Re: Stuff on gliding vs non-gliding (was Re: Protoavis (was Re: solnhofen)

[Silvio Renesto <renesto@mailserver.unimi.it>]

Some comments to many  messages on the same thread:

>Certain studies have claimed that modern gliding mammals (by that I mean 
true patagial gliders, as opposed to modern leaping primates) do show 
certain derived *skeletal* traits not seen in non-gliding relatives.

I was aware of this, and avoided to use a broader term, restricting my
comparison to small ringtails (Acrobates and its kin)


>  Specifically, the dorsoventrally-flattened body, flattened
>tail with hair spray a la "tail fan," extended carpal cartilage,
>with mebrane works for these fellows.

This is the big problem with a gliding Megalancosaurus: the long tail is
*laterally* flattened, NOT dorsoventrally, so it provided no lift and might
have hindered balance. 
On this last topic however I'd speculate if the tail and the head + long
neck might have balanced each others ...
Is there anyone who is aware of long necked and long (not flattened) tailed
gliders? Note: just gliders, not *powered* fliers.


Okay, onto drepanosaurids....
a suspicious scapula with bent shaft
(curving forward or back?);

FORWARD.

 This suggests that portions of *Protoavis* may be
drepanosaurid in nature.... The elements of *Dolabrosaurus* from
the Chinle are not immediately comparable from what I've seen (I
have only the paper by Berman and Reisz in _J. Paleo._),

They comprise mainly a series of articulated tail vertebrae, some trunk
vertebrae with fused ribs and fragments  of manus and posterior limb. While
they can allow to ascribe this animal to drepanosaurids without any doubt,
the relevant elements for other comparison (head, neck pectoral girdle
etc.) are just lacking. Pity.

 >and
>there is a partial pectoral girdle in press in _JVP_ from >the
>Chinle. These may allow us to compare what has been released >on *Protoavis*

Being still unpublished, I cannot comment anything on the new drepanosaurid
pectoral girdle from the Dockum, but, having seen the specimen, I can say
however that it is **really** amazing stuff, especially for a better
understanding of drepanosaurid forelimb biomechanics.
Cheers,

                                Silvio (first name)
                                Renesto (last name)


 





















 
 

-

"Before being enlightened,   hard work; after enlightenment, hard work"
(Guo Yunshen).

Dr. Silvio Renesto
Dipartimento di Scienze della Terra
Università degli Studi di Milano
via Mangiagalli 34
I 20133 Milano
Italy

phone +39-0223698232
fax  +39-02-70638261

e-mail:    renesto@mailserver.unimi.it

or/and     Silvio.Renesto@unimi.it