3D skeletal pelvic landmarks from anthropoid primates
Data files
May 28, 2021 version files 1.41 MB
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AllSpecies_54L.txt
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README.txt
Abstract
Objectives: The presence of sexual dimorphism in the birth canals of anthropoid primates is well-documented, and birth canal dimorphism tends to be especially robust among species that give birth to relatively large neonates. However, it is less clear whether birth canal dimorphism is accompanied by dimorphism in parts of the pelvis not directly under selection for birth, particularly including bi-iliac breadth, biactetabular breadth, lengths of the ischium and ilium, and 3D shape. This study investigates the patterns of dimorphism among anthropoid primates in those parts of the pelvis which do not directly contribute to the bony birth canal, here termed the non-obstetric pelvis.
Methods: 3D landmark data were collected on the bony pelves of 899 anthropoid primates. Specifically, landmark data were collected on parts of the pelvis not thought to be directly involved in selection for parturition, including portions of the posterior and superior ilium, acetabulum, and lateral ischium. principal components analysis and Euclidean distance matrix analysis were used to ascertain sexual dimorphism in pelvic sizes and shapes within each species.
Results: Results show that dimorphism in non-obstetric pelvic size and shape exists across anthropoids, just as is seen in the birth canal. However, the magnitude of dimorphism in non-obstetric pelvic shape tends to be greater among anthropoid species that give birth to relatively large neonates compared to those birthing smaller neonates relative to maternal pelvic size.
Conclusions: Though all anthropoids included in the study show some degree of sexual dimorphism in non-obstetric pelvic size and/or shape, species which give birth to large neonates relative to maternal pelvic size have the highest levels of dimorphism in pelvic shape. Moreover, the magnitude of dimorphism in certain parts of the non-obstetric pelvis mirrors patterns seen in the birth canal. The results of this study are promising for ascertaining pelvic dimorphism and relative neonate size in fossil primates, particularly in fragmentary remains which do not preserve a complete bony birth canal.
Methods
The 3D coordinates in this dataset were collected using a Microscribe MX 3D Digitizer. The dataset included here are the raw landmark data for each specimen. Skeletal pelves were articulated using putty and rubber bands, and the following landmarks were collected:
Landmark # | Landmark Title | Description |
1 | L PIIS | Left Posterior Inferior Iliac Spine |
2 | L PSIS | Left Posterior Superior Iliac Spine |
3 | L sup iliac crest | Left superior-most point on iliac crest |
4 | L ASIS | Left Anterior Superior Iliac Spine |
5 | L lat SI joint | Left lateral-most point on SI joint |
6 | L arcuate SI ilium | Left intersection of arcuate line & SI joint |
7 | L lateral arcuate line | Left lateral-most point on arcuate line |
8 | L ant iliac neck | Left narrowest point along the anterior iliac neck |
9 | L dors iliac neck | Left narrowest point along the posterior iliac neck |
10 | L pubis arcuate line | Left intersection of pubis & ilium on arcuate line |
11 | L pub acetabulum | Left intersection of pubis & ilium on acetabular rim |
12 | L sup acetab | Left superior-most point on acetabular rim |
13 | L dorsal acetab | Left dorsal-most point on acetabular rim |
14 | L caudal acetab | Left caudal-most point on acetabular rim |
15 | L acetab center | Left center of acetabular fossa |
16 | L dorsal acetab isch | Left intersection of ilium and ischium posterior to acetabulum |
17 | L ischial spine | Left ischial spine along medial-most point |
18 | L post ishial ramus | Left narrowest point along the posterior ischial ramus |
19 | L post tuberosity | Left posterior-most point along ischial tuberosity |
20 | L ant tuberosity | Left anterior-most point along ischial tuberosity |
21 | L lat ischial ramus | Left lateral point along deepest curve of ischial ramus |
22 | L obt ischial ramus | Left inferior-most point along ischiopubic ramus |
23 | inf pub symphysis | Midline Inferior-most point on pubic symphysis |
24 | sup pub symphysis | Midline superior-most point on pubic symphysis |
25 | dorsal S1 | Midline dorsal point on S1 vertebral body |
26 | ventral S1 | Midline ventral point on S1 vertebral body |
27 | left S1 | Left lateral-most point on S1 vertebral body |
28 | left sup ala | Left lateral-most point on superior sacral ala |
29 | inf S1 | Midline junction of S1-S2 |
30 | inf S2 | Midline junction of S2-S3 |
31 | inf Sacrum | Midline inferior-most point on sacrum |
32 | right S1 | Right lateral-most point on S1 vertebral body |
33 | right sup ala | Right lateral-most point on superior sacral ala |
34 | R PIIS | Right Posterior Inferior Iliac Spine |
35 | R PSIS | Right Posterior Superior Iliac Spine |
36 | R sup iliac crest | Right superior-most point on iliac crest |
37 | R ASIS | Right Anterior Superior Iliac Spine |
38 | R lat SI joint | Right lateral-most point on SI joint |
39 | R lateral arcuate line | Right lateral-most point on arcuate line |
40 | R ant iliac neck | Right narrowest point along the anterior iliac neck |
41 | R dorsal iliac neck | Right narrowest point along the posterior iliac neck |
42 | R pubis arcuate line | Right intersection of pubis & ilium on arcuate line |
43 | R pub acetab | Right intersection of pubis & ilium on acetabular rim |
44 | R sup acetab | Right superior-most point on acetabular rim |
45 | R dorsal acetab | Right dorsal-most point on acetabular rim |
46 | R caudal acetab | Right caudal-most point on acetabular rim |
47 | R acetab center | Right center of acetabular fossa |
48 | R dorsal acetab isch | Right intersection of ilium and ischium posterior to acetabulum |
49 | R ischial spine | Right ischial spine along medial-most point |
50 | R post ishial ramus | Right narrowest point along the posterior ischial ramus |
51 | R post tuberosity | Right posterior-most point along ischial tuberosity |
52 | R ant tuberosity | Right anterior-most point along ischial tuberosity |
53 | R lat ischial ramus | Right lateral point along deepest curve of ischial ramus |
54 | R obt ischial ramus | Right inferior-most point along ischiopubic ramus |
The following link is a figure depicting the location of each landmark collection location (only the left side is shown for bilaterally collected landmarks):
https://docs.google.com/document/d/1CJvDDgeio2lVgV32lewatqEBzdR6SIrGD01tIdu1_-4/edit?usp=sharing
Usage notes
The dataset included here has 921 specimens, as some sample sizes collected were too small for sufficient power to include in the published AJPA article. However, these extra specimens are included in the dataset for completeness.