A Primate Presence in a Coal Mine
In the lignite layers of northern Thailand's Mae Moh Basin, miners uncovered fossils. They found the fossilized remains of a previously unknown primate, a creature that lived between 13.1 and 13.3 million years ago. This region, specifically the Mae Moh coal mine in Lampang province, has yielded one of the extensive Miocene vertebrate fossil records in all of Southeast Asia. The primate fossil from this site is a sivaladapid, a group of Asian adapiform primates known from the Eocene through the late Miocene. Named Siamoadapis maemohensis, this specimen is scientifically important because it is the first and only Miocene monkey relative discovered in the region.
The fossil itself is small, but it shows a distinct biogeographic province. The primate fauna of middle Miocene Thailand, which includes Siamoadapis, a loris, tarsiids, and hominoids, shows a composition similar to assemblages from southern China and the Indian subcontinent. Yet, the Thai fossils represent unique genera, suggesting the area had distinctive paleoenvironments. The collection and study of these fossils, including work by paleontologist Takeshi Setoguchi of Kyoto University, has helped define this unique ancient ecosystem. These collections are now part of the resources at Kyoto University.