Skull proportions and size of the pre-orbital bar

Skull proportions and size of the preorbital bar (32)

1. Compared to many other ancient Northamerican equids (SD-2) Scatter diagram 2, all ‘typical’ Cormohipparion A and B (morphs 1) have a longer bar (32) relative to the length of the NIN (30).

2. The separations is, however, not so sharp (SD-3) when other morphs A and B are plotted :

– the skull from June Q. 613-150 (A-7) occupies an intermediate position between Cormohipparion A and B ;

– the skull 107764 from Trail Side Kat (B-2) plots close to Leptarchus 108644 (A-7) ;

– Cormohipparion goorisi 69600 is not very far from the ‘small 32’ group.

3. The next scatter diagram (SD-4) shows the overlap between Cormohipparion A and all other Group A skulls, including those without POF.