My students and I at UW-Oshkosh, as well as a few collaborators around the country, are working on a study involving abnormal structures on pachycephalosaurid crania. Our goal is to differentiate taphonomic artifacts from structures that have potential to be paleobiological in origin. We have just submitted two abstracts for North Central GSA for 2011 dealing with this current project.
From interactions I've had with other researchers in marginocephalian paleobiology or dinosaur taphonomy in general, I'm getting the impression that there is an assumption that if you are studying abnormal structures on a dinosaur skull, you are probably going to call everything a pathology. While I understand the concern based on how common it is to come across manuscripts that make such leaps, this is something we are being very careful not to do. It should be noted, however, that there are manuscripts that have labeled lesions as "pathologies" and have not done so haphazardly (e.g. Wolff et al., 2009; Peterson et al., 2009; Longrich et al., 2010).
Most abnormal structures seen on pachycephalosaur crania are casually disregarded as "water wear". However, this has yet to be tested and reported on in the literature. I have yet to see a thorough, detailed analysis of pachycephalosaur dome "lesions" in order to investigate potential etiologies. As such, that is our main goal. A similar approach was taken by Tanke and Farke (2006), in which bone resorption was identified as a primary etiology for abnormal cranial lesions on ceratopsians.
And, of course, there is the real question regarding pachycephalosaurs: frontoparietal dome function. What might these little erosive structures suggest about the function of a pachycephalosaurid dome? That is the real question.