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., :
Elanus
Gampsonyx
Chondrohierax
Leptodon
Elanoides
Rostrhamus
Helicolestes [not sampled in either study]
Harpagus
Ictinia
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.
Lit Cit
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.”