Article: Musculature and asymmetry in a Carboniferous pseudo-bellerophontoidean gastropod (Mollusca)

A single pair of well-preserved muscle attachment scars showing excellent detail on the umbilical surface is described in a supposed bellerophontoidean gastropod from the Carboniferous of Britain. Ontogenetic study reveals that the bilateral symmetry of the thick-shelled adult masks an anisometric early growth stage, indicating that the gastropod is a pleurotomarioidean vetigastropod masquerading as a bellerophontoidean.