Re: Livezey and Zusi's big bird morph analysis [...]

[evelyn sobielski <koreke77@yahoo.de>]

> > - given the sheer amount of chromosomal
> rearrangements
> > present in Accipitridae, one could actually ponder
> > whether it is wise to include them at all -
> 
> That doesn't matter for the mitochondrial genome.

True, but at the presently available amount of
sequenced mtDNA sequences, signal is probably too
noisy to be of much use. Doesn't matter for this
analysis though.

> > As regards their phylogeny:
> > (Isn't their use of Neoaves fairly unusual?)
> 
> Livezey & Zusi use it just like everyone else: it's
> the sister-group of 
> Gallanseres.

kk, I think it left me wondering because it's nothing
I worry much anymore these days. There is not much to
say about it in any case; even "stuff" like Laornis
can usually be firmly placed therein.

> > Group B is generally well-supported, though the
> timing
> > of the galliform/anseriform split is debatable,
> 
> Do you mean Fig. 10B = Fig. 13 (which is
> paraphyletic)? 

Yes

> anything about timing?

I was mistaken.

> > the ratite morphotype, however
> > similar it may look, is certainly a (partly)
> neotenic
> > homoplasy, with moa probably becoming flightless
> first
> > and ostriches last.
> 
> I agree, but this doesn't tell us anything about
> ratite monophyly (which 
> both morphology and molecules consistently support
> -- Livezey & Zusi cite 10 
> references).

True, but it advises caution for an apomorphy-based
definition of ratites. It's a case where defining that
clade is liable to include a fair bit of sophistry
given the sheer amount of homoplasies and the lack of
good stem taxa.

I find ratite monophyly a valid hypothesis, but still
not more than the best currently available working
hypothesis, though it depends much on the definition.
Ratites are a good example where at present, a
node-based definition is superior to an
apomorphy-based one, even though node-based
definitions always run danger of excluding the next
lowest branch because nodes are both rarely known and
usually not identifiable as such, making them de facto
entities with hypothetical properties.

> better. -- At least 
> *Aptornis* is in (sister-group of *Rhynochetos*,
> both together sister-group 
> of *Eurypyga*), as are the dodo and the solitaire
> (sister-groups, together 
> the sister-group of *Goura* and then *Didunculus*).

It is satisfying to see this. The molecular phylogeny
(the "Caloenas" scenario) is not satisfactory at all,
given that the analysis gave at least one major error
in the phylogeny (Ectopistes/Zenaida I think), and
that the blatant oddities in regards to
(paleo)biogeography are not even discussed. What can
be said at present - and this paper agrees - is that
the didines were the part of the ancient
Pacific/Indian Ocean expansion of columbiforms, and
that Raphidae is probably not acceptable (though I
wouldn't dismiss it yet). But "closest living
relative" is a somewhat farcical concept here because
it seems the didines don't have *any* living relatives
that are actually close... of course there is always a
closest one, but the entire stem of the didine lineage
is as of yet missing. The avian fossil record from
Miocene India needs to be expanded IMHO before
anything can be said with certainty.

> I wonder if that's why *Lithornis* was found to be
> the sister-group of 
> Neornithes. I also wonder if adding some palaelodids
> and *Juncitarsus* would 
> separate Gaviidae and Podicipedidae. Interestingly,
> Zusi & Storer (1969) are 
> cited for myological evidence for a relationship
> between Podicipedidae, 
> *Rhynochetos*, and *Eurypyga* -- all of them
> Metaves...
> 
> What might happen if someone adds the
> plotopterids...? Livezey and Zusi 
> outright say (p. 26) that they "did not merit
> analysis herein" because their 
> skulls are "woefully incomplete". They don't seem to
> have tried if their 
> inclusion produces phylogenetic grass.

Yes, yes, and yes. As regards the merit of Metaves,
the flamingo-grebe clade case seems to harden, this
analysis nonwithstanding - no matter whether the
Metaves are a homoplastic assemblage by and large
(which I find easier to believe at present given that
they fail to turn up elsewhere), it's the internal
structure of theat clade that is well worth the effort
of further research: even if its subclades are grouped
together by an artefact, they may still be valid on
their own; a trtat can be a homoplasy for a group at
large, but still be a synapomorphy for subgroups
within it. Indeed, this scenario is more parsimonious
than assuming that the homoplasy is entirely
autapomorphic for each and every lineage.

> Among the living, the Acanthisittidae were not
> available for study (p. 88) 
> and are not included.

Regrettable, but not as much as plotopterids etc.

> Finally, I don't understand how using the ICZN,
> acting as if it extended to 
> all ranks,

:( I have some issues with phylo-taxo still, but I
recognize that it has a valid point, and IMHO such a
thing as done here should never ever be done. The ICZN
does have its limited scope for a very valid and
significant reason, and being somewhat of a bystander,
I find the issue of establishing nomenclatorial
principles that adequately represent evolutionary
reality too important for "just because" sniping (if
it's that what it is).

> acting as if the principle of exhaustive
> subsidiary taxa were 
> real, and not using phylogenetic definitions, let
> alone erecting 
> paraphyletic taxa (!!!),

As above - something there is no reason to anymore
except "because". And this being science, not a Cheech
& Chong movie, it's like pouring oil into a fire that
really needn't burn as bright even as it does.

> Linnaean codes and the PhyloCode (p. 87)... At least
> there is now a taxon 
> called Raptores.

As if anyone really needed that...


Regards,

Eike




        
                
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