Re: Archaeopteryx with bird book, was Re: Archaeopteryx flight

[Tim Williams <twilliams_alpha@hotmail.com>]

Patrick Norton wrote:

> This is speculation, of course, apparently based mostly on similarities in 
> overall size and wing aspect
> ratios and the lack of evidence of gastroliths in Archie (suggesting it may 
> have been a meat
> eater, like the Corvids).  It probably couldn't fly as well as crows and 
> magpies, though, so it's lifestyle had to be somewhat different in that 
> respect. If gastroliths are found in some future specimen of Archie, 
> however, this might suggest a different diet as well.

I'm not so sure the presence or absence of gastroliths can be used to infer 
diet.  Several non-avian theropods have gastroliths, including _Baryonyx_ , 
_Lourinhanosaurus_,  _Poekilopleuron_, _Caudipteryx_, _Nqwebasaurus_ and 
_Sinornithomimus_.  The skull is not known for the carnosaurs 
_Lourinhanosaurus_ and _Poekilopleuron, so it is possible (but not likely) 
that neither were carnivores; but _Baryonyx_ was certainly carnivorous.

The presence of gastroliths in _Caudipteryx_ were actually cited in support 
of insectivory in this critter, using the modern aardwolf (_Proteles 
cristatus_) as an analogy.

Cheers

Tim