New records of Ctenopholeus in the early Devonian Hunsrück Slate of Bundenbach, SW Germany

The rare trace fossil Ctenopholeus kutscheri Seilacher & Hemleben, originally described from the type area of the early Devonian Hunsrück Slate at Gemünden (Germany), refers to initially open horizontal tunnels with vertically to obliquely oriented serial shafts opening to the sediment-water interface. Occurrences of frequent and partly exceptionally large specimens from Bundenbach, tentatively assigned to C. kutscheri, reveal that these burrows, were constructed in larger numbers in the Hunsrück Slate. This happened when environmental conditions were favorable for the producer(s). Contributing factors presumably include substrate cohesion and stability being suitable for the maintenance of open burrow systems, as well as sustainable food resources during the time interval when the burrows were occupied. The new material confirms that the course of the shafts in C. kutscheri varies from almost straight to slightly bent to circular in cleavage plane view and may overlap with morphologies observed in Heliochone hunsrueckiana Seilacher & Hemleben. Holothurians and, more likely, crustaceans are discussed as possible producers of C. kutscheri from the Hunsrück Slate.