Watch List notes:

THRACO-MACEDONIAN REGION, Uncertain. Mid 5th century BC. AR Tetartemorion (6mm, 0.30 g). Primate crouching left / Incuse square. CNG E-390, lot 35 (same dies); otherwise, unpublished in the standard references with this reverse type. Lightly toned, slightly granular. VF. Extremely rare.

The thick fabric of this piece, as well as the plain reverse punch, suggests that it is probably the earliest issues of the primate type, as the usual pieces are of a flatter, spread flan, and have a reverse incuse square containing a pellet or shield device.