My purpose in joining EVAN was to test whether geometric morphometrics (GMM) is a good tool to assess and visualize shape variations among hominoid tibiae. Indeed lower limb bones are among the most extensively investigated of the hominoid skeleton with respect to function and growth. Since the femur and tibia are the two largest bones of the skeleton, they are usually among the best preserved in the fossil record. Nevertheless most studies focus on femoral morphology, the tibia being relatively understudied. No detailed quantitative anthropometric analyses of the complete tibial surface exist, with previous studies using limited sets of distances/angles or focusing on limited surface regions.

First I surface scanned a sample of tibiae representative of the variability among hominoids (28 Homo sapiens, 19 Pan troglodytes, 20 Gorilla gorilla and 10 Pongo pygmaeus). In parallel, I build up a emplate of landmarks and semilandmarks on curves (498 landmarks in total) that describes best the shape of the tibia regarding its biomechanical characteristics. A standard Procrustes analysis of landmark-semilandmark configurations was then performed on the 77 tibiae represented by their surface scans. To reduce the influence of the length of the shaft, we "sphericized" the originally axial forms in the average of lateral and frontal views and used traditional statistical analysis (PCA, PLS and regressions) to visualize the patterns of variations, and to assess the relationship between arboreal locomotion, centroid size and body mass, and tibial shape.

Results, published soon, are confirming what is generally accepted in qualitative and comparative analysis of the tibia of humans and apes. And also show that in Apes, the shape of the adult tibia is highly adapted to arboreal locomotion and to body mass. These results lead thus to a new question, as how the lower limb adapts to the loads arising during locomotion acquired during developmental growth.

In the course of my contract, I participated to 6 EVAN training workshops which allowed me to enlarge my field of competence and skills. I visited 2 exterior institutions (Natural History museum of Vienna, Anthropological Institute and Museum of Zurich University) to build up my sample. And I presented my work at 2 international congresses (Colloque international de la Société d’Anthropologie de Paris and Annual Meeting of the American Association of Physical Anthropologists). See references below. This position thus offers me the opportunity to establish scientific relations with researchers of other countries, to develop new collaborations that will likely be important for life and enlarge my European network of interactions and colleagues, thus providing the opportunity to reach a leading position in my field.

Published Abstracts:

FRELAT Mélanie, BOOKSTEIN Fred L., WEBER Gerhard W., 2009. Tibial shape analysis – a quantitative approach for the whole bone. Am J Phys Anthropol, Suppl. (48), pp. 130.

FRELAT Mélanie, BOOKSTEIN Fred L., WEBER Gerhard W., 2008. "Variation of human tibial shape: a 3D approach using virtual specimens" Actes des 1834ème Journées annuelles de la Société d'Anthropologie de Paris, Paris, p37-38.