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

 

 

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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."