The Therapsids

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Bone Heads? — the Behaviour of Dinocephalians
The dinocephalians were probably not the brightest of creatures (their brain was the one part that didn't get bigger). But, here we mean 'bone heads' quite literally.  Although most noticeable in later dinocephalians, all of these animals featured pachyostosis — a great thickening of the bones on the top of the skull which increased as the animal grew into adulthood.  We suspect that these animals engaged in head-butting contests because of the arrangement of their skull bones. Tremendously thick, the dino- cephalians' skulls would also transfer impact forces directly to their sturdy neck vertebrae and powerful muscles [see below]. These dinocephalian jousts would have been relatively sedate affairs — more of a pushing contest, really. The dinocephalians could not have matched the agility of modern head-butters such as Big Horn Sheep.  That’s the trouble with being a Bone Head — there's just not a lot of room left in that thick skull for brains!

Moschops capensis establish dominance  —  top
Pachyostosis — head-bone thickening — reached its Dinocephalian extreme with Moschops.  The top of an Moschops adult’s 38cm-long skull was at least 11.5mm thick! The smaller animals in the foreground are plant- eating dicynodonts  —  Chelydontops ('toothed turtle face' — 1m long) on the right, and Pristerodon ('sawn from the earth tooth' —  50cm long)  scattering on the left. We will be hearing more about dicynodonts later.

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