While researching Stegosaurus for the reconstruction test above, some kind soul (Nick Gardner?) from the DML referred me to this insightful article on Stegosaur lips by Stephan A.Czerkas. To Nick or whoever it was who gave me this tip, please allow me to properly give credit! I did this a while back – feels like ages – and drag it out now in response to Jaime’s theropod lips post.
The paper deals with a number of observations and comparative analysis – the deep-set teeth, the ambiguity of an upper beak, feeding necessities, cladistic inference and the similarity in bone surface to turtle jaws. Overall very convincing, particularly when formulated as a sculpture by the masterful hand of the author himself:
Most convincing of all is the general flimsiness of cheeked alternatives. The more realistic they are, the less seem plausible. There seems to be a cheek-meme in which they look like a sock-like, rubbery jaw-sleeve. I even see it in digital TV versions and the JP Triceratops is at least related. Where does this come from?
I tried to reproduce it here, with closed and open incarnations. Not convinced? Me neither. Czerkas extends likely liplessness to all advanced ornithischians, and except for mention of the many beaked theropods, leaves saurischians open to interpretation.