and their foot bones are generally slender anyway, implying they weren't used in any apprehensive fashion. However, this is not to say that some pterosaurs don't have well-developed pedal claws: UV light on Pterodactylus and tapejarid material from the Solnhofen and Crato limestones show that some pterosaurs had enormous, recurved claws on their feet. They are relatively slender despite their length though, so any pterosaur trying to grab struggling prey with claws like these might've done more damage to itself than it would to its prey.
One more word on this: if, like me, you're a broad-wing proponent, you
might find it hard to imagine a pterosaur employing pedal apprehension
of aerial prey at least without compromising the wing membrane, an
action unlikely to increase the chance of prey acquisition at best. I
suppose you could still drop, hawk-style, onto an unbearably cute
Mesozoic bunny analogue, but then the points above come into play.