Stromatoporoids are common shallow marine hypercalcified sponges in two major episodes with distinctive skeletal architectures: 1) Palaeozoic: Ordovician to Late Devonian; and 2) Mesozoic: Late Triassic to Cretaceous and rare Cenozoic, but not confirmed in Permian and earlier Triassic strata. Stromatoporoids appeared in Early to Middle Ordovician strata, important in buildups from late Middle Ordovician metazoan expansions (part of the Great Ordovician Biodiversification Event). Throughout the Palaeozoic, some stromatoporoid taxa occur across several palaeocontinents, and, if they are the same taxa, presumably migrated as larvae across oceans. Palaeozoic stromatoporoids suffered 5 events of decline; Event 1): end-Ordovician Mass Extinction; surviving forms are typical Silurian taxa, marking change of abundance from labechiid to clathrodictyid forms. Event 2): late Silurian to Early Devonian contraction: stromatoporoids became scarce with low generic diversity, presumably related to global sea-level fall. Intra-Silurian extinction events principally affected conodonts and graptolites, associated with positive carbon isotope excursions, but not stromatoporoids, likely because of their shallow marine benthic habit, contrasting pelagic oceanic planktonic and nektonic fauna influenced by oceanographic changes. Stromatoporoid expansion to their late Early to Middle Devonian (Eifelian and Givetian) acme, forming a major Phanerozoic global reef system, was likely linked to global sea-level rise, when epeiric seas expanded, but followed by Event 3): end-Givetian extinction, possibly related to cooling; Event 4): Frasnian-Famennian (FF) extinction; and Event 5): end-Devonian (Hangenberg Event) extinction; 4 and 5 may be related to sea-level fall, cooling, anoxia and potentially, magmatism. The apparent stratigraphic gap between end-Devonian and Triassic stromatoporoids was not extinction of Palaeozoic stromatoporoids, because rare Carboniferous examples in England, Russia, USA and Japan prove survival in shallow marine environments. Prior interpretation that stromatoporoid-grade sponges lost ability to calcify is unlikely, because chaetetid hypercalcified sponges expanded and built Carboniferous reefs. Important is that skeletal architectures of stromatoporoid and chaetetid hypercalcified sponges are regarded as ‘grades of organisation’ of the skeleton, lacking phyletic value; living stromatoporoid- and chaetetid-grade sponges occur in the classes Demospongiae and Calcarea based on their spicules. This implies that extinction of sponge taxa that just happened to have been stromatoporoid-grade hypercalcifiers may explain stromatoporoid loss in the end-Devonian, and may point to unpreserved crises in non-calcifying Porifera, noting poor sponge records in end-Devonian strata. Having also survived the end-Permian and end-Triassic extinctions, stromatoporoid-grade hypercalcification expanded again in the Jurassic, together with sphinctozoan and inozoan grades, and then survived the K-Pg extinction although stromatoporoid-grade sponges are rare after the Cretaceous, perhaps due to the large progressive sea-level fall of the Cenozoic and consequent loss of habitat. Stromatoporoids appear to be more abundant during calcite seas times, so there may be both an oceanographic chemical control on their development and a preservation bias towards calcite rather than aragonite mineralogy. Overall, the ability of sponges to hypercalcify was not lost throughout their Phanerozoic history; thus, stromatoporoids and other hypercalcified sponges are preserved evidence of the resilience of sponges to environmental change, in contrast other famous reef-building forms, such as tabulate and rugose corals, and rudist bivalves, which became extinct.

中文翻译：

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层孔虫和灭绝：回顾

层孔类海绵是常见的浅海超钙化海绵，有两个主要时期，具有独特的骨骼结构：1）古生代：奥陶纪到晚泥盆世； 2）中生代：晚三叠世至白垩纪和罕见的新生代，但在二叠纪和早三叠世地层中尚未得到证实。层孔类生物出现在早奥陶世至中奥陶世地层中，对于中奥陶世晚期后生动物扩张（奥陶世生物多样性大事件的一部分）的形成很重要。在整个古生代，一些层孔类类群出现在几个古大陆上，如果它们是相同的类群，那么它们可能以幼虫的形式跨越海洋迁移。古生代层孔虫经历了5次衰退事件；事件1）：奥陶纪末大规模灭绝；幸存的形式是典型的志留纪类群，标志着丰度从拉贝奇类到笼形类的变化。事件2）：志留纪晚期到泥盆纪早期收缩：层孔类动物变得稀缺，且属多样性较低，可能与全球海平面下降有关。志留系内灭绝事件主要影响与正碳同位素漂移相关的牙形刺和笔石，但不影响层孔类动物，可能是因为它们的浅海底栖习性，与受海洋变化影响的中上层海洋浮游和游动动物群形成鲜明对比。层孔类扩张到早泥盆世晚期到中泥盆世（埃菲勒期和吉维特期）的顶点，形成了一个主要的显生宙全球珊瑚礁系统，可能与全球海平面上升有关，当时表海扩张，但随后发生了事件 3）：吉维特期末灭绝，可能与冷却有关；事件4）：法拉斯尼阶-法门阶（FF）灭绝；事件5）：泥盆纪末（汉根堡事件）灭绝； 4和5可能与海平面下降、变冷、缺氧以及潜在的岩浆作用有关。泥盆纪末和三叠纪层孔类之间明显的地层差距并不是古生代层孔类的灭绝，因为英国、俄罗斯、美国和日本的罕见石炭纪例子证明它们在浅海环境中生存。先前关于层孔级海绵失去钙化能力的解释不太可能，因为毛壳类高钙化海绵扩张并形成了石炭纪珊瑚礁。重要的是，层孔类和毛毛类超钙化海绵的骨骼结构被视为骨骼的“组织等级”，缺乏系统学价值；活的层孔海绵和毛毛海绵根据其针状体分为蠕海绵纲和钙海绵纲。这意味着恰好是层孔类超钙化物的海绵类群的灭绝可以解释泥盆纪末期层孔类的消失，并可能指出非钙化多孔类动物未受保护的危机，注意到泥盆纪末地层中海绵记录较差。在二叠纪末期和三叠纪末期的灭绝中幸存下来后，层孔类超钙化在侏罗纪再次扩大，同时还有括约虫级和恐龙级，然后在 K-Pg 灭绝中幸存下来，尽管白垩纪之后层孔级海绵很少见，这可能是由于新生代海平面大幅下降以及随之而来的栖息地丧失。层孔类生物在方解石海洋时期似乎更加丰富，因此可能存在对其发育的海洋化学控制以及对方解石而不是文石矿物学的保存偏向。总体而言，海绵的超钙化能力在整个显生宙历史中并未丧失。因此，层孔类和其他超钙化海绵是海绵对环境变化具有恢复能力的证据，与其他著名的造礁形式形成鲜明对比，例如板状珊瑚和皱纹珊瑚以及已灭绝的红壳双壳类。