Lizards with deltopectoral crests?

[David Peters <davidrpeters@earthlink.net>]

On a recently dissected Chlamydosaurus kingii (Australian frilled
lizard), I found small squarish deltopectoral crests, ala pterosaurs, on
the proximal humerus. I was looking for a keeled sternum, but did not
find one.

Since frilled lizards spend up to 95% of their day clinging to trees, a
behaviour hypothesized for basal pterosaurs if not all of them, the
convergence made me wonder what other lizards sport such dp crests. As
the hypothesis goes, the adduction powers of a tree-clinging
pre-pterosaur, like Longisquama, would have been modified only slightly
morphing into the adduction powers of a flapping pterosaur.

If anyone knows whether Chlamydosaurus is unique in this regard, or not,
I would be happy to hear from them.  Just how widespread are those
squarish deltopectoral crests?

On a secondary note, I've been impressed by the similarity in overall
body shape of Longisquama + the most basal pterosaurs to modern lemurs.
Short cervical series. Tail elevated at a high angle from the dorsal
series. Etc. This convergence, of course, gives further credence to
Bennett's modern hypothesis of an arboreal leaping origin to pterosaurs
which follows similar hypotheses from decades ago. If anyone would like
to discuss these convergences we can do so, either privately or
publicly.

David Peters
St. Louis