Proposal (#371) to
Split Phacellodomus ferrugineigula from P. erythrophthalmus
Effect on South American CL: This proposal would split Phacellodomus erythrophthalmus (Red-eyed Thornbird) into two species, P. erythrophthalmus and P. ferrugineigula.
Phacellodomus erythrophthalmus has two traditionally recognized subspecies: the nominate form of forest borders in eastern Brazil, and P. e. ferrugineigula of swampy areas and of more westerly distribution (Hellmayr 1925, Peters 1951, Meyer de Schauensee 1966, Pinto 1978, Sick 1985, Sibley & Monroe 1990, Sick 1993, Sick 1997, Dickinson 2003, Remsen 2003).
However, Simon et al. (2008) demonstrated that two taxa must be treated as distinct species based on clear differences in their external morphology, habitat, nesting, and vocalizations. The two taxa breed in sympatry in some areas of the Paraiba do Sul River valley (São Paulo and Rio de Janeiro states) and in eastern Minas Gerais, without evidence of intergradation between them.
The wholly reddish-chestnut color of the rectrices of P. erythrophthalmus versus the brownish-olive central rectrices of P. ferrugineigula, and the much darker red iris of the latter, are the principal diagnostic characters in external morphology. They serve well for species identification in the field.
Both taxa construct pendant nests in the shape of a retort. The nest of P. ferrugineigula is composed of leaves and stems of various types of grasses, resulting in a malleable and tightly woven structure, whereas the one built by P. erythrophthalmus is constructed of woody twigs, and is more robust and irregular.
Recommendation: As co-author of this article, I naturally recommend a "YES" vote on accepting this thornbird as a biological species to our list. Suggestion of new English names presented by Simon et al. (2008): Orange-eyed Thornbird to P. erythrophthalmus and Chestnut-eyed to P. ferrugineigula are pending of separate proposal.
Dickinson, E. C. (2003). The Howard and Moore Complete Checklist of the Birds of the World. Princeton, N. J.: Princeton Univ. Press.
Hellmayr, C. E. (1925). Catalogue of birds of the Americas and the adjacent islands in Field Museum of Natural History (C. B. Cory & C. E. Hellmayr, eds.). Part IV. Furnariidae - Dendrocolaptidae. Chicago: Field Museum of Natural History. [Zool. Series, Vol. XIII. Publ. 234]
Meyer de Schauensee, R. (1966). The birds of South America and their distribution. Philadelphia: Academy of Natural Sciences.
Peters, J. L. (1951). Check-list of birds of the world. Vol. 12. Cambridge, Mass.: Harvard University.
Pinto, O. M. O. (1978). Novo catálogo das aves do Brasil. Primeira parte. São Paulo: Empresa Gráfica da Revista dos Tribunais.
Remsen Jr., J. V. (2003). Family Furnariidae (ovenbirds). Pp. 162_357. In: Handbook of the Birds of the World, Vol. 8. Broadbills to tapaculos (J. del Hoyo, A. Elliot & D. Christie, eds.). Lynx
Sibley, C. G. e Monroe Jr., B. L. (1990). Distribution and Taxonomy of Birds of the World. New Haven: Yale Univ. Press.
Sick, H. (1985). Ornitologia brasileira, uma introdução. Brasília: Editora Universidade de Brasília. Vol. 2.
Sick, H. (1993). Birds in Brazil. A Natural history. Princeton: Princeton University Press.
Sick, H. (1997). Ornitologia Brasileira. Edição revista e ampliada por J. F. Pacheco. Rio de Janeiro: Nova Fronteira.
Simon, J. E., Pacheco, J. F., Whitney, B. M., Mattos, G. T. & R. L. Gagliardi (2008) Phacellodomus ferrugineigula (Pelzeln, 1858) (Aves: Furnariidae) é uma espécie válida. Revista Brasileira de Ornitologia 16(2):107-124.
José Fernando Pacheco, September 2008
Comments from Cadena: "YES. The maintenance of all these difference in sympatry implies these taxa are different species. Very nice paper, by the way."
Comments from Nores: "YES, especialmente por la simpatría en Sao Paulo, Rio de Janeiro y Bahia y por el tipo de nido. También en menor medida por el color. Lo del hábitat es relativo. Satrapa icterophrys hellmayri, por ejemplo, habita bosques de alisos en las montañas del noroeste argentino, mientras que Satrapa icterophrys icterophrys habita en las llanuras inundables del este de Argentina. Melanopareia maximiliani maximiliani frecuenta terrenos arbustivos húmedos de montaña en las Yungas de Bolivia, mientras que M. m. pallida frecuenta terrenos arbustivos xerófilos en las llanuras de Argentina y Paraguay. Aunque en la propuesta no se describen las diferencias en vocalizaciones, si lo hacen en la publicación, lo cual también apoya la idea de que son especies diferentes."
Comments from Zimmer: "YES. This change is long overdue, and the authors are to be congratulated for so nicely summarizing all of the various reasons why these two forms should be considered separate species. The vocal and morphological differences are pronounced, and the fact that the two forms occur syntopically at several sites without evidence of interbreeding, cinches the deal. I've recorded assortatively mated pairs of both species in the same marshes that respond aggressively to tape playback of their own voices, while completely ignoring tape of the other species.
"My only quibble would be with the proposed English names. Before the split, the species was known by the English name of "Red-eyed Thornbird". That was a misleading name, because erythrophthalmus has glaring yellow-orange eyes, and ferrugineigula, although arguably having dark reddish or reddish-brown eyes, doesn't look obviously red-eyed under typical field conditions. The authors suggest "Orange-eyed Thornbird" for erythrophthalmus, and that is probably the most appropriate and descriptive name. They propose "Chestnut-eyed Thornbird" for ferrugineigula. Although that name is not inaccurate, I would argue that it is not particularly helpful, since the color does not jump out at an observer under typical field conditions, when eye color of such a skulking bird typically just appears dark (dilated pupils of a bird buried in vegetation typically obscuring the chestnut color of the irides pretty effectively). Conversely, of all of the thornbirds, ferrugineigula is by far the most extensively rufescent, and the only one that is extensively ferruginous on the breast. I would suggest either "Ferruginous Thornbird" or "Ferruginous-breasted Thornbird", either of which would be much more descriptive, as well as being in agreement with the Latin name. This lacks the obvious symmetry with the name of erythrophthalmus that the authors obviously had in mind, but I think it would convey much more information. Since the split has just occurred, I don't think the name "Chestnut-eyed Thornbird" has gained any particular traction."
Comments from Robbins: "YES, Simon et al. have thoroughly documented why ferrugineigula deserves species rank."
Comments from Stiles: "YES. Maintenance of ecological, behavioral and morphological differences in sympatry mandate species status for both. (T'would be nice to have such data for other taxa in what seems to be a decidedly "over-lumped" genus)."
Comments from Schulenberg: "YES. The outlines of this story have been known for a long time; it's nice to see the argument for splitting these two taxa appear at last, and so well documented."