Re: DINOSAUR digest 3384

[Michael Mortimer <mickey_mortimer111@msn.com>]

T. Michael Keesey wrote-

> As I alluded to under this comic: 
> http://www.parryandcarney.com/comic/8.html
> ...I've yet to see anybody come up with a decent explanation for why
> crown clade avians made it through while other ornithothoracean birds
> didn't. Teeth aren't a good criterion, because some enantiornitheans
> were toothless.

Well, we'd have to turn to other avian (sensu Gauthier) synapomorphies for 
the explanation then.  It was no doubt their fifteen or more fused sacrals, 
completely heterocoelous dorsals, pneumatic foramina between costal facets 
on the sternum, and/or pneumatized coracoids, none of which are found in 
other theropods.  Each and every one of these features would save them from 
a bolide impact, yessiree.  Or maybe Limenavis, the Lance ?ichthyornithid, 
the Maastricht carinate, Potamornis, Canadaga, Judinornis, Gargantuavis and 
Vorona were unlucky, while the Maastrichtian enantiornithines were selected 
against due to their physiology.

Mickey Mortimer