Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1387 
Martini, Pangerl 95
dolphin r. with uncertain objects
rectangular 
12 x 6 mm 
on reverse; Pangerl gives as applied in Moesia and Thrace 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 2235 Show 2235 47 1
RPC I, 4100 Show 4100 35 1
RPC I, 4100 Show 4100 35 1
Show 111
Show 361