Data from: No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the late Miocene of Peru

Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid–fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator–prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine (Sardinops sagax). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins.尽管现代喙鲸科（Ziphiidae）是高度特化的齿鲸类，已知主要于深海栖息，以底栖与底中水层生物为食，但记录这一重大生态转变的古生物学数据却较为匮乏。本文报道一套产自秘鲁晚中新世的喙鲸-鱼类化石组合，我们将其解读为喙鲸与远洋上层鱼类之间存在捕食关系的首个直接实证。该化石保存在白云岩结核中，一具基干喙鲸类格雷戈里梅萨喙鲸（Messapicetus gregarius）的骨架，与大量亲缘关系接近于现生远洋上层太平洋沙丁鱼（Sardinops sagax）的鲱形目鱼类骨架一同被发现。基于鱼类个体沿喙鲸头部与胸部的分布位置、鱼类遗骸未发现消化痕迹，以及个体大小均一这三项依据，我们提出该化石组合源于这头鲸在从单个鱼群捕获猎物后不久死亡（推测可能为毒素中毒所致）。结合形态学数据，以及深海沉积中频繁发现冠群喙鲸化石的记录，这一罕见的化石记录支持两项假说：一是仅更为衍化的喙鲸类才是常规深潜者；二是远洋上层喙鲸类的灭绝或与真海豚的辐射演化同步发生。