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Re: (Paleognath monophyly)



----- Original Message -----
From: "John Pourtless" <vindexurvogel@hotmail.com>
Sent: Friday, January 30, 2004 1:49 PM

> I view it is a fundamental dichotomy between the morphological data on one
> hand and the molecular data on the other.  Morphological data is
unambiguous
> in its support for the neotenic state of paleognaths, and it remains a
fact
> that time and again alleged synapomorphies of this assemblage are in fact
> symplesiomorphies.

I don't understand why you state all these as facts. For example,
*Hesperornis* is not paleognath, and this has been known for decades. In
addition, Cracraft & Clarke (2001) have identified the following 5 character
states -- none of which is palatal! -- as apomorphies of Palaeognathae (all
unambiguous):

- Posterior portion of dentary strongly forked
- Inflated alaparasphenoid
- Skull with highly pneumatic bone posterior to quadrate articulation
- Loss of caudal maxillary sinus
- Parental care involving primarily males

Sure, Cracraft has supported several suspect hypotheses, such as ostriches
and rheas being sistergroups, or ratites having lost flight only once, or
loons & grebes being sistergroups.  But if you can deconstruct the above 5
characters, then please tell us how.

> Given the significant problems with molecular
> phylogenies of Neornithes (e.g., the placement of Aramidae
> in Sibley & Ahlquist 1990, which contradicts two centuries of
> morphological work including cladistic analysis),

Wait a little. Sibley & Ahlquist 1990 is molecular, but _not_ a phylogeny.
It's DNA-DNA hybridization -- in other words, _phenetics_. Pure phenetics.
For phylogenetic purposes, it can therefore be quite safely ignored.