Data from: The evolution of scarab beetles tracks the consecutive rise of angiosperms and mammals

Extant terrestrial biodiversity arguably is driven by the evolutionary success of angiosperm plants, but the evolutionary mechanisms and timescales of angiosperm-dependent radiations remain poorly understood. The Scarabaeoidea is a diverse lineage of predominantly plant- and dung-feeding beetles. Here, we present a phylogenetic analysis of Scarabaeoidea based on four DNA markers for a taxonomically comprehensive set of specimens and link it to recently described fossil evidence. The phylogeny strongly supports multiple origins of coprophagy, phytophagy and anthophagy. The ingroup-based fossil calibration of the tree widely confirmed a Jurassic origin of the Scarabaeoidea crown group. The crown groups of phytophagous lineages began to radiate first (Pleurostict scarabs: 108 Ma; Glaphyridae between 101 Ma), followed by the later diversification of coprophagous lineages (crown-group age Scarabaeinae: 76 Ma; Aphodiinae: 50 Ma). Pollen feeding arose even later, at maximally 62 Ma in the oldest anthophagous lineage. The clear time lag between the origins of herbivores and coprophages suggests an evolutionary path driven by the angiosperms that first favoured the herbivore fauna (mammals and insects) followed by the secondary radiation of the dung feeders. This finding makes it less likely that extant dung beetle lineages initially fed on dinosaur excrements, as often hypothesized.

现存陆地生物多样性的形成，通常认为有赖于被子植物（angiosperm）的演化成功，但依赖被子植物的辐射演化的具体机制与时间尺度，目前仍未得到充分阐释。金龟总科（Scarabaeoidea）是一类物种丰富的昆虫支系，其成员大多以植物或粪便为食。本研究基于涵盖广泛类群的标本的4组DNA标记（DNA markers），开展了金龟总科的系统发育分析，并将该系统发育树与最新发表的化石证据相结合。该系统发育树有力地证实了食粪行为（coprophagy）、植食行为（phytophagy）以及花粉食性（anthophagy）均多次独立起源。基于内类群的化石定标（fossil calibration）分析，广泛验证了金龟总科冠群（crown group）起源于侏罗纪（Jurassic）。植食性支系的冠群最先开始辐射演化（侧背金龟类：108 Ma；斑金龟科（Glaphyridae）：101 Ma前后），随后食粪性支系发生次级辐射演化（粪金龟亚科（Scarabaeinae）冠群距今76 Ma；蜉金龟亚科（Aphodiinae）：50 Ma）。花粉食性的起源则更晚，最古老的花粉食性支系的起源时间不晚于62 Ma。植食类群与食粪类群的起源存在显著的时间差，这表明演化路径由被子植物主导：首先推动植食性动物群（包括哺乳动物与昆虫）的繁盛，随后食粪类群发生次级辐射演化。该研究结果使得“现存粪金龟支系最初以恐龙粪便为食”这一常见假说的可信度大幅降低。