Mélanie Frelat is employed as a Marie Curie post-doctoral fellow (EVAN training network) at the Department of Anthropology of the University of Vienna, since September 2009.
Department of Anthropology University of Vienna Althanstraße 14 1090 Vienna AUSTRIA Phone:+43 (0)1 4277 54716 Fax:+43 (0)1 4277 9547 Skype:melanie-au-cambodge email@example.com
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.
Figure 1. Group mean shape of the four species.
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
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.
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.