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Re:prolacertiformes as arboreal leapers,.

At 09.39 16/03/01 -0500, you wrote:

>I agree with George that Dave Peters makes an excellant case for a close
>kinship between prolacertiformes and pterosaurs.


>The prolacertiforms seem an amazingly odd group in their extreme
>diversification of form. It seems (to me) that they were most likely
>arboreal (for the most part), and might have been experimenting with varios
>forms of gliding, or parachuting behavior.


>Dave Peters calls the prolacertiforms "terrestrial" forms. Although by this
>(I`m sure) he didn`t mean they didn`t climb trees, I would go one step
>further, and call ,the majority of the group "arboreal". IMHO.
I also agree with you and George that David is right about strict
relationships between prolacertiform and pterosaurs. 
  I find difficult however to find *most* of them arboreal (it is OK for
Longisquama;  Sharovipteryx? I dont' know, the 6m long Tanystropheus
surely not!).
 On some prolacertiforms (= Macrocnemus, Langobardisaurus and Cosesarus) I
basically share David Peters opinion: they  were probably facultative
bipedal runners  in the manner of some modern lizards (David and I have a
submitted  paper on this, together with Fabio dalla Vecchia). It is under
review so I cannot give further details at present. 
I have studied (in press  in Neues Jarbuch) a juvenile Macrocnemus with
skin partially preserved (not skin impression, but fossilized scales): it
looks like that of an extant european Green Lizard (Lacerta viridis).
Scales are very well preserved on part of the sacrum, tail and on the
proximal portions of the femur: no (uro)patagium there  (unless we advocate
a taphonomic bias).                        ;-)                          


                                Silvio Renesto


"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

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

e-mail:    renesto@mailserver.unimi.it

or/and     Silvio.Renesto@unimi.it