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Re: PROTOAVIS IN PHYLOGENY



Gareth Dyke has asked me to fwd this on. 
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In his 1991 paper on the crania, Chatterjee ran a data matrix, the whole  hog,
and generated a cladogram (I forget the exact details) somewhat different from
the one in 'Archaeopteryx'. This has (this is from memory, so might be a bit
dodgy) _Protoavis_ as an outgroup to _Avimimus_, _Ichthyornis_,
hesperornithiforms and _Gobipteryx_ (I think that's the right branching order).

_Avimimus_ as a true bird really deserved checking out - well, in the  character
list, _Avimimus_ had been coded 1 for 'toothed premaxilla'. Unfortunately,
Chatterjee has confused the spiky denticulations on the premaxilla with teeth!
Re-coding and re-running the analysis through PAUP resulted in the spitting out
of a new tree.. though admittedly, only the positions of _Ichthyornis_, the
hesperornithiforms and _Gobipteryx_ were changed.
 
G.D. - if this doesn't wake you up nothing will! 

This isn't a reply seperator but, hey, a guy can dream.
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> Cheers Darren - yes, I actually did a small amount of work last year
> re-working the data matrix in the 1991 paper. We did indeed find that
> characters regarding _Avimimus_ were incorrect - checked in the Kursanov
> papers. 

> The fact that C thought it had
> teeth is a crucial flaw in his phylogenetic interpretation. It means that
> the published values for Tree Length and CI are significantly incorrect
> and there is actually no support for the final dichotomy seen in the
> cladogram. I am working from memory as I do not have the paper in front of
> me - what should be seen instead is a trichotomy involving the highest tree
> clades seen.
> 
> Will write again with the actual values + the cladogram that should have
> been published in a few days.
> 
> Making a basic error like this means we should treat with caution any
> phylogeny that this bloke may publish - I am waiting with interest !!.
> 
> Gareth Dyke,
> Dept of Geology,
> BRISTOL.
> 
> email gd4328@bris.ac.uk

And remember: "Don't give up 'cus life's too slow, boy we're gonna succeed with
another blow". Quite!

DARREN NAISH,
blah blah blah..