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Getting to the Point: Defining, Reconstructing and Investigating Shape Through a Procrustean Protocol Cover

Getting to the Point: Defining, Reconstructing and Investigating Shape Through a Procrustean Protocol

Open Access
|May 2025

Figures & Tables

jcaa-8-1-161-g1.png
Figure 1

Modules of the os coxae (lateral view of the left side). The ilium, ischium and pubis are illustrated and, in light blue, their secondary ossification centres and the joints which fuse in maturity (Gray 1918: 238).

jcaa-8-1-161-g2.png
Figure 2

Os coxae digitisation templates created in Viewbox 4. The first template (a) substantially over-sampled the os coxae with coordinate points located at landmarks (dark blue), semi-landmarks along curves (light blue at extremal borders and red at borders between modules) and surface semi-landmarks (green). The revised template (b) contained fewer coordinate points and included landmarks (dark blue) and semi-landmarks along extremal borders (light blue). The final template is available at: https://doi.org/10.15131/shef.data.25498276) (Wigley and Blackwell 2024).

Table 1

The levels of ‘missingness’ introduced into simulated datasets.

‘MISSINGNESS’CONFIGURATIONS AFFECTEDVOLUME OF NAS IN DATASETSIMULATED SCENARIO
Low25%10%Small patches of NAs simulating a reasonably complete assemblage with minor cortical erosion
High75%30%Large patches of NAs mimicking assemblages affected by post-mortem disturbance and severe fragmentation
Diffuse100%20%Patches of NAs reflecting an assemblage deposited in a substrate incompatible with cortical preservation and affected by factors promoting moderate fragmentation
jcaa-8-1-161-g3.png
Figure 3

LaSEC sampling results. Plots illustrate the ‘fit’ between full and sampled configurations achieved by each of the ten iterations of sampling (grey lines) as well as the overall median fit (black line) for the whole os coxae (a), ilium (b), ischium (c) and pubis (d).

Table 2

Procrustes ANOVA to investigate factors affecting os coxae morphology. Significance determined through RRPP with 1000 permutations.

EFFECTSDFSSMSR2FP
site10.01350.01350.06992.17560.004
sex10.01830.01830.09472.94750.001
residuals260.16120.00620.8354
Total280.1929
Table 3

Numerical summary of the distances between consensus configurations from datasets with imputed coordinate points and the consensus of the observed data.

MISSING VALUESALIGNMENTMETHODMINIMA1ST QUARTILEMEDIANMEAN3RD QUARTILEMAXIMA
LowunalignedRF0.0094520.0120470.0135770.0136640.0149650.021430
TPS0.0012090.0013870.0014980.0015190.0016420.001906
alignedRF0.0015930.0021490.0023200.0023070.0024650.002744
TPS0.0012140.0013900.0015030.0015210.0016390.001909
HighunalignedRF0.0504200.0664900.0739600.0748800.0832800.100650
TPS0.0053110.0065650.0070050.0070460.0075200.009426
alignedRF0.0055850.0072050.0077870.0077980.0083450.009446
TPS0.0052280.0064640.0069080.0069400.0073650.009446
DiffuseunalignedRF0.0470700.0622500.0662900.0678400.0739400.087280
TPS0.0061120.0068540.0073830.0073200.0077170.008631
alignedRF0.0059730.0066550.0069730.0070910.0073640.009446
TPS0.0061960.0069210.0075060.0074420.0078390.008845
jcaa-8-1-161-g4.png
Figure 4

Boxplots evaluating the performanace of imputation methods. These represent the distance between the observed consensus configuration and the consensus configurations of unaligned and Procrustes-aligned simulated datasets with ‘low’ (a), ‘high’ (b) and ‘diffuse’ (c) missing data after NAs had been filled by either RF or TPS imputation. On the righthand, the CRν coefficients associated with unaligned RF (1), aligned RF (2), unaligned TPS (3) and aligned TPS datasets (4) are also contrasted to the observed coefficient (blue line) and the upper and lower 95% CIs suggested by boostrapping (red lines).

jcaa-8-1-161-g5.png
Figure 5

PCA visualisations. Plots illustrate the relationship between the observed consensus configuration (green) and consensus configurations associated with aligned and unaligned datasets with ‘low’ (a), ‘high’ (b) and ‘diffuse’ (c) levels of missing values filled by RF (blue) and TPS (red) imputation.

DOI: https://doi.org/10.5334/jcaa.161 | Journal eISSN: 2514-8362
Language: English
Submitted on: Apr 3, 2024
Accepted on: Mar 25, 2025
Published on: May 6, 2025
Published by: Ubiquity Press
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year

© 2025 Ben R. Wigley, Paul G. Blackwell, published by Ubiquity Press
This work is licensed under the Creative Commons Attribution 4.0 License.