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Pterosaur structure, good job JC



Dear John and dinolisters,

John Conway's excellent restoration of pterosaur anatomy is well worth the look. His artwork, I think, places him as the heir apparent to Doug Henderson.

John has envisioned the big traps and lats that so many artists miss. But I notice John does not put adductors on the prepubis.

I would like John to comment on his placement of the pteroid in the bowl of the pre-axial carpal, a placement that is not reflected in the fossil record, as recently shown by Chris Bennett.

I also note that the radius and ulna are not in the neutral position, but are suppinated. To move the radius to the neutral position requires not more than about a quarter of an inch move distally closer to the medial edge of the ulna and another look at the carpals orientation. With wings extended that places metacarpals I-III in the plane of the wing, as in other tetrapods and basal pterosaurs, not pasted against the leading edge as it appears in John's drawing. I'm also looking for and having a hard time seeing the big unguals in fingers I-III. When the wing fingers are placed into the standard tetrapod configuration and the radius is in the neutral position, the fingers face each other during tree trunk climbing and they hyperextend laterally during walking (with elbows oriented posterolaterally), matching ichnites. How can this happen in this configuration without some sort of strange humeral configuration?

I cannot agree with John's hypotheses on wing folding = extension and wing deployment = flexion. I'll await a further explanation that is more parsimonious than the torsioned wing metacarpal hypothesis. Hopefully it will include a phylogenetic demonstration using nonvolant sister taxa of how flexion was prevented and extension became hyper-extension. I also don't understand why palmar flexors can't flex (fold) the torsioned fourth digit.

I also liked John's earlier version of hind limb configuration during flight in which the hind limbs were more laterally oriented forming horizontal stabilizers. He mentioned examples of wing connection to the thigh or ankle. I'd be very interested in seeing those delineated.

A tip of the hat to a great artist and visionary, Hope to see the same specimen walking one of these days.

David Peters
St. Louis