Wikipedia
Isopodichnus
Isopodichnus is an ichnogenus of trace fossil. Ribbon-like in form, Isopodichnus traces were likely formed by the activity of an isopod crustacean foraging within the preserved sediment. Parallel to the bedding plane, a central furrow is flanked by two hypichnial ridges. Trails may also exhibit scratch marks and be associated with Rusophycus-like resting traces. Isopodichnus are very similar in form to Cruziana traces, making delineation of the two forms difficult, and controversial.
Image:trace2.jpg|Isopodichnus trace fossil from the upper carboniferous - (Scotland, St Monans, Fife) (two penny piece for scale) Image:trace3.jpg|Close up Image:Cruziana2.jpg| Cruziana trace, possibly formed by a Trilobite.