Trusheimichnus franconicus (Trusheim, 1934)

Description: The subvertical to oblique burrows have a sharp outline and a circular cross section with a constant diameter of 2–4 mm. Their maximum observed length is about 50–80 mm, though many burrows are only fragmentarily preserved as their upper part. The upper part of some burrows is enlarged in form of a deeply inclined funnel, whereas the lower termination may have an increased burrow diameter. Burrow morphology is rectilinear, J- or L-shaped, and winding or loosely sinusoidal components are common.