The Paleocene (Danian) Clayton Formation of western Alabama, USA, includes multiple marine shelf parasequences, each comprising a relatively thick marl, capped by a thin limestone, the latter variably reflecting marine flooding episodes. The marls host relatively large firmground burrow systems that penetrate 50–60 cm beneath, and are cast by, superjacent limestones. Excavation of two partially exposed burrow systems – one beneath a highstand parasequence‐bounding flooding surface and the other beneath an overlying coplanar sequence boundary/transgressive surface (SB/TS) – reveals complex, primarily horizontal, irregularly branching networks. The former, allied with Thalassinoides paradoxicus, lacks wall bioglyphs, whereas the latter, allied with Spongeliomorpha iberica, is characterized by pervasive, mainly rhombohedral wall bioglyphs that reflect a relatively more firm substrate. Contrasts between these burrow systems are consistent with sequence stratigraphical context and inferred differences in the mechanism and magnitude of depositional hiatuses responsible for firmground development. Both excavated burrow systems likely represent cumulative structures produced by multiple organisms over extended periods of time. The cumulative nature and potential taphonomic biases associated with these and comparable burrow systems in the stratigraphical record preclude confident interpretation of tracemakers and their behaviours. The Clayton burrow systems likely were produced by one or more species of decapod crustacean that engaged in suspension‐feeding, surface detritus feeding, gardening or some combination thereof.

中文翻译：

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美国阿拉巴马州古新世克莱顿组海相陆架沉积物中的坚硬甲壳类洞穴系统（Glossifungites ichnofacies）

美国阿拉巴马州西部的古新世（达尼安）克莱顿地层包括多个海相陆架副序列，每个副陆相包括相对较厚的泥灰岩，上面覆盖着一层薄薄的石灰岩，后者可变地反映了海洋洪水的发生。泥灰岩拥有相对较大的坚硬的洞穴系统，这些洞穴系统穿透下面的50–60 cm，并由上层的石灰石铸造而成。开挖两个部分裸露的洞穴系统-一个在高架顺序层序洪泛面之下，另一个在上覆共面序列边界/海侵面（SB / TS）下-揭示了复杂的，主要是水平的，不规则分支的网络。前者，与盟军Thalassinoides paradoxicus，缺乏墙bioglyphs，而后者，与盟军Spongeliomorpha IBERICA，其特点是普遍存在，主要是菱面体壁的字形，反映出相对较牢固的底物。这些洞穴系统之间的对比与层序地层背景一致，并推断出负责实地发育的沉积裂隙的机理和大小的差异。两种挖掘的洞穴系统都可能代表了多种生物在长时间内产生的累积结构。与地层记录中的这些和类似的洞穴系统相关的累积性质和潜在的地形学偏误，排除了对示踪剂及其行为的自信解释。克莱顿洞穴系统可能是由一种或多种十足足甲壳类动物产生的，它们从事悬浮饲料，表面碎屑饲料，园艺或它们的某种组合。