Ophthalmichnus Wisshak, Alexandrakis et Hoppenrath, 2014

Attachment; substrate calcareous; tracemaker plant

Category of architectural design: 2.76. Single circular to tear-shaped attachment bioerosion traces.

Diagnosis: Shallow elliptical micro-etching.

Differential Diagnosis: Distinguished from the ichnogenus Oichnus Bromley, 1981, by its elliptical as opposed to a circular outline and by never completely penetrating the substrate. The non-penetrating Oichnus excavatus Donovan and Jagt, 2002, is much larger, always circular, and has a deeper relief relative to the diameter of the trace. In contrast to Kardopomorphos Beuck, Lopez Correa and Freiwald, 2008, the outline is strictly elliptical or mandorla-shaped and the traces are smaller. The trace is distinguished from much larger Centrichnus concentricus Bromley and Martinell, 1991 by the elliptical delineation and the absence of multiple concentric etching grooves. The closest affinity exists to Fossichnus solus Nielsen, Nielsen and Bromley, 2003, which is of similar size but more circular in outline, never exhibits a faint linear or dotted sculpture, and in advanced stages may completely penetrate the substrate to form Oichnus simplex Bromley, 1981.