Using cranial metrics to explore ancestry
How to use:
In the side menu, you will find the Simulator tab, which allows you, through 29 classic cranial measurements, to understand how morphology influences the probability of belonging to a specific population (or the other way around!). This is accomplished through a dataset of 3163 crania from 74 worldwide samples, which were measured in 29 parameters (check these in the Manual tab). This dataset was obtained from the cranID software (Wright, 2012). Using a simple machine learning algorithm it was possible to create a prediction function which reactively generates a barplot of probabilities.
Classification Model:
Flexible Discriminant Analysis.
Code & App Development:
João Coelho, M.Sc.
joao@osteomics.com
Department of Life Sciences, University of Coimbra, Portugal
osteomics.com, Instituto Pedro Nunes
Reference:
Wright R. 2012. Guide to using the CRANID programs CR6bIND: For linear and nearest neighbours discriminant analysis. https://www.box.net/shared/static/qyaq6thdds.pdf
1. GOL Glabello-occipital length
Greatest length, from the glabellar region, in the median sagittal plane.
2. NOL Nasio-occipital lengthGreatest cranial length in the median sagittal plane, measured from nasion.
3. BNL Basion-nasion lengthDirect length between basion and nasion.
4. BBH Basion-bregma heightDistance from basion to bregma, as defined.
9. BPL Basion-prosthion lengthThe facial length from basion to prosthion, as defined.
5. XCB Maximum cranial breadth
The maximum cranial breadth perpendicular to the median sagittal plane (above the supramastoid crests).
6. XFB Maximum frontal breadthThe maximum breadth at the coronal suture, perpendicular to the medial plane.
14. JUB Bijugal breadthThe external breadth across the malars at the jugalia, i.e., at the deepest points in the curvature between the frontal and temporal process of the malars.
17. ZMB Bimaxillary breadthThe breadth across the maxillae, from one zygomaxillare [anterior] to the other.
7. AUB Biauricular breadth
The least exterior breadth across the roots of the zygomatic processes, wherever found.
8. ASB Biasterionic breadthDirect measurement from one asterion to the other.
16. MAB Palate breadth, externalThe greatest breadth across the alveolar borders, wherever found, perpendicular to the median plane.
10. NPH Nasion-prosthion height
Upper facial height from nasion to prosthion, as defined.
11. NLH Nasal heightThe average height from nasion to the lowest point on the border of the nasal aperture on either side.
15. NLB Nasal breadthThe distance between the anterior edges of the nasal aperture at its widest extent.
19. FMB Bifrontal breadthThe breadth across the frontal bone between frontomalare anterior on each side, i.e., the most anterior point on the fronto-malar suture.
23. WMH Cheek heightThe minimum distance, in any direction, from the lower border of the orbit to the lower margin of the maxilla, mesial to the masseter attachment, on the left side.
12. OBH Orbit height, left
The height between the upper and lower borders of the left orbit, perpendicular to the long axis of the orbit and bisecting it.
13. OBB Orbit breadth, leftBreadth from ectoconchion to dacryon, as defined, approximating the longitudinal axis which bisects the orbit into equal upper and lower parts.
21. EKB Biorbital breadthThe breadth across the orbits from ectoconchion to ectoconchion.
22. DKB Interorbital breadthThe breadth across the nasal space from dacryon to dacryon.
Not defined in any image:
18. SSS Zygomaxillary subtenseThe projection or subtense from subspinale to the bimaxillary width [ZMB].
20. NAS Nasio-frontal subtenseThe subtense from nasion to the bifrontal breadth.
24. FRC Nasion-bregma chord (Frontal chord)
The frontal chord, or direct distance from nasion to bregma, taken in the midplane and at the external surface.
25. FRS Nasion-bregma subtense (Frontal subtense)The maximum subtense, at the highest point on the convexity of the frontal bone in the midplane, to the nasion-bregma chord.
26. PAC Bregma-lambda chord (Parietal chord)The external parietal chord, or direct distance from bregma to lambda, taken in the midplane and at the external surface.
27. PAS Bregma-lambda subtense (Parietal subtense)The maximum subtense, at the highest point on the convexity of the parietal bones in the midplane, to the bregma-lambda chord.
28. OCC Lambda-opisthion chord (Occipital chord)The external occipital chord, or direct distance from lambda to opisthion, taken in the midplane and at the external surface.
29. OCS Lambda-opisthion subtense (Occipital subtense)The maximum subtense, at the most prominent point on the basic contour of the occipital bone in the midplane.
Source:
Wright R. 2012. Guide to using the CRANID programs CR6bIND: For linear and nearest neighbours discriminant analysis. https://www.box.net/shared/static/qyaq6thdds.pdf