Centrichnus Bromley et Martinell, 1991

Emended diagnosis.—Roughly circular to elliptical, or tearshaped bioerosion structures on the surface of carbonate lithic or skeletal substrates, shallower than wide, comprising centrically arranged arcuate or ring-shaped grooves, surrounded or bounded by a deeper groove and/or a series of pits.

Remarks.—The original diagnosis is emended to better cover all morphologies under this ichnogenus, including the more complex morphology of the type ichnospecies C. eccentricus. The variance of the outline and the shallow nature of the depression have been added (see also remarks to the ichnofamily Centrichnidae) and the trace margin has been characterised as “surrounded or bounded by a deeper groove and/or a series of pits”. The latter addition also suits the inclusion of the new ichnospecies described herein. Furthermore, it better accommodates the morphology of the former ichnospecies of Anellusichnus Santos et al., 2005, regarded by Wisshak et al. (2019) as a subjective junior synonym of Centrichnus Bromley & Martinell, 1991.

Attachment; substrate calcareous; tracemaker invertebrate

Category of architectural design: 2.77. Multiple attachment bioerosion traces.

Unbranched, groove.

Diagnosis– (After Bromley & Martinell, 1991, p. 247.) “Shallow biogenic etching traces on carbonate lithic or skeletal substrates comprising centrically arranged arcuate or ring-shaped grooves.”

Diagnosis: Shallow biogenic etching traces on carbonate lithic or skeletal substrates comprising centrically arranged arcuate or ring-shaped grooves (Bromley and Martinell,1991).