T. Michael Keesey wrote:
CMIIW, but don't both the ornithodiran archosaur and the prolacertiform hypotheses advocate _Sharovipteryx mirabilis_ as a pterosaur sister taxon?
As I recall, there was a talk at SVP this year showing that the mutation for yielding long fingers is relatively simple, so bats may have evolved practically overnight (in geological terms, of course).
Of course, you'd still expect there to be some gliding outgroups,
and we haven't found those, but small, arboreal animals (particularly tropical rainforest dwellers) are notoriously rare in the fossil record.
I missed that talk, unfortunately, but perhaps someone else can say more.
Cheers
Tim