Department of Geology, University of South Florida, Tampa, FL 33620, USA.
Proc Natl Acad Sci U S A. 2013 Jun 25;110(26):10495-500. doi: 10.1073/pnas.1222559110. Epub 2013 Jun 3.
The enhanced dietary flexibility of early hominins to include consumption of C4/crassulacean acid metabolism (CAM) foods (i.e., foods derived from grasses, sedges, and succulents common in tropical savannas and deserts) likely represents a significant ecological and behavioral distinction from both extant great apes and the last common ancestor that we shared with great apes. Here, we use stable carbon isotopic data from 20 samples of Australopithecus afarensis from Hadar and Dikika, Ethiopia (>3.4-2.9 Ma) to show that this species consumed a diet with significant C4/CAM foods, differing from its putative ancestor Au. anamensis. Furthermore, there is no temporal trend in the amount of C4/CAM food consumption over the age of the samples analyzed, and the amount of C4/CAM food intake was highly variable, even within a single narrow stratigraphic interval. As such, Au. afarensis was a key participant in the C4/CAM dietary expansion by early australopiths of the middle Pliocene. The middle Pliocene expansion of the eastern African australopith diet to include savanna-based foods represents a shift to use of plant food resources that were already abundant in hominin environments for at least 1 million y and sets the stage for dietary differentiation and niche specialization by subsequent hominin taxa.
早期人类在饮食上的灵活性增强，包括食用 C4/景天酸代谢（CAM）食物（即来自热带稀树草原和沙漠中常见的草、莎草和肉质植物的食物），这可能与现存的大猿类以及我们与大猿类共有的最后一个共同祖先有明显的生态和行为上的区别。在这里，我们使用来自埃塞俄比亚哈达尔和迪基卡的 20 个南方古猿afarensis 样本的稳定碳同位素数据（>3.4-2.9 Ma），表明该物种食用了含有大量 C4/CAM 食物的饮食，与假定的祖先 Au.anamensis 不同。此外，在所分析的样本年龄范围内，C4/CAM 食物的摄入量没有时间上的趋势，而且 C4/CAM 食物的摄入量高度可变，即使在单个狭窄的地层间隔内也是如此。因此，Au.afarensis 是中上新世早期南非古猿 C4/CAM 饮食扩张的关键参与者。中上新世东非南方古猿饮食向包括基于热带稀树草原的食物的扩张，代表了对已经在人类环境中丰富存在至少 100 万年的植物食物资源的利用的转变，为随后的人类分类群的饮食分化和生态位特化奠定了基础。
