Proposal (552) to South American Classification Committee
Add subfamilies to Columbidae
Effect on SACC: This proposal would divide the South American
representatives of the family into two subfamilies.
Background & new information: Although many classifications have used
subfamily designations in the Columbidae, SACC has not, as explained in the
SACC footnote excerpt below. New
data, as also explained in the footnote, however, confirm that the Columbidae
contains three deeply divergent lineages that could be designated as
subfamilies:
Within the Columbidae, Goodwin (1983) recognized five subfamilies,
only one of which, Columbinae, occurs in the Western Hemisphere. These
subfamily designations do not correspond to deep splits in the family. In fact,
genetic data (Johnson 2004) indicate that the New World ground-doves are a
distinctive group that are the sister group to a large sample of Old World and
New World genera. SACC proposal passed to
change linear sequence of genera to the one used here. Pereira et
al. (2007) confirmed the distinctiveness of the New World ground doves but did
not find that they were the sister to all other columbids, but rather that the Columba group was; they also found
strong support for the sister relationship between Columbina and Metriopelia. Gibb and Penny (2010) also found that
the Columba group was sister to all
other pigeons. Proposal needed to recognize three subfamilies and to modify sequence
of genera.
Here is the Bayesian tree from Pereira et al. (2007):
Their maximum likelihood and maximum parsimony trees are
consistent with this one. Gibb and
Penny’s tree is consistent except that the support for Columbina (squammata) and
Claravis (pretiosa) as separate from the other Old World genera was not
solid. I can send pdfs of both paper
to anyone who needs them.
Discussion: We have no formal definition of “subfamily” beyond the
obvious, namely monophyletic groups within a family. Under “Taxonomy” in our Introduction, we have the following
statement: “Most traditional subfamilies are
omitted unless supported by multiple independent data sets that mark major,
deep branches within a family.”
Personally,
I increasingly see the value in emphasizing strong within-family monophyletic
groups with subfamily rank, particularly as confidence increases with better
and better DNA-based data. Not
only is it helpful to have official names for such groups, but the names
emphasize monophyletic groupings.
We have no objective definition of “major, deep”, but no one else does
either; in fact, objective definitions of any higher rank are largely
nonexistent. Regardless of rank,
marking the well-supported nodes with names increases the information content
of classification.
With
that preamble, I think the data sets of Pereira et al. (2007) and Gibb and
Penny (2010) indicate that the family contains at least three major divisions:
(1) Columbinae (Columba through Geotrygon in our list); (2) the New
World ground doves (Columbina through
Uropelia); and (3) Raphinae (all
remaining Old World genera except Streptopelia,
Nesoenas, Macropygia, Turacoena, Reinwardtoena; this group has a strongly
Indomalayan-Australasian biogeographic theme).
Now for
the bad part. After considerable
deliberation with colleagues Edward Dickinson and Dick Schodde, both of whom
are members of the Standing Committee on Ornithological Nomenclature of the
IOC, the name of the ground dove subfamily has to be Peristerinae, which
predates (Reichenbach, 1850) any group name derived from currently used
genera and has actually been in use relatively “recently” (I can send a Gifford
1941 reference if interested). I
don’t like the ICZN’s rules on group names, but that’s the way it is.
If we
accept the results of Pereira et al. (2007) and Gibb and Penny (2010), then we
should also use their results, i.e. Columbinae + (Peristerinae + Turturinae) in
sequencing the subfamilies, namely Columbinae first, not the New World ground
doves as in our current sequence.
Recommendation: I recommend a YES on the following change in classification:
Columbinae
Columba through Geotrygon
Peristerinae
Columbina, Claravis, Metriopelia, Uropelia
And if we ever get an introduced, established population of
one of those Old World tropical genera, or a vagrant Turtur,
then:
Raphinae (thanks to John Boyd for
pointing out that this is the oldest group name)
Literature:
GIBB,
G. C., AND D. PENNY. 2010. Two aspects along the continuum
of pigeon evolution: A South-Pacific radiation and the relationship of
pigeons within Neoaves. Molecular
Phylogenetics and Evolution 56: 698–706.
PEREIRA,
S. L., K. P. JOHNSON, D. H. CLAYTON, AND A. J. BAKER. 2007. Mitochondrial and
nuclear DNA sequences support a Cretaceous origin of Columbiformes and a dispersal-driven
radiation in the Paleogene. Systematic
Biology 56: 656–672.
Van Remsen,
October 2012
Comments from Zimmer: “YES.
I agree that there is value in
emphasizing strong, within-family monophyletic groups with formal names. Given that, the treatment advocated by
Pereira et al (2007) and Gibb and Penny (2010) appears to be the best path
forward, with three subfamilies recognized (only two of which pertain to the
SACC area of coverage).”
Comments from Stiles:
“A tentative YES. At least for the New
World, these two could easily be recognized. However, I note that one could as easily divide this group
into four subfamilies. There are
four well-defined clades separated by very short branch lengths (scarcely less
than the branches separating groups B and C) and with rather poor support a
several nodes, such that a two- subfamily grouping (Columbinae and
“everythingelsinae”) would do no violence to the facts.”
Comments from Nores: “NO, it doesn’t seem necessary. With this
criterion, we should be recognized subfamilies in many other families. For example Cracidae: 1) curassows,
2) chachalacas, 3) horned guan, 4) guans, and 5) Chamaepetes or 1) Chamaepeetes
and 2) everything else.”
Response
from Remsen:
There may indeed be many other major subdivisions within families that should
be recognized as subspecies, but we have to take them on a case-by-case basis.”
Comments from Robbins: “I’m apathetic with regard to the use of subfamily
names; not really much information is conveyed when one has a tree to
effectively illustrate relationships. Perhaps useful if one is using a
one-dimensional linear arrangement in a book. See my additional comments under proposal #s 555 and 560.”