Abstract A trace fossil assemblage from the Silurian (Llandovery) black shales of the Genna Muxerru Formation is reported for the first time. The ichnofossil record is abundant, well-preserved and comprises Alcyonidiopsis, Cochlichnus, Phymatoderma, Planolites (large morphotype), Planolites (rough morphotype) and a ‘Small chondritid’. Sedimentological and ichnological evidence indicates that the bioturbated black shales were deposited in outer shelf (or deeper) settings with severe depletion in oxygen. The seafloor provided a high food supply for the infauna. The palaeoenvironment of the Genna Muxerru Formation is an ancient analogue of modern oxygen-minimum zones. Burrow fills are apparently massive in macroscopic view, whereas observations under the petrographic and stereoscopic microscope show that a lifestyle dominated, i.e. that of pellet-filling sediment-feeders. As such, the Genna Muxerru Formation provides not only a new ethologic reference for low-oxygen settings but also a methodological benchmark for ichnological analysis of black shales. Bioturbation in black shales may be commoner than expected but its recognition requires microscopic observation.

中文翻译：

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近缺氧条件下的生活：意大利撒丁岛志留纪笔石黑色页岩的物种学和底栖生态学案例研究

摘要 首次报道了来自Genna Muxerru 组志留纪（Llandovery）黑色页岩的微量化石组合。鱼化石记录丰富且保存完好，包括 Alcyonidiopsis、Cochlichnus、Phymatoderma、Planolites（大形态型）、Planolites（粗形态型）和“小球粒陨石”。沉积学和地质学证据表明，生物扰动的黑色页岩沉积在外大陆架（或更深）环境中，氧气严重枯竭。海底为动物群提供了大量的食物供应。Genna Muxerru 组的古环境是现代最低氧区的古老类似物。从宏观上看，洞穴填充物显然是巨大的，而在岩相和立体显微镜下的观察表明，生活方式占主导地位，即 颗粒填充沉积物喂食器。因此，Genna Muxerru 组不仅为低氧环境提供了新的行为学参考，而且为黑色页岩的地质分析提供了方法基准。黑色页岩中的生物扰动可能比预期的更常见，但其识别需要微观观察。