Proposal 7: Combine New World barbets and toucans into a single family, Ramphastidae, as in AOU (1998)

Synopsis from Rick Prum:

The monophyly of the New World barbets and toucans is
probably the
most well verified clade in Aves! It has been
established by
morphology (first proposed in my undergrad thesis in
1982!), DNA
hybridization by S&A, and several DNA studies by Lanyon
and Co. I
think Lester Short was the only one to disagree with
this issue, but
he actually agreed with the facts and suggested the be
separate for
classification. Further, all studies including both
Semnornis and
Capito or Eubucco have determined that New World barbets
are
paraphyletic- me proposing the Semnornis is closer to
toucans, and
recently Barker and Lanyon proposing that Capito and
Eubucco are
closer to toucans. Either way, Capitonidae is
paraphyletic.

Basically, there is no way to recognize Capitonidae with
New World
barbets alone that does violate the well established
congruence among
many independent phylogenetic hypotheses. Now, given
that South
America does not include any Old World barbets, it is
hard to know
exactly what this classification implies for them. One
could be most
historical by splitting them into at least two new
families. But the
paraphyly of the new world barbets would still make
Capitonidae
paraphyletic.

In 1987 (in '82 in the thesis), I suggested that all
barbets and
toucans be lumped into one family, which I called
Ramphastidae
because the name is older than Capitonidae. Although
strict priority
does not apply to family names, I did this to prevent
arbitrariness.
Over the years, I have sat on the side lines and seen
this very
reasonable suggestion be ignored by most major
classifications, field
guide, and reference works even though repeated studies
have found
that the toucans and barbets are monophyletic, that the
New World
taxa are monophyeltic, that the toucans are
monophyletic, but that
NONE of the continental assemblages of barbets is
monophyletic.
Finally, the AOU in 1998 recognized a single
Ramphasitidae including
the barbets, but they still recognized a single
Capitoninae which
would ALSO be paraphyletic.

So, I don't know what you all think, but I think we
should lump all
barbets and toucans into one family! At the very least,
we are
required to lump all the New World barbets and toucans
in this
checklist into one family. I chose Ramphasitidae. Call
it anything!
But splitting them as suggested here would be rejecting
one of the
single BEST supported, most agreed upon results in avian
systematics
in recent decades!


Let's compare that to recognizing the Galubuliformes as
separate from
Piciformes. All though this split has been recognized,
there is far
from agreement about it. Morphological phylogenetic
papers have put
them within Piciformes (Cracraft, Raikow). Criticism of
this by Olson
was completely unanalytical. Sibley and Ahlquist put
them in outer
space, but didn't really conclude what they could be
related to. So,
this situation is not universally accepted, has not been
repeatedly
supported. No relationships for the Gabuliformes have
been proposd,
as far as I know, other than in Piciformes or" we dont
know." I am
all for progress, but we dont know isn't progress
because only by
showing that the group is closer to something else than
to Piciformes
can you claim that the obvious similarities they share
in the
hindlimb are convergent and not due to shared ancestry.
So, I
wouldn't necessarily vote against the recognition of
Galbuliformes,
but in comparision to the toucan/barbet situation, this
idea is half
baked and poorly supported.


Of course, the earnest discussions have never really
started over
this checklist's mission. Perhaps we will have votes for
maintaining
the Capitonidae for the status quo. But that doesn't
explain the
non-traditional Galbuliformes.

I would LOVE to hear any comments on these thoughts!


Cheers,

Rick

========

Prum/Remsen comments: "

Van:



>-- Semnornis is the "problem" taxon, right, so another
possibility would
>be to create a third family for that genus until the
relationships among
>the 4 monophyletic groups (assuming the two Semnornis
are sisters) is
>resolved. (That's actually what I recommended to H-M
group). That way, 4
>certain monophyletic lineages would be given taxonomic
recognition.

Semnornis is not the only problem taxon. The others are
Trachyphonus-
the ground barbets, and Calorhamphus - the little brown
cooperative
Asian barbets.Neither Barker and Lanyon (Mol.Phyl. Evol.
15:215-234)
nor I found any support for Sibley's two Old World
Families. The
problem is that Sibley didn't include the problematic
taxa Semnornis
and Trachyphonus, Nor the Asian Calorhampus which is
very different
from Megalaima and Psilopogon (the members of
Megalaimidae). Barker
and Lanyon lacked the latter two.

So, there is essentially no support for the monophyly of
any proposed
concept of Lybiidae or Megalaimidae including
Calorhamphus. And the
only critical tests come from my work and Barker and
Lanyon, and
Lybidae flunks both tests. There are no ageed upon
clades within Old
World barbets

So the solution presented here represents the following
notion: There
are at least four families of barbets:

Lybiidae
Megalaimidae (including Calorhamphus?)
Capitonidae
Semnornithidae
Ramphastidae.

There is no support for the monophyly of the first two,
and POSTIVE
evidence in the only studies with enough sampling that
they are NOT
monophyletic. The third family is ok. The fourth is ok.
It should be
a separate family given that it is either the sister
group to
Ramphstidae or the sister group to Cap.+Ramph. (Barker
and Lanyon).
Given the volumes of data and analysis, I would happlily
concede that
Barker's hypotheses is better supported than mine. So,
if you split
up the barbets into multiple families, then you need to
recognize
Semnornithidae.

But, why on earth would we want to recognize four
families of
barbets, two of which have no support when a completely
rational
alternative option exists that is congruent with all
data? Will we
soon recognize five families of hummingbirds once we get
a better
idea of their phylogeny. Or 17 families of tanagers?
etc?

Believe me, I am all for saving the Linnean system,
which many
phylogenetists are abandoning or simply ignoring. But to
make it work
we have to make rational changes to the system to
reflect history. I
think proliferation of subfamilies within a family is
much more
tolerable than proliferation of uncertain families.

I say, we go with the AOU solution.


>-- note that AOU'98 used subfamily taxa for al three
lineages above.


I stand corrected! And about this, I am pleased to be
wrong!


>-- (just to make sure you know ... H-M does have Old
World barbets in two
>separate families, the sibley families).
>


See above. This alternative is NOT supported by any
data, and is
contradicted by BOTH morphology and DNA sequence data.


Thanks for more information!

Rick

--

Richard O. Prum

===========

>SACLC: a couple of points concerning Rick's proposal:
>
>-- just for clarification ... the H-M classification
does not include any
>Old World barbets within Capitonidae and recognizes its
sister relation to
>Ramphastidae.
>
>-- additional solutions to the "Semnornis problem" that
would maintain
>family rank for toucans and barbets: (1) elevate the
AOU's Semnornithinae
>to family rank; (2) place Semnornis as Incertae Sedis
(as AOU does with a
>bunch of tyrannoid genera, largely as a result of
Rick's studies, to avoid
>collapsing Tyrannidae, Pipridae, and Cotingidae into 1
family).

Is incertae sedis something checklist's do when Rick
Prum suggests a
change? (This is not a serious question!)


>-- if we collapse birds as "different" as New world
barbets and toucans
>into 1 family (as does AOU '98), then it would be
difficult to argue that
>Furnariidae+Dendrocolpatidae should not also be merged
into 1 family, as
>well as other 9-primaried oscine families.

What birds that are so different? What about the
variation in size of
falcons? Does anyone doubt that the smallest Old World
falcons are
really falcons? Some of them might even be genus Falco!?
Do we loose
any information by expanding our concept of Ramphastidae
by including
some small ones? And is Semnornis big enough to be a
toucan but
Capito is not? What about Psilopogon? Looks kind of
toucan-like to me.

The problem is not whether the members of various family
groups are
variable, but whether the groups are monophyletic. The
question of
ovenbirds and woodcreepers is whether ovenbirds are
monophyletic
without woodcreepers, not whether they are too different
to be
combined or too similar to be separated. Families are
not comparable
levels of diversity. They are just clades with names
(hopefully).
Some families ar big and some little. Some homogenious
and others
variable. We should give up making them parallel or
consistent since
they never can be. We should just make them
monophyletic. SO, I think
we ought to mess with tradition only enough to render it
historically
accurate.


Cheers,

Rick
--

Richard O. Prum
Associate Professor, Ecology and Evolutionary Biology

=============

Remsen: "

Rick et al. -- I'm not getting my point across. The
monophyly of the Dendrocolaptidae or Furnariidae is not an issue*. The
reason I brought
that up is that your (and AOU '98's) broad Ramphastidae
encompasses taxa
that are less "similar" by traditional, admittedly
non-phylogenetic
reasoning (as evidenced by placement of barbets in
separate family for a
century or so), and in my subjective opinion as well,
than does the Dendro
+ Furn group. A century of taxonomic ranking as
separate families would
suggest to most that the difference between toucans and
New world barbets
is qualitatively different than your example of small
Falco from large
Falco. I don't think most of us think of barbets as just
smaller toucans.
Given that ranking of higher-level taxa is largely
subjective and guided
mostly by historical momentum, I think it is worth
considering two
alternative solutions, namely (1) three families
(Capitonidae,
Semnornithidae, Ramphastidae) or (2) two plus Incertae
Sedis status for
Semnornis**... Looming ahead is the same problem with
the Schiffornis bunch
-- leave them as Incertae Sedis or do away with
traditional family-level
taxa Tyrannidae, Pipridae, and Cotingidae.

* I'm at home so can't check, but other than one
phenotypic character
noted by Clench (with incomplete taxon sampling), is
there any evidence
that the Dendros and Furnariidae are monophyletic with
respect to each
other?

** Other than the distinctive bill tip, is there any
evidence that
Semnornis itself is monophyletic?


Van Remsen,

==============

Bret Whitney:

"

Hi all,

I agree with Rick, Mark, and probably about everyone
else that we ought to
leave systematics alone unless well-corroborated
evidence for monophyly
dictates a change. I also feel that "incertae sedis" is
a useful place to put
things that represent problems, or about which there
exists significant doubt
for whatever reason. This has two benefits: 1) it goes
on hold rather than
getting lost somewhere at a higher taxonomic rank, and
2) it is probably more
likely to receive special attention, which is always
good. I see no
disadvantages to calling something or even a small group
of taxa "incertae
sedis". Is there a disadvantage I'm overlooking? C'mon,
Rick, it's not all
that many taxa!

Thus, I favor leaving "the big ones" as Ramphastidae and
"the little ones" as
Capitonidae. We all know what we are talking about, in
part because that's
how we grew up, in part because these are unambiguous
phenotypic groups (with
Semnornis the odd one, "incertae sedis"). That said, and
after reading the
latest rounds of correspondence, I am still unclear as
to whether
phylogenetic analysis identified ANY break between these
traditional
assemblages or not. I'd like to have that answered;
sorry if I've missed it
along the way. I would be comfortable with Semnornis as
"incertae sedis" for
now. And yes, Van, let's wait to verify that Semnornis
is indeed monophyletic
(if that piece of the puzzle is still missing).

As for Dendro and Furnar... if the tail is entirely
rufous with powerful,
sharp, strongly curved, well-exposed spines, it's a
woodcreeper. If not, it
isn't. I don't think it needs to be any more complicated
than that. One of
these days, genetic evidence should reveal the split
that's clearly there --
if indeed it is recoverable from the organisms extant
today.

All fur now, Bret

======================

From Doug Stotz:

"My feeling on 7 is that I'm not sure what the best treatment is, but I feel like putting everything in Ramphastidae sweeps remaining issues under the rug. Given that the old World Barbets are now usually split into multiple families, I would think we could survive the same with the new world taxa.

Doug
Douglas Stotz

======================

From Alvaro Jaramillo:

"I vote no on this one, mainly because the option of separating the Ramphastidae, Capitonidae and Semnornithidae as Incertae Sedis is reasonable. I don't like the idea of lumping all into Ramphastidae, it makes the family less meaningful, information is lost in terms of understanding that a Ramphastid is. I prefer the option of expanding the families rather than lumping. "