On Friday I gave you this piece of skull to identify:
It was in the Horniman collections with no identification beyond a pencil note saying ‘Monkey?’, but that seemed to be a bit of an odd suggestion, since primates have very rounded braincases – even the longer skulled ones like baboons. I think the person who made the tentative identification had got the section the wrong way round – thinking that the nuchal crest was a part of a brow-ridge or something – a mistake that Jake certainly didn’t make. They also missed what several of you spotted – the rugose (sort of wrinkly) structure that supported the olfactory epithelium (the inner back part of the nose where the receptors for smell are located).
What most of you did miss however, was the lack of fusion of the cranial sutures, which indicates that this was from a juvenile animal. As a result it is smaller and has far less well-developed muscle scars than an adult animal would have. A faint muscle scar can be seen converging on what looks like the beginnings of a sagittal crest (as pointed out by Manabu Sakamoto), so it seems reasonable to guess that the adult animal would have a reasonably well developed crest on the top of the braincase.