Trigonia irregularis ? Seeb.

Scale bar = 5cm

Description

Upper Jurassic, Oxford Clay
Weymouth
Dorset
England
M2071
Description:

Belonging to a large family of bivalves that flourished in the Mesozoic, Trigonia is a genus easily identified by the ornamentation of their shells, in this case irregular nodes. Only one genus of the family Trigoniidae(Neotrigonia) remains extant.
Moore, C.

Classification

Mollusca
Loboconcha
Bivalvia
Palaeoheterodonta
Trigonioida
Superfamily Trigonioidea
Trigoniidae
Trigonia
irregularis