TABLE 1. Summary of Canis dirus cranial material used in the course of this study. Pit deposit information and dates in years before present condensed from O'Keefe et al., 2009; for calibration information see that reference and Meachen et al., 2014. The quoted pit ages are median ages in the windows of deposition, and constraint on the duration and time of each window is currently poor for most pits. For further discussion see O'Keefe et al., 2009.
Pit Number |
Pit Age |
N, Fracture |
N, Wear |
N, Skulls |
61/67 |
13.8 kya |
1120 |
106 |
17 |
13 |
17.9 kya |
797 |
37 |
16 |
2051 |
26.1 kya |
568 |
115 |
22 |
91 |
28 kya |
367 |
75 |
18 |
TABLE 2. Fracture and Wear Data. Table shows number of teeth examined for fracture in each pit, number of broken teeth found, and percentage. For wear data, N = the number of worn teeth identified, SW denotes slight wear, SMW slight to moderate wear, MW, medium wear, MHW, medium to heavy wear, H, heavy wear. Weighted wear percent is the average wear score for each pit. These data are plotted in Figures 1 and 2.
Pit |
Teeth, N |
Teeth, Broken |
Broken % |
SW |
SMW |
MW |
MHW |
H |
N |
Weighted Wear % |
61/67 |
1120 |
25 |
2.23 |
39 |
29 |
28 |
8 |
2 |
106 |
2.104 |
13 |
797 |
55 |
6.90 |
5 |
16 |
12 |
3 |
1 |
37 |
2.432 |
91 |
367 |
27 |
7.36 |
17 |
23 |
20 |
9 |
6 |
75 |
2.520 |
2051 |
568 |
12 |
2.11 |
40 |
38 |
20 |
11 |
6 |
115 |
2.174 |
TABLE 3. Pairwise comparisons among pits for tooth fracture and tooth wear. P values calculated from correspondence analysis and Wilcoxon nonparametric rank sums test; values were very similar for both tests. For raw percentages and wear values see Figures 1 and 2. Single stars indicate significance below the 0.05 level; double stars indicate significance below the 0.01 level.
Comparison |
61/67-2051 |
61/67-13 |
61/67-91 |
13-91 |
2051-91 |
2051-13 |
Tooth Fracture |
p<.8743 |
p<.0001** |
p<.0001** |
p<.7778 |
p<.0001** |
p<.0001** |
Tooth Wear |
p<.8464 |
p<.0455* |
p<.0180* |
p<.9306 |
p<.0275* |
p<.0518 |
TABLE 4. Description of landmarks used in this study. See Figure 3 for locations.
Landmark |
Description |
|
1 |
prosthion |
Premaxilla between medial incisors |
2 |
nasion |
Farthest posterior extent of nasals on midline |
3 |
bregma |
Frontal/parietal suture at midline |
4 |
inion |
Posterior tip of sagittal crest |
5 |
opisthion |
Posterior border of foramen magnum at midline |
6 |
basion |
Inferior border of foramen magnum at midline |
7 |
staphylion |
Posterior tip of palatines at midline |
8 |
pal/max sut |
Palatine-maxillary suture at midline |
9 |
incisivon |
Midline suture at anterior border of incisive foramina |
10 |
postI3 |
Posterior border of I3 alveolus |
11 |
antC1 |
Anterior margin of C1 alveolus |
12 |
postC1 |
Posterior margin of C1 alveolus |
13 |
antP1 |
Anterior margin of P1 alveolus |
14 |
antP4 |
Anterior margin of P4 alveolus |
15 |
P4/M1 |
Posterior margin P4 alveolus/anterior margin M1 alveolus |
16 |
postM2 |
Posterior margin M2 alveolus |
17 |
prm/max/nas |
Posterior end of dorsal premaxillary process |
18 |
orbitinf |
Inferior margin of orbit |
19 |
postorb |
Tip of postorbital process |
20 |
opticinf |
Inferior border of optic canal |
21 |
par/tmpzyg |
Location on parietal-temporal suture directly above posterior root of zygomatic process |
22 |
porion |
Superior margin of external auditory meatus |
23 |
antbulla |
Posterior border of pharyngotympanic tube |
24 |
prm/maxC1 |
Location of premaxilla-maxilla suture on medial margin of C1 alveolus |
25 |
prm/maxinc |
Location of the premaxilla-maxilla suture on lateral margin of incisive foramen |
26 |
M2postmed |
Closest point of M2 alveolus to the midline |
27 |
M1med |
Closest point of M1 alveolus to the midline |
TABLE 5. Centroid size pairwise comparisons.Significance of pairwise comparisons among pits based on one-way Student's T tests among means. For distributions see Figure 4. Single stars indicate significance below the 0.05 level; double stars indicate significance below the 0.01 level.
Comparison |
61/67-2051 |
61/67-13 |
61/67-91 |
13-91 |
2051-91 |
2051-13 |
Size |
p<.3300 |
p<.0669 |
p<.0735 |
p<.0021** |
p<.3493 |
p<.0092** |
TABLE 6. Results of a permutation test on Procrustes shape coordinates. Reported values are summed Procrustes distances among all landmarks for each pairwise pit comparison, as listed. All pits are significantly different in aggregate. For visualization of landmark locations among mean shapes from each pit, see Supplementary Animations 1, 2, 3. Single stars indicate significance below the 0.05 level; double stars indicate significance below the 0.01 level.
Pairwise Pit Comparisons |
Total Procrustes Distance |
P value, alpha < |
UCMP vs. p13 |
0.0189778 |
0.000** |
UCMP vs. p61 |
0.0187161 |
0.000** |
UCMP vs. p91 |
0.0267971 |
0.000** |
p13 vs. p61 |
0.0154740 |
0.004** |
p13 vs. p91 |
0.0191137 |
0.000** |
p61 vs. p91 |
0.0226563 |
0.000** |
TABLE 7. Proportions of total Procrustes distance accounted for by the factors centroid size, individual pits, and all pits.
Factor |
Procrustes sum of squares |
Percentage of total |
Total |
0.0012216192 |
100.0% |
Ln(centroid size) |
0.0000400096 |
3.3% |
All Pits |
0.0001652656 |
13.5% |
Pit 61 |
0.0000373441 |
3.1% |
Pit 13 |
0.0000259306 |
2.1% |
Pit UCMP |
0.0000761901 |
6.2% |
Pit 91 |
0.0000838070 |
6.9% |
Size + Pits |
0.0001933500 |
15.8% |
TABLE 8. One-way ANOVAs of principal components by pit derived from ordination of the covariance matrix of three-dimensional landmark data. First five components are shown; they account for 47% of the variance in the data set. Ninety percent of the variance was accounted for by 28 principal components. Regression results for correlation with centroid size are also shown. For plots of PCs 1 and 4 see Figure 6; for plots of PCs 2 and 3 see Figure 7. Shape transitions along each principal component are visualized in Supplementary Animations 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15. Single stars indicate significance below the 0.05 level; double stars indicate significance below the 0.01 level.
PC |
Percent Explained |
One-way ANOVA, by Pit |
Means, T 61/67-2051 |
61/67-13 |
61/67-91 |
13-91 |
2051-91 |
2051-13 |
Regression, Centroid size |
PC I |
14.42 |
F ratio 0.8770 p < 0.4574 |
0.4361 |
0.4564 |
0.6867 |
0.2509 |
0.7162 |
0.1224 |
F ratio 4.8319 p < 0.0312* |
PC II |
13.09 |
F ratio 20.1406 p < 0.0001** |
0.0119* |
0.3909 |
0.0001** |
0.0003** |
0.0001** |
0.0009** |
F ratio 1.5024 p < 0.2244 |
PC III |
7.75 |
F ratio 3.9191 p < 0.0121* |
0.0590 |
0.9496 |
0.1868 |
0.2162 |
0.0012** |
0.0547 |
F ratio 1.5624 p < 0.2154 |
PC IV |
6.81 |
F ratio 6.0364 p < 0.0010** |
0.0046** |
0.0173* |
0.0001** |
0.1061 |
0.1468 |
0.7706 |
F ratio 4.1100 p < 0.0464* |
PC V |
5.60 |
F ratio 4.9423 p < 0.0036** |
0.0019** |
0.9834 |
0.440 |
0.4348 |
0.0164* |
0.0021** |
F ratio 0.0775 p < 0.7815 |
TABLE 9. Interlandmark Distances. Significance of pairwise comparisons of wireframe distances among pits based on one-way Student's T tests among means. Single stars indicate significance below the 0.05 level; double stars indicate significance below the 0.01 level. Illustrated in Figures 8 and 9.
Comparison |
61/67-2051 |
61/67-13 |
61/67-91 |
13-91 |
2051-91 |
2051-13 |
Prosthion-Nasion |
0.2964 |
0.0001** |
0.1639 |
0.0035** |
0.6697 |
0.0006** |
Prosthion-Staphylion |
0.3797 |
0.0066** |
0.9458 |
0.0071** |
0.4118 |
0.0393* |
Staphylion-Basion |
0.8047 |
0.0054** |
0.048* |
0.3555 |
0.0194* |
0.0016** |
antC1-postC1 |
0.2661 |
0.0031** |
0.0002* |
0.4126 |
0.0027** |
0.0354* |
P4/M1-PostM2 |
0.0197* |
0.0084** |
0.0198* |
0.6880 |
0.9104 |
0.5972 |
postC1-antP4 |
0.0329* |
0.0217 |
0.0022** |
0.4585 |
0.2469 |
0.7275 |
postC1-PrMxC1 |
0.0080** |
0.0419* |
0.0403* |
0.9646 |
0.5838 |
0.6286 |
Staphylion-postmedM2 |
0.1439 |
0.4394 |
0.0005** |
<0.0001** |
0.0199* |
0.0259* |
Prosthion-C1mxpremx |
0.1411 |
0.1356 |
0.0855 |
0.0018** |
0.0012** |
0.8909 |
P4/M1-postmedM2 |
0.1411 |
0.1356 |
0.0855 |
0.0018** |
0.0012** |
0.8909 |
antC1-PrMxC1 |
0.2067 |
0.9331 |
0.0776 |
0.0687 |
0.0021** |
0.2487 |
Prosthion-antC1 |
0.0696 |
0.0671 |
0.2301 |
0.0030** |
0.0023** |
0.8728 |
Pros-M1med |
0.0736 |
0.2629 |
0.2344 |
0.0230* |
0.0026** |
0.5580 |