Proposal
(274) to South American Classification Committee
Recognize
sister relationship between Podicipediformes and Phoenicopteriformes
Effect on SACC: This would move the two orders next to each
other in the linear sequence to recognize their sister relationship.
Background and New Information: The relationships of these
two orders to other bird groups have always been controversial -- see synopses
in our Notes section under each. Perhaps the single most-surprising result from
analyses of DNA sequence data so far has been the association of grebes with
flamingoes, first found by van Tuinen (2001) and subsequently also by three
independent genetic data sets (Chubb 2004a, Cracraft et al. 2004, Ericson et
al. 2006). One analysis of morphological data also supports this relationship,
but another (Livezey & Zusi 2007) does not. Recently, DNA sequence data
(Johnson et al. 2006) [let me know if you want a pdf] also showed that their ischnoceran
lice were sisters. Johnson et al. (2001) also cited a Bob Storer monograph on
grebe parasites to the effect that they shared parasites with flamingos.
Analysis and Recommendation: I vote YES because consistency
between multiple independent data sets is convincing to me that this
relationship is solid and needs to be recognized in our classification.
References:
CHUBB, A.
L. 2004a. New nuclear evidence for the oldest divergence among neognath birds:
The phylogenetic utility of ZENK (i). Molecular Phylogenetics and Evolution 30:
140-151.
CRACRAFT,
J., F. K. BARKER, M. BRAUN, J. HARSHMAN, G. J. DYKE, J. FEINSTEIN, S. STANLEY,
A. CIBOIS, P. SCHIKLER, P. BERESFORD, J. GARCÍA-MORENO, M. D. SORENSON, T.
YURI, AND D. P. MINDELL. 2004. Phylogenetic relationships among modern birds
(Neornithes): toward an avian tree of life. Pp. 468-489 in "Assembling the
Tree of Life" (Cracraft, J. and Donoghue, M. J., eds.). Oxford University
Press.
ERICSON, P.
G. P., C. L. ANDERSON, T. BRITTON, A. ELZANOWSKI, U. S. JOHANSSON, M.
KALLERRSJO, J. I. OHLSON, T. J. PARSONS, D. ZUCCON, AND G. MAYR. 2006.
Diversification of Neoaves: integration of molecular sequence data and fossils.
Biology Letters 2: 543-547.
JOHNSON, K.
P., M. KENNEDY, AND K. G. McCRACKEN. 2006. Reinterpreting the origins of
flamingo lice: cospeciation or host-switching? Biology Letters 2: 275-278.
LIVEZEY, B.
C., AND R. L. ZUSI. 2007. Higher-order phylogeny of modern birds (Theropoda,
Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion.
Zoological J. Linnean Society 149: 1-95.
MAYR, G.
2004. Morphological evidence for sister group relationship between flamingos
(Aves: Phoenicopteridae) and grebes (Podicipedidae). Zoological J. Linnean
Society 140: 157-169.
VAN TUINEN,
M., D. B. BUTVILL, J. A. W. KIRSCH, AND S. B. HEDGES. 2001. Convergence and
divergence in the evolution of aquatic birds. Proceedings Royal Society London
(Biological Sciences) 268: 1345-1350.
Van Remsen, May 2007
_______________________________________________________________________________________________
Comments from Stiles: "YES. Multiple data sets
support this. Place them together in the sequence, I´d suggest
grebes-then-flamingoes as representing the least drastic change (but this is
clearly a minor point)."
Comments from Cadena: "YES. The sister
relationship between these two clades appears to be strongly supported. Perhaps
we could add an additional citation to the proposal or to the notes on the SACC
site: Sangster, G. 2005. A name for the flamingo-grebe clade. Ibis 147:612-615.
This author presented a review of the evidence, listed synapomorphies for the
group, and proposed to name it "Mirandornithes". Although Sangster's
naming of the clade was based on the principles of "phylogenetic
taxonomy" (i.e. PhyloCode), he suggested that under the Linnean system,
this clade could be ranked at the superorder level (I'm not sure if the SACC
will deal with categories like superorders)."
Comments from Robbins: "YES, given the independent
data sets that support this change."
Comments from Pacheco: "YES. Diversos estudos independentes dão um suporte
contundente a esta proposição. Aproveitando da questão colocada por
Cadena, é oportuno lembrar que o sufixo de "Mirandornithes"
Sangster, 2005 parece sugerir Subclass (vide A.O.U 1999)."
Comments from Nores: "NO. Y no es porque esté en total desacuerdo con la propuesta, sino porque
veo una marcada tendencia en el "SACC Committee" a considerar todo lo
molecular como infalible e irrefutable. Después de leer el paper de Livezey
& Zusi (2007), en particular los árboles de las Figs. 1-9, y especialmente
el estudio molecular de Mindell et al. (1997) (Fig. 4) pienso que la veracidad
de los estudios moleculares es relativa. Por ejemplo, Van Tuinen et al. (2000),
ponen los Podicipedidae junto con Cuculidae y muy cerca de Charadriidae y en el
2001 (sólo un año después) los ponen junto con Phoenicopteridae y muy lejos de
Charadriidae (Fig. 6A, B). Yo pienso que hay que tener en cuenta el paper de
Livezey & Zusi antes de seguir con las propuestas y repuestas. A continuación,
he puesto algunos párrafos que aparecen en Livezey & Zusi que me parecen
importantes.":
"In
the published record of phylogenetics, it has become virtually customary simply
to generate phylogenetic hypotheses of varying consonance with little or no
consideration of factors underlying divergent inferences. This tradition has
led to a false sense of congruence among studies, especially among molecular
systematists. There was considerable disagreement among recent molecular
studies alone (e.g. Espinosa de los Monteros, 2000; Johansson et al.,
2001; Poe & Chubb, 2004), regardless of data analysed (Philippe et
al., 1996; Graur & Li, 2000), which reveals contrasts only between
morphological and molecular inferences to be over simplifications of modern
study (e.g. Braun & Brumfield, 1998; Van Tuinen, 2002). Studies based both
on molecular and morphological phylogenetics (Figs 1-9) manifest substantial
disagreement both within and between schools.
We do not intend an assault on molecular methodology, but seek to refute
persistent prejudices that afflict morphological phylogenetics. At present,
molecular systematics is characterized both by the coexistence of general (if
not unbridled) optimism (Van Tuinen, 2002) and by profound doubts regarding
resolution of substantial segments of neornithine phylogeny (Poe & Chubb,
2004). Perhaps the deficiency attributed most widely to morphological
phylogenetics stems from suspicions of morphological convergence, concerns
seldom empirically substantiated and to which molecular methods are widely
assumed to be immune. Without a consensus regarding a relationship between the
Podicipedidae and Gaviidae, the former have been the subject of several
extraordinary proposals, based on relatively weak evidence or mere speculation.
See also Bourdon et. al (2005)."
Comments from Jaramillo: "YES - Manuel's point is
well taken, but it is hard to refute independent molecular data sets, as well
as lice data. The two groups are not obviously related to anything else, so
form that perspective, anything is possible. The long-held relationship of
Gaviidae to Podicipedidae did not make much sense to me, no more than
Podicipedidae to any other swimming bird. The two are actually quite different.
In terms of courtship, I have no idea if anyone has done any work, but some of
the synchronized swims by grebes, and walks by flamingos are actually somewhat
similar, including mechanical head turning and following behavior."