For the past several years or so, there has been a particular trend in the reconstruction of ceratopsian dinosaurs. Specifically, it has become relatively commonplace to depict the horned dinosaurs with a set of quills, either on the tail or throughout the body. Here I wish to discuss the origin of this trend, and give my thoughts on the issue.
It all started with the description of a spectacular Psittacosaurus specimen from Liaoning, China, which included not only the outline of the animal's body, but also a series of quills sticking out from the top of its tail. Since this discovery, it has become the rule to depict this genus with quills, in keeping with the revelation of this find. Eventually, some artists began to take this even further, and began portraying other ceratopsians with a similar set of quills on the tail, or a covering of quills on the back and torso area. I don't know exactly when this began, but it seems to have been spurred on by a Triceratops specimen, nicknamed Lane, preserving some of the skin. Among the different types of scales, some are elevated and vaguely cone-like. It has been speculated that these scaled may have served as bases for quills, no doubt inspired by the Psittacosaurus specimen from China.
What do I make about all this? Let's start off with Psittacosaurus. The presence of quills on the famous specimen is indisputable. However, I can't help but wonder how widespread this feature actually was among the genus. Psittacosaurus is a diverse genus with many species. Is it possible that some species had quills while others didn't? Also, could different species have had different arrangements of quills? Maybe some species had quills throughout their bodies while others just had them on their tails. Or maybe the size of the quills varied by species. We do not even know how the quills varied within the species. Ontogeny, gender, or other factors might have influenced features of the quills, or even whether they were present at all. With only one specimen (as far as I know anyway), we cannot be certain as to how widespread these features were.
What about Lane the Triceratops? While the discovery of the fossilized skin is undoubtedly a cool find, I'm not convinced they show evidence of quills. It's quite possible the tall scales in question are just that. Maybe Triceratops was just a bumpy dinosaur. While it's not impossible that they were bases for quills, I do not think the evidence is strong enough yet to say for certain that Triceratops was a bristly dinosaur.
All this being said, however, I am not necessarily opposed to the depiction of ceratopsians other than Psittacosaurus having quills. I just think it remains a speculative issue at the moment. If you feel like giving your ceratopsians quills, feel free to do so, I will not complain. As for Psittacosaurus, I don't think it's wrong to depict them with the same quill arrangement as shown for the one fossil. However, I would also suggest maybe getting a little creative with them. There are many possibilities out there, and until more fossils turn up, I think it would be interesting to explore more of them in art. Just my two cents.