As with the dromaeosaur tails, the teeth of Sinornithosaurus also allow us to revisit a recent post on anatomy – the anatomy of theropod teeth. As before the photo isn’t perfect, but should be well enough to illustrate a few points.
The point where the root ends and the crown starts is quite well demarked. Although the teeth are loose in the sockets and have extruded, the crown is curved where the root is straight and there’s a slight colour difference too. There is also a deep groove on the tooth root and in some cases this extended part-way onto the crown.
Astute readers will be thinking about a recent paper on this very taxon and its tooth a jaw morphology, but I’m not going to comment here on it (that’s what the literature is for, not blogs, or comments as far as I’m concerned). I do think it’s safe and uncontroversial to say that more work is needed in this particular area however.