Primate postcrania from the late middle Eocene of Myanmar

Fossil primates have been known from the late middle to late Eocene Pondaun g Formation of Myanmar since the description of Pondaungia cotteri in 1927. Th ree additional primate taxa, Amphipithecus mogaungensis, Bahinia pondau ngensis and Myanmarpithecus yarshensis, were subsequently described. These primates are represented mostly by fragmentary dental and cranial remains. Here we describe the first primate postcrania from Myanmar, including a com plete left humerus, a fragmentary right humerus, parts of left and right ul nae, and the distal half of a left calcaneum, all representing one individu al. We assign this specimen to a large species of Pondaungia based on body size and the known geographic distribution and diversity of Myanmar primate s. Body weight estimates of Pondaungia range from 4,000 to 9,000 g, based o n humeral length, humeral midshaft diameter, and tooth area by using extant primate regressions. The humerus and ulna indicate that Pondaungia was cap able of a wide variety of forelimb movements, with great mobility at the sh oulder joint. Morphology of the distal calcaneus indicates that the hind fe et were mobile at the transverse tarsal joint. Postcrania of Pondaungia pre sent a mosaic of features, some shared in common with notharctine and adapi ne adapiforms, some shared with extant lorises and cebids, some shared with fossil anthropoids, and some unique. Overall, Pondaungia humeral and calca neal morphology is most consistent with that of other known adapiforms. It does not support: the inclusion of Pondaungia in Anthropoidea.