This coin is RIC VIII Siscia 247.
Siscia used a series a strange symbols as control marks, I copied these from Dane's excel sheet. There are more symbols shown here than in RIC and Siscia only had five workshops at the time, so this issue seems confusing.
The symbols seem to be used by specific workshops-- symbol 1 is used in the first workshop and so on. This is symbol 4 (or a variation of it) used for the first workshop. I am not familiar enough with this issue to know offhand if this happened frequently though.
