EDIACARAN-STYLE DECAY EXPERIMENTS USING MOLLUSKS AND SEA ANEMONES
EDIACARAN-STYLE DECAY EXPERIMENTS USING MOLLUSKS AND SEA ANEMONES
复制标题
DOI：
10.2110/palo.2017.091
复制
发表时间：
2018-05-01
期刊：
影响因子：
1.6
通讯作者：
Darroch, Simon A. F.
中科院分区：
文献类型：
--
作者：
Gibson, Brandt M.;Schiffbauer, James D.;Darroch, Simon A. F.
最新的新元古代埃迪卡拉生物群是一个神秘的软体真核生物的集合，它们被不同地解释为双胚层和三胚层，并且被认为是作为黄铁矿的“死亡面具”保存下来的。我们对海葵（Condylactis giguntea）和软体动物（Dolabella auricularia）在"正常"（即，基线）和埃迪卡拉风格的条件下，这使我们能够构建这些生物群的衰减指数，测试埃迪卡拉埋藏情景对衰减速率和模式的影响，并可能限制埃迪卡拉化石的系统发育亲和力。我们发现，在这两种类型的生物体中，最不稳定的组织优先丢失，并且组织类型对保存的控制比总体的二胚层组织与三胚层组织更强。因此，总的来说，在二胚层和三胚层生物体之间的保存没有很大的差别。从周围的尸体沉积物的地球化学分析表明，黄铁矿的“死亡面具”式的保存是依赖于铁的可用性。也许最重要的是，在埃迪卡拉风格的埋藏方案下的实验表现出更快的不稳定组织，如海葵触角和软体动物的内部肠道系统，比基线实验的衰减。这一发现突出了对新元古代晚期后生动物特征保存的潜在偏见，这可能影响了对许多标志性埃迪卡拉生物的解释。
The latest Neoproterozoic Ediacara biota are a collection of enigmatic soft-bodied eukaryotes that have been variously interpreted as both diploblasts and triploblasts, and which are thought to have been preserved as pyritic 'death masks'. We perform decay experiments on sea anemones (Condylactis giguntea) and mollusks (Dolabella auricularia) under both `normal' (i.e., baseline) and Ediacaran-style conditions; this allows us to construct decay indices for both these organismal groups, test the influence of Ediacaran taphonomic scenarios on rates and patterns of decay, and potentially constrain the phylogenetic affinities of Ediacaran fossils. We find that in both types of organisms the most labile tissues are preferentially lost, and tissue type exerts a stronger control on preservation than overall diploblastic versus triploblastic organization. Thus, in sum, there is not a large differential of preservation between diploblastic and triploblastic organisms. Geochemical analyses of sediment from around the carcasses indicate that pyritic 'death mask'-style preservation is dependent on the availability of Fe. Perhaps most importantly, experiments under Ediacaran-style taphonomic scenarios exhibit more rapid decay of labile tissues, such as anemone tentacles and the internal gut system of mollusks, than in baseline experiments. This finding highlights potential biases against the preservation of metazoan characters in the late Neoproterozoic, which may have influenced the interpretation of many iconic Ediacaran organisms.