Re: Late night thoughts: Pathetica and Interspersal

[Tim Williams <twilliams_alpha@hotmail.com>]

David Marjanovic wrote:

> Easy: you said there was "a dramatic increase in size that occurred early 
> in their evolution (from _Anchisaurus_-sized to _Isanosaurus_-sized and 
> beyond"; I said there was no such increase, only diversification.

So diversification entailed both a decrease and increase in size?  How much 
is this predicated upon the exact topology of non-eusauropod sauropodomorphs 
(you know, basal sauropodomorphs, plateosaurs, basal sauropods, etc)?

> I didn't mention that *Anchisaurus* comes out as the result of a dwarfing 
> event; the first sauropod is reconstructed as larger.

Ah, that little detail might have helped.  :-)

Note that there is a possibility that _Anchisaurus_ is based on immature 
specimens...

Fedak, T.J., and Galton, P.M. (2007). New information on the braincase and 
skull of _Anchisaurus polyzelus_ (Lower Jurassic, Connecticut, USA; 
Saurischia: Sauropodomorpha): implications for sauropodomorph systematics; 
pp. 245-260 in Barrett, P.M. and Batten, D.J. (eds.), Evolution and 
Palaeobiology of Early Sauropodomorph Dinosaurs. Special Papers in 
Palaeontology 77. Palaeontological Association, London.

(I don't actually have a pdf of this paper.  If somebody could send a copy 
my way, I'd be FOREVER in your debt.)

> The same, incidentally, holds even for *Saturnalia* and the first 
> sauropodomorph.

Now THAT'S a surprise.

Cheers

Tim

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