|A. Reading from the bottom up, and recognizing that we are looking
only at the Oscine Passerine trunk of the tree, we see the first major
branch goes to the corvoid assemblage, including a "crown" Corvida — a
huge set of bird families that include crows,, birds-of-paradise, shrikes,
and vireos. Here is our first major surprise. The bird know as White-bellied
Yuhina — and even listed among the genus Yuhina within the Babblers — is
not even close to babblers! It should be called White-bellied Erpornis
Erpornis zantholeuca and assigned to the Corvida (Cibois 2003).
It is most closely related to Vireo;, I've assigned it to its own family
on my family listing
for the time being. Whether other, unstudied "babblers" or other birds
belong here is yet to be determined.
B. Next thing up the tree is a side-branch to the Rockjumpers,
endemic to South Africa. [Cape Rockjumper is shown; hereafter, please refer
to the discussion
of the "old" tree for a key to photographs]. The Rockjumpers were usually
listed as Babblers or Thrushes but they are not close to either. There
are their own distinct group that diverged from the main Passerine tree
about 45 million years ago (Barker et al. 2004, Cracraft et al. 2004).
The Picathartes Rockfowl (2 species in tropical Africa; not
pictured) also diverged at this time, and the split from the Rockjumpers
about 31 million years ago (Beresford et al. 2005). It is obvious to me
that each deserve their own family ranking. Two other strange 'babblers'
or 'thrushes'— Spot-throat Modulatrix stictigula and Dapple-throat
orostruthus, from the Tanzania mountains [not pictured] — remain enigmatic.
Some studies suggest they are most closely related to the Sugarbirds of
South Africa [Promeropidae] but others found that "although it was not
statistically rejected ... additional data ... are clearly needed in order
to evaluate the validity of this 'clade' of very different-looking birds"
(Fuchs et al. 2006).
C. Slightly up the Passerida tree are two small branches, to
and to Hyliotas. Kinglets seem to "jump around" in the taxonomic
tree, depending on the methodology used, and so are just tentatively placed
here, near the base of the Passerids, pending further research (Jønsson
& Fjeldså 2006). The Hyliotas of Africa have recently
been shown to be a very isolated deep branch of the Passerida (Fuchs et
al. 2006); it seems likely they will achieve family rank if these data
D. We now come to the major three-way division of the Passerines
into Muscicapoidea (green background), Sylvioidea (blue background), and
Passeroidea (yellow background). There are many new research findings of
interest in each of these three groups but, for this discussion, we focus
only on those that impact the 'old' Sylviidae family. The Gnatcatchers
are not Sylvids but are closer to Wrens and Nuthatches, and these families
(along with Dippers) are on the Muscicapid branch, and thus not close to
the Tits & Chickadees (Paridae) as they were thought to be before.
E. Finally our tree climbs into the Sylvioidea, the group of
birds once dominated by the Old World Warblers. Jønsson & Fjeldså
(2006) recognized 13 branches (="clades") in this group of birds,
and the numbers on this tree are the same as the numbers of the Sylvioidea
"clades" in their paper. They recognize that many of these are poorly resolved,
and especially the uppermost branches, clades 9-13 [note that I have clades
12 & 13 on the same orange-colored branch; that will be explained later
in this discussion]. Some of the clades represent familiar families: Larks
(clade 3), Swallows (clade 6), and Bulbuls (clade 9, but
now missing the two special groups pictured among the Bulbuls in the "old"
tree). Some of these clades are well supported but others (e.g., clades
2, 7, 11) are not.
However, some of our familiar families are now "sub-clades". For example,
the branch leading to Tits & Chickadees (clade 2) now also has
the Penduline-Tits (including Verdin of North America) and a third
group, the Stenostirids. Within clade 2, each of these three groups
forms a monophyletic group of birds on their own evolutionary branch. Taxonomists
often like to think of themselves as "rank-free." They are interested in
the finding that these three groups are monophyletic, but don't care whether
each of the three groups is called a Family or not. It is equally
correct to list the three groups as 3 families — Paridae, Remizidae, and
Stenostiridae — or to lump the entire clade together as just one family.
If the latter, the Paridae would become a much bigger family that includes
the penduline-tits, Verdin, and all the Stenostirid 'flycatchers' that
are not flycatchers at all.
I much prefer the former approach for both practical and
historical reasons. Stating that there are three families in clade 2 violates
no rule of taxonomy but does preserve the historic and well-entrenched,
familiar families (Tits & Chickadees on the one hand, Penduline-Tits
on the other hand) and allows us to recognize the previously overlooked
group of African & Asian 'flycatchers' in their own right, undiluted
by titmice and Verdins. This is exactly what Beresford et al. (2005) proposed:
that the Stenostiridae be accepted as its own family.
In my layout, I have picked out those monophyletic groups that seem
to me to warrant recognition as Families, whether they are "clades" or
"sub-clades" in Jønsson & Fjeldså (2006). These prior
members of the Old World Warbler family now appear in ten different
or subclades, representing 7-10 or more different families, not
even counting the two (Kinglets, Hyliotas) that now fall outside this group
completely! The 13 clades of the Sylvioidea are discussed next. However,
the fact that Jønsson & Fjeldså (2006) recognized 13 clades
— and not 10 or 16 or whatever — was entirely arbitrary and was as much
influenced by layout of the paper as anything (Knud Jønsson, in
litt.). So not too much emphasis should be placed on any apparent different
between "clades" and "subclades."
Clade 1 is just one species, the Bearded Reedling Panurus
biarmicus, of the Palearctic. Its true position is still uncertain
(Alström et al. 2006, Jønsson & Fjeldså 2006) but
it is not a traditional parrotbill, as had previously been thought. Whether
it deserves family rank is not yet known [I do so in my family listing
provisionally, because it 'must' appear somewhere for world birding purposes]
and further research may show it is actually closer to the other parrotbills
than this assignment might suggest.
Clade 2 is discussed just above, and includes the Paridae and Remizidae.
The most interesting finding is that some African & Asian 'flycatchers'
are not flycatchers at all but within this sylvioid assemblage. The Stenostirids
include Fairy Flycatcher Stenostira scita (shown), various crested-flycatchers
& blue-flycatchers assigned to
Elminia or Trochocercus,
and two species of canary-flycatcher [Culicicapa] from Asia. Support
for including these among clade 2 is not strong, and further research may
alter the tentative arrangement here.
Clade 3 is the Larks [Alaudidae]; nothing new here except
than some genera (e.g., Mirafra, Eremalauda) prove to be polyphyletic
and need revision
Clade 4 is a newly discovered lineage of African warblers &
crombecs [Beresford et al. 2005; these could be called the Sylviettidae]
which include the Sylvietta crombecs, Damara Rockrunner Achaetops
pychopygius, Cape Grassbird Sphenoeascus afer, Victorin's Scrub-Warbler
"Bradypterus" victorini, Yellow Longbill Macrosphenus
flavicans, Moustached Grass-Warbler Melocichla mentalis, and
probably others as yet unreviewed.
Clade 5 is composed the three Nicators of Africa (although
only Yellow-spotted Nicator N. chloris has been reviewed genetically)
Clade 6 is the Swallows; genetics confirm that the two river-martins
(one in s.e. Asia, one in central Africa) are quite remote from the rest
of the world's swallows
Clade 7 is an interesting group of 2 or 3 subclades.
The most remote — best suited to remain as a Family, in my view — are the
Tits [Aegithalidae], which include the Bushtit of the New World. The
two Leptopoecile tit-warblers of China are in this Family
(having observed both in China, this makes good sense to me). Alström
et al. (2006) call this "clade G" in their study and, while confirming
it is near the next group to be discussed, propose that the family name
remain as Aegithalidae. This is an example of how different taxonomists,
using more or less the same information, can differ is what is a "clade"
and what is a "subclade" within a clade.
The other main subclade here are the Cettid Warblers & allies.
These include the 15 or so species of Cettia bush-warblers [Cettia
proves to be polyphyletic] and an eclectic group of odd warblers: Mountain
Tailorbird "Orthotomus" cucullatus [most of the other Orthotomus
tailorbirds are in a different clade], the almost tail-less Tesia
warblers and Asian Stubtail Urosphena squameiceps, and Broad-billed
Warbler Tickella hodgsoni. Close to this subclade are Asian warblers
in genus Abroscopus, the African 'flycatcher' Erythrocercus,
Green Hylia Hylia prasina, and Tit-Hylia Pholidornis rushlae.
Alström et al. (2006) propose that this group ("clade H" in their
study, which did not include all the taxa in Jønsson & Fjeldså
2006) be formally named as the family Cettiidae. The complete parameters
of this family have yet to be worked out.
Clade 8 is composed of the 68 or so leaf-warblers assigned to the
genera Phylloscopus and
Seicercus (Seicercus is 'embedded'
within Phylloscopus; there will be generic name changes in due course).
Alström et al. (2006) formally propose that this clade [termed "clade
F" in their study but composed of the same species] be named as the family
Phylloscopidae. So far, all the members are currently assigned to Phylloscopus
Clade 9 is the Bulbuls, a nice monophyletic group once the
two non-bulbul groups are removed [Nicators to clade 5 and Madagascar species
to clade 11]. A major study on the genetics of this family will be published
in the near future (Moyle & Marks in press) that confirms this is a
monophyletic family but shows that some of the relationships within the
family are different than previously assumed.
Clade 10 is the family Cisticolidae [Cisticolas &
allies]. This family was recognized by some recent world checklists
(e.g., Dickinson 2003); some 110 species were among them, including 50+
species of cisticolas, genus Cisticola, and ~60 species of Prinia,
& allies. To this set can now be added most of the Orthotomus
Mountain Tailorbird proved to be in clade 7, among the Cettiidae, and possible
a couple of other tailorbirds go there as well. The remaining dozen or
so species now go to the Cisticolidae (to date the species known to be
here are Common Tailorbird O. sutorius and Dark-necked Tailorbird
atrogularis; Alström et al. 2006). Also added to this family are
3 of the
Neomixis Jerys from Madagascar (Cibois et al. 1999),
and three odd warblers from Africa: Oriole Warbler Hypergerus atriceps,
Eminia lepida, and Kopje Warbler
subcinnamomea (Beresford et al. 2005)
Clade 11 is a newly discovered group that may include up to 4 subclades.
It is possible that each of these subclades should be treated as a family;
it is also possible that additional research will suggest other arrangements.
Two of the subclades have already been proposed to be families by Alström
et al. (2006): the Megaluridae [Grassbirds & allies] and the
[Acrocephalid warblers; these were clades "C" and "D" of their study].
This leaves unresolved two other groups. The full set are:
the 40+ species of Acrocephalus & Hippolais warblers,
plus a couple of Chloropeta yellow warblers in Africa, and the Streaked
Scrub-Warbler Scotocerca inquieta of the s. Palearctic (but not
yet well-supported). Excepting for some questions on the latter species,
this is the well-defined group proposed to be the Acrocephalidae.
a largish group of grass or marsh-loving skulkers, which will be known
as the Megaluridae. Among them are Megalurus grassbirds,
Schoenicola broad-tailed & fan-tailed warblers, the 9 species
of Locustella grasshopper-warblers, the Cincloramphus songlarks
of Australia, and most of the 20+ species of Bradypterus bush-warblers
related to the Megaluridae is Black-capped Donacobius of South America.
Barker (2004) showed it was not a wren or related to any other New World
but was, instead, a sylvoid — an ice-age remnant, if you will, long isolated
in the Amazon Basin. Its exact position is uncertain as studies are incongruent
(Alström et al. 2006). The three other sylvoids to reach the New World
do so only near the once-extant Bering landbridge. Arctic Warbler Phylloscopus
borealis breeds in both Siberia & Alaska, but the Wrentit Chamaea
fusciata (in clade 12) and Bushtit Psaltriparus minimus (in
clade 7) are restricted primarily to the western United States, where isolated
after the Pleistocene ice age. The Wrentit diverged from its babbler ancestors
only 6.5—8 million years ago (Burns & Barhoum 2006). More data are
needed, but it seems likely the Donacobius diverged and was isolated from
its Old World relatives much longer ago than that, and therefore likely
warrants Family rank [more on this topic below; it is more philosophy than
finally, and perhaps most fascinating of all, there is a radiation of
birds in Madagascar that fit in here, either as a family (perhaps called
Bernieriidae?) or a subfamily. It makes much better sense to me to rank
them as a family. In this group are birds originally assigned to Old World
Warblers — Wedge-tailed Jery Neomixis flavovirdis, Thamnornis Warbler
chloropetoides, and the recently described Cryptic Warbler Cryptosylvicola
randrianasoloi — plus birds assigned to Babblers — White-throated
Oxylabes Oxylabes madagascarienses, Yellow-browed Oxylabes
xanthoprys — plus birds once considered Bulbuls — Long-billed
"Greenbul" Bernieria madagascariensis, and 4 species of Xanthomixis
"greenbuls," all now known as Tetrakas.
Clade 12 is an interesting group that includes the 18 species of
& Parisoma warblers [Parisoma should likely be subsumed
into Sylvia], the Wrentit Chamaea fasciata of North America,
and the 18 species of Paradoxornis parrotbills plus Conostoma
[Great Parrotbill]. This wipes out the Parrotbill family for good (and
remember that Bearded Reedling apparently turns out not to be a parrotbill,
but an odd lineage in clade 1). In addition, various babblers go here:
Golden-breasted Fulvetta "Alcippe" chrysotis, Streak-throated Fulvetta
"Alcippe" cinereiceps, Yellow-eyed Babbler Chrysomma sinense,
African Hill-Babbler "Illadopsis" abyssinica, and the White-browed
Chinese Warbler Rhopophilius pekinensis, usually listed in the Old
World Warblers. This clade can be thought of as the Sylvia babblers,
parrotbills, and allies. If the clade is given Family rank, the
name "Sylviidae" is available to represent this group, now much reduced
from the previous Sylviidae.
There is a problem here. Although Jønsson & Fjeldså (2006)
assign this group to their own clade, it is a sister group to the final
clade, the remaining Babblers [Timaliidae]. Alström et al. (2006)
combined these clades 12 & 13 into just one clade (called "clade E"
of their study, although they did recognize 12 & 13 as clades as "E1"
and "E2" in their work) and proposed that the single, enlarged group be
called the Timaliidae. They said "Cibois (2003) suggested that if the Timaliidae
and several groups of warblers are recognized at the same family level,
then Sylviidae (Leach, 1820) should be suppressed and the name Timaliidae
(Vigors and HorsWeld, 1827) kept for the babblers and Sylvia. We agree
with this, and consequently propose that the name Timaliidae refers to
clade E of the present study. However, formal suppression of Sylviidae
can only be sanctioned by the International Commission on Zoological Nomenclature."
It may be too early to suggest suppression of Sylviidae, at least while
it looks like Jønsson & Fjeldså's "clade 12" is a useful,
monophyletic group that could use that name. This will all be worked out
in time. But it is possible that Babblers/Sylvia warblers could
become two families: Typical Babblers [Timaliidae] and Sylvid Babblers
[Sylviidae or some other name, if Sylviidae were suppressed].
Clade 13 is the final sylvioid group, and it is the remaining Babblers
[Timaliidae]. As discussed just above, it may or may not include the "Sylvid
Babblers" of clade 12. Standing alone as clade 13, it is composed of 50+
species of Garrulax laughingthrushes, all the Zosterops white-eyes
that have been studied [the family Zosteropidae bites the dust], plus hundreds
of "typical" babblers of many genera, which are known to include some of
the Alcippe babblers (others in clade 12), the Yuhina babblers
(minus White-bellied Erpornis), and at least these genera: Stachryris,
Babax, Turdoides, Cutia, Actinodura, Minla, Liocichla, Heterophasia, Leiothrix,
Pomatorhinus, Illadopsis (minus African Hill-Babbler), Xiphirhynchus,
Macronous, Timalia, Spelaeornis, Graminicola, Malacopteron Gampsorhynchus,
Pellorneum, Jabouileia, Napothera, Malacocincla, and Kenopia
[some of these genera are polyphyletic and new assignments among the genera
will occur in due course]. There are quite a number of other genera that
have yet to be genetically analyzed, including Malia, Neolestes, and
Alström P., P.G.P. Ericson, U. Olsson, and P. Sundberg.
2006. Phylogeny and classification of the avian superfamily Sylvoidea.
Molecular Phylogenetics & Evolution 38: 381-397.
Barker, F.K. 2004. Monophyly and relationship of wrens (Aves: Troglodytidae):
a congruence analysis of hererogeneous mitochondrial and nuclear DNA sequence
data. Molecular Phylogenetics & Evolution 31: 486-504.
Barker, F.K., A. Cibois, P. Schikler, J. Feinstein, and J. Cracraft.
2004. Phylogeny and diversification of the largest avian radiation. Proc.
Nat. Acad. Sci. 101: 11040-11045.
Beresford, P., F.K. Barker, P.G. Ryan, and T.M. Crowe. 2005. African
endemics span the tree of songbirds (Passeri): molecular systematics of
several evolutionary 'enigmas'. Proc. R. Soc. B 272: 849-858.
Burns, K.J., and D.N. Barhoum. 2006. Population-level history of the
wrentit (Chamaea fasciata): implications for comparative phylgeography
in the California Floristic Province. Molecular Phylogenetics & Evolution
Cibois, A., E. Pasquet, and T.S. Schulenberg. 1999. Molecular systematics
of the Malagasy babblers (Timaliidae) and Warblers (Sylviidae), based on
cytochrome b and 16S rRNA sequences. Molecular Phylogenetics & Evolution
Cibois, A., B. Slikas, T.S. Schulenberg, and E. Pasquet. 2001. An endemic
radiation of Malagasy songbirds is revealed by mitochondrial DNA sequence
data. Evolution 55: 1198-1206.
Cibois, A. 2003. Mitochondrial DNA phylogeny of babblers (Timaliidae).
Auk 120: 35-54.
Cracraft, J., F.K. Barker, M. Braun, J. Harshman, G.J. Dyke, J. Feinstein,
S. Stanley, A. Cibois, P. Schikler, P. Beresford, J. García-Moreno,
M.D. Sorenson, T. Yuri and D.P. Mindell. 2004. Phylogenetic relationships
among modern birds (Neornithes): toward an avian tree of life. Pp. 468-489
J. Cracraft & M. J. Donoghue, eds. Assembling the Tree of Life. Oxford
University Press, New York.
Dickinson, E.C., ed. 2003. The Howard & Moore Complete Checklist
of the Birds of the World. 3d ed. Princeton Univ. Press, Princeton, N.J.
Ericson, P.G.P., M. Irestedt, and J.S. Johansson. 2003. Evolution, biogeography,
and patterns of diversidfication in passerine birds. Jour. Avian Biol.
Fuchs, J., J. Fjeldsa, R.C.K. Bowie, G. Voelker, and E. Pasquet. 2006.
The African warbler genus Hyliota as a lost lineage in the Oscine
songbird tree: molecular support for an African origin of the Passerida.
Molecular Phyolgenetics & Evolution 39: 39: 186-197.
Jønsson, K.A., and J. Fjeldså. 2006. A phylogenetic supertree
of oscine passerine birds. Zoologica Scripta 35: 149-186.
Moyle, R.G., and B.D. Marks. In press. Phyogenetic relationships of
the Bulbuls (Aves: Pycnonotidae) based on mitochrondrial and nuclear DNA
sequence data. , Molecular Phylogenetics & Evolution
Sibley, C.G., and J.E. Ahlquist. 1990. Phylogeny and Classification
of Birds: A Study in Molecular Evolution. Yale Univ. Press, New Haven,
Sibley, C. G., and B.L. Monroe, Jr. 1990. Distribution and Taxonomy
of Birds of the World. Yale Univ. Press, New Haven, CT.