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

Abstract

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. 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 (~2Ma), Guangxi, China, is undertaken. The δ13 C values of Liucheng fauna range from -12.9 to -19.0‰ with an average of -16.1 ± 1.3‰ (n=58) and the δ18 O values range from -4.3 to -9.6‰ with an average of -6.9 ± 1.2‰ (n=58). The δ13 C values of G. blacki range from -15.9‰ to -17.0‰ with an average of -16.5 ± 0.4‰ (n=12), and the δ18 O values vary from -5.9‰ to -7.5‰ with an average of -6.6 ± 0.5‰ (n=12). The isotopic data show Guangxi was characterized by closed C3 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.