Paranthropus robustus is a small-brained extinct hominin from South Africa characterized by derived, robust craniodental morphology. The most complete known skull of this species is DNH 7 from Drimolen Main Quarry, which differs from P. robustus specimens recovered elsewhere in ways attributed to sexual dimorphism. Here, we describe a new fossil specimen from Drimolen Main Quarry, dated from approximately 2.04–1.95 million years ago, that challenges this view. DNH 155 is a well-preserved adult male cranium that shares with DNH 7 a suite of primitive and derived features unlike those seen in adult P. robustus specimens from other chronologically younger deposits. This refutes existing hypotheses linking sexual dimorphism, ontogeny and social behaviour within this taxon, and clarifies hypotheses concerning hominin phylogeny. We document small-scale morphological changes in P. robustus associated with ecological change within a short time frame and restricted geography. This represents the most highly resolved evidence yet of microevolutionary change within an early hominin species.

傍人粗壮种是从南非的一个小脑袋的灭绝古人类特征的衍生，稳健craniodental形态。这个物种的最完整的已知的头骨是DNH 7从Drimolen主采石场，这不同于P.粗壮的标本归因于性别差异的方式在其他地方恢复。在这里，我们描述了一个来自 Drimolen Main Quarry 的新化石标本，其年代可追溯到大约 2.04-195 万年前，它挑战了这一观点。DNH 155 是一个保存完好的成年雄性头盖骨，与 DNH 7 共享一套原始和派生特征，与成年P.robustus 不同来自其他年代较年轻的矿床的标本。这驳斥了在该分类群中将性二态性、个体发育和社会行为联系起来的现有假设，并澄清了有关人类系统发育的假设。我们记录了与短时间范围内和受限制的地理范围内的生态变化相关的P.robustus 的小规模形态变化。这代表了早期人类物种内微进化变化的最高分辨率证据。