The heads of diplodocids have been widely depicted with the nostrils on top due to the position of the nasal openings at the apex of the skull. There has been speculation over whether such a configuration meant that diplodocids may have had a trunk. A 2006 study surmised there was no paleoneuroanatomical evidence for a trunk. It noted that the facial nerve in an animal with a trunk, such as an elephant, is large as it innervates the trunk. The evidence suggests that the facial nerve is very small in diplodocids. Studies by Lawrence Witmer (2001) indicated that, while the nasal openings were high on the head, the actual, fleshy nostrils were situated much lower down on the snout.
