Re: bottom decker?? pteros

[david peters <davidrpeters@earthlink.net>]

> The reason Quetz. has a lower glenoid has more to do with its terrestrial 
> adaptations.

Jim C. wrote:
I do disagree with this.  In Quetz, the lower glenoid appears to me to
be related to the high wingloading and flapping power.  


>>>  Would the same hold true for Scaphognathids (small pteros with relatively 
>>> high wingloading)? I do note that the various nyctosaurs have a 
>>> middle-decker scapulocoracoid and relatively low wing-loading and an 
>>> extended dp crest and a relatively shallow chest.


Moving the
glenoid downward allows a more powerful upstroke.  Extending the dp
crest further down allows a more powerful downstroke with muscles that
are operating more horizontally along the more horizontal coracoid. 
It's a way to get more bang for the buck without increasing the depth of
the torso.

>>>>>>
Think of the set (=possibly many clades) of birds that have long necks and 
soar. How do they feed? Storks, cranes and flamingoes all walk while feeding. 
Swans and geese swim. Pelicans are an exception. If we consider the set of long 
necks, soaring and long legs, pelicans drop out.

The soaring birds with short necks include gulls, albatross, boobies, skimmers, 
etc.  All feed on the wing. Vultures are an exception. If we think of marine 
birds only, then vultures drop off the list.

I see trends. 

David Peters