07 May 2014
Darren Naish has questioned these in the past, stating that they might be either tendon attachment points or they may indeed be quill knobs but extremely primitive versions of quill knobs. Skepticism in science is a good thing, and there is nothing wrong with putting different ideas out there as well. To my knowledge the knobs have not been investigated by themselves to date, so the describing authors and Naish's different views are all potentially valid argument points. Someone will some day pick up the ulna of Concavenator and publish a decision, but even that might take some intense testing to stand up against scrutiny. Time will tell, and some future student somewhere has a project waiting for them.