Thank you very much, @lcone and @bill-heim, for the thoughtful responses. They make a lot of sense and frankly it feels good to know that I’m not completely clueless and even pros like you find ambiguity in these teeth. I’m interested in the root differences and will explore that a little more. If you could point me to some scans when you get the chance that would be super. Incidentally, I’ll be heading back to STH in Sept. While I’m there I’ll try to find a completely associated set of teeth from C. planus and another from C. hastilis just to put this matter to rest once and for all. 😉 Thanks again!