subsequently from the two earlier areas along with specimens from new localities near Bahin, in the Pondaung Formation (5 — 9). Mogaung localities are middle Eocene (late Lutetian to early Bartonian) while localities near Pangan and Bahin are late middle (late Bartonian) to late (Priabonian) Eocene (10). A Bartonian age for localities in the Bahin area is supported by a fission-track date of 37.2 + 1.3 mega-annum (Ma) on zircon crystals from a tuffaceous bed that outcrops at several localities (35).

Primates known from Myanmar include at least four taxa, the original two species plus Bahinia pondaungensis (7) and Myan marpithecus yarshensis (36). An additional species of Pondaungia, P. minuta [holotype NMMP (National Museum of Myanmar Primate) 4] was proposed by Jaeger et al. (6), and another species of Amphipithecus, "A. bahinensis" (NMMP 7) was informally cited by Thein (8). Jaeger et al. (6) questioned the distinctiveness of A. bahinensis, instead regarding it as A. mogaungensis, while Takai et al. (5) have questioned the validity of I'. Iinuta, a species based on a heavily worn and eroded specimen.

7672-7677 ~ PNAS ) July 3, 2001 ( vol. 98 ~ no. 14

New discoveries of primate remains from the Pondaung Formation are the result of a Myanmar joint government- university initiative begun in 1997 by the Office of Strategic Studies, Ministry of Defense and the University of Taunggyi, Dagon University, and Hlaing College. In April 1997 this team discovered new fossil localities in the Bahin area (Fig. 1) that led to the recovery of the first complete jaw of Amphipithecus mogaungensis now designated NMMP 7. At this point, an invitation was made to one of us (R.L.C.) to mount a joint Myanmar-American field project to the Bahin area. On De- cember 26, 1997 members of this international team discov- ered the first primate postcrania in the Pondaung Formation at a locality less than 2 km from Yarshe kyitchang where NMMP 7 was found (Fig. 1).

Pondaungia Postcrania