Is there any evidence (imprints or phylogenetic bracketing) that Pteranodon specifically had the fuzz that some pterosaurs do?

In general, just how widespread is is ptero fuzz thought to have been?

Thanks!

There's nothing specific for Pteranodon in the sense that there are no fossils of it directly preserved with fuzz (aka pycnofibers). However, this is only very rarely preserved, so our record o fit in pterosaurs is currently very limited. We do though see it in some of the most basal pterosaurs (anurognathids) and other basal forms as well as a couple of basal pterodactyloids. That's about it for now, but of course the more material we find, the more likely we are to turn up specimens.

I, and I think for other pterosaur researchers, would say that it's more likely than not that most if not all pterosaurs had pycnofibers. Pterosaurs were actively flying animals and regardless of their physiology, would be interested in retaining heat, and some kind of fiber covering would do that. Given how early this eveolves and that it's retained in a variety of forms for at least 100 mya, it would seem most odd if other pterosaurs didn't have it.