Proposal (332) to South American Classification Committee
Recognize
Atlapetes blancae as a species
Effect on SACC: This would add a newly
described species to the list.
New information: Donegan (2007) described a new
species of Atlapetes based on the discovery of 3 old skins, one each at
three different Colombian collections, previously labeled as A. schistaceus
from remnant forest patches in the n. Central Andes of Colombia. Searches by
Donegan and others at and near the type locality have not revealed any
additional specimens. Only one of the three has a date (1971), and one of the
three has no locality data other than "Antioquia."
Although sharing overall gray plumage and rufous crown with A.
schistaceus, the new taxon, A. blancae, differs in being
paler throughout and in having a much less prominent malar (see color
illustration by Restall in Donegan 2007). Although very similar in pattern to
the subspecies (elaeoprorus) of A.
latinuchus that occurs in the n. Central Andes, blancae differs
in being gray throughout, with no yellow anywhere (see the illustration).
Critical to the argument that blancae is a separate
species is that typical A. latinuchus and A. schistaceus have
been found at or near the type locality and are (were?) therefore syntopic
with blancae or nearly so.
Donegan (2007) noted that one of the specimens of blancae has
enlarged testes, and so blancae is unlikely to represent and undescribed
juv./imm. plumage of one of the two Atlapetes known from the area (schistaceus
or latinuchus). Further, juvenile plumages of all Atlapetes taxa
present in the region are known and do not fit blancae.
As for the possibility of blancae representing a
hybrid combination or undescribed color morph of an existing, Donegan (2007)
noted that (1) the existence of three specimens, not one, makes it less likely
that they are hybrids, and (2) blancae has plumage features not found in
either of the potential parental species, namely a smaller white wing speculum,
paler back, and paler crown. Further, Donegan (2007) noted: "Neither a simple yellow to grey
pigmentation switch (from A. l. elaeoprorus) nor a reduction in the moustachial
marking (from A. s. schistaceus) could explain all of the morphological
features exhibited by A. blancae. Surveys in the type locality region
did not reveal any unusual plumages amongst A. l. elaeoprorus or A.
s. schistaceus, nor are such aberrations evident in specimens from any
region."
Analysis: As noted by Donegan (2007), a species description based on only
three skins, and without vocalizations or other observations, will always be
vulnerable to skepticism, and without a DNA sample, elimination of the
possibility of a hybrid population or local color morph involving the other two
sympatric species is more difficult. Nonetheless, I think that Donegan makes a
reasonable case, given the circumstances, for treating blancae as a
species as the best hypothesis for the available data. As Donegan pointed out,
this genus has a propensity for having small isolated populations treated as
species, e.g., A. pallidiceps and A. melanopsis. Further, I am
not aware of any hybrid populations, despite a high degree of parapatry and
syntopy, or local color morphs in any other species in the genus that would
provide an analog for such explanations for blancae. Therefore, I
recommend a YES on this one. Obviously, this could be fortified or reversed by
discovery of an extant population
Literature Cited
DONEGAN, T.
M. 2007b. A new species of brush finch (Emberizidae: Atlapetes) from the
northern Central Andes of Colombia. Bulletin British Ornithological Club 127:
255-268.
Van Remsen,
Jan. 2008
________________________________________________________________________________________________________
Comments from Cadena: "YES. Although I often
advocate for stability of the status quo in the absence of unambiguous data,
I'd rather be more liberal here just in case we might loose a species to
extinction by failing to recognize it in the absence of ideal data. I actually
tried to convince Donegan on numerous occasions that he should delay the
publication of his paper until thorough surveys of the type locality had been
conducted in order to have a stronger case (provided he found the bird), but I
have to admit that he has done a good job of convincing me that this appears to
be a diagnosable population that, given sympatry or close parapatry with A.
schistaceus and A. latinuchus, is best treated as a species. Having
DNA data would have been nice, but knowing that many of the northern Andean Atlapetes are
weakly differentiated and often non-monophyletic in mtDNA probably as a
consequence of rapid radiation (John Klicka, Jorge Pérez and I should finally
have a manuscript on this soon), I'm not sure that such data would have much to
say either way. What we really need are field studies, which may or may not
validate this finding."
Comments from Stiles: "YES. Given the number of
specimens, two with good locality data and one with gonad data, I find Thomas's
arguments sufficiently convincing. Hopefully further fieldwork will locate an
extant population. I might add that this is quite a different situation from
that of Heliangelus zusii, which is known from one much older specimen
of unknown provenance (possibly not even from Colombia), taken during a period
when local depletion of hummingbird populations was accompanied by a burst of
not only hybrids but also aberrant plumages that has fortunately not been
duplicated since."
Comments from Zimmer: "YES. In spite of the small
sample size and lack of vocal and genetic data sets, Donegan makes a good case
for treatment of blancae as a distinct species. As Van notes, the case
for this treatment could go either way with discovery of an extant population,
but I'd say that the best available evidence sides with recognition at the
species level."
Comments from Robbins: "NO. I'm not sure what the
story is, but something is odd with this whole scenario. Atlapetes tend
to be common and can survive it badly degraded habitat (even the highly local pallidiceps
is common in severely degraded habitat). Hence, the fact that this taxon
can't be relocated is suspicious. The plumage characters that are described
seem pretty marginal for species level treatment in a group that is known for
plumage variation (c.f., Atlapetes schistaceus). I presume if this taxon
is truly syntopic or parapatric with schistaceus the voice will
prove to be quite distinct. Until those data are forthcoming, I vote
"no".
Comment from Thomas Donegan: "As noted in the description and above proposal, the relatively low
number of old specimens used in the description of Atlapetes blancae,
together with the lack of field data, may give rise to skepticism. However,
Mark Robbins' putative grounds for rejection (that the plumage of Atlapetes
blancae could be down to individual variation in Atlapetes
schistaceus) are so fanciful that they can be rejected immediately. As
noted in the description (cross-referencing the specimen list in Donegan &
Huertas 2006 and additional diligence), I directly inspected and took
biometrics of 138 specimens of A. schistaceus occurring in the northern
Andes, including 97 of the nominate race A. s. schistaceus that
occurs with A. blancae in the northern Central Andes. The overwhelming
majority of such specimens inspected were collected in Colombia and many are
from the Central Andes. I have also carried out fieldwork and mist-netting
throughout Colombia for 10 years, where A. schistaceus is a common
high elevation bird. Finally, I checked Project Biomap data and then also
inspected photographs of all other Central Andes A. schistaceus specimens.
None of the A. schistaceus in museums or the field are really anything
like A. blancae. The three specimens of the new species all differ from
the A. s. schistaceus series in: moustachial pattern (presence of
strong, long white malar and black moustachial stripe), contrast between white
breast and grey belly plumage, width of crown stripe, shade of grey on back,
shade of red on crown stripe, extent of wing speculum and bill morphology.
Restall's plate in the description shows these differences well. The
differences between A. schistaceus and A. blancae include
significant differences in structure and patterning as well as plumage hue.
Such differences are notably greater than those between A. blancae and A.
"latinuchus" elaeoprorus. As a result and as noted in the paper, A.
schistaceus is probably not even very closely related to A. blancae.
"Persons looking hard for a reason to
reject this proposal (on the basis of not liking descriptions without field
data) might want to do so on the basis that A. blancae might be some A.
l. elaeoprorus mutant or the result of a hybridization event involving
multiple heteroses. Each of these hypotheses are unlikely for the reasons set
out in the description, meaning in my view that the new species hypothesis is
by far the more likely one."
Comments from Nores: "YES, aunque no muy convencido. Por un lado, se ve que es algo diferente,
especialmente marcado en el joven, pero por otro, no se descarte que sea un
morfo gris de A. latinucha elaeoprorus o ejemplares con
la banda malar menos marcada de A. schistaceus. En el dibujo hecho
por Restall (Fig. 1), A. schistaceus aparece con la corona muy diferente
en color y restringida que A. blancae, pero en Hilty y Brown ya no es
tan así. La corona tiene un color similar al que aparece en la Fig. 2 de
Donegan y le llega hasta la base del cuello."
Comments from Jaramillo: "YES - But tentative, not
because I do not trust the data but because I like things to all add up nicely.
Here the one bit that is missing is the live bird, a population. If this
creature is real, and I figure it must be, it surely is out there still."
Comments from Stotz: "YES. I would be happier if
an extant population were found, but based on the data presented, I think
treatment as a distinct species seems like the best course."