First middle Miocene sivaladapid primate from Thailand

Area of Science:

• Paleontology
• Primate Evolution
• Asian Paleoanthropology

Background:

• Sivaladapids are Asian adapiform primates known from the Eocene to late Miocene in South and East Asia.
• Previously, sivaladapids in Thailand were only known from Eocene deposits.
• The persistence of sivaladapid genera into the late Miocene is a notable evolutionary feature.

Purpose of the Study:

• To describe the first Southeast Asian Miocene sivaladapid.
• To analyze the paleoecological implications of this new discovery in Thailand.
• To compare the middle Miocene primate fauna of Thailand with contemporaneous assemblages from other Asian regions.

Main Methods:

• Excavation and analysis of fossiliferous lignite layers from the Mae Moh coal mine, Thailand.
• Morphological examination of dental and skeletal features of the newly discovered primate.
• Comparative analysis with known sivaladapid fossils from other Asian localities.

Main Results:

• Description of Siamoadapis maemohensis gen. et sp. nov., a new sivaladapid genus and species.
• The fossil dates to 13.3–13.1 million years ago (middle Miocene).
• Siamoadapis maemohensis is distinguished by its smaller size and unique dental characteristics compared to other Miocene sivaladapids.

Conclusions:

• This discovery expands the known diversity of middle Miocene primates in Thailand.
• The Thai middle Miocene primate community composition is similar to those in China, India, and Pakistan.
• The distinctiveness of the Thai genus suggests a separate biogeographic province with unique paleoenvironments.