Proposal (98) to South American Classification Committee

Delete the family Coerebidae

Effect on South American CL: This proposal would delete the family-level taxon Coerebidae from our classification (and a subsequent proposal would determine the placement of Coereba).

Background: We currently follow the classification of the AOU (1998) and Dickinson (2003), which maintains the monotypic family Coerebidae for Coereba flaveola. The AOU (1998) maintained Coereba in its own family solely because of lack of information at that point as to its family assignment; the AOU (1983) and Ridgely & Tudor (1989) treated Coereba in a monotypic subfamily, with equivalent rank to tanagers (Thraupinae), in a broad Emberizidae. (The other genera in the Coerebidae/Coerebinae had already been placed in other families, primarily the Thraupidae).

New information: Two genetic data-sets (Sato et al. 1999, Burns et al. 2002, 2003) now show that Coereba is embedded in a clade of "island" taxa, most of which were formerly classified as sparrows (Emberizidae/Emberizinae): Euneornis, Loxigilla, Loxipasser, Melanospiza, Melopyrrha of the West Indies, Tiaris of primarily the Caribbean Basin, and all of the Geospizinae (Galapagos finches). Of these, only Euneornis was a member of an earlier constitution of the Coerebidae. Based in 1045 bp of cytochrome b, the bootstrap support value for this clade (parsimony /PAUP) in Burns et al. (2003) is 98%; the same group is supported by a 100% posterior probability value in a Bayesian analysis. Based on ca. 2000 bp of cytochrome b, plus ca. 1500 bp of numt2 and numt3, in Sato et al. bootstrap support for this group was 74% (parsimony/PAUP) and 77% (maximum likelihood/PAUP); Sato et al. did not have as complete a taxon-sampling as Burns et al. for the non-Galapagos taxa, but had more geospizines, including Pinaroloxias of Cocos Island.

Therefore, maintaining the family Coerebidae, as constituted solely by Coereba, is untenable.

Recommendation: Unless we wish to add all of the above taxa to the Coerebidae, we have to abandon family-level classification for Coereba. A YES vote for this proposal means only that we "do something" with Coereba other than keep it as a monotypic family. If this proposal passes, then I will do a subsequent proposal to deal with those options (other than keep monotypic Coerebidae), i.e., (a) move Coereba into our current Emberizidae next to Tiaris [minimum "disturbance" to classification but maximum perpetuation of a classification that maintains polyphyletic Emberizidae]; (b) placement of Coereba and all other taxa in this group in Incertae Sedis category in nine-primaried oscines; and (c) placement of Coereba and all other taxa in this group in the Thraupidae [probably most consistent with current genetic data].

Literature Cited

BURNS, K. J., S. J. HACKETT, AND N. K. KLEIN. 2002. Phylogenetic relationships and morphological diversity in Darwin's finches and their relatives. Evolution 56: 1240-1252.

BURNS, K. J., S. J. HACKETT, AND N. K. KLEIN. 2003. Phylogenetic relationships of Neotropical honeycreepers and the evolution of feeding morphology. J. Avian Biology 34: 360-370.

SATO, A., C. O'HUIGIN, F. FIGUEROA, P. R. GRANT, B. R. GRANT, H. TICHY, AND J. KLEIN. 1999. Phylogeny of Darwin's finches as revealed by mtDNA sequences. Proc. Nat. Acad. Sci. 96: 5101-5106.

Van Remsen, February 2004

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Comments from Zimmer: "YES. Evidence outlined by Van would seem to suggest that we have little choice here, and that the hard part will be figuring out what to do with Coereba once we've taken it out of its own family."

Comments from Stiles: "YES. The genetic data do seem convincing, and do resolve, at least in part, inconsistencies regarding nest type and placement that led me to recognize "Coerebidae" for Coereba in the Costa Rica guide. I am somewhat less convinced regarding placing Coereba et al. in the Thraupidae without more extensive taxon sampling. On the other hand, while perhaps more intuitively satisfying, placing the whole group in Emberizidae does not resolve problems of polyphyly (prob. more data needed here). "Incertae sedis" is intuitively irritating but perhaps more accurate given current uncertainties."

Comments from Nores: "Si. Aunque no tengo fundamentos propios para opinar sobre esto, pienso que los datos genéticos son bastante convincentes."

Comments from Jaramillo: "YES. Independent data sets saying the same thing. Bye-bye Coerebidae."