小柯机器人

近日，加拿大劳伦森大学Elizabeth C. Turner发现，新元古代早期微生物礁中可能存在海绵动物身体化石。相关论文于2021年7月28日发表在《自然》杂志上。

据研究人员介绍，分子系统学表明，后生代（动物）在新元古代早期就出现了，但缺乏实物证据。寻找原生代的动物化石，由于不知道应该有哪些物理特征而受到阻碍。海绵是已知的最基本的动物类型；迄今为止尚未发现的元古代后生动物的身体化石有可能与显生宙的海绵化石相似。蠕虫状微结构一个在显生宙珊瑚礁和微生物碳酸盐中的复杂岩石学特征，现在已知是nonspicular keratosan demosponges的身体化石。

研究人员报道了来自大约8.9亿年前珊瑚礁的岩石学上相同的蛭形微结构。这种毫米级到厘米级的蠕虫状微结构生物只生活在由钙化蓝藻（光合作用者）建造的珊瑚礁上、里面和旁边，并且占据了这些钙化微生物无法生活的微环境。如果蠕虫状微结构实际上是角质海绵的组织化石，这里描述的发现将代表迄今为止已知的最古老动物体化石证据，并将提供第一个物理证据，证明动物在新元古代产氧事件之前出现，并在成冰纪的冰川期存活。

附：英文原文

Title: Possible poriferan body fossils in early Neoproterozoic microbial reefs

Author: Turner, Elizabeth C.

Issue&Volume: 2021-07-28

Abstract: Molecular phylogeny indicates that metazoans (animals) emerged early in the Neoproterozoic era1, but physical evidence is lacking. The search for animal fossils from the Proterozoic eon is hampered by uncertainty about what physical characteristics to expect. Sponges are the most basic known animal type2,3; it is possible that body fossils of hitherto-undiscovered Proterozoic metazoans might resemble aspect(s) of Phanerozoic fossil sponges. Vermiform microstructure4,5, a complex petrographic feature in Phanerozoic reefal and microbial carbonates, is now known to be the body fossil of nonspicular keratosan demosponges6,7,8,9,10. This Article presents petrographically identical vermiform microstructure from approximately 890-million-year-old reefs. The millimetric-to-centimetric vermiform-microstructured organism lived only on, in and immediately beside reefs built by calcifying cyanobacteria (photosynthesizers), and occupied microniches in which these calcimicrobes could not live. If vermiform microstructure is in fact the fossilized tissue of keratose sponges, the material described here would represent the oldest body-fossil evidence of animals known to date, and would provide the first physical evidence that animals emerged before the Neoproterozoic oxygenation event and survived through the glacial episodes of the Cryogenian period.

DOI: 10.1038/s41586-021-03773-z

Source: https://www.nature.com/articles/s41586-021-03773-z

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html