Ooh, this is lovely. The texture is beautiful and even though it's a 2D sideview, the pose is really good, and it has this sense of energy and motion to it even though the animal is standing still. Love it!
I really like it. But I think Kaz made a point, unless I have a different opinion. I think the Metatarsal is indeed too thick, but that may depend on the slim appearing shank (my guess is, that the shank looks like that because of the shading of the right leg).
Looks good overall and I like the pose, but something about the left hind limb really jumps out at me. I could easily be wrong here, but to my eyes, the metatarsal area looks very thick in relation to the rest of the leg and it looks as if the toes, particularly the outermost one, are just a bit too long. The forelimbs on the other hand, look really good.
The study does not include ceratopsians, but have a look at the hadrosaur. I have also included substantial padding on the bottoms of the feet, which what information we have seems to indicate dinosaurs as a whole possess (see: birds, Concavenator, various footprints). None of this mentioning the overall thickness and the mass required to support weight here.
The bottom-line being I do not support the classic Paulian slimline ankle for large ornithischians.
Aren't there some undescribed Triceratops specimens that may preserve evidence of quills? I may be wrong (my knowledge on ornithiscians is spotty), but I remember hearing something about that some time ago.
No there is not. Horner and others have interpreted the 'nipple' scales as being the bases of quills, but this would require a quill and scale to share the same folicle which is of course to our knowledge impossible.
Are you sure they're scales? Looking at the skin of ostriches, they also have nipple-like structures. Which if they were fossilized would probably resemble scales, especially if there is actual scales surrounding them. So that could be the case...