Palaeoenvironments and hominin evolutionary dynamics in southeast Asia

Area of Science:

• Paleoanthropology
• Paleoecology
• Stable Isotope Analysis

Background:

• Secure environmental contexts are vital for understanding hominin evolution and inter-species comparisons.
• Denisovan fossils have been found in diverse latitudes, including subtropical Asia and the Palearctic, necessitating environmental context.
• Previous research on Denisovans focused on northern latitudes, leaving their adaptations in tropical regions less understood.

Purpose of the Study:

• To reconstruct the paleoenvironment and diet of Denisovans at Tam Ngu Hao 2 (Cobra) Cave in Laos.
• To compare the environmental adaptations and dietary strategies of Denisovans in Southeast Asia with those in Eurasia.
• To investigate potential responses of Denisovans to local climate change, specifically rainforest expansion.

Main Methods:

• Stable isotope analysis of faunal remains from Tam Ngu Hao 2 (Cobra) Cave.
• Analysis of faunal evidence and climate proxy indicators to reconstruct local environments.
• Comparative analysis of hominin diets and habitats across different cave sites and time periods.

Main Results:

• The Denisovan individual from Cobra Cave primarily consumed resources from open forests and savannah, despite nearby canopy forests.
• Faunal and climate data indicate a local rainforest expansion around 130,000 years ago.
• Early Homo sapiens from Tam Pà Ling Cave (Laos) appear to have been the only hominin species capable of exploiting rainforest resources.

Conclusions:

• Denisovans in Southeast Asia exhibited distinct dietary and habitat preferences compared to those in northern latitudes.
• The findings raise questions about Denisovan adaptability to rapid environmental shifts, such as rainforest expansion.
• This study underscores the ecological niche differentiation between Denisovans and Homo sapiens in Southeast Asia.