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Re: avian nomenclature
> The trouble is that (with few exceptions) we lack fossils
> from at or near the critical branching points in neornithean
> evolution, corresponding to when different 'orders' first
> appeared. A similar problem occurs with
> placentals. I'm certain we know more about the
> relationships of non-avian theropod taxa than we do about
> the relationships of modern bird orders (Neornithes).
It's not that bad, actually. Apart from the "uncertainty region" - which
according to what fossils pop up when is the 5 Ma or so just after the K-Pg
boundary; go figure! - between "higher waterbirds" and "near passerines", a
very large amount of diversity is placed quite firmly.
The second Mayr et al paper for example was mainly taxonomic cleanup work.
Everyone who cared knew where it was heading; the morph and mol data fits
together very nicely here. but it needed to be published.
And that's why it seems to be so confusing: even if following the literature of
the last 5 years or so will yield a pretty good idea of what's going on,
without the fossil data being formally reevaluated in the light of the
molecular data, and vice versa, and all that being integrated with biodiversity
it's not solid enough.
We're even making good way out of the ratite tangle! The "Falconiformes" and
"Gruiformes" are perhaps the two really large problems that remain, because the
latter and at leats part of the former are at the junction between "higher
waterbirds" and "higher landbirds", and the effect on the cladistic structure
is of course severe (are "higher landbirds" a clade? are "higher waterbirds"
*without* "higher landbirds" a clade?).
The rest is mainly questions like "what is the exact nature of the relationship
between Hoatzin versus cuckoos and turacos versus pigeons and sandgrouse, and
how far are these from passerines?"
But given that passerines make up 60% of all living bird species, and that the
phylogeny of 95% of all passerine species is essentially known (or we can at
least make a well-founded guess that is very unlikely to be wrong - plumage is
helpful ;-) ), it's really well resolved, compared to other taxa of such age
And that is very good, because given the popularity of songbirds, knowledge of
their phylogeny is *really* helpful in convincing people that Darwin was right.
For almost any phenomenon in the field of evolutionary biology, among the
Passeri(formes) an example is to be found.t
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