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 has 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 studiesalone (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."