Table 4.
Mesiodistal (MD) length and buccolingual (BL) width of the M2, and the subnasal clivus (ns-pr) angle to the postcanine alveolar margin. The sample size (n), mean, minimum, maximum and standard deviation (s.d.) are given. Comparisons by t-test of KNM-WT 40000 with hominin species list the probability (p, one-tailed) and significance (n.s., not significant; multiple comparisons with sequential Bonferroni correction). MD1 and BL1 defined after White (1977), MD2 and BL2 after Tobias (1967). The subnasal clivus angle was measured among adult and subadult specimens (M2 in full occlusion) listed in the electronic supplementary material, S3. *p < 0.05; **p < 0.01; ***p < 0.001.
|
M2 size |
subnasal angle | ||||||
|---|---|---|---|---|---|---|---|
| MD1 | MD2 | BL1 | BL2 | source | |||
| KNM-WT 40000 | 11.4 | 11.9 | 12.4 | 12.8 | Leakey et al. (2001), this study | 47 | |
| A. anamensis | n | 8 | — | 8 | — | Ward et al. (2001), White et al. (2000) | 1 |
| mean | 12.88 | 14.50 | 27 | ||||
| min. | 11.4 | 12.9 | |||||
| max. | 14.3 | 16.7 | |||||
| s.d. | 1.04 | 1.19 | |||||
| A. afarensis | n | 12 | — | 13 | — | Kimbel & Delezene (2009) | 6 |
| mean | 13.00 | 14.80 | 34.6 | ||||
| min. | 12.1 | 13.4 | 29 | ||||
| max. | 14.1 | 15.8 | 39 | ||||
| s.d. | 0.60 | 0.60 | 3.5 | ||||
| A garhi | n = 1 | 14.4 | — | 17.7 | — | Asfaw et al. (1999) | 27 |
| A. africanus | n | — | 24 | — | 28 | Moggi-Cecchi et al. (2006), J. Moggi-Cecchi (2006, personal communication), this study | 9 |
| mean | 14.12 | 15.95 | 34.2 | ||||
| min. | 12.6 | 13.5 | 30 | ||||
| max. | 16.6 | 17.9 | 37 | ||||
| s.d. | 1.09 | 1.23 | 1.9 | ||||
| P. aethiopicus | n = 1 | — | — | — | — | 31 | |
| P. robustus | n | — | 24 | — | 24 | J. Moggi-Cecchi (2006, personal communication), this study | 8 |
| mean | 14.00 | 15.73 | 36.8 | ||||
| min. | 11.6 | 14.0 | 32 | ||||
| max. | 15.7 | 16.9 | 39 | ||||
| s.d. | 0.99 | 0.94 | 4.1 | ||||
| P. boisei | n | — | 6 | — | 6 | Tobias (1967), Leakey & Walker (1988), Wood (1991), this study | 2 |
| mean | 15.84 | 18.18 | 35.9 | ||||
| min. | 14.7 | 16.6 | 33 | ||||
| max. | 17.2 | 21.0 | 39 | ||||
| s.d. | 1.03 | 1.55 | |||||
| comparison with A. afarensis | |||||||
| p | 0.013 | 0.001 | 0.011 | ||||
| sign. | * | ** | * | ||||
| comparison with Australopithecus and Paranthropus | |||||||
| A. anamensis | p | 0.111 | 0.073 | ||||
| sign. | n.s. | n.s. | |||||
| A. afarensis | p | 0.013 | 0.001 | 0.011 | |||
| sign. | n.s. | ** | * | ||||
| A. africanus | p | 0.029 | 0.010 | 0.000 | |||
| sign. | n.s. | * | *** | ||||
| P. robustus | p | 0.024 | 0.003 | 0.024 | |||
| sign. | n.s. | * | * | ||||
| P. boisei | p | 0.008 | 0.012 | ||||
| sign. | * | * | |||||