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RE: New Cretaceous bird and other papers




>In 2000 a joint venture project of the Institut fur Palaontologie of
>the Freie Universite in Berlin (Germany), the Zoological Institute of
>the Russian Academy of Sciences in St. Petersburg (Russia), and
>Institute of Geology of the National Academy of Science in Bishkek
>(Kirghizia) was started in the Republic of Kirghizia to recover
Jurassic mammals. 

I'm glad to hear that the Fergana valley is available for excavation.  Not
too long ago, this neck of the woods was a little hairy, owing to local
"trouble" from Islamic insurgents.

http://www.cmnh.org/fun/dinosaur-archive/2000Jun/msg00753.html


John Bois wrote:

>A bigger stretch is imagining how a limited neornithine diversity in LK
>could survive while the _total_ diversity of enantiornithes is knocked >out
by bolide magic bullets. 

It may not be a stretch if the deciding factor was physiological.  _IF_
enantiornithines had a less endothermic/homeothermic metabolism compared to
the super-active ("hot-blooded") neornithines, then the former may have been
more susceptible to a protracted period of cold ambient temperatures. Sure,
many "cold-blooded" reptile groups survived the K/T boundary; but it's
always possible that they entered torpor - an option that was unavailable to
the enantiornithines.

This is all "just-so"ing - I don't have the foggiest idea on why
neornithines survived and enantiornithines (and the other non-neornithines)
didn't.  But it's just one of many reasons why neornithines and
enantiornithines should not be tarred with the same brush when constructing
hypothetical K/T extinction scenarios.  What's good for the neornithine
goose, may not be good for the enantiornithine
gander.


Ken Kinman wrote:

>In June 2001, I first proposed my hypothesis that protofeathers may have
>started out on the end of the tail as a predator evasion strategy (sort >of
like lizards that have colorful wiggly detachable tail-tips.   

This reminds me of the suggestion that ankylosaur tail-clubs, when held off
the ground, mimicked the head and neck of sauropods in order to confuse
would-be predators.  However, I just don't think theropods were that stupid.

The tails of drop-tail lizards wriggle after their detachment from the
lizard's body.  This isn't really comparable to the "predator evasion
strategy" suggested above.  This tail-feather-first predator evasion
strategy also assumes that theropod predators grabbed prey by their tails.
Not only is the tail the skinniest part of the body (and therefore difficult
to hold onto - especially considering the big, long maniraptoran hand poorly
designed for an opposable grip), but certain dinosaurs are thought to have
used their tail as a weapon against predators.  I think theropod predators
would have targeted the torso or neck - as in modern mammal hunters - and
avoided the tail.


Tim


------------------------------------------------------------ 

Timothy J. Williams 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 3163