Renichnus arcuatus Mayoral, 1987

Original description: “Set of more or less shallow scars, in an aligned form or a sinuous to spiral trajectory (Figures 2A–D, 3G–H). They may occur isolated or in groups. The scars are usually smaller at one end (and much more regular, with an elongated, ovoid outline) and larger at the opposite end. In this case, the impressions are distinctly reniform, with one side highly arched.”

Emended diagnosis: Bioerosion structures that develop on the surface of calcareous hard substrates as nested reniform or crescentic depressions arranged in straight, sinuous, or strongly bent series or rows. Solitary depressions may also occur. The size of the depressions can be constant or vary in a gradual manner, reducing in size toward the concave-pointing end of the nested series.

Remarks: As originally defined, ichnogenus Renichnus (Mayoral, 1987) and its only known ichnospecies, Renichnus arcuatus (Mayoral, 1987), should be used only to refer to a series of reniform depressions.