This is a joke ... I used to live on a farm ... Mud even half a meter deep stops you from moving ... Almost makes you immobile I am happy to see you test that theory out.
Firstly, since I safely assume that you're not a pterosaur, I don't much see the relevance of your personal experience with mud.
Secondly, I've been in mud. Seeing as I didn't die of hunger because I was indefinitely stuck in it, you can tell that i moved through it.
But you know what? Fine. I'll accept your completely unverified assertion that all pterosaurs died out before other organism because they all just so happened to be standing in muddy water, if you can answer one question for me:
Why did all the pterosaurs die out before the blind mole rats did? And why are pterosaurs found below human artifacts?
If you have a look at what animals were there you see large leopards and other big game hunters.
Which are far from the only carnivores.
As for some one who mentioned crocodiles their diet consists of mainly fish. Snakes like lizards could survive off insects I would imagine.
You can imagine it, but you need to do a little more than that. Do you have any evidence that animals like, say, anancondas can survive off insects? Or that they're even known to eat them?