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.

关于真核生物 (eukaryotes) 在新元古代早期的扩张，一种主流解释为噬真核生物捕食者 (eukaryovorous predators) 的出现——即捕食其他原生生物 (protists) 的原生生物类群。不过，彼时噬真核生物活动的相关证据均为间接证据，其依据包括基于性状状态重建 (character state reconstructions) 与分子钟 (molecular clocks) 的推断，以及部分原生生物化石 (protistan fossils) 中发现的潜在防御结构。本文报道了产自美国亚利桑那州 (Arizona) 大峡谷 (Grand Canyon) 、距今约7.8亿至7.4亿年的丘尔群 (Chuar Group) 中7种有机壁微化石 (organic-walled microfossils) 内的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。尽管这类"vampire-like"的取食行为在vampyrellid变形虫 (vampyrellid amoebae) 中最为人熟知，但该行为在真核生物中分布广泛，因此难以确切推断捕食者的具体类群。尽管如此，猎物的身份却十分明确：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，该丘尔群上部的瓶形微化石 (vase-shaped microfossils) 中还发现了约15~35微米的半月形与圆形孔洞，这类孔洞也可能由"tiny vampires"捕食者造成。上述发现共同表明，古丘尔海 (Chuar sea) 中曾存在多种噬真核生物捕食者。