic variation in voice, the type localities of
various of the names and priority issues. Committee members who wish
to consider the issues in more detail may wish to consult the paper, alongside
Nyári (2007)’s maps and phylogeny. Donegan et al. presented a series
of sonograms and studied recordings with a broader geographical sample for recognized
subspecies. Donegan et al differed from Nyári (2007) in a handful of aspects,
but the bulk of Nyári (2007)’s proposals were supported by additional materials
now available.
The turdina group
needs splitting even under the most conservative of species
concepts. Although this aspect was not highlighted by Nyári (2007),
two of the taxa in the turdina group are sympatric in Central
Panama (Ridgely & Gwynne 1989) and two others of them replace one another
by elevation in the Amazon-Andes interface of Ecuador and Peru (Ridgely &
Greenfield 2001, Krabbe & Nilsson 2003). Moreover, various other
populations are vocally distinct. This proposal should therefore
involve a discussion of the extent and manner in which one ought to go about
cutting off various limbs in this group so as to produce a set of species which
are vocally cohesive or, for those interested in such matters, monophyletic
(rather than a question of whether sub-division is warranted at all).
Donegan et al. (2011) proposed recognising the following species
(using Nyári 2007’s vernacular names):
1. Thrush-like
Schiffornis S. turdina (provisionally including
subspecies steinbachi, amazonum, wallacii and intermedia) of
the Amazon region and Atlantic forest, including the Amazonian region of
Colombia.
2. Slender-billed
Schiffornis S. stenorhyncha (including panamensis)
of the Tacarcuna region of Panama and Colombia, Magdalena valley and Central,
East and Merida Andes of Colombia and north-western Venezuela.
3. Brown
Schiffornis S. veraepacis (including dumicola,
rosenbergi, “buckleyi” and acrophites) of the Chocó from
northernmost Peru through Ecuador to Colombia and Central America from
northern/western Panamá northwards.
4. Foothill
Schiffornis S. aenea of the western Amazon region of Ecuador
and Peru.
5. Olivaceous
Schiffornis S. olivacea of the Guianan shield.
The
table below summarises the range of named populations and other
proposed treatments:
Population name |
Range |
Nyári Vocal group |
Nyári’s molecular group |
Nyári’s PSC approach |
Nyári’s BSC approach |
Nyári’s SACC proposal |
Donegan et al. 2011 BSC approach |
veraepacis, dumicola |
Central America (S Mexico and Belize to
N/W Panama) |
A |
1 |
veraepacis |
veraepacis |
veraepacis |
veraepacis |
rosenbergi / buckleyi / acrophites |
Chocó of Colombia and N Ecuador |
A |
3 |
rosenbergi |
veraepacis |
veraepacis |
veraepacis |
olivacea |
Guianan shield of Venezuela to
Suriname, N. Brazil |
A |
7 |
olivacea |
veraepacis |
olivacea |
olivacea |
aenea |
West Amazon in Ecuador and Perú |
B |
4 |
aenea |
aenea |
aenea |
aenea |
stenorhyncha / panamensis |
Northern Colombia, Venezuela, S/E
Panama |
E |
2 |
stenorhyncha |
stenorhyncha |
stenorhyncha |
stenorhyncha |
turdina, intermedia |
Atlantic forest region of Brazil |
D |
6 |
turdina |
turdina |
turdina |
turdina |
steinbachi |
Southern Amazonia in Peru, Bolivia,
Brazil |
C |
6 |
amazonum |
amazonum |
amazonum |
turdina |
wallacii |
Para, Brazil and surrounding region |
A/C |
6/7 |
amazona / olivacea |
amazonum / veraepacis |
amazonum / olivacea |
turdina |
amazonum |
Northern Amazonia in Colombia,
Venezuela, Peru, Bolivia, Brazil. |
C |
5 |
amazonum |
amazonum |
amazonum / turdina |
turdina |
Sub-proposals: This proposal set is
split into various cumulative sub-proposals, such that if the SACC disagrees
with Donegan et al. (2011)’s treatment or wishes to adopt some other
arrangement, it can stop at an earlier or later stage of limb separation and
still come up with a new taxonomy.
A:
Split veraepacis (with dumicola, rosenbergi,
buckleyi, acrophites, aenea and olivacea), from turdina (with wallacii,
amazonum, intermedia, steinbachi, stenorhyncha and panamensis). Taxa dumicola (of
the veraepacis group) and stenorhyncha (sister
to eastern races for which the name turdina is senior) are
sympatric in Central Panama (Ridgely & Gwynne 1989) and differ in their
voice and plumage. Recordings of the two vocal types that these
names represent by Ken Allaire, Mike Nelson and others from Panama (of which
sonograms were presented in Donegan et al. 2011) overlap geographically,
confirming sympatry or elevational parapatry. According to recordist
notes, the two do not respond to playback of one
another. Separately, subspecies aenea (east slope
Ecuador) replaces the Amazonian lowland groups (amazonum) by elevation
in the Andes-Amazon interface. This split is an easy one under a BSC
approach, mandated by two instances of sympatry, but it produces two vocally
non-cohesive species with weird distributions, one of which is
polyphyletic. It is strongly recommended that this proposal be
accepted as a starter, in the context of the next following sub-proposals.
B. Split stenorhyncha (with panamensis)
from turdina (with wallacii, amazonum,
steinbachi and intermedia). These populations
are allopatric sister populations. Nonetheless, this is a
straightforward split in light of them having perhaps the strongest pairwise
vocal differences of any two groups, which are equivalent to those between sympatric
Schiffornis. This proposal, if accepted, clears up some of
the strange distribution caused by A and deals with vocal non-cohesiveness of
the eastern group. The plumage differences between the three species
split by proposals A and B together are also very strong, as illustrated by
photographs of examples of the three taxa from Colombia in Donegan et al.
(2011). Daniel Cadena fairly criticised Nyári (2007)’s
split of this taxon on account of it not being based on recordings from
different biogeographic regions within the range of stenorhyncha (including
‘panamensis’). Donegan et al. (2011) presented or studied sonograms of
birds from near the type locality of stenorhyncha (Falcon,
Venezuela), the Merida Andes (including near the southernmost extent of the
East slope population), the Magdalena valley, Serranía de San Lucas (Cauca
valley border, it does not go further south in this region) and eastern Panama
(near the type locality of “panamensis”), confirming the consistency of
the song throughout the range of Nyári (2007)’s proposed species stenorhyncha.
---
These first two proposals come very highly recommended for acceptance and
should be regarded as uncontroversial under any species
concept. There now follow two further splits of allopatric
populations which Nyári proposed making in his SACC proposal and with which
Donegan et al. (2011) agreed. ---
C. Split aenea (monotypic) from veraepacis (with dumicola,
rosenbergi, buckleyi, acrolophites; and olivacea if
D fails). S. aenea is the Andean East slope population
in Ecuador and Peru. It may also extend in range into southern
Colombia, although there are no records there yet. The two
populations subject to proposal C are apparently allopatric sister populations
which straddle the Andes. When split, they appear as mutually
monophyletic (c.3% mtDNA difference). Rejecting this split does not
therefore produce polyphyly or paraphyly. S. aenea is
however vocally rather different from veraepacis, leading
to various authors such as Ridgely & Tudor (2001) and Krabbe & Nilsson
(2003) noting that more than one species may be involved (see sonograms in
Donegan et al. 2011). The differences are not as great as those
shown by stenorhyncha (Proposal B), with various of the note
shapes of the aenea song having equivalents in a different
order in the songs given by the veraepacis group, but the
differences in note shape or order of note shape are consistent and
diagnosable. Doenagn et al. preferred to spit aenea, based on
vocal differences, molecular data, and their distributions - which straddle the
Andes in a very high part of the mountain range. Taken together,
these factors put the burden of proof on those who would have these
two lumped.
D. Split olivacea (monotypic) from veraepacis (with dumicola,
rosenbergi, buckleyi and acrolophites; and aenea if
C fails). This is the troubling Guianan shield
population. This proposed split was subject to a differing treatment
by Nyári (2007) in his BSC interpretation (lumped) versus his SACC proposal and
PSC interpretation (split). Olivacea is vocally very
similar to the veraepacis group, with no differences
elucidated by Nyári (2007). Donegan et al. (2011) noted small
differences in the extent of the upturn of the main note. In the
previous proposal, there was some speculation as to whether the vocal
similarities here are a result of limited divergence or convergence, although
most committee members seemed in favour of splitting this
taxon. It is basal to all other current turdina in
the Nyári (2007) phylogeny, showing 9%+ mtDNA differentiation from all other
taxa. Donegan et al. (2011) presented additional information
suggesting that olivacea is indeed the correct name for this
population, as provisionally treated by Nyári (2007). Not
splitting olivacea produces a veraepacis group
which is polyphyletic and which has a strange distribution. Because
Proposal A should not be regarded as optional (and B and C are strongly
recommended), it would be reasonable also to make this split.
---
Donegan et al. (2011) went this far and did not adopt any further splits. ----
E.
Split amazonum (with wallacii) from turdina (with intermedia and steinbachi). This
is the “North Amazon vs. South Amazon and Atlantic forest” split that Nyári
(2007) proposed. There is clearly vocal variation in the southern
part of the greater ‘turdina’ range, but this split raises various
difficulties, some of which were discussed by Doug Stotz and Van Remsen as
being unfavourable factors towards adopting the treatment in the
previous proposal. Further research indicates that turdina in
the subspecies sense (South Atlantic forest) resembles amazonum (North
Amazon) vocally; whilst intermedia (North Atlantic forest)
generally resembles assumed steinbachi (south Amazon of
Bolivia to Peru) vocally. All these eastern and southern populations
are monophyletic when taken together. Their songs are all generally
comprised of longer notes than the other species, differing among one another in
the shapes of up or down-turns at the start of end of particular notes (see
sonograms in Donegan et al. 2011). These vocal differences exceed
those shown by olivacea but do not reach the differentiation
shown by aenea. Given the scope of our paper (Colombia),
a detailed examination of the Bolivian and Brazilian types, their localities
and sound recordings on different sides of major Amazonian rivers was out of
scope, but could be recommended for further research. This split or
other possible treatments for the southern populations may be warranted but
lumping them does not cause paraphyly or polyphyly, nor does it produce a
vocally uncohesive group or preclude further studies from taking
place. Donegan et al. did not recommend adopting this split for the
time being, but further research is clearly warranted.
---
Nyári (2007) went this far and did not adopt any further splits. ---
F.
A further possible alternative for the Eastern taxa based on tentative vocal
data would be to split turdina (with wallacii and amazonum)
from intermedia (with steinbachi). This produces two
species of strange distribution, and it is unknown how this would hang with
molecular data, owing to the lack of sampled individuals from very close to the
type localities of some of these names in Nyári (2007). Donegan et
al. did not take this step, but SACC members with greater familiarity with
southern Amazonian and Atlantic forest birds may wish to comment on this option
or consider it, for completeness, as an alternative to E.
G.
Split veraepacis (with dumicola) from rosenbergi (with buckleyi and acrophites). Proposals
A-C, if accepted, result in veraepacis including two disjunct
populations, one in the Chocó-Tumbes and another broadly in Central
America. The ranges of the two are bisected in the Tacarcuna region
to southern/eastern Panama by that of stenorhyncha. The veraepacis and rosenbergi groups
are apparently mutually monophyletic, although with low molecular
differentiation (0.8% mtDNA) and with small vocal differences. This
would be a possible split under some species concepts (e.g. PSC) but Donegan et
al. did not adopt it. Tentative differences in secondary calls
(based on only a single Central American recording of the secondary song)
should be regarded as a matter for further research. As with the
possible Amazonian splits, not adopting this treatment does not preclude
further studies of these birds.
Recommendation: A resolute YES to A
and B; YES to C and D for the reasons set out in Donegan et al. (2011) and
Nyári (2007). NO to E, F and G for the
time being, with a note that further research could shed light on variation
among these populations and that other splits may be warranted in the future.
English
names:
If any of these proposals pass, then the English names suggested by Arpad Nyári
in Proposal 327 (see above) would be adopted. If anyone prefers a
different vernacular name for a narrower turdina, then
they can raise a separate proposal on that issue.
References:
Donegan, T.M., Quevedo,
A., McMullan, M. & Salaman, P. 2011. Revision of the status of
bird species occurring or reported in Colombia 2011. Conservación
-Colombiana 15: 4-21.
Nyári, Á. S. 2007.
Phylogeographic patterns, molecular and vocal differentiation, and species
limits in Schiffornis turdina (Aves). Molecular
Phylogenetics & Evolution 44: 154-164.
Other
references are cited in these papers.
Anonymous, October 2011
___________________________________________________________________________________________
Comments
from Robbins:
“YES to subproposals A (veraepacis), B (stenorhyncha), C (aenea),
and D (olivacea). Nyari’s genetic and preliminary vocal
data clearly established that these taxa should be elevated to species level;
Donegan et al.’s (2011) more in-depth vocal analyses corroborated those
results. Undoubtedly, recognition of additional species will be
warranted when more detailed information becomes available.”
Comments
from Stiles:
“This proposal would split Schiffornis turdina into at least
four species, based primarily upon data from the genetic analysis of Nyári and
a more detailed analysis of vocalizations by Donegan. The latter are
a definite step forward and incline me to agree with the proposal, although
given the abundant material available, I would have felt more comfortable if
statistical analyses of the vocalizations had been
performed. However, with the data at hand I agree that the burden of
proof has now shifted onto those who would retain a single species. I have now
had a chance to examine the Colombian material here and have obtained
information on the plumage differences of at least the Colombian taxa, and this
leaves me with strong doubts regarding the English names proposed by Nyári –
given the rather subtle differences between most taxa and the uncertainty
regarding the limits of some distributions, I feel that appropriate and
descriptive English names may be important, and will make a series of
suggestions below (which might warrant a separate proposal). For now, regarding
the splits proposed by Anonymous:
A.
Split the veraepacis group from a broad turdina:
YES. The sympatry of the two groups in central Panamá, plus differences in
vocalizations and evidence that the two do not respond to each other’s songs
makes this split mandatory.
B.
Split the eastern amazonum group from the northern stenorhyncha group:
YES. Both the genetic data and information from vocalizations, as well as
biogeography, make this split logical and desirable.
C.
Split aenea from the veraepacis group: YES.
Although the genetic data are not quite as definitive, both vocalizations and
biogeography seem better addressed by splitting.
D.
Split olivacea of the Guyana Shield from the veraepacis group:
YES. This split will avoid massive polyphyly in the genus as a whole and makes
good biogeographical sense as well.
“I
agree with Anonymous that although some further splits could be made,
especially in the amazonum group, more data are required. The
split of rosenbergi-acrolphites from veraepacis has
no genetic backing and mainly reflects the gap in distributions, which might be
better explained by historical factors. For now, the four splits
suggested are sufficient and desirable.
“Now,
for the messy part: English names. Because the splits have as yet
not been “officially” adopted, it seems appropriate to make these suggestions
now. To begin with, I feel strongly that the name “Brown
Schiffornis” for the veraepacis group (species) is singularly
inappropriate. The two Colombian races (acrolophites and rosenbergi)
are much the greenest of all the taxa. By far
the brownest of all is stenorhyncha (which is
also not the “slenderest-billed”; that distinction belongs
to amazonum). Hence, I would propose that the name
“Brown Schiffornis” be applied to stenorhyncha (or “Brownish
Schiffornis” if one wishes to avoid confusion with Nyari’s names). “Greenish
Schiffornis” could then be applied to veraepacis. I make
this latter suggestion a bit tentatively, as I do not have material of the
northern races of the latter for direct comparison, although my description and
the plate in the Costa Rican guide (as well as the descriptions in Ridgway)
emphasize olive-green to olive-brown tones. (The name “olivaceous” would also
be appropriate, but is perhaps best reserved for olivacea of
the Guyana Shield – although for the latter “Guianan Schiffornis” would also be
appropriate). Aside from its overall brownish coloration, the most
trenchant plumage characters of stenorhyncha are the decidedly
rufescent color of the wings and the sharp division of the brownish to
olive-brown breast band and the grayish-olive lower breast and belly; it is
also the largest taxon. Hence
“Rufous-winged” or “Grayish-bellied” would not be inappropriate for this
taxon. I note here that none of our series of stenorhyncha show
the clear gray belly of the bird in the proposal photo: given the yellowish
coloration of the basal tomia and gape, I suspect that his bird was
young – I suspect that young birds in this genus in general are brighter and
more contrasty than adults, though few of our specimens are reliably
aged. Actually, the belly in amazonum is also grayish
olive and in some is grayer than in most stenorhyncha, although the
contrast with the breast is not nearly so sharp. The wing in amazonum is
a darker, duller brown than in stenorhyncha so “Brown-winged
Schiffornis” would emphasize this difference, but I think that “Amazonian
Schiffornis” is certainly simpler and appropriate, and could be kept for amazonum should
this group be split further - although such a split (or splits) seem
problematic for the present.
Comments
from Stotz:
“YES on subproposals A, B, C, and D. NO on subproposals E, F, and
G. I am much more comfortable with this proposal than the previous
proposal. We will probably have to split other taxa farther down the
line, but this is a reasonable first step on this complicated
group. I agree with Gary that we need to think about English
names. However, his suggestion of “Greenish” for veraepacis won’t
work. Greenish Schiffornis is the name of Schiffornis virescensof SE
Brazil. I think that it would be a mistake to use Olivaceous for veraepacis with
S. olivaceus being one of the names. So I don’t have a good
alternative in mind, but I agree with Gary that Brown would not be a great
choice. I would go for Brownish for stenorhyncha, and
while I am okay with Olivaceous for S. olivaceus, I think we would be
better served to adopt a geographic modifier Guianan for that
species. One further issue is a name for the reduced turdina. Given
the complications in that group, and how much of the turdina (sensu
lato) has been carved off from it. I think we absolutely have to
have an alternate English name for this new turdina. Unfortunately, I have not come up with a
great answer. These are really dull birds. My only
thought is Southern Schiffornis.”
Comments
from Pérez:
“YES to subproposals A, B, C, and D. I think molecular, vocal and
distributional data support this awaited treatment for S. turdina.
NO to subproposals E, F and G; more in-depth treatments, as suggested by
Donegan et al. (2011), would likely provide information for further splitting.”
Comments
from Jaramillo:
“YES – accept A, B, C, and D. I am not comfortable going further with it,
particularly as vocal data are relatively common, and further separations
require a higher level of scrutiny. Having said this, once we determine which
forms the committee has decided to split off, or not, I think we need a
separate simple proposal on the English names.”
Comments
from Nores:
“YES to subproposals A (veraepacis), B (stenorhyncha), C (aenea),
and D (olivacea). I consider that the molecular and vocal data
support this treatment. However, I did not find either in the proposal or
the Nyári´s paper a clear relationship between the new species and
the regions 1-7 of the phylogeographic tree of Nyári. How much easier would
have been to interpret the Nyári´s tree if he would have put the name
of the subspecies or species next to the name of
the region.
Comments
from Remsen:
“YES to subproposals A (veraepacis), B (stenorhyncha), C (aenea),
and D (olivacea). Echoing the comments of others, there is
good evidence for at least 5 species, and more will likely come from additional
analyses. By the way, I strongly agree with Manuel’s comment on the
poor labeling in Nyári´s tree – just one more example of how poorly
edited MPE is.
“English
names are a real problem. Ridgway and Hellmayr both used
“Olivaceous” for S. olivacea, so I would favor retaining that
one. Gary’s comment on “Brown” for veraepacis is correct – “Brown”
is perhaps the worst name possible for this species, even though used by
Ridgway and Hellmayr. Ridgway used
“Russet” for stenorhyncha, but I do think Gary’s name is
better. Hellmayr used “Slender-billed”, but no reason to perpetuate
that if inaccurate. Also, Doug’s comments are also correct –
“Greenish” is not available, and we really cannot retain “Thrush-like” for a
dramatically diminished S. turdina (and besides, it’s a poor
name, species epithet not withstanding). So, I am installing some
temporary English names based on Gary’s recommendations and will be appointing
someone to make a formal proposal to examine carefully the English names before
they get any traction.”