Re: genealogy and divergence

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: <NJPharris@aol.com>
Sent: Tuesday, October 30, 2001 7:33 PM


> In a message dated Tue, 30 Oct 2001 12:40:13 AM Eastern Standard Time,
"Ken Kinman" <kinman@hotmail.com> writes:
>
> > Demetrios M Vital wrote:
> > >    What's the purpose of a taxonomy that doesn't reflect phylogeny?
> > ******************************************
> >      Another misconception.  Traditional eclecticism also reflects
> > phylogeny---but it's not based *solely* on phylogeny.  Cladism does not
go
> > the extra step to add anagenetic information (i.e. divergence).
>
> Of course it does.  Just look at any reasonably comprehensive phylogenetic
taxonomy of Aves.  You can still look at it and say, "Geez, there's a lot of
stuff in there!", even if Aves is itself nested deeply within Dinosauria.

You can also look at the _diagnoses_ and say "oh, wow, 'tail reduced to
stub, perching foot, funky ribbonlike tail feathers...' -- great changes
took place around the origin of Pygostylia! ... So _that_'s where the
perching foot evolved! I always thought that was earlier, later, whatever!
Hey, I'd never have thought of this & that obvious synapomorphy!" and so on.
Phylogenetic taxonomy can be done as pure theory, but it rarely is.

It also does a good job of diluting the impression of anagenesis to our real
knowledge. "Hey, I thought all birds had tiny fused 3rd fingers, but the
basalmost ones didn't! And *Yandangornis* already had the broadened proximal
end of mtIII but is just outside! Wow, some real birds had gastralia!" and
so on, unlike the situation when Mammalia was defined by the secondary jaw
joint, and there are animals with all kinds of multiple jaw joints, splenial
and coronoid remnants and so on all around its base. I'm really impressed by
the Hennigian comb (Confuciusornithidae (*Protopteryx* (*Longipteryx*
(*Jibeinia* (Ornithothoraces))))).

Why use morphological gaps for taxonomy when they all dry up sooner or
later, and even the evaporite deposits are eroded away soon after? :-)