Hyperostotic traits

The hyperostotic traits included in this study are the pterygospinous spur (Ps), pterygobasal spur (Pb), clino-clinoid bridge (Cl), carotico-clinoid bridge (Ca), trochlear spur (Ts), divided hypoglossal canal (Dh), precondylar tubercle (Pt), mylohyoid bridge (Mh), ossified apical ligament (Oa), divided jugular canal (Dj), marginal foramen (Mf), supraorbital foramen (Sf), and the intermediate condylar canal (Ic). Table 5.9 lists the p-values (above the dash) and phi coefficients (below the dash) for the male pairwise comparisons of the hyperostotic traits.

Table 5.9 Male hyperostotic trait correlations, p-values above phi coefficients

In the male population, there are 9 significant correlations at the 0.05 significance level (Mf/Oa, Mf/Sf, Ps/Mh, Cl/Ca, Cl/Sf, Ca/Dj, Ca/Mh, Ts/Dj, and Ic/Sf). One of these can be excluded as it has a negative phi coefficient (Ts/Dj), leaving eight significant correlations at the 0.05 level. Of those eight traits, four (Ps/Mh, Cl/Ca, Ca/Dj, and Ca/Mh) are also significant at the 0.01 level. Because there were 78 pairwise comparisons calculated, we would expect to see fewer than four

significant correlations at the 0.05 level and just under one significant correlation at the 0.01 level. Thus there are approximately four times the number of

significant correlations expected at the 0.01 level, and so the hypothesis of independence in hyperostotic traits (Ps, Mh, Cl, Ca, and Dj) is rejected. A common genetic origin may be a plausible explanation for the high positive correlations between these traits. The most significant of the correlations will be explored further in chapter 6.

For the female population, table 5.10 lists the pairwise correlations between hyperostotic traits. Mf Ps Pb Cl Ca Ts Dh Pt Dj Mh Oa Ic Sf Mf 2 0.76 0.74 0.82 0.89 0.63 0.24 0.97 0.98 0.59 0.02 0.98 0.04 Ps 20.02 2 0.92 0.30 0.39 0.17 0.76 0.38 0.25 0.00 0.59 0.41 0.89 Pb 20.02 0.01 2 0.69 0.93 0.76 0.47 0.30 0.75 0.53 0.43 0.27 0.72 Cl 20.02 20.08 0.03 2 0.00 0.52 0.55 0.53 0.73 0.78 0.39 0.98 0.03 Ca 0.01 0.06 20.01 0.33 2 0.64 0.22 0.72 0.01 0.00 0.91 0.67 0.21 Ts 20.03 0.10 0.02 20.05 20.04 2 0.98 0.11 0.02 0.99 0.10 0.49 0.36 Dh 0.09 0.02 0.05 20.04 0.09 0.00 2 0.88 0.11 0.17 0.53 0.57 0.87 Pt 0.00 20.07 20.08 0.05 20.03 0.12 0.01 2 0.71 0.79 0.23 0.12 0.98 Dj 0.00 0.08 0.02 0.03 0.18 20.16 0.12 20.03 2 0.06 0.56 0.64 0.67 Mh 0.05 0.28 0.06 0.03 0.34 0.00 0.12 20.02 20.17 2 0.94 0.45 0.34 Oa 0.17 0.04 0.06 0.06 0.01 0.12 0.05 20.09 20.04 20.01 2 0.56 0.08 Ic 0.00 0.06 0.08 0.00 0.03 0.05 0.04 0.12 0.03 0.07 20.04 2 0.02 Sf 0.15 20.01 0.03 0.17 0.09 20.07 20.01 0.00 0.03 20.08 0.13 0.18 2 Male?Hyperostotic?Trait?Comparisons

Table 5.10 Female hyperostotic trait correlations, p-values above phi coefficients

In the female population, there are six significant correlations at the 0.05 level (Ps/Mh, Cl/Ca, Ts/Mh, Ts/Ic, Dh/Dj, Pt/Oa), two of which have negative phi coefficients indicating independence of the two traits (Ts/Ic and Dh/Dj). All of the four remaining traits (Ps/Mh, Cl/Ca, Ts/Mh, Pt/Oa) are significant at the 0.01 level. In a test of 78 pairwise comparisons, we would expect to see just under four significant correlations at the 0.05 level and just under one significant

correlation at the 0.01 level. Because there are four significant correlations at the 0.01 level, which is more than four times what would be expected by chance, it is possible that some of the hyperostotic traits are linked to one another (Ps, Mh, Cl, Ca, Pt, and Oa) using the 0.01 significance level. Highly significant correlations will be further investigated in chapter 6.

5.3.3 Ossicles

The ossicle-related traits included in this study are the coronal ossicle (Co), bregmatic ossicle (Bo), sagittal ossicle (So), lambdic ossicle (Lb), lambdoidal ossicle (Lo), asterionic ossicle (As), occipito-mastoid ossicle (Om), parietal notch ossicle (Pn), squamosal ossicle (Sq), and pterionic ossicle (Po). Table 5.11 lists

Mf Ps Pb Cl Ca Ts Dh Pt Dj Mh Oa Ic Sf Mf 2 0.19 0.47 0.55 0.16 0.46 0.06 0.09 0.28 0.59 0.80 1.00 0.84 Ps 0.09 2 0.63 0.71 0.34 0.92 0.15 0.38 0.77 0.01 0.38 0.73 0.93 Pb 0.05 0.03 2 0.12 0.56 0.49 0.61 0.43 0.19 0.22 0.54 0.09 0.57 Cl 0.04 0.05 0.10 2 0.00 0.48 0.35 0.21 0.93 0.69 0.21 0.50 0.81 Ca 20.10 0.06 20.04 0.26 2 0.89 0.36 0.66 0.47 0.34 0.18 0.44 0.90 Ts 20.05 0.01 20.05 0.05 20.01 2 0.20 0.90 0.59 0.01 0.90 0.03 0.08 Dh 20.13 0.10 20.03 0.06 0.06 20.08 2 0.24 0.00 0.24 0.62 0.43 0.42 Pt 0.11 20.06 0.05 20.08 20.03 20.01 20.08 2 0.12 0.36 0.01 0.59 0.44 Dj 0.07 20.02 0.09 0.01 20.05 0.04 20.19 0.10 2 0.33 0.10 0.58 0.57 Mh 20.04 0.20 0.09 20.03 20.07 0.19 20.09 20.07 0.07 2 0.36 0.12 0.72 Oa 20.02 20.06 20.04 20.08 20.09 20.01 20.03 0.16 20.11 20.07 2 0.20 0.43 Ic 0.00 0.02 20.11 0.05 0.05 20.14 0.05 20.04 0.04 20.12 20.09 2 0.93 Sf 20.01 20.01 20.04 0.02 0.01 20.12 20.05 20.05 0.04 0.03 20.05 20.01 2 FemaleAHyperostoticATraitAComparisons

the correlations for the male population subset for the ossicles, with p-values above the dashed line and phi coefficients under the line.

Table 5.11 Male ossicle trait correlations, p-values above phi coefficients

For the male population subset, there are 10 pairwise correlations significant at the 0.05 level, none of which have negative phi coefficients (Co/Pn, So/Lo, So/Po, Lo/As, Lo/Pn, Lo/Sq, Lo/Po, As/Pn, Om/Pn, and Pn/Sq). Of these

significant correlations, six are significant at the 0.01 level (So/Po, Lo/Pn, Lo/Sq, As/Pn, Om/Pn, and Pn/Sq). In a sample of 45 pairwise comparisons, two to three significant correlations are expected by chance at the 0.05 level and less than one significant correlation at the 0.01 level. Because there are 10 significant correlations at the 0.05 level in this sample and six significant correlations at the 0.01 level, it is hypothesized that there is a genetic connection between the ossicles, with the exception of the bregmatic ossicle (Bo) and the lambdic ossicle (Lb) in the male population, a connection that will be further discussed in chapter 6.

Table 5.12 lists the correlations for the female population of the subset for the ossicle-related traits, with the p-values above the dashed line and the phi coefficients below the line.

Co Bo So Lb Lo As Om Pn Sq Po Co . 0.82 0.65 0.78 0.59 0.08 0.17 0.03 0.03 0.49 Bo .0.02 . 0.78 0.18 0.95 0.58 0.72 0.64 0.80 0.63 So .0.03 .0.02 . 0.35 0.05 0.96 0.50 0.73 0.09 0.00 Lb 0.02 0.10 0.07 . 0.21 0.29 0.81 0.90 0.22 0.47 Lo 0.04 0.00 0.15 0.09 . 0.03 0.61 0.00 0.01 0.03 As 0.13 .0.04 0.00 .0.08 0.16 . 0.16 0.00 0.14 0.10 Om 0.10 .0.03 .0.05 0.02 0.04 0.10 . 0.00 0.54 0.87 Pn 0.16 .0.04 0.03 0.01 0.21 0.23 0.23 . 0.00 0.43 Sq 0.16 .0.02 0.12 0.09 0.19 0.11 .0.05 0.24 . 0.06 Po 0.05 .0.04 0.30 .0.05 0.16 0.12 .0.01 0.06 0.13 . Male>Ossicle>Trait>Comparisons

Table 5.12 Female ossicle trait correlations, p-values above phi coefficients

For the female population, the bregmatic ossicle (Bo) was absent in all crania in the population. Thus phi coefficients could not be generated (shown as ‘–‘ in the table). Of the 36 pairwise comparisons that were completed, 10 trait pairs were found to be significant at the 0.05 level (Co/As, So/Lb, So/As, So/Om, Lb/Lo, Lo/Pn, As/Om, Pn/Sq, Pn/Po, and Sq/Po), none of which had negative phi coefficients. Of the 10 traits, seven were significant at the 0.01 level (Co/As, So/Lb, So/As, Lo/Pn, As/Om, Pn/Sq, and Sq/Po). In a sample size of 36 pairwise comparisons, we would expect to see less than two significant correlations at the 0.05 level and less than one correlation at the 0.01 level, so we are seeing more than seven times the expected level of correlation at the 0.01 level. Because of this higher than expected rate of correlation, it is hypothesized that there is a genetic linkage between the ossicle traits in the female population, which will be discussed further in chapter 6.