Irhopalia catenata (Radtke, 1991)

Original ichnospecies diagnosis: A tubular system oriented parallel to the substrate surface, often radiating from a central area, with ramifications in pointed angles, with spherical to ellipsoidal swellings along the galleries, bifurcations or gallery terminations, and linked to the substrate surface by thin rhizoidal appendages (after Radtke 1991).

Description. There is a considerable morphological variability and size range of this ichnotaxon, but all representatives show a closely substrate-parallel system of branched tunnels with prominent spherical to irregular-shaped swellings at the branching points and at the terminations of short lateral side branches (Fig. 6F-H). The galleries and swellings may be connected to the substrate by thin apophyses, which, if present, are often hidden underneath the trace.