Proximal Femoral Anatomy of a Sivaladapid Primate From the Late Middle Eocene Ponduang Formation (Central Myanmar)

Proximal Femoral Anatomy of a Sivaladapid Primate From the Late Middle Eocene Ponduang Formation (Central Myanmar)
2008

By: Laurent Marvaux, K Christopher Beard, Yaowalak Chiamanee, Jeans-Jacques Jaeger, Bernard Marandat, Aung Naing Soe, Soe Thura Tun, and Aung Aung Kyaw

Printed in American Journal Of Physical Anthropology 137:263-273.

This article examines the morphology of a proximal femur recovered from the Ponduang formation in central Myanmar. The proximal femur is part of the hip joint “which supports the weight of the body in both static and dynamic postures” (pp 269). The specimen that was utilized for analysis was well preserved and represented a significant portion of the femur. From the measurements that were obtained the research team was able to discern features such as, the creature was a proficient leaper which is evident because the “overhang of the trochanter” would have provided more leverage (pp270). Another characteristic of the femur suggested that the creature was able to freely move its hip a possible sign of climbing. In general these features suggested that this primate was “engaged in a kind of active arboreal quadrupedalism with some degree of proficiency” (pp 270).
What is interesting about this specimen is that in the Pongduang formation only two primate clades had been previously identified; the eosiimids and the amphipithecids. However, this new specimen exhibits characteristics of adapiforms and extent strepsirhines. This, in turn, challenges what was previously thought of this area and suggests that there was a greater diversity of primates in the area than previously thought (pp 263-265).