Umbichnus Martinell, Domènech et Bromley, 1999

Macroboring; substrate calcareous; tracemaker invertebrate

Diagnosis: Sack-shaped boring having a single aperture, etched into both valves of bivalves in the hinge plates beneath the umbones.

Umbichnus Martinell et al., 1999 is an unusual pouch-shaped boring cut into the hinge plates of both valves of bivalves. The authors, though, cannot dismiss the possibility that it is a dissolution feature and not a boring (Martinell et al., 1999).

Category of architectural design: 2.65. Pouch borings.

Unbranched, pouches.