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Monroe 1990) based largely on unpublished data on pterylosis -- see summary in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:
http://www.tc.umn.edu/~barke042/pdfs/Barker04.pdf
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in the Troglodytidae was based on unpublished data, and it never should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.
Literature Cited:
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)
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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."