Table 1.

PCs of the maxillary shape analysis. The landmarks of KNM-WT 40000 are corrected for distortion. The sample size (n), mean, minimum, maximum and standard deviation (s.d.) are given, and the comparisons of KNM-WT 40000 by t-test list the probability (p; one-tailed, except ⁺two-tailed) and the significance (multiple comparisons after sequential Bonferroni correction). n.s., not significant; *p < 0.05; **p < 0.01.

		PC1	PC2	PC4	PC5
KNM-WT 40000		−0.068	−0.003	0.049	0.065
A. anamensis	n = 1	0.167	0.064	−0.045	−0.009
A. afarensis	n	6	6	6	6
	mean	0.1285	−0.0742	−0.0012	0.0014
	min.	0.053	−0.129	−0.024	−0.030
	max.	0.198	−0.001	0.018	0.038
	s.d.	0.0623	0.0498	0.0136	0.0262
A. garhi	n = 1	0.178	0.029	−0.011	−0.027
A. africanus	n	4	4	4	4
	mean	0.1065	0.0558	0.0076	−0.0004
	min.	0.064	0.025	−0.046	−0.015
	max.	0.152	0.092	0.043	0.030
	s.d.	0.0401	0.0316	0.0382	0.0208
P. aethiopicus	n=1	−0.152	0.068	−0.010	−0.040
P. robustus	n	6	6	6	6
	mean	−0.1879	0.0073	−0.0040	0.0014
	min.	−0.259	−0.070	−0.087	−0.024
	max.	−0.070	0.142	0.048	0.019
	s.d.	0.0654	0.0855	0.0488	0.0169
P. boisei	n = 1	−0.194	0.020	0.018	−0.005
comparison with A. afarensis
	p	0.016	0.120	0.010	0.037
	sign.	*	n.s.	**	*
comparison with Australopithecus and Paranthropus
A. afarensis	p	0.016	0.120	0.010	0.037
	sign.	*	n.s.	*	*
A. africanus	p	0.015	0.098	0.204	0.034
	sign.	*	n.s.	n.s.	n.s.
P. robustus	p	0.151+	0.919+	0.182	0.009
	sign.	n.s.	n.s.	n.s.	*