STL Science Center

STL Science Center

21 June 2011

Prenocephale News and Theories

Type II and Type I skulls, respectively
left to right.
There isn't much to share today as far as published papers are concerned. In an article in American Paleontologist's Fall 2008 edition Peter Dodson dedicated his column to Osmolska and mentions Prenocephale briefly as he talks about her research and findings in Mongolia and the Gobi desert. One of the better papers I've been able to find today, however, is a general overview of the head-butting behavior that is typically thought to exist in pachycephalosaurs. This paper is older, from 1997 originally, and therefore uses Stygimoloch as a separate species (which is still in debate for and against its inclusion in Pachycephalosaur as a species) while examining two types of head ornamentations used by head-butting dinosaurs; domed frontoparietal domed skull and blunt horned squamosal skulls. I'll leave you to read the conclusion of the paper and create your own judgement.

In addition we can look at the Prenocephale ourselves a little to augment what is presented above. Prenocephale, being a pachycephalosaur of the frontoparietal domed skull variety had a large rounded roof to their skull formation. Unlike many pachycephalosaurs where the skull is typically the only complete skeletal region recovered the skull of Prenocephale was mostly complete and a majority of the skeleton was also found in the Gobi desert by a joint venture of Mongolian and Polish scientists and described in 1974. Its name means "sloping head" and this clearly refers to the slope seen in the dome toward the front of the skull.

The clipping beak of Zuniceratops
Like most pachycephalosaurs an omnivorous diet has been proposed for Prenocephale which included ferns, soft leaves, fruits, and insects and small lizards that the animal could catch. The idea put forth quite a long time ago that pachycephalosaurs could use their head to stun and knockout small prey is pretty much an antiquated theory and largely believed to be wrong (there is always someone that believes something somewhere so don't count it totally out even today!). Prenocephale would have to stick to soft leaves and fruits as an herbivorous diet due to its lack of a clipping beak found in other marginocephalian clades (i.e. the beaks of ceratopsians) which would make stripping leaves more difficult for the animal unless it had more articulated hands with which to grab leaves. Also unlike its sister clade, the pachycephalosaurs had less of a dental grinder and this would cause them to seek softer foods and fruits as well.

Though from an upward angle below
the skull, we can see that there is the
potential for the fields of vision to at
least slightly overlap.

The general idea with the skull, actually, is thought to be centered around intra-specific combat (other Prenocephale) and at extreme moments inter-specific defense (against predators mostly) of the individual. However, below that domed skull Prenocephale appears to have had rather large eyes for a pachycephalosaur and, though I have not seen a study on this, appears to have had the ability to possess some area of binocular vision. If it did indeed possess a solid field of binocular vision, this would give it depth perception and make head-butting, feeding, running in a herd, and life in general much more three dimensional for these animals which would give them quite an advantage over other dinosaurs. It is a pretty interesting theory to start off with.

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