Data from: Comparative experimental taphonomy of eight marine arthropods indicates distinct differences in preservation potential

Global biodiversity patterns in deep time can only be understood fully when the relative preservation potential of each clade is known. The relative preservation potential of marine arthropod clades, a diverse and ecologically important component of modern and past ecosystems, is poorly known. We tackled this issue by carrying out a 205-day long comprehensive, comparative, taphonomic experiment in a laboratory by scoring up to ten taphonomic characters for multiple specimens of seven crustacean and one chelicerate species (two true crabs, one shrimp, one lobster, one hermit crab, one stomatopod, one barnacle and one horseshoe crab). Although the results are preliminary because we used a single experimental setup and algal growth partially hampered observations, some parts of hermit crabs, stomatopods, swimming crabs and barnacles decayed slowly relative to other parts, implying differential preservation potentials within species, largely consistent with the fossil record of these groups. An inferred parasitic isopod, manifested by a bopyriform swelling within a hermit crab carapace, decayed relatively fast. We found limited variation in the decay rate between conspecifics, and we did not observe size-related trends in decay rate. Conversely, substantial differences in the decay rate between species were seen after c. 50 days, with shrimps and stomatopods decaying fastest, suggesting a relatively low preservation potential, whereas the lobster, calico crabs, horseshoe crabs and barnacles showed relatively slow decay rates, suggesting a higher preservation potential. These results are supported by two modern and fossil record-based preservation potential metrics that are significantly correlated to decay rate ranks. Furthermore, we speculate that stemward slippage may not be ubiquitous in marine arthropods. Our results imply that diversity studies of true crabs, lobsters, horseshoe crabs and barnacles are more likely to yield patterns that are closer to their true biodiversity patterns than those for stomatopods, shrimps and hermit crabs.唯有明确每一个演化支（clade）的相对保存潜力，方能充分理解深时全球生物多样性格局。海洋节肢动物演化支作为现代与古生态系统中多样且生态意义重大的组成部分，其相对保存潜力至今仍鲜为人知。为此，我们在实验室开展了一项为期205天的综合性对比埋藏学（taphonomic）实验，对7种甲壳类与1种螯肢类（chelicerate）物种的多份标本开展最多10项埋藏学特征评分；所涉物种包括2种真蟹、1种虾、1种龙虾、1种寄居蟹、1种口足类（stomatopod）、1种蔓足类（barnacle，俗称藤壶）以及1种鲎（horseshoe crab）。尽管本研究仅采用单一实验装置，且藻类生长一定程度上干扰了观测，导致实验结果尚属初步，但寄居蟹、口足类、游泳蟹与蔓足类的部分躯体相较于其他部位腐烂更缓，暗示物种内部存在差异化的保存潜力，这与对应类群的化石记录大体相符。一件寄居蟹甲壳上表现出鳃虱型肿胀的疑似寄生等足类（isopod）标本，腐烂速度相对较快。我们发现同物种种群（conspecifics）间的腐烂速率差异有限，且未观测到腐烂速率与个体大小相关的变化趋势。与之相反，实验开展约50天后，不同物种间的腐烂速率出现显著差异：虾与口足类腐烂最快，预示其保存潜力相对较低；而龙虾、斑纹蟹、鲎与蔓足类的腐烂速率相对较缓，预示其保存潜力更高。两项基于现代与化石记录的保存潜力指标（metrics）均与腐烂速率排序显著相关，佐证了本研究结果。此外，我们推测向基干滑移（stemward slippage）现象可能并非海洋节肢动物中的普遍现象。本研究结果表明，相较于口足类、虾与寄居蟹的多样性研究，针对真蟹、龙虾、鲎与蔓足类的多样性研究所得结果，更有可能接近类群真实的生物多样性格局。