Valves i (head), ii & iii. Split, Croatia. July 2012. © Prkić.
The exposed tegmentum, has crowded, uniformly small, circular, evenly distributed granules, except on the narrow triangular jugal area (1) which has longitudinally arranged ridges and grooves. The jugal area is often coloured distinctly different from the rest of the valve; sometimes paler (1), sometimes darker (2).
Growth lines are obscured by the dense granules.
Intermediate valves have a protruding posterior beak (3).

KEY ID FEATURES : 01 Acanthochitona fascicularis