RE: Climbiing Dinosaurs (RE: a little background)

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Mike Skrepnick wrote:

> It seems to me that in combination, the plane of the ungual on pedal 
> digit two ( offset medially ) for that modified "climbing lumberjack" 
> movement, 

Just a few very quick thoughts...  In support of this, seriemas have been
reported to apply their enlarged inner toe claws for tree-climbing - as
mentioned a few times on this list.

> along with retroverted pubes (reorientation of attachment for hindlimb 
> adductors) 

Is this the same as Chatterjee's explanation for the retroverted pubis in
"proto-dromaeosaurs" (i.e. pro-avians)?

> So really then, all the work in tree climbing
> dromaeosaurs is done through leg propulsion with the arms and tail
> secondarily helping in manoeverability, in more lateral movements onto
> tree limbs, etc...  The only thing that appears to me to be slightly
> problematic is moving its body and tail through more densely limbed 
> conifers, if they attempted that.  

The above objections pertain to trunk-climbing - sort of like the way
Pacific islanders climb up palms to reach the coconuts at the top.  However,
what if little eumaniraptorans were adapted to branch-climbing instead -
using branches for handholds and footholds in a hoatzin-like fashion when
ascending trees, rather than straddling the trunk.



Tim


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

Timothy J. Williams 

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

Phone: 515 294 9233 
Fax:   515 294 3163