Diet is a driving force in human evolution. Two species of Plio-Pleistocene hominins, Paranthropus robustus and Australopithecus africanus, have derived craniomandibular and dental morphologies which are often interpreted as P. robustus having a more biomechanically challenging diet. While dietary reconstructions based on dental microwear generally support this, they show extensive dietary overlap between species, and craniomandibular and dental biomechanical analyses can yield contradictory results. Using methods from anthropology and engineering (i.e. anthroengineering), we quantified the molar biomechanical performance of these hominins to investigate possible dietary differences between them. Thirty-one lower second molars were 3D printed and used to fracture gelatine blocks, and Bayesian generalized linear models were used to investigate the relationship between species and tooth wear, size and shape, and biomechanical performance. Our results demonstrate that P. robustus required more force and energy to fracture blocks but had a higher force transmission rate. Considering previous dietary reconstructions, we propose three evolutionary scenarios concerning the dietary ecologies of these hominins. These evolutionary scenarios cannot be reached by investigating morphological differences in isolation, but require combining several lines of evidence. This highlights the need for a holistic approach to reconstructing hominin dietary ecology.

饮食是人类进化的驱动力。Plio-Pleistocene hominins 的两个物种，Paranthropus robustus和Australopithecusafricanus，已经衍生出通常被解释为P. robustus的颅下颌和牙齿形态具有更具生物力学挑战性的饮食。虽然基于牙科微磨损的饮食重建通常支持这一点，但它们显示出物种之间广泛的饮食重叠，并且颅下颌和牙科生物力学分析可能会产生矛盾的结果。使用人类学和工程学（即人类工程学）的方法，我们量化了这些古人类的摩尔生物力学性能，以研究它们之间可能的饮食差异。31 颗下第二磨牙被 3D 打印并用于破坏明胶块，并使用贝叶斯广义线性模型来研究物种与牙齿磨损、大小和形状以及生物力学性能之间的关系。我们的结果表明P. robustus需要更多的力和能量来破坏块，但具有更高的力传递率。考虑到以前的饮食重建，我们提出了三种关于这些古人类饮食生态的进化情景。这些进化场景不能通过孤立地研究形态差异来达到，但需要结合几条证据。这凸显了重建古人类饮食生态的整体方法的必要性。