Data from: Tiny vampires in ancient seas: evidence for predation via perforation in fossils from the 780–740 million-year-old Chuar Group, Grand Canyon, USA

One explanation for the early Neoproterozoic expansion of eukaryotes is the appearance of eukaryovorous predators—i.e. protists that preyed on other protists. Evidence for eukaryovory at this time, however, is indirect, based on inferences from character state reconstructions and molecular clocks, and on the presence of possible defensive structures in some protistan fossils. Here I describe 0.1–3.4 µm circular holes in seven species of organic-walled microfossils from the ~780–740 million-year-old Chuar Group, Grand Canyon, Arizona, USA, that are similar to those formed today by predatory protists that perforate the walls of their prey to consume the contents inside. Although best known in the vampyrellid amoebae, this “vampire-like” behavior is widespread among eukaryotes, making it difficult to infer confidently the identity of the predator. Nonetheless, the identity of the prey is clear: some—and perhaps all—of the fossils are eukaryotes. These holes thus provide the oldest direct evidence for predation on eukaryotes, and together with ~15–35 µm half-moon-shaped and circular holes in vase-shaped microfossils from the upper part of the unit that may also be the work of “tiny vampires”, they suggest a diversity of eukaryovorous predators in the ancient Chuar sea.关于新元古代早期真核生物的辐射扩张，学界提出的一种解释是噬真核生物捕食者的出现——即一类以其他原生生物为食的原生生物。然而，彼时噬真核捕食行为的相关证据均为间接证据，其依据包括基于性状状态重建与分子钟的推演，以及部分原生生物化石中发现的潜在防御结构。本文报道了产自美国亚利桑那州大峡谷地区约7.8亿至7.4亿年前丘尔群的7种有机质壁微体化石中的0.1~3.4微米圆形孔洞，这类孔洞与现今捕食性原生生物通过穿孔猎物细胞壁以摄取内部内容物所形成的孔洞形态高度相似。尽管这种“类吸血鬼”的捕食行为在vampyrellid变形虫（vampyrellid amoebae）中最为典型，但该行为在真核生物类群中分布广泛，因此难以确切推断此次捕食事件的捕食者身份。尽管如此，猎物的类群却十分明确：这些化石中的部分乃至全部均为真核生物。因此，这些孔洞是目前已知最早的真核生物捕食行为直接证据；此外，该地层上部的瓶状微体化石中发现的约15~35微米半月形与圆形孔洞，也可能是“微型吸血鬼”捕食者留下的痕迹。二者共同表明，古代丘尔海洋中存在多样的噬真核生物捕食者类群。