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.

唯有明确各演化支（clade）的相对埋藏潜力，方能全面理解深时（deep time）的全球生物多样性格局。海洋节肢动物作为现代与古生态系统中兼具多样性与重要生态功能的组分，其演化支的相对埋藏潜力迄今仍鲜有研究。为此，我们开展了一项为期205天的实验室综合性比较埋藏学（taphonomic）实验：为7种甲壳类（crustacean）与1种螯肢类（chelicerate）的多份标本共计10项埋藏学特征进行评分，所涉类群包含2种真蟹、1种虾、1种龙虾、1种寄居蟹、1种口足类（螳螂虾，stomatopod）、1种蔓足类（藤壶，barnacle）与1种鲎（horseshoe crab）。尽管本研究结果尚属初步——仅采用单一实验装置，且藻类生长一定程度上干扰了观测——但寄居蟹、口足类、游泳蟹与藤壶的部分组织相较于其他组织腐烂速率更慢，暗示物种内部存在差异化埋藏潜力，这与对应类群的化石记录大体一致。一例被推断为寄生等足类（isopod）的个体，其寄居蟹头胸甲内呈现鳃虱型肿胀，腐烂速度相对较快。我们发现同种个体间的腐烂速率差异有限，且未观察到腐烂速率与体型相关的变化趋势。与之相对，约50天后不同物种间的腐烂速率出现显著分化：虾与口足类腐烂最快，暗示其相对埋藏潜力较低；而龙虾、花斑蟹、鲎与藤壶的腐烂速率相对较慢，埋藏潜力相对更高。上述结果得到两项基于现代与化石记录的埋藏潜力指标的支持，这两项指标与腐烂速率排名显著相关。此外，我们推测基干偏移（stemward slippage）可能并非海洋节肢动物化石记录中的普遍现象。我们的研究结果表明，相较于口足类、虾与寄居蟹，针对真蟹、龙虾、鲎与藤壶的多样性研究所得出的格局，更贴近其真实的生物多样性格局。