Isopodichnus in a trace fossil assemblage from the Old Red Sandstone

Isopodichnus stromnessi sp. nov. from the Lower Stromness Flags of Orkney is described in detail, and the range of variation in the traces ascribed to different habits of different sized individuals producing the traces. Activity diagrams illustrate scme of the burrowing habits of the organism. Isopodichnus is typical of non-marine strata, particularly those of shallow impermanent lacustrine environments, and can be distinguished from Cruziana on the basis of the shape of the trace ending. Associated burrows are briefly described and indicate the presence of a hitherto undescribed invertebrate fauna associated with the Orcadian flagstone sequence of the Middle Old Red Sandstone.