You guys would know better than I, but last I looked, pedal digit V in
basal pterosaurs may be long, but it still only consists of two
phalanges.
Indeed. I was just making the general point that even reversals in phalanx
number are possible.
That certainly suggests to me that it's been re-elongated
secondarily.
To me, too, but of course another possibility is that the claw was lost
because it was unnecessary, like in the 3rd to 5th fingers of bats other
than *Onychonycteris*.