Re: Remember the Alamosaurus (was RE: taxonomy is not stratigraphy)

[Denver Fowler <df9465@yahoo.co.uk>]

  Let's hope the
> type material for 
> _Alamosaurus sanjuanensis_ is diagnostic...

When alamosaurus was described, the holotype material
was diagnostic. But a scapula (holotype) and (possibly
associated) ischium (paratype), are now
indistinguishable from all sorts of other Late K
titanosaurs.

Furthermore, there is observable variation in N.Am
'Alamosaurus' material from within the same formation,
that may suggest different species.

Denver.

> 
> >In fact, 'Alamosaurus' is probably a very bad
> choice for a biomarker since 
> >the holotype material bears no synapomorphies.
> 
> Oh dear.  Looks like I spoke too soon.  Nevetheless,
> the _Alamosaurus_ 
> holotype material may show a unique combination of
> characters, even if 
> autapomorphies are not present.  But you're right:
> it's a terrible choice 
> for biomarker.  The jury's still out whether it's a
> valid taxon.
> 
> Cheers
> 
> Tim
> 
> 
> 



                
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