Proposal (403) to South American Classification Committee
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| Proposal (403) to South American Classification Committee
Elevate Pyrrhura griseipectus to species rank Effect on South American CL: this would recognize P. griseipectus as distinct from P. leucotis, overriding part of Proposal #306. Background: SACC has recently reviewed the status of several Pyrrhura of the picta-leucotis group based on genetic analysis of mtDNA by Ribas et al. Among the results was the downgrading of P. griseipectus to a subspecies of P. leucotis based on SACC considering them closely related because they were not reciprocally monophyletic in the mitochondrial DNA analysis, "similar in plumage, and more or less weakly differentiated ecologically". Reassessment of available information: SACC adopts the biological species concept, which we all acknowledge to be problematical and vulnerable to subjective assessments. Also, we think that the differences between P. leucotis and P. griseipectus should have been described in better detail for a proper evaluation. This may have affected judging the status of Pyrrhura griseipectus. Full species status for P. griseipectus can be argued based on the following: 1 - Sorting lineages from the evidence in Ribas et al (2006) is problematical and, although reciprocal monophyly is desirable, this is not a determining condition to consider an allopatric taxon as part of another. Care should be taken in such analysis, since recent work on Monarcha flycatchers (and other taxa) has shown that very small genetic differences may be sufficient to promote speciation. It should also be mentioned all specimens of leucotis and griseipectus used in the analysis were captive and the risk of hybridization in such conditions is not beyond doubt. 2 - P. griseipectus shows diagnosable plumage characters from P. leucotis or P. pfrimeri summarized by Olmos et al. 1998, 2005, and further elaborated here: a - Head color: leucotis has a blue suffusion on the forehead (sometimes extending to above the eyes), nape and sides of the neck, the rest of the head being buffy-gray; griseipectus only has the blue suffusion on the sides of the neck, the crown being entirely grey. b - Auricular patch: cream to yellowish in leucotis, most birds showing a buff tinge; pure white to cream, and notably larger, in griseipectus. In the latter the ear-patch connects with the pale breast (see photos of live birds below).
d - Breast feathers: in leucotis these are green with a blue suffusion, more intense near the neck, and with a broad pale grey or buff subterminal band and black terminal one; in griseipectus the breast feathers are dusky grey with a broad cream to pale buff terminal band. These color differences result in strikingly different birds, no overlap in character condition being noticeable in the specimens we have studied either in collections or in the field. Photos of specimens showing the breast pattern are attached. See also the following for photos of live free-living P. griseipectus and P. leucotis.
3 - Besides color differences, P. griseipectus has a significantly longer bill and broader and deeper mandible (Olmos et al. 1998). This results in a more robust bill and the birds looking distinctly larger-headed compared to leucotis, which certainly reflects ecological differences. These are also evident in the different habitats and ecological and biogeographical settings in which the taxa live. 4 - P. leucotis is a bird of the lowland Atlantic forest from southern Bahia to Rio de Janeiro (which might be considered as a discreet endemism center defined by species such as Cotinga maculata), whereas P. griseipectus is restricted to montane forest enclaves that have strong Amazonian affinities in otherwise semi-arid Ceará and Pernambuco. In between there are thousands of kms that include a whole endemism center devoid of any Pyrrhura (the Pernambuco Center) despite the presence of Atlantic forest, which should have a taxon of the group, and the area from Bahia de Todos os Santos to the mouth of the São Francisco river, which some might consider a discrete subcenter based on endemic taxa such as Pyriglena atra. So, from a biogeographical standpoint, P. griseipectus is a quite particular entity that should be considered distinctive from P. leucotis. 5 - Although the information on vocal differences between the taxa is as yet unpublished, the 'song' of P. leucotis and P. griseipectus shows diagnosable differences allowing one to tell them apart based on vocalizations only, with that of griseipectus being of a higher frequency compared to leucotis. This difference can be appreciated in the attached sound file, sonogram, and the table below:
Recommendation: The available evidence is enough to consider P. griseipectus a full species distinctive from P. leucotis (and other species of the group). Morphologically it shows both plumage, and structural differences rendering it perfectly diagnosable (with no character overlap) from any other taxa in the group, including P. leucotis. It is restricted to a particular habitat with distinctive biogeographical history, being quite isolated from P. leucotis. Vocal evidence, although in need of further study, shows further differences between P. griseipectus and P. leucotis. Literature cited Olmos, F., P. Martuscelli, and R. Silva e. Silva. 1998. Ecology and habitat of Pfrimer's Conure Pyrrhura pfrimeri, with a reappraisal of Brazilian Pyrrhura leucotis. Ornitología Neotropical 8: 121-132. Olmos, F., W. A. G. Silva & C. Albano. 2005. Grey-breasted Conure Pyrrhura griseipectus, an overlooked endangered species. Cotinga 24: 77-83. Ribas, C. C., L. Joseph, and C. R. Miyaki. 2006. Molecular systematics and patterns of diversification in Pyrrhura (Psittacidae) with special reference to the picta-leucotis complex. Auk:123: 660-680. Fabio Olmos, Ciro Albano, Alberto Campos, Weber Girão, & Jeremy Minns July 2009 Comments from Zimmer: “YES. Following are my comments from the earlier massive Pyrrhura proposal (#306) as regards Doug’s recommendations at that time for the treatment of griseipectus and leucotis as conspecific: I disagree with Doug's recommendation on subproposal B. I agree that pfrimeri is morphologically and ecologically more distinct from leucotis and griseipectus than either is from one another. However, the morphological and ecological differences between griseipectus and leucotis are at least on a par with those between various members of the picta group that are here being recognized as or recommended for separate species status. When this yardstick is applied, in combination with the recognition of the formidable disjunction between the ranges of griseipectus and leucotis - which effectively means that the two forms are on independent evolutionary trajectories - it seems that recognition as separate species is warranted. I am not troubled by the lack of genetic evidence supporting this move - see Gary's comments under Proposal #181, which nicely sum up the arguments against giving too much weight to genetic evidence in matters of resolving species limits.’ ” “I think that Fabio and his co-authors of this proposal raise an interesting point in noting that the ranges of griseipectus and leucotis are separated by a large geographic area containing Atlantic Forest and known to be a separate center of endemism (the Pernambuco Center), which lacks any taxon representing this group of Pyrrhuras. This complete disjunction really does suggest different biogeographical histories for these birds. The biometric differences in bill size certainly suggest different ecologies, and the vocal differences, although still unpublished, present additional evidence. Again, we run into the problem that no analysis presenting all of this data has been published, but I’ll go with my earlier position on this until published evidence proves me wrong.” Comments from Nores: “NO. En mi respuesta a la propuesta #181 yo puse: “Pienso que las diferencias de plumaje, genéticas y de hábitat que existen son suficientes para separarlas, especialmente a pfrimeri. No obstante, pienso que antes de tomar una decisión sería importante consultarle a Ribas para que opine si griseipectus y leucotis son especies diferentes, ya que él encontró una estrecha relación entre estas dos especies." Ahora tenemos publicado el análisis de Ribas et al. (2006) donde griseipectus y leucotis están juntos en un “clade” bien soportado y presentan distancias genéticas bajas (0.5% para el citocromo b y 1.0% en la región control entre individuos de griseipectus y leucotis), lo cual ha sido indicado por Ribas et al. como una divergencia reciente de los dos taxas. También coincido con lo dicho por Douglas en la propuesta #306 “They are closely related, similar in plumage, and more or less weakly differentiated ecologically. Olmos et al. described them as more distinct morphologically than are leucotis and pfrimeri, which personally I don't see” Tampoco veo que la distancia que existe entre los rangos de los dos taxas sea un factor tan importante para considerar a ambos taxas especies. 700 km no parece una distancia tan grande para un loro y más cuando ambas zonas pueden haber estado unidas o muy cercanas durante períodos más húmedos que el presente. Hay muchísimos ejemplos de subespecies separadas por igual o mayor distancia.” Comments from Robbins: “YES. After reading Kevin’s earlier comments about morphological and ecological differences between leucotis and griseipectus being on the same level as those in the picta group, which we recognize as distinct species, coupled with Olmos et al.’s new comments, I support recognizing griseipectus as a species.” Comments from Jaramillo: “YES. A nice summary and convincing argument by Olmos et al. I appreciate the comments by Kevin. Disjunctions like the one in this situation are an interesting data point we don’t tend to think about in as great detail as we do about voice, appearance and such. However, from my southern cone perspective it often is a real pointer of where to look for potential unresolved taxonomic issues for me. There are several taxa in Chile-Argentina where the distribution pattern alone suggests good biological species may be involved, let alone the ecological differences of the isolates (Accipiter bicolor chilensis, Megaceryle torquata stellata, etc.).” Comments from Remsen: “YES, but with hesitation given the unclear species boundaries in Pyrrhura as a whole. My interpretation of the arguments is that these two are “as different ” or more so as many other taxa treated as species in the genus, although without a rigorous comparative framework, this remains a qualitative assessment. I hope Olmos et al. will publish the sonograms – this could launch an investigation of voices in the genus to see if these can be used in delimiting species.” Comments from Pacheco: “YES. The set of information submitted by Olmos and colleagues to support the reconsideration of the taxonomic treatment for griseipectus is persuasive. They are important, in my opinion, vocal differences and the obvious disjunction in the distribution between the two forms involved.” Comments from Bret Whitney: “Yes. I echo Remsen on this one as concerns the “as different as...” idea. As for the “ecological” differences cited by some of us, I really don’t see any or many. This bird feeds on a wide variety of fruits ranging from introduced plants to Cecropias (heavily on the latter, like all members of the genus), nests in existing/natural tree cavities like all the rest, and flies around and vocalizes like all the rest — it is simply an isolate of the picta radiation in the Barurité of Ceará. I don’t doubt that some vocal differences could be teased out among these picta-types if worked over hard enough. Griseipectus has undergone some modification primarily (I would argue) because it is genetically isolated and small chunks that are isolated from larger blocks are going to develop “differences” more quickly. In line with its conservative morphological and vocal distinctions, it appears that genetic differentiation of griseipectus is slight relative to the whole group, all of which probably indicates a recent isolation. Nonetheless, recognizing the biogeographical patterns characteristic of eastern Brazil, it is on an independent trajectory at this point and will continue to evolve as an integral species would. Thus, I think it is more appropriate to recognize it today as an integral species than as, for example, a subspecies that ornithologists at some indeterminate moment in the future, after the genetic transitions add up to a more divergent story, will reevaluate as one that’s now “gone far enough” to be classified at the species level. The alternative to recognizing it as an integral species is to call it an incipient species — but I think the word “species” is the best operative term in these cases of clear allopatry (no very close relative abutting) with evidence of divergence among populations.” Comments from Stiles: “YES. Evidence from morphology, ecology, biogeography and vocalizations all point to species status for griseipectus. I share Van’s misgivings in that there are a number of taxa in this group that might well be deserving of species status as well, but for which similarly detailed analyses are lacking. However, given that these occur in several different countries over a wide area, it seems unrealistic to expect a global solution to this problem in the near future, so perhaps a piecemeal approach on a case-by-case basis is the best one can hope for at present.” Comments from Schulenberg: “YES. I twice earlier voted in favor of recognizing griseipectus as a species (Proposals 181, 306B), and so just am sticking to my position.” |
