Confounded!

Damn cranial deformation. I can't use geometric morphometrics to analyze whether cranial robusticity diminished in populations that switched from hunting and gathering to agriculture if the agricultural populations engaged in the cultural practice of artificial, intentional cranial deformation. Look at these folks. They're all adults...

The crania are all from a Central Illinois prehistoric agricultural population. In the last picture, the lighter colored cranium on the right is not intentionally deformed, and provides a good comparison. Clearly, I can't use the posterior cranium data from the deformed individuals. The problem is, I might not be able to use mid-cranial data either. I'm not sure exactly how far forward on the cranium intentional posterior deformation has an effect. I suspect far enough that it could raise and widen the posterior aspect of the frontal bone, where I take several landmarks. Where else? Temporals? Probably. Maxillary? At least where they articulate with the temporals.

Cranial deformation could even affect the shape of the mandible: it could, for example, change the shape of the condyles, change overall shape by altering the angle of muscle attachments, or push the ramus (posterior portion of the mandible) farther forward.

Cranial deformation isn't present on all individuals in this Central Illinois population. But even that presents something of a problem. With the naked eye, it's not easy to tell the difference between an individual with a naturally broad, round cranium side-to-side (brachicephaly) and an individual with cranial deformation.

Like I said, not everyone in this population has artificial deformation, so this is not a total disaster. But it is very annoying.

Background reading:

http://www.clas.ufl.edu/users/nparr/index_files/Page398.htm