Re: Genealogy of Scaly Reptiles Rewritten by New Research

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

--- Ursprüngliche Nachricht ---
Von: Jura <pristichampsus@yahoo.com>
Datum: Fri, 25 Nov 2005 19:42:53 -0800 (PST)

>   And so another molecular tree comes out ass backwards from every 
> morphological tree.

It does have morphological features that fit it, such as the previously 
completely overlooked poison glands. The fact that the poison glands of 
Iguania were overlooked makes it probable (to me) that those animals are 
gravely underresearched in other aspects as well, which in turn could 
explain why morphological trees have so far found them as the sister-group 
to the rest of Squamata while this molecular tree gets them clustered with 
anguimorphs and snakes.

On the other hand, I wonder if the position of Dibamidae is due to long-
branch attraction. It doesn't help, of course, that these same animals 
also exhibit morphological long-branch attraction... if you look like an 
earthworm, you look like an earthworm, period.

> Has there ever been a molecular study on dogs (_Canis familiaris_)
> or cats (_Felis domesticus/cat[...]us_)? You know, a study that
> has the molecular data  verifying the
> known relationships between different breeds.

Apart from the problem of reticulation, such a study would have to use 
totally different genes because of the totally different time frame. This 
would lead to a different set of problems.

>   Jason - (who is still not willing to call turtles archosaurs)

Neither am I. This is a case where I think the molecular long-branch 
attraction is even worse than the morphological one. However, there 
doesn't seem to be a really good morphological analysis of that problem... 
partly because it would need a _very_ large data matrix...

Well, praise the cleithrum of *Kayentachelys* and *Proganochelys*, 
something crown-group diapsids are supposed to have lost. And let's wait 
for more fossils.

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