瑞典乌普萨拉大学Ben J. Slater报道了即寒武纪早期瑞典特异性保存的节肢动物和软体动物微体化石。相关论文发表在2024年1月25日出版的《地质学》杂志上。

研究人员报道了浅海沉积物(瑞典寒武纪第三世Mickwitzia砂岩)中发现的、迄今为止未知的寒武纪节肢动物和软体动物化石的多样性。这些微化石包括各种节肢动物角质层，其中保存了亚微米尺度的内部结构以及丰富的来自软体动物齿舌的口器，这是已知最古老的节肢动物和软体动物小型碳质化石之一。

值得注意的是，至少有三种不同类型的齿舌化石可以被识别出来(单轴、双轴和多轴形式)，结果表明，在寒武纪早期，基本的软体动物齿舌已经发生了实质性的多样化。这些生物群的神秘元素提供了对寒武纪初级消费者，以及在深水伯吉斯页岩型沉积物中缺少的动物群方面的新见解。

据介绍，伯吉斯页岩型(BST) Lagerstatten记录了异常多样的寒武纪软体动物群，但这些沉积物通常局限于距离古海岸线大于1000公里的外侧沉积环境中。人们对浅层、氧气充足的陆架环境以及非矿化动物(大多数的多样性)的了解非常有限，这导致了人们对寒武纪生物群的认识存在很大的偏差。探测寒武纪软体动物群的另一种方法是使用酸浸渍法提取未矿化的微观有机残余物，被称为“小型碳质化石”。

附：英文原文

Title: Life in the Cambrian shallows: Exceptionally preserved arthropod and mollusk microfossils from the early Cambrian of Sweden

Author: Ben J. Slater

Issue&Volume: 2024-01-25

Abstract: Burgess Shaletype (BST) Lagerstatten record an exceptional variety of Cambrian soft-bodied fauna, yet these deposits are typically restricted to outboard depositional settings >1000 km from the paleocoastline. For shallow, well-oxygenated shelf environments, our knowledge of non-mineralized animals (the majority of diversity) is severely limited, giving rise to substantial bias in our perception of Cambrian biotas. An alternate means of detecting soft-bodied Cambrian fauna, independent of paleobathymetry, is to use acid maceration to extract microscopic organic remains of non-mineralized animals, known as “small carbonaceous fossils” (SCFs). Here, a hitherto unknown diversity of Cambrian arthropod and mollusk remains are reported from shallow-marine sediments (Cambrian Stage 3 Mickwitzia Sandstone, Sweden). These microfossils comprise a variety of arthropod cuticles preserving sub-micron-scale anatomy alongside abundant radular mouthparts from mollusks—among the oldest known arthropod and molluscan SCFs on record. Significantly, at least three distinct types of fossil radula are identifiable (uniseriate, distichous, and polystichous forms), revealing that substantial diversification of the basic molluscan radula had already taken place by the early Cambrian. These cryptic elements of the biota—otherwise undetectable in such deposits—offer novel insights into Cambrian primary consumers as well as aspects of the fauna that are absent from deeper-water BST deposits.

DOI: 10.1130/G51829.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G51829.1/633578/Life-in-the-Cambrian-shallows-Exceptionally