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Magnifying the cause of extinction of the largest ever ape (Gigantopithecus blacki) through micro-analytical techniques

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posted on 2024-10-30, 03:36 authored by Juliën Kavish Lubeek

Gigantopithecus blacki (G. blacki) is considered the largest ape that ever lived. Its fossil record is limited to fragmented mandibles and isolated teeth that are mostly derived from karstic cave sites across southern China. G. blacki roamed the (sub)tropical forests of oriental Asia during the Pleistocene (~2.6 million to 11.75 thousand years ago) but mysteriously went extinct during the Middle Pleistocene, while other great apes in the region (such as Pongo, orangutans) survived significantly longer. The cause of G. blacki’s extinction is unknown. This thesis is part of the overarching ‘Giganto Project’ that attempts to unravel why, how, where and when the giant ape went extinct. As such, this thesis aims to identify the environmental and behavioural drivers (the how and where) behind the extinction. With a unique multi-proxy-approach of complimentary micro-analytical techniques applied to fossil molars and in-situ cave sediments, G. blacki’s post-cranial preservation, dietary behaviour, and environment are examined with regards to the extinction period. Microtaphonomic analysis reveals that sediment facies (at or above the locally recognised fifth cave horizon) comprising medium grain sizes high in calcite and apatite, with little diagenetic alteration and less evidence of redoximorphism, bioturbation and phosphatisation, hold the highest potential of finding G. blacki bones. Combined environmental and dietary results demonstrate that G. blacki seemed more vulnerable/susceptible to rapid climatic-induced changes of its habitat over the course of the Middle Pleistocene. In comparison to the more flexible Pongo, G. blacki seemed more restricted in its mastication, dietary preferences and possibly associated (terrestrial) lifestyle (somewhat resembling extant mountain gorillas). Over the course of the Pleistocene, the environment probably shifted from stable, warm and drier during the late Early Pleistocene to highly unstable in the late Middle Pleistocene, after which it stabilised again in the early Late Pleistocene. G. blacki seemed unable to adapt at the same pace as Pongo during the late Middle Pleistocene. Insights in the dramatic fate of this iconic taxon may play a crucial role in the conservation of modern great apes, and other megafauna, on the verge of extinction.

History

Table of Contents

Chapter 1. General introduction -- Chapter 2. Microscopes as time machines -- Chapter 3. Gigantopithecus' (lack of) remains -- Chapter 4. Gigantopithecus' mastication and dietary behaviour -- Chapter 5. Gigantopithecus' deteriorating habitat over time -- Chapter 6. General discussion and conclusion -- Appendix I. Supplementary Information (SI) and raw data -- Appendix II. Miscellaneous

Notes

Thesis by publication ADDITIONAL SUPERVISOR 3: Russell L. Ciochon

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

Doctor of Philosophy

Department, Centre or School

School of Natural Sciences

Year of Award

2023

Principal Supervisor

Kira Westaway

Additional Supervisor 1

Yingqi Zhang

Additional Supervisor 2

Mike W. Morley

Rights

Copyright: The Author Copyright disclaimer: https://www.mq.edu.au/copyright-disclaimer

Language

English

Extent

356 pages

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