Proposal (804) to South American
Classification Committee
Reorganize the
taxonomic ranks within Accipitridae
Effects
on South American CL:
This proposal would reorganize the taxonomic ranks within Accipitriformes based
in a more appropriate interpretation of available data.
Background: Currently SACC
classifies diurnal raptors in three separate orders: Cathartiformes,
Accipitriformes and Falconiformes, based on the results of recent molecular
studies. Thus, the families Cathartidae, Accipitridae and Falconidae, ascends
to ordinal rank. Accipitridae is the most diverse clade of diurnal raptors,
with more than 200 species of a great variety of sizes, morphology, diets and
lifestyles. Many recent phylogenetic analyses confirm that Accipitridae
contains several deeply divergent linages, which have been designated as
subfamilies, tribes and subtribes, depending on the different interpretations. Up
to date, SACC recognize that Accipitriformes include only two families in South
America: Pandionidae and Accipitridae, which is divided into three subfamilies,
following (with some modifications) Griffiths et al. (2007).
New
information:
According to some previous studies, Accipitridae contains from eight (Griffiths
et al. 2007), to twelve separated
linages (Lerner & Mindell 2005). Most recent data show ten recognizable
linages (Barrowclough et al. 2014,
Nagy & Tokolyi 2014). In addition, Jarvis et al. (2014) recognize the superorder Accipitrimorphae, which contains Cathartiformes and
Accipitriformes.
Recommendation: Modern taxonomy should
reflect phylogenetic relationships between taxa, and at the same time most be
pragmatic. The current classification of
major clades, such as orders, is more pragmatic, and do not reflect necessarily
the time in which those groups radiate (all the orders differ of each other at
different times). In my view, that pragmatic practice should be used also in
lower classification levels such as families. Up to now, everything
seems to indicate that the extraordinary diversity within Accipitridae is
masked by the presence of Pandionidae and Sagitariidae
as families, which forces to subdivide the other groups of more recent diversification.
Since many general publications do not include the last
branches of the cladograms (subfamilies, tribes, etc.), this diversity remains
invisible to the eyes of most readers. As an example, for any of us an Elanus kite does not seem to be part
from the same family of a Spizaetus
eagle, or does it? Think in that way, this obviously is only a problem of focus rather than of phylogenetic relationships.
Remembering that you modified the Griffiths´ nomenclature from Tribes to
Subfamily, I suggest that a better classification is ascending all subfamilies
to family rank, maintaining Pandionidae as a family or, alternatively,
ascending it to ordinal rank, sister to Accipitriformes, forming the superorder
Accipitrimorphae, which also include Cathartiformes
(Jarvis et al. 2014), but I think the
first proposition is better. I recommend recognizing at least six families
(plus Pandionidae) within Accipitriformes following Nagy & Togolgyi (2014): Accipitridae (Accipiter and Circus), Aquilidae (Spizaetus),
Buteonidae (Busarellus,
Buteo, Buteogallus, Geranoaetus, Geranospiza, Ictinia, Leucopternis, Parabuteo,
Rupornis and Rostrhamus), Elanidae (Elanus
and Gampsonyx), Harpiinae
(Harpia and Morphnus) and Perninae (Chondrohierax, Elanoides and Leptodon). These authors recognize other
four groups that have not representatives in South America: Aegypiidae,
Gypaetidae, Heliaeetinae
and Circaetidae.
Literature
Cited:
Barrowclough, G. F., J.
G. Groth, J. E. Lai & S. M. Tsang. 2014. The phylogenetic relationships of
the endemic genera of Austral-Papuan hawks. Journal
of Raptor Research. 48(1): 36-43.
Griffiths, C. S.,
Barrowclough, G. F., Groth, J. G. & Mertz. L. A. 2007. Phylogeny,
diversity, and classification of the Accipitridae based on DNA sequences of the
RAG1 exon. – Journal of Avian Biology 38:
587–602. DOI: 10.1111/j.2007.09088857.03971.x
Jarvis, E. et al. 2014. Whole-genome analyses
resolve early branches in the three of life of modern birds. Science. 346 (6215): 1230-1331.
Lerner, H.R.L. &
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.
Nagy, J. & J. Tokolyi. 2014. Phylogeny, historical biogeography and the
evolution of migration in accipitrid birds of prey (Aves: Accipitriformes). Ornis Hungarica.
22(1): 15-35.
Tomás Rivas-Fuenzalida, August 2018
Comments
from Remsen:
“NO. All of these groups have formal
names already, and no objective rationale is presented for why they should be
changed.”
Comments
from Areta:
“NO. I don´t see anything wrong in the families of the Accipitriformes as
currently defined and sub-familial and generic groupings seem good enough to
sort out variation within Accipitridae.”
Comments from Stiles: “NO. The fact that there are
several well-defined, speciose clades in Accipitridae does not in itself
justify elevating then to family rank, much less elevating Accipitridae to
ordinal rank. Rivas himself admits that there is considerable heterogeneity in
the age of splits among these clades, and this is where (if anywhere) standardization
of higher taxonomic ranks should be attempted. Moreover, phenotypic differences
do not always correlate with phylogenetic age in rapidly radiating clades, and
this could well be true among raptors, predatory specialists high on the food
chains. The present division of Accipitridae into subfamilies adequately
expresses diversity in this family.”
Comments from Claramunt: “NO. Although Accipitridae is
very diverse, I don’t see compelling arguments supporting the proposed change,
in particular, I don’t see substantial phenotypic gaps between the proposed families.
Subfamily and tribe categories take care of subdividing the main subgroups.”
Comments from Pacheco: “NO. I consider the subdivision in sub-families and tribes
as satisfactory for recognized groups.”
Comments
from Zimmer:
“ “NO. I would echo all of Gary’s
comments on this, particularly regarding the considerable heterogeneity in the
age of splits among the various clades, and the point that phenotypic
differences do not always correlate with phylogenetic age in rapidly radiating
clades. I would also have to say that
I’m with Santiago in not being particularly impressed with the implied
phenotypic gaps between most of the proposed families. Existing subfamily, tribe and generic
groupings already adequately frame the diversity within Accipitridae as far as
I’m concerned.”
Comments
from Robbins:
“NO. Comments by Gary and Santiago underscore why
this is not necessary.”
Comments
from Stotz:
“NO I don’t see anything to be gained by
raising the subfamilies within Accipitridae to family level.”