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
_____________________________________________________________________________________
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."