Proposal (118) to South American Classification Committee
Remove Donacobius from the Troglodytidae
Effect on South American CL: This would remove a species from the Troglodytidae and place it as Incertae Sedis.
Background: Donacobius atricapilla was formerly (e.g., Meyer de Schauensee 1970) placed in the Mimidae until transferred to the Troglodytidae (AOU 1983, Sibley & Monroe 1990) based largely on unpublished data on pterylosis -- see summary in Barker (2004).
New information: Barker (2004) found strong support for removal of Donacobius from the Troglodytidae and placing it somewhere in the Old World Sylvioidea assemblage. Barker's data, sequence data from mtDNA (cytochrome b) and nuclear DNA (intron 4 of beta fibrinogen), show that the Troglodytidae in their traditional sense are more closely related to Polioptilidae, Certhiidae, and Sittidae than they are to Donacobius. The latter groups with Prinia (Old World "warbler") and Zosterops with high bootstrap and Bayesian support, but further taxon-sampling in that diverse Old World assemblage is required before any familial assignment is possible.
Get a pdf of Barker (2004) at:
Analysis: Barker's genetic data show that Donacobius is neither a wren nor a mimid, but belongs in some "Old World" sylvioid group (to be determined). To retain it in the same monophyletic family as the Troglodytidae would require a massive merger of "Passerida" families into one. Inclusion of Donacobius in the Troglodytidae was based on unpublished data, and it never should have been transferred there, although evidence for its retention in the Mimidae was equally lacking in evidence. Donacobius is a truly enigmatic taxon whose relationships, once elucidated, will be a biogeographical blockbuster.
Recommendation: I see no reason to perpetuate a misleading classification any longer and see no reason to vote any other way than YES.
BARKER, F. K. 2004. Monophyly and relationships of wrens (Aves: Troglodytidae): a congruence analysis of heterogeneous mitochondrial and nuclear DNA sequence data. Molecular Phylogenetics and Evolution 32: 486-504.
Van Remsen, April 2004 (in consultation with Keith Barker)
Comments from Jaramillo: "YES _ It is definitely the correct course of action here."
Comments from Stiles: "Although frustrating, incertae sedis seems the only alternative in accord with the evidence (or lack thereof), so YES.
Comments from Zimmer: "YES. I'd rather treat it as incertae sedis than continue to perpetuate what seems to be an obvious error."
Comments from Robbins: "YES, for removing Donacobius from the Troglodytidae. Barker's data unequivocally demonstrate that Donacobius is not a wren nor a mimid."
Comments from Nores: "SI, estoy de acuerdo. Los datos provenientes de dos tipos de análisis moleculares: mtDNA (cytochrome b) y nuclear DNA (intron 4 of beta fibrinogen), parecen ser concluyentes en este aspecto."