Proposal (502) to South American
Classification Committee
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 São Paulo, and was found around the city
of Mogi das Cruzes, São 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 São 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).
Literature
Cited:
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 Ciências, 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 simpatría
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-Emán: “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.”