Deconstructing Biases in the Fossil Record of the Oldest Animals: Experimental and Geochemical Studies in Soft-Tissue Preservation

化石记录是变化无常和有偏见的。与典型的骨骼、牙齿和贝壳化石组合不同，保存软体生物的遗址极其罕见，也是真正的例外（Seilacher的Konservat-Lagerstätten，1970）。Lagerstätten代表了灭绝物种最丰富的解剖信息来源，提供了更完整的深时多样性模式视图，并最终打开了一扇通常只为研究现代系统的生物学家提供的了解古代生态系统运作的窗口。然而，越来越多的人认识到，拉格斯塔滕充满了民族偏见，迫切需要系统地描述。例如，Lagerstätten在地质时期分布不均匀，通常限于特定的环境设置，并优先保存某些组织类型（Allison和Briggs，1993; Schiffbauer和Laflamme，2012）。跨学科的研究，检查控制化石保存（埋藏学）的节奏和模式的物理，化学和生物因素提供了重要的新观点的内容和准确性的化石记录，是正确识别生命进化趋势的必要的第一步。我的长期研究目标是阐明埋藏的途径负责化石化，并确定物理，化学和生物控制偏化石记录。软组织保存的实验和埋藏学研究对评估化石记录的保真度具有深远的意义，特别是在动物生命的黎明。我的工作建议进行第一次全面调查埃迪卡拉时代的埋藏情景，结合实验埋藏学和地球化学分析，以最终了解它们在时间和空间上的分布。最终，埋藏学地面实况调查是必要的，以验证所有古生物学的趋势，在任何规模的化石记录外推。

The fossil record is fickle and biased. Sites that preserve soft-bodied organisms, as opposed to typical fossil assemblages of bones, teeth, and shells, are exceedingly rare and truly exceptional (Konservat-Lagerstätten of Seilacher, 1970). Lagerstätten represent the richest source of anatomical information for extinct species, offer more complete views of diversity patterns in deep time, and ultimately open a window into the workings of ancient ecosystems typically afforded only to biologists studying modern systems. However, there is a growing recognition that Lagerstätten are fraught with preservational biases, which are in urgent need of systematic characterization. For instance, Lagerstätten are unevenly distributed through geological time, are typically restricted to specific environmental settings, and preferentially preserve certain tissue types over others (Allison and Briggs, 1993; Schiffbauer and Laflamme, 2012). Interdisciplinary studies that examine the physical, chemical, and biological factors controlling the tempos and modes of fossil preservation (taphonomy) are offering critical new perspectives on the content and accuracy of the fossil record, and are a necessary first step in correctly identifying trends in the evolution of life. My long-term research objective is to elucidate the taphonomic pathways responsible for fossilization, and to identify physical, chemical, and biological controls biasing the fossil record.****The proposed experimental and taphonomic studies of soft-tissue preservation have profound implications on evaluating the fidelity of the fossil record, specifically at the dawn of animal life. My work proposes to undertake the first comprehensive investigation of Ediacaran taphonomic scenarios, combining experimental taphonomy, and geochemical analyses in order to finally understand their distribution in time and space. Ultimately, taphonomic ground-truthing is necessary to validate all paleontological trends at any scale extrapolated from the fossil record.