Diagnosis: Sedilichnus consisting of smooth-walled, bowl-shaped pits with a circular outline and rounded edge (Zonneveld and Gingras, 2014).

However, Sedilichnus is nomenclaturally unavail able, because it is an atelonym (conditionally proposed). In addition, reinvestigation of the type material of ‘Sedilichnus’ shows that it probably describes variably shaped oscula and thus is a genuine morphological character of the host sponge Prokaliapsis janus, rather than a bioerosion trace fossil.