Proposal (384) to South American Classification Committee
Effect on SACC: This move the positions of several genera in our current linear sequence.
Background: Our current linear sequence is the product largely of historical momentum and interpretations of comparative morphology. The kite genera are placed first, followed by the accipiters and kites, then the buteonines, and then the eagles.
New data: Lerner & Mindell (2005) sampled members of all 14 subfamilies in the Peters Check-list using about 2100 bp of mtDNA and nuclear DNA (beta-fibrinogen intron 7). They found that the various kite subfamilies were not each other’s closest relatives. Specifically,
• Elanus was sister to all other Accipitridae (100% Bayesian support)
• Elanoides, Chondrohierax, and Leptodon were members of a strongly supported (100% Bayesian support) clade that included many Old World genera
• Rostrhamus was nested in the Buteoninae
Griffiths et al. (2007) also sampled sequenced 2872 bp of the nuclear gene RAG-1 for members of 8 subfamilies, none of which they found to be monophyletic (a good illustration of why SACC should remain very conservative in adopting this category from traditional sources). Therefore, the results of this study represent an independent assessment. These results were concordant with those of Lerner & Mindell, namely:
• Elanus + its sister Gampsonyx were sister to all other Accipitridae (95% ML bootstrap support)
• Elanoides and Leptodon were members of a strongly supported (94% ML bootstrap support) clade that included many Old World genera
• Harpagus, Rostrhamus, and Ictinia are nested within a large group that is strongly supported (95% ML bootstrap support) that includes Accipiter, Circus, Busarellus, and all the buteonines, to name a few; each falls in a different position, but none of the internal nodes receives strong support.
Analysis and Recommendation:
Because our sequence does not include Old World genera, to make our linear sequence correspond to the best available hypotheses on the relationships within the family requires only a minor change, namely moving Elanus + Gampsonyx first. i.e., :
Helicolestes [not sampled in either study]
This only aims to rearrange our current sequence of kites to the extent of moving Elanus and Gampsonyx first. This is not attempt to fix the positions of Harpagus, Ictinia, and Rostrhamus, which you will note are almost certainly deeper in the true sequence. However, their positions are best left to a subsequent proposal, perhaps one that will need better taxon sampling.
I recommend a YES on this one – it doesn’t get much better than two concordant independent data sets.
GRIFFITHS, C. S., G. F. BARROWCLOUGH, J. G. GROTH, AND L. MERTZ. 2007. Phylogeny, diversity and classification of the Accipitridae based on DNA sequences of the RAG-1 exon. J. Avian Biology 38: 587-602.
LERNER, H. R. L., AND D. P. MINDELL. 2005. Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA. Molecular Phylogenetics and Evolution 37: 327-346.
Van Remsen, November 2008
Comments from Stiles: “YES. Having two concordant multigene studies is sufficiently convincing evidence for this change, especially as the changes required are not that profound however, I get the intimation that at some point Harpagus, Ictinia, Rostrhamus and (presumably) Helicolestes may be off to different destinations among the hawks in the near future – and note that Harpagus is not included in the proposed new sequence (¿qué le pasó?).”
Comments from Nores: “YES. Aunque me pregunto sino debería también incluir a Geranospiza caerulescens como parecen indicar los análisis moleculares de Lerner y Mindell (2005) y de Griffiths et al. (2007).”
Comments from Jaramillo: “YES – Two concordant datasets are good to have. Also understood is that some of these taxa may move deeper into the Accipitridae in the future.”
Comments from Zimmer: “YES, with the understanding that we are only really dealing with the basal position of Elanus/Gampsonyx relative to everything else.”
Comments from Pacheco: "YES. Corroborado por dois independentes trabalhos.”