Proposal (233) to South American Classification Committee
Include Oroaetus
isidori and Spizastur melanoleucus in Spizaetus
The proposed change would subsume both monotypic genera Oroaetus
and Spizastur into Spizaetus to indicate the close relationship
and monophyly of the New World hawk-eagles.
Two independent DNA sequence data studies (involving a combined
three mitochondrial & four nuclear genes; Helbig et al. 2005, Lerner and
Mindell 2005) concluded that Spizaetus ornatus and Oroaetus isidori
are sister species, and Spizastur melanoleucus is sister to those two
species. The Black Hawk-Eagle (Spizaetus tyrannus) is “basal” to the
entire clade. The Old World "Spizaetus" are not sister to the
New World Spizaetus (S. ornatus has priority for this
generic name, as subsequently designated by Vieillot 1816). An earlier
morphological data set indicated that New and Old World Spizaetus were
not sisters (Jollie 1976-1977). As a result of these data, Helbig et al. (2005)
formally proposed that the four New World taxa be included in Spizaetus.
Given that two independent genetic data sets, both with strong
nodal support, clearly indicate that the two genera Oroaetus and Spizastur
are imbedded within the New World hawk-eagle clade, I strongly support this
change.
If the above taxonomic treatment is accepted then the following
linear sequence should be adopted:
Spizaetus tyrannus
Spizaetus melanoleucus
Spizaetus ornatus
Spizaetus isidori
References:
Helbig,
A.J., A. Kocum, I. Seibol, M.J. Braun. 2005. A multi-gene phylogeny of aquiline
eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level.
Molecular Phylogenetics & Evolution 35:147-164.
Jollie, M.
1976-1977. A contribution to the morphology and physiology of the Falconiformes.
Evol. Theory 1, 285-298; 2, 115-300; 3, 1-141.
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 & Evolution
37:327-346.
Mark
Robbins, August 2006
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Comments
from Remsen:
"YES. Concordant, independent data-sets make this decision
noncontroversial."
Comments
from Cadena:
"YES. The genetic data from multiple loci in both genomes leaves no doubt
that a rearrangement needs to be done, and placing these taxa in Spizaetus
is necessary because S. ornatus is the type species of the genus.
Although with this we would make the Spizaetus in our region a
monophyletic group, the problem of the polyphyly of Spizaetus won't
be solved until Old World species are transferred to a different genus."
Comments
from Stiles:
"YES. Both genetic and morphological data clearly support this move."
Comments
from Zimmer:
"YES. This doesn't resolve the problem of the relationship of Old World Spizaetus,
but at least it tidies up the Neotropical picture."
Comments
from Stotz:
"YES. Molecular data looks clear."
Comments
from Jaramillo: "YES. Superb to have independent data sets to support this,
apart from the fact that it makes sense on many levels. The question of what to
do with the Old World Spizastur is not our job, so that doesn't concern
me other than I hope it is clarified by appropriate authorities."
Comments
from Pacheco:
"YES. Os dois trabalhos, de forma independente,
são claros em apontar o mesmo melhor arranjo."