Deciphering the exposome signals of hominid fossil remains in southern China: A biogeochemical and palaeontological investigation.
Creators: name: Bailey, Marian Elizabeth
Publisher: name: Southern Cross University
Year: 2024
Subjects: Gigantopithecus blacki
Stable isotopes
Trace-element analysis
Dietary reconstruction

description: This thesis investigates the early life behaviours and extinction drivers of Gigantopithecus blacki. G. blacki is a unique primate species that represents the only ape genus to have gone extinct in the last 2.6 million years, disappearing from the fossil record in the Middle Pleistocene. This species is poorly represented in the fossil record, with only several thousand teeth and four mandibles, primarily from southern China. This study integrates a multi-modal analytical framework, with high-resolution laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and stable isotope techniques to analyse trace elements and isotopic compositions in dental tissue. The comparative analysis extends to modern and archaeological Pongo, which are phylogenetically proximate to G. blacki.
description: The methodological approaches capitalise on the incremental mineralisation of enamel and dentine in teeth, which serves as a chronologically layered archive of an individual's early life chemical exposures. This includes both exogenous environmental factors and endogenous metabolic byproducts. This research, supplemented by insights from Zhang et al. (2024), leverages well-preserved elemental and isotopic information to reconstruct trophic levels, dietary habits, and lactational histories.
description: High-resolution trace-element geochemical mapping on 29 Gigantopithecus blacki teeth and 9 Pongo sp. reveals supplemental nursing behaviours and a weaning period analogous to extant Pongo species. Furthermore, the data suggest a potential fat catabolising response to resource scarcity, a physiological adaptation previously theorised in other primate species. The study also explores the role of lead exposure. Notably, lactation is a significant vector for lead transfer, with lead mobilised from maternal bone stores becoming bioavailable in breast during periods of accelerated bone remodelling. This lead is subsequently sequestered in the infant's dental tissues, serving as a long-term biomarker of exposure. Carbon and oxygen stable-isotope analyses on 34 G. blacki and 37 Pongo sp. fossil teeth revealed that G. blacki exhibited a broad dietary spectrum, with δ 13C values ranging from -15.7 to -6.0, indicating a varied diet of both C3 and C4 plants. In contrast, both fossil and modern Pongo species displayed more constrained δ13C values (-14.9 to -12.4), signifying a specialised diet within dense forest ecosystems. Statistical analysis underscored dietary distinctions between G. blacki and fossil Pongo, while revealing no substantial dietary differences between G. blacki and modern orangutans.
description: This research advances archaeological science and palaeontology, furthering trace element analysis methods and providing a nuanced understanding of the early-life behaviours and
description: ecological adaptations in G. blacki that may have predisposed the species to extinction.