Early Devonian trace fossils from a marginal-marine deltaic setting of the Rhenish Slate Mountains (SW Germany)

We describe and discuss invertebrate trace fossils originating from a limited, less than 2 m-thick sequence of sandstone beds from the Emsian Klerf Formation of the Olkenbach Syncline (SE Eifel) in Germany. The trace fossil suites are characterized by vertical and horizontal dwelling or feeding burrows or trails with relatively simple constructions and show a low to moderate ichnodiversity (about 15 ichnotaxa), although some ichnotaxa are abundant. The following ichnogenera are recorded: ?Arenicolites (and possibly Skolithos), Conichnus, Gyrochorte, Helminthopsis, Lockeia, Nereites, Palaeophycus, Planolites, Psammichnites, Ptychoplasma, Rosselia, and Spirophyton. Lockeia alfbachensis isp. nov. is proposed for a resting trace probably produced by bivalves. The overall geological and sedimentological context, the presence of adjacent mudstones with non-fully marine biota, low amount of bioturbation, and a sporadically heterogeneous distribution of the trace fossils suggest a stressed environmental setting, possibly induced by reduced salinity and/or subjected to episodic erosion and deposition. We propose a marginal-marine, deltaic setting, probably a distal tidal flat, as sedimentary environment for the trace fossil-bearing bedset under consideration.