Cruziana reticulata is an arthropod‐related ichnospecies that is characterized by a conspicuous net‐like scratch pattern whose initial formation and later preservation require the presence of consolidated substrates in shallow marine fine‐grained bottoms. There are two scenarios in which epifaunal to shallow infaunal benthic organisms may access firm siliciclastic substrates: first, by exposure of the compacted bottom after erosion of the upper, water‐saturated and usually soft portion of sediment column; and, second, by primary fast substrate stabilization in the absence of biogenic sediment mixing. Whereas the first mode occurs throughout the Phanerozoic, the latter is only prevalent in marine bottoms during the Early Palaeozoic mainly as a consequence of poorly developed infaunal bioturbation. However, by eradicating burrowing organisms, mass extinctions are known (i.e. the end‐Permian extinction) to ‘reset’ intensity of ecospace utilization, which entails the return to this anachronistic style of trace fossil preservation in younger times. An earliest Carboniferous ichno‐assemblage dominated by Cruziana reticulata from Morocco attests the spread of firm substrates in the aftermath of the Hangenberg Event – a major extinction at the end of the Devonian period. Since evidence for erosion is lacking in accompanying sedimentary rocks and the ichno‐assemblage shows characteristics of opportunistic exploitation of the nutritious muddy seabed, we favour the interpretation of this assemblage to represent a post‐extinction ichnofauna. It shows that other taxonomically less severe mass extinctions may also exhibit transient but severe ecological effects in open marine ecosystems such as the collapse of vital sediment mixing. Such post‐extinction effects may distort the perception of the stratigraphical record as a firmground ichno‐assemblage often taken as evidence for submarine erosion and are crucial in highlighting sequence boundaries. We, thus, encourage appreciating macroevolutionary framework of respective ichnofaunas.

中文翻译：

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灭绝后的鱼类动物的确凿证据：摩洛哥Anti-Atlas最早的石炭纪Cruziana reticulata组合

十字花是一种与节肢动物有关的鱼类种类，其特征是明显的网状划痕图案，其初始形成和后期保存需要在浅海细粒海底中存在固结的基质。在两种情况下，从表层到浅层的底栖底栖生物可能会进入牢固的硅质碎屑基底：首先，在沉积柱上部，水饱和且通常较软的部分侵蚀后，暴露于压实的底部。第二，在没有生物沉淀物混合的情况下，通过主要的快速基质稳定作用。第一种模式发生在整个生代时代，而后者仅在古生代早期在海床中盛行，这主要是由于未充分发育的生物扰动造成的。但是，通过消灭穴居生物，众所周知，大规模灭绝（即二叠纪末期的灭绝）会“重置”生态空间的利用强度，这意味着在更年轻的时候恢复这种过时的痕迹化石保存方式。最早的石炭系鱼类组合，以十字花 来自摩洛哥的消息证明了在Hangenberg事件之后坚硬基质的扩散-泥盆纪时代末期的一次大灭绝。由于伴随的沉积岩缺乏侵蚀证据，并且鱼鳞组合显示出对营养性泥质海床的机会性开采特征，因此我们赞成将该组合解释为灭绝后的鱼鳞动物。它表明，其他分类学上不太严重的物种大灭绝在开放的海洋生态系统中也可能表现出短暂但严重的生态影响，例如重要沉积物混合的崩溃。此类灭绝后的影响可能会使人们对地层记录的看法有所误解，认为它是坚硬的鱼鳞组合，通常被视为海底侵蚀的证据，对于强调层序边界至关重要。因此，我们