I noticed this particular coin a while ago and was interested both in the way the
reverse was depicted (which is quite unusual with the
jugate busts) but also in the underlying crescent and the
radiate crown.
This coin was (I think) issued between 201 and 206, while the
antoninianus which
Caracalla introduced came in at the start of 215 - with the empress's version having the crescent as the distinguishing feature.
Did this earlier, and similarily placed, use of the crescent have some other meaning? (the
radiate crown I know more about).
many thanks
Malcolm