Yi Zhixing, Zanolli Clément, Liao Wei, Wang Wei
Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China; Guangxi Academy of Sciences, Beihai, 536000, China.
Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600 Pessac, France.
J Hum Evol. 2023 Feb;175:103313. doi: 10.1016/j.jhevol.2022.103313. Epub 2023 Jan 27.
Gigantopithecus blacki is hypothesized to have been capable of processing mechanically challenging foods, which likely required this species to have high dental resistance to fracture and/or large bite force. To test this hypothesis, we used two recently developed approaches to estimate absolute crown strength and bite force of the lower postcanine dentition. Sixteen Gigantopithecus mandibular permanent cheek teeth were scanned by micro-computed tomography. From virtual mesial cross-sections, we measured average enamel thickness and bi-cervical diameter to estimate absolute crown strength, and cuspal enamel thickness and dentine horn angle to estimate bite force. We compared G. blacki with a sample of extant great apes (Pan, Pongo, and Gorilla) and australopiths (Australopithecus anamensis, Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, and Paranthropus boisei). We also evaluated statistical differences in absolute crown strength and bite force between the premolars and molars for G. blacki. Results reveal that molar crown strength is absolutely greater, and molar bite force absolutely higher, in G. blacki than all other taxa except P. boisei, suggesting that G. blacki molars have exceptionally high resistance to fracture and the ability to generate exceptionally high bite force. In addition, G. blacki premolars have comparable absolute crown strength and larger bite force capabilities compared with its molars, implying possible functional specializations in premolars. The dental specialization of G. blacki could thus represent an adaptation to further facilitate the processing of mechanically challenging foods. While it is currently not possible to determine which types of foods were actually consumed by G. blacki through this study, direct evidence (e.g. dental chipping and microwear) left by the foods eaten by G. blacki could potentially lead to greater insights into its dietary ecology.
黑猩猩被认为有能力处理机械性难咬的食物，这可能要求该物种具有较高的牙齿抗折断能力和/或较大的咬合力。为了验证这一假设，我们使用了两种最近开发的方法来估计下后犬齿的绝对冠部强度和咬合力。通过微计算机断层扫描对16颗黑猩猩下颌恒颊齿进行了扫描。从虚拟近中横截面，我们测量了平均釉质厚度和双颈直径以估计绝对冠部强度，以及尖部釉质厚度和牙本质角以估计咬合力。我们将黑猩猩与现存的大猩猩样本（黑猩猩、猩猩和大猩猩）以及南方古猿样本（南方古猿阿法种、南方古猿阿法种、南方古猿非洲种、粗壮傍人、鲍氏傍人）进行了比较。我们还评估了黑猩猩前磨牙和磨牙在绝对冠部强度和咬合力方面的统计差异。结果显示，除了鲍氏傍人外，黑猩猩的磨牙冠部强度绝对更大，磨牙咬合力绝对更高，这表明黑猩猩的磨牙具有极高的抗折断能力和产生极高咬合力的能力。此外，与磨牙相比，黑猩猩的前磨牙具有相当的绝对冠部强度和更大的咬合力能力，这意味着前磨牙可能具有功能特化。因此，黑猩猩的牙齿特化可能代表了一种适应，以进一步促进对机械性难咬食物的处理。虽然目前通过这项研究无法确定黑猩猩实际食用的食物类型，但黑猩猩食用的食物留下的直接证据（如牙齿崩裂和微磨损）可能会为其饮食生态学带来更多见解。
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