Last night’s durdle might not have been able to do much even if he were on all four, so I took another look at him:
He’s supposed to be resting on the lower hemisphere of his belly in the sketch at left, but it looks a bit like he’s flying. I was having a bit of trouble making him look spherical- as much as I like the sketch at right, he just looks like he has a very deep chest as opposed to being a round little dragon with stubby limbs.