Fossil group

Trigonia-type bivalves

Molluscs · Cambrian – Recent

Trigoniid bivalves have a distinctively triangular to rhomboidal shell that is strongly ornamented with ribs or rows of tubercles, and a complex interlocking (schizodont) hinge. Active, shallow-burrowing suspension-feeders, they were widespread and diverse in Mesozoic shallow seas, with the living Neotrigonia of Australian waters as their sole surviving relative.

A broad fossil group rather than a single taxon — the units below record it among their fauna or flora.