Extended Data Fig. 9: Vertebral morphology.

A) Articular pillar morphology and lower facet orientation. Comparison in dorsal and caudal views of the seventh cervical vertebra from ThI-GH-10717/3 compared to KNM-WT 15000 and to a recent Homo sapiens (figures not to scale). The arrow indicates the presence of a marked notch in the articular pillars between the upper and the lower articular facets. The black lines indicate the approximate orientation of the lower articular facets, which are slightly convex and display a ventral-lateral orientation in ThI-GH and KNM-WT 15000, while they are flatter with a ventral to ventral-medial orientation in recent Homo sapiens. B) Box plots of vertebral canal area relative to vertebral body geometric mean (following and modified from¹³⁴). All the Casablanca specimens fall close to the H. sapiens mean, except for the T2, where both KNM-WT 15000 and ThI-GH specimens show very low value. In the boxplots, the whiskers represent the 1.5 times the interquartile range, the box represents the interquartile range, and the centre represents the median. The Pan troglodytes sample was compared to the Homo sapiens sample using a two-tailed Student’s T-tests. The different fossil specimens (Dmanisi, Sima de los Huesos, ThI-GH, KNM WT-15000 and Gran Dolina-TD6 and MH1) were compared to the Homo sapiens sample using a z-score analysis. * = significantly different from Homo sapiens (p < 0.05); ** = significantly different from Homo sapiens (p < 0.01). Comparative sample sizes: Pan troglodytes (C3: n = 18; C7: n = 13; T1: n = 10; T2: n = 19); Homo sapiens (C3: n = 62; C7: n = 37; T1: n = 25; T2: n = 52)¹³⁴.