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Re:prolacertiformes as arboreal leapers,.



-----Original Message-----
From: Renesto Silvio <renesto@mailserver.unimi.it>
To: larryf@capital.net <larryf@capital.net>
Cc: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Friday, March 16, 2001 10:38 AM
Subject: Re:prolacertiformes as arboreal leapers,.



>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!).

Yeah! (That`s why I said "most"). But surely Tanystropheus must have had
smaller ancestors that may have climbed trees??


> 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).                        ;-)
>

Macrocnemus seems (to me) to have a body plan that resembles present day
monitors, the smaller of which do climb trees. Seems too front -heavy to
have been bipedal,...but maybe with a good running start??? It might also be
too large (at 33" adult size) to have been a glider. There must be some
cutoff size beyond which an animal would be too heavy to glide effectively.