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Re: SICB Report, part 1 (long)



I would like to praise Thom Holtz report on SICB. Very informative and
admirably restrained in all its ironic glory. Looking forward to part II.

>One new analysis
>showed the difference in scaling (numerical, not integumentary) between
>typical theropods and modern ground birds when total hind limb length was
>plotted against trunk size.  (_Caudipteryx_ plots with the birds,
>incidentally).

Another red herring? Strange as it seems Caudipteryx has also  a very short
tail. Could it be related to the fact that modern birds don't have a long
bony tail, thus implying obviously different characteristics in locomotion?
What has this got to do with Dinosaur-Bird phylogeny? Could it simply be a
case of: the shorter the tail the shorter the trunk (or some other
anatomical characteristic related to flightlessness in an 'advanced'
state?)
Dinobirds shortened the tail little by little (I suspect as they got better
at the flying business,the trunk also automatically adapted to that)
What about the very short legs of Confuciusiornis and other primitive birds?
How would the trunk-limb scaling of Archaeopteryx rate against Gallimimus?
I bet Gallimimus would be closer to (at least) cursorial birds. And
cursorial birds  would be closer to dinosaurs.
The difference would be that Gallimimus still had a long tail to balance a
longer trunk. An ostrich don't have a tail, so you would expect a  shorter
trunk. Pure functionality and very little to do with a clear 'split'
between dinosaurs and birds (to my eyes).
Longer legs to me imply ground cursoriality. And ground birds couldn't get
their long bony tail back, so flightless birds (note: descended from fully
modern-looking volant forms) should have different locomotory
characteristics, keeping the shorter trunk.

As Thom pointed out this might be not a dichotomy, just a transition. And
at the end it tell us nothing at all about dinosaurs being related to birds
or not.



Luis Rey

Visit my website on http://www.ndirect.co.uk/~luisrey