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RE: Several New Papers



-------- Original-Nachricht --------
Datum: Tue, 28 Nov 2006 04:32:47 +0100 (CET)
Von: evelyn sobielski <koreke77@yahoo.de>

> Tempting but insufficient for me, because it is full
> of weakly-supported and otherwise spurious nodes

That means that _those_ nodes have to be regarded with caution. It doesn't say 
much about the rest. Have you seen the papers that name Ecdysozoa (1995) and 
Lophotrochozoa (1997)? As you can expect of such early molecular analyses, the 
trees look simply horrible; for example they fail to find the monophyly of 
Mollusca. The nodes newly named, however, have been found again and again in 
just about every later molecular analysis of that part of the tree.

> and as a whole is not supported well by
> other than molecular data:

But then what is within Neornithes.

> 4 characters,

Those are just the most morphological-like ones. I'm sure there are hundreds of 
ordinary substitutions, too, that are autapomorphic for Metaves and Coronaves.

> each one of which is *known* to occur as homoplasy,

1. So what.
2. Indels are less common than substitutions.

> and as such could have switched state once
> or (unlikely) repeatedly since the Cenomanian,
> approximately (as delimited by Galloanserae and
> Syrrhaptes). Hm.

Exactly. That's what parsimony is for. :-)

> > Wasn't that what Ericson et al.'s analysis was?
>
> I'd rather call it a good review/meta-analysis.

How so? They took actual data and ran it through an actual analysis -- that's 
original scientific research. I can't see why you think otherwise.

> They didn't set out to refute anything,

Sure they did -- deliberately or not. Apart from the choice of an outgroup, 
they did not constrain their phylogenetic analysis: each taxon was free to fall 
where the data would put it. This is an explicit test of all theoretically 
possible relationships between the taxa in the data matrix, whether they have 
ever been proposed or not.

> Biogeographical data, the incompleteness of the fossil
> record nonwithstanding, should be moe used to put
> hypotheses to the test methinks.

I'd rather say that phylogenetics makes biogeography possible than the other 
way around. Think of "pantropical distributions": in the Eocene there were 
trogons in Denmark.

> (Is there a good paleogeographical atlas on the Web? I
> don't really want to have to make my own.)

It doesn't get better than http://www.scotese.com and the links from there... 
making your own, especially on the basis of the most recent primary literature, 
would be a very useful -- if humongous -- work...

> > But they basically ignore
> > Cretaceous neornithine fossils,

Of these, only *Vegavis* and the presbyornithid crumbs like *Teviornis* have a 
reasonably certain phylogenetic position.

> > and by only using Eocene fossils as calibration,
> > force a result where the
> > main neoavian 'orders' diverge after the K-T
> > boundary.

That's not true, IIRC. These constraints are minimal ages, not maximal ones.

> They could have made an explanatory
> drawing though, indicating the uncertainty caused by
> "stuff" like Tytthostonyx,

Might have been a good idea.

> I expect ATM that eventually, the Coronaves-Metaves
> concept as proposed will fail, with "Metaves" as it
> presently stands turning out to be paraphyletic "waifs
> and strays" and perhaps one or two minor clades, but
> that the 4 major neornithine lineages will hold.

I expect that, once enough Eocene and older neornithine fossils will have been 
discovered and thoroughly studied -- the "Odontanseres hypothesis", or, better 
yet, Mayr's discovery of (*Juncitarsus* + (flamingos + grebes)) being cases in 
point --, morphological autapomorphies will be found for Metaves and Coronaves 
:o)

Anyway, I expect plenty of morphological surprises. There is, after all, not a 
single morphological phylogenetic analysis of Neornithes of a size that can be 
taken even remotely seriously. The one in preparation by Livezey & Zusi will be 
the first.

> I wonder why Poe & Chubb's "Birds in a Bush"
> (Evolution 58:404) is missing from the references.
> Have I missed something? Was it ripped to pieces?

Could you remind me what that was about?
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