# Ontogenesis of femoral biomechanical properties in non human primates: study of olive baboon

Quentin Cosnefroy, Gilles Berillon, François Marchal

► To cite this version:

Quentin Cosnefroy, Gilles Berillon, François Marchal. Ontogenesis of femoral biomechanical properties in non human primates: study of olive baboon. 11th Annual Meeting of the European Society for the Study of Human Evolution, Sep 2021, Online, France. 2021, 10.13140/RG.2.2.13863.83365. hal-03897723

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Submitted on 14 Dec 2022

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# Ontogenesis of femoral biomechanical properties in non-human primates:
study of olive baboon

ADES

UMR
7268

HN
HP

UMR 7194
Histoire
Naturelle
de l'Homme
Préhistorique

(Aix*Marseille
université
Initiative d'excellence)

EFS

ÉTABLISSEMENT FRANÇAIS DU SANG

<figure><img src="image_2.png" /></figure>

UPVD
Université de Perpignan Via Domitia

<figure><img src="image_3.png" /></figure>

MUSÉUM
NATIONAL D'HISTOIRE NATURELLE

<figure><img src="image_4.png" /></figure>

Quentin Cosnefroy¹, François Marchal¹, Gilles Berillon²

1 - UMR 7268 ADES, Aix Marseille Univ - EFS - CNRS, Marseille, France 2 - UMR 7194 HNHP, CNRS - MNHN - UPVD, Paris, France

## Introduction

The locomotor repertoire of olive baboons (*Papio anubis*) evolves through age. Autonomous around 0.5y old, diversified in infants (< 1.8y), the repertoire becomes highly stereotyped with an extreme predominance of quadrupedalism in adults (> 4.75y). Biomechanical properties of the femoral diaphysis are considered to record the locomotor strains; it is thus expected that they reflect behavioral changes and diversity through age.

**Material** - A transversal ontogenetic sample of olive baboons: 65 3D-reconstructed femora

- A single social group, from Primatology Station, UPS 846 of CNRS, (Rousset, France)

- Changes in locomotor repertoire are known [1]

**Method** - Cross-section geometry parameters: cortical area (%CA) and bending rigidity on the mediolateral (ML) and anteroposterior (AP) axes (Ix/Iy and Zx/Zy) along the diaphysis

- Cortical thickness maps

- Morphomap R-package [2]

<figure><img src="image_5.png" /><figcaption>**PERCENTAGE OF LOCOMOTOR MODES**
After [1] and [3]</figcaption></figure>

## CROSS SECTION GEOMETRY PARAMETERS

### Results

Newborns and young infants present:

- The highest %CA

- Symmetrical cortical bone distribution along the longitudinal axis

- AP orientation of bending rigidity at midshaft

In later stages:

- Cortical bone distribution shifts proximally and posteriorly

- Bending rigidity is ML oriented in the distal half

<figure><img src="image_6.png" /><figcaption>Cross section geometry parameters along in the femoral diaphysis, mean by stage.</figcaption></figure>

## CORTICAL THICKNESS MAPS

<figure><img src="image_7.png" /><figcaption>Scale 0: thinnest point; 1: thickest point. Sides: A (anterior), M (medial), P (posterior) and L (lateral).</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>PCA based on thickness values of maps coordinates.</figcaption></figure>

**Discussion** The pattern of newborn femora reflects conditions where locomotor strains are nil: a centrifuge ossification from the center of ossification. From this condition, biomechanical properties evolve quickly through age toward a pattern largely impacted by quadrupedal locomotion, as soon as the locomotor autonomy is established. Contrary to what was expected, biomechanical properties of the femoral diaphysis do not reflect the behavioral changes and diversity but seem to be linked to the most predominant mode.

## References

[1] Druelle, F., Aerts, P., Berillon, G., 2016. Am. J. Primatol. 78, 1201-1221. https://doi.org/10.1002/ajp.22575

[2] Hunt, K.D., 2016. J. Anat. 228, 630-685.

https://doi.org/10.1111/joa.12454

[3] Profico, A., Bondioli, L., Raia, et al., 2020. Am. J. Phys. Anthropol. 174, 129-139.

https://doi.org/10.1002/ajpa.24140

## Acknowledgements

This research is realized in the frame of a doctoral contract of the Aix-Marseille University, Doctoral School ED251. Additional financial support for the data acquisition was provided by the CNRS-INEE International Research Network no. GDRI0870 Bipedal Equilibrium and the French National Agency ANR-18-CE27-0010-01 HoBiS. The authors wish to thank CT-scan providers : the Centre Européen de Recherche en Imagerie Médicale (Marseille, France), Voxscan (Dommartin, France), Hôpital Raymond-Pointcarré (Garches, France) and Centre d'Imagerie Médicale Bachaumont (Paris, France). We also thank A. Profico for methodological discussions, F. Druelle for personal advices.