First direct evidence of conservative foraging ecology of early Gigantopithecus blacki (∼2 Ma) in Guangxi, southern China

Objectives: Gigantopithecus blacki, the largest hominoid known, is one of the representative Pleistocene mammals in southern China and northern Southeast Asia. Here we investigate the feeding ecology of G. blacki in its core habitat (Guangxi, Southern China) during the early Early Pleistocene, which was the early period in its evolution. Materials and methods: The stable isotopic (C, O) analysis of tooth enamel of the fauna associated with G. blacki (n = 58), including the largest number of G. blacki teeth (n = 12) to date from the Liucheng Gigantopithecus Cave (similar to 2 Ma), Guangxi, China, is undertaken. Results: The delta C-13 values of Liucheng fauna range from -12.9 to -19.0 parts per thousand with an average of -16.1 +/- 1.3 parts per thousand (n = 58) and the delta O-18 values range from -4.3 to -9.6 parts per thousand with an average of -6.9 +/- 1.2 parts per thousand (n = 58). The delta C-13 values of G. blacki range from -15.9 parts per thousand to -17.0 parts per thousand with an average of -16.5 +/- 0.4 parts per thousand (n = 12), and the delta O-18 values vary from -5.9 parts per thousand to -7.5 parts per thousand with an average of -6.6 +/- 0.5 parts per thousand (n = 12). Conclusions: The isotopic data show Guangxi was characterized by closed C-3 forest and humid climate in the early Early Pleistocene. Niche partitioning is found among G. blacki, Sinomastodon, Ailuropoda and Stegodon, the typical megafauna in South China in the early Early Pleistocene. This could be one of the important factors for them to co-exist until the Middle Pleistocene. Smallest isotopic variations of G. blacki are found compared with those of contemporary animals, indicating a conservative foraging ecology i.e., limited foraging area and/or narrow dietary flexibility. Furthermore, the more confined foraging ecology of G. blacki is also seen in comparison with fossil and extant large-bodied primates. However, the unique dietary pattern of G. blacki does not seem to have hindered its survival. The environment in Guangxi during the early Early Pleistocene offered the suitable conditions for G. blacki to become one of the typical species in the faunal assemblages.

Automated summary

The study reveals that in the early Early Pleistocene, the climate in Guangxi was suitable for the survival of Gigantopithecus blacki and other large mammals. There was clear niche partitioning among G. blacki, Sinomastodon, Ailuropoda, and Stegodon, potentially allowing them to coexist until the Middle Pleistocene. Gigantopithecus blacki exhibited a conservative foraging ecology with limited dietary flexibility, which did not hinder its survival in the region.