Proposal
(133) to South American
Classification Committee
Remove
"Schiffornis group" from Cotingidae
Effect on SACC: This
would remove the genera Tityra, Schiffornis, Laniocera, Iodopleura,
Laniisoma, Xenopsaris, and Pachyramphus from the Cotingidae.
Background: The above
genera have been shuffled between Tyrannidae and Cotingidae for much of this
century. See Prum & Lanyon (1989) and Prum (1990) for a review. Prum &
Lanyon's 1989) and Prum's (1990) analyses of morphological data were
sufficient to convince some (e.g. AOU 1998) to place them as Incertae Sedis
until their relationships were resolved. Then, Prum et al.'s (2000) analysis of
mtDNA sequence data placed them within a broadly defined Cotingidae, and that's
why and where they reside in our current sequence.
New data:
Johansson et al.'s (2002) analysis of mitochondrial and nuclear DNA sequences
(but with perhaps the all-time extreme in limited taxon-sampling) found little
or no support for a sister relationship between the Schiffornis group
(represented by Schiffornis, Pachyramphus, and Tityra)
and core cotingas (represented by Pyroderus).
Chesser (2004) used DNA
sequence data (mt and nuclear) from a broader range of taxa and found that
the Schiffornis group (represented by the same 3 genera above plus Laniocera and Iodopleura)
was not the sister group to core cotingas (represented by Rupicola and
Procnias) nor to the Tyrannidae (the traditional alternative), but
rather to the Pipridae (bootstrap support 84% with maximum likelihood).
In both cases, support was
strong for monophyly (albeit with limited taxon-sampling) of the Schiffornis
group.
Analysis: The
basis for inclusion of the Schiffornis bunch in the Cotingidae is Prum et al.
(2000). I think that Rick would be the first to point out that Prum et al.'s
(2000) analysis would not be publishable now because only 375 bp of sequence
were analyzed (vs. 1000++ for such analyses "nowadays"). Furthermore,
they analyzed only cytochrome b, whose utility at higher-level systematics may
be limited, and did not report bootstrap values. Although they concluded that
the Schiffornis group should be included as a subfamily of the Cotingidae, the
node supporting this (vs. relationship to Pipridae or Piprites) has
essentially no support in their analysis, and no Tyrannidae were included in
the analysis.
Given the two more recent
studies above and given that Rick's previous morphological studies did not find
strong support for inclusion of these genera in the Cotingidae, my conclusion
is that we essentially have no data to support the current classification and
plenty of contrary data.
Recommendation: I vote
YES on this because the combination of recent genetic and morphological
evidence reduces our evidence for their inclusion in Cotingidae to near zero.
If the proposal passes,
then we have to decide WHERE to place these genera. I'll do a separate proposal
for that. The only two options that I see are to place them in our suboscine
Incertae Sedis (as in AOU 1998 and currently occupied only by Piprites in
SACC) or to create a family-level taxon for them (Tityridae).
Literature Cited
CHESSER,
R. T. 2004. Molecular systematics of New World suboscine birds. Molecular
Phylogenetics and Evolution 32: 11-24.
JOHANSSON,
U. S., M. IRESTEDT, T. J. PARSONS, AND P. G. P. ERICSON. 2002. Basal phylogeny
of the Tyrannoidea based on comparisons of cytochrome b and
exons on nuclear c-myc and RAG-1 genes. Auk 119: 984-995.
PRUM,
R.O. 1990. A test of the monophyly of the manakins (Pipridae) and of the
cotingas (Cotingidae) based on morphology. Occ. Papers Museum of Zoology, Univ.
of Michigan 723: 1-44.
PRUM, R.
O., AND W. E. LANYON. 1989. Monophyly and phylogeny of the Schiffornis group
(Tyrannoidea). Condor 91: 444-461.
PRUM,
R.O., N. H. RICE, J. A. MOBLEY JA, AND W, W. DIMMICK. 2000. A preliminary
phylogenetic hypothesis for the cotingas (Cotingidae) based on mitochondrial
DNA. Auk 117: 236-241.
Van
Remsen, September 2004
_____________________________________________________________________________________
Voting chart for SACC proposals 100-218
Comments from Stiles:
"YES. I agree that the best current evidence indicates that these birds
are neither cotingids nor tyrannids. I would not be unhappy with Tityridae
(presumably Piprites would also fall here? In its singing
behavior it reminds me somewhat of Laniocera)."
Comments from Robbins:
"YES; Chesser's molecular data are convincing."
Comments from Nores:
"YES, aunque esta propuesta me resulta un
poco extraña debido a que nunca observe que el género Schiffornis estuviera
en Cotingidae o Tyrannidae. Yo siempre lo vi ubicado en Pipridae. De todos
modos, si considero que Schiffornis group debe ser removido de
Cotingidae. Los datos modernos de Johansson (2000) y Chesser (2004), parecen
tener mucho más fundamento que aquellos de Prum y Lanyon."
Comments from Silva:
"Yes. I think that a family-level new group (Tityridae) should be the best
option given the uncertainties associated with this problem."
Comments from Zimmer:
"I vote "YES". No real evidence for maintaining these within
Cotingidae. I also think that given the evidence for monophyly within the
Schiffornis group (even if all genera weren't included in the analysis), the
best thing to do is to create a new family-level grouping (Tityridae), possibly
to include Piprites."
Comments from Stotz:
"YES. The basis for placing the Schiffornis group within Cotingidae was
always very weak, so weak that the Northern AOU never followed Prum 2000
treatment. The mitochondrial DNA sample was too limited, and it has become
clear that cytochrome B is not very useful at this taxonomic level. My personal
feeling is that the current data really suggests that a new family, Tityridae,
is the way to go."
Comments from Pacheco: "[YES] Após analisar as informações disponíveis,
o CBRO (o que coordeno) também acatou estar emoção e, adicionalmente, decidiu
adotar a família Tityridae Gray para acomodar melhor a presente situação."