Split Sporophila pileata from S. bouvreuil
Effect on South American CL: This proposal would split Sporophila bouvreuil (Capped Seedeater) into two species, S. bouvreuil and S. pileata.
Background: Four taxa of Capped Seedeater (Sporophila bouvreuil) have been traditionally accepted: S. b. bouvreuil, S. b. pileata, S. b. saturata and S. b. crypta. The nominate form occurs in open areas from N. South America to central and southern Brazil; S. b. pileata is found in C. and SE. Brazil, as well as in Paraguay and Argentina; S. b. saturata occurred near Ipiranga, a part of the city of Sčo Paulo, and was found around the city of Mogi das Cruzes, Sčo Paulo State; and S. b. crypta is endemic to the state of Rio de Janeiro (Meyer de Schauensee 1952, 1966; Sick 1967, 1997; Ridgely & Tudor 1989; Stotz et al. 1996; Machado & Silveira 2010).
New information: Morphometric data did not show significant differences among these taxa, and only S. b. bouvreuil and S. b. pileata were fully diagnosable by plumage. Because S. b. bouvreuil, S. b. saturata, and S. b. crypta were not diagnosable based on morphometric or plumage coloration, Machado & Silveira (2011) also proposed that those taxa should be synonymized into Sporophila bouvreuil (Müller, 1776).
Machado & Silveira (2010) identified two areas of sympatry between S. bouvreuil and S. pileata in localities in western Minas Gerais, as well as in western and southeastern Sčo Paulo State. The sympatry reveals that two species should be recognized under any species concept. Based on those results, Machado e Silveira (2011) proposed that S. b. pileata should be considered a full species, namely Sporophila pileata (Sclater, 1864).
Machado, E. & Silveira, L.F. (2010) Geographical and seasonal distribution of the Seedeaters Sporophila bouvreuil and Sporophila pileata (Aves: Emberizidae). Papéis Avulsos de Zoologia, 50 (32):517-533.
Machado, E. & Silveira, L.F. (2011) Plumage variability and taxonomy of the Capped Seedeater Sporophila bouvreuil (Aves: Passeriformes: Emberizidae). Zootaxa, 2781: 49-62.
Meyer de Schauensee, R. (1952) A review of the genus Sporophila. Proceedings of the Academy of Natural Sciences of Philadelphia, 104, 153–196.
Meyer de Schauensee, R. (1966) The species of birds of South America with their distribution. Philadelphia: The Academy of Natural Science of Philadelphia. 577 pp.
Müller, P.L.S. (1776) Natursystem Supplementum, 154 pp.
Ridgely, R.S. & Tudor, G. (1989) The birds of South America. vol. I. Oxford: Oxford University Press.
Sclater, P.L. (1864) Descriptions of seven new species of birds discovered by the late Dr. John Natterer in Brazil. Proceedings of the Zoological Society of London, 607 pp.
Sick, H. (1967) “Bico de Ferro” – Overlooked Seedeater from Rio de Janeiro (Sporophila, Fringillidae, Aves). Anais da Academia Brasileira de Ciźncias, 39, 307–314.
Stotz, D.F., Fitzpatrick, J.W., Parker III, T.A. & Moskovits, D.K. (1996) Neotropical Birds: Ecology and Conservation. Chicago: University Chicago Press.
Erika Machado & Luís Fábio Silveira, September 2011
Comments from Stiles: “YES – given the sympatry, pileata is best considered a species apart from bouvreuil.”
Comments from Pacheco: “YES. Em vista da simpatria entre os dois táxons mencionados, apresentada e discutida no corpo do trabalho, considero a proposta perfeitamente coerente,“
Comments from Cadena: “YES, but with some doubt. Sympatry of forms without evidence of intergradation would generally convince me we are dealing with different species, but given recent studies showing that reasonably discrete "morphs" exist within populations of Sporophila seedeaters (papers by Areta and othes) I am a little wary. Could someone comment on the possibility that these may represent conspecific morphs as documented for other cases? I realize this is unlikely considering they are allopatric in a large portion of their range (thus my vote), but I am curious to know whether the authors have considered the possibility.”
Comments from Pérez: “A tentative YES. I think Machado and Silveira provided enough information to support species status for both pileata and bouvreuil, highlighting patterns of plumage variation and Campagna et al (2010)’s results of intraspecific genetic divergence (based on a small number of samples). As Daniel pointed out, decisions on species level in this genus are complex, especially when we are based mostly on patterns of plumage color. A mostly allopatric distribution argues in favor of recognizing both pileata and bouvreuil; however, the map on Fig. 4 of Machado and Silveira (2010) shows a larger plumage color diversity in the contact or sympatry zone, and most of the pinkish gray birds are found there, which one could argue represent intermediate plumage patterns (?). Also, no information on songs and habitat specificity is provided for these forms, an important piece of information to understand plumage patterns in this genus as shown in other studies. Actually, this extra piece of information might end to be more critical for supporting inclusion of bouvreuil, crypta, and saturata in one form than as evidence against the split of the nominal species in two. Comments from Nacho Areta, a person with large field experience in this genus, might be appropriate to evaluate this proposal.”
Comments from Jaramillo: “YES – The sympatry is the part that sold the idea of a split for me. Regarding morphs, all of the known morphs in the “Capuchino” Seedeaters, recently described, or re-defined (Narosky’s) are present entirely within the range of the primary morph, and they are quite rare overall. Thus far, no geographically separated morph that is partially sympatric with the other morph exists. So this pattern appears to be entirely different in characteristics from the ever-growing cadre of morphs in the “Capuchinos”.”
Comments from Zimmer: “YES. I think that Alvaro’s comments regarding the distribution pattern of these two forms (i.e. largely allopatric, but with a couple areas of sympatry) relative to that of other Sporophila species with known morphs (the less common morph rare overall, and completely nested within the range of the more common morph) are spot-on.”