TF0103 - Trigonia

Age

Jurassic

Stratigraphic Range

Jurassic to recent

Taxonomy

Phylum: Mollusca
Class: Bivalvia
Order: Trigoniida
Family: Trigoniidae

Distinctive Features

Ribs
Dentition, hinge
Growth lines

Preservation

Set 1:
Mineral replacement of shell (aragonite to calcite)
Set 2:
Disarticulation of valves
Sediment infil (oolitic ironstone, which gives the reddy colour to the specimen)
Mineral replacement of shell (aragonite to calcite)

Advanced notes

Strong ribs are present on the anterior part of the shell - perhaps to discourage predators or as a response to a high energy environment?
TF0103 - Trigonia