The trace fossil Sulcolithos variabilis igen. et isp. nov. is described from the Middle Triassic (Ladinian) Muschelkalk Group of Germany. The groove-like structures occur on the surface of limestone beds that provided firm to hard substrate to the burrowing and/or boring organisms. The grooves have an elongate, straight or curved course and can be compound with subsurface burrow systems of Balanoglossites. Similar trace fossils have been reported from Late Ediacaran to Holocene deposits, and seem to be prevalent in Ordovician, Triassic and Jurassic time. Based on indirect evidence (e.g. morphology, interrelationship with Balanoglossites, substrate property), S. variabilis is attributed to the combined burrowing and boring activity of polychaetes. This interpretation is supported by direct evidence, such as the occurrence of exceptionally preserved polychaete remains in the traces, both in the Triassic material from Germany and the Ordovician specimens from Anticosti Island, Canada. However, morphologically similar traces in soft and firm substrate can also be produced by other organisms (e.g. bivalves) and represent behavioural convergence.

中文翻译：

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Sulcolithos variabilis igen。等 十一月：牢固而坚硬的床上用品表面上的凹槽

微量化石Sulcolithos variabilis igen。等 十一月 由德国中三叠纪（拉丁尼亚）Muschelkalk集团描述。沟状结构出现在石灰岩层的表面上，为洞穴和/或无聊的生物提供了坚硬的坚硬基质。凹槽具有细长的，笔直的或弯曲的路线，并且可以与Balanoglossites的地下洞穴系统复合。据报道，从爱迪生晚期至全新世沉积物中也发现了类似的痕迹化石，这些化石似乎在奥陶纪，三叠纪和侏罗纪时期盛行。基于间接证据（例如形态，与Balanoglossite的相互关系，底物性质），变异链球菌归因于多毛羚的挖洞和钻孔活动的结合。这种解释得到了直接证据的支持，例如在德国的三叠纪材料和加拿大的安蒂科斯蒂岛的奥陶纪标本中都发现了痕迹中保存得极为特殊的多毛羚遗骸。但是，其他生物（例如双壳类动物）也可以在软而牢固的基质中形成形态相似的痕迹，并代表行为收敛。