Another look at Anomocephalus

Figure 1. Anomocephalus skull with teeth replaced, no longer loose. It is apparent that the teeth ground against one another and that no tusks or enlarge canines were present.

Figure 1. Anomocephalus skull with teeth replaced, no longer loose. It is apparent that the teeth ground against one another and that no tusks or enlarge canines were present. Maybe less tilt to the qj and qu which would push the posterior mandible elements forward. Original tracing from Modesto and Rubidge 2000. Are some teeth upside down? Maybe. 

Earlier I made several mistakes on the skull of Anomocephalus, BP/1/5582, (since repaired). I made those mistakes because I had crappy data (small retracings of the original). And I didn’t wrap my mind around the concept of flat-topped teeth. These were novel structures, not seen in sister taxa.

Figure 2. The original reconstruction by Modesto et al.  1999.

Figure 2. The original reconstruction by Modesto et al. 1999.

You know,
it didn’t take much to reconstruct this skull from the in situ tracing by Modesto and Rubidge (2000) that I ran across recently. I just had to replace the teeth in their sockets reasonably. Here there are no canines and no sharp teeth whatsoever. The teeth are still strikingly odd, but now (Fig. 1) everything seems to ‘fit’ just fine. Perhaps  a wee bit different from the original reconstruction (Fig. 2) by Modesto et al. 1999, assuming all the scattered teeth come from the same side of the skull, the exposed side.

This, too, is an example of DGS
It is easy to see that the original reconstruction by Modesto et al. 1999 (Fig. 2) is a free hand sketch, streamlined to removed odd bumps and such. Such sketches tend to be conservative, following in patterns established by other taxa, because that’s the way the artists’ mind works. Mine does, too. However, if you just take Photoshop and cut out the teeth (Fig. 1), then put them back into the skull (DGS, digital graphic segregation) and test their occlusion by rotating the entire tooth-filled mandible within the software program, then you’ve got something that minimizes preconceptions — so you can go with what you’ve got — not what you preconceive.

Looks more “real” too, doesn’t it? There are fewer degrees of separation in figure 1 compared to figure 2.

References
Modesto S, Rubidge B and Welman J 1999. The most basal anomodont therapsid and the primacy of Gondwana in the evolution of the anomodonts: Proceedings of the Royal Society of London, series B, 266: 331-337.
Modesto S and Rubidge B 2000. A basal anomodont therapsid from the lower Beaufort Group, Upper Permian of South Africa. Journal of Vertebrate Paleontology 20(3):515-521.

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