This reverse type is accepted to celebrate the destruction of Privernum in 329/328 by Gaius Plautius Decianus Hypsaeus the consul. He triumphed on 1 March. BUT what does Jupiter and a Scorpion have to do with that?
My colleague Lucia Carbone recently published an ANS Magazine piece on the Alexandrian Zodiac coins.
I wonder if the family claimed a tradition that the triumph or the actual sack took place when Jupiter was in Scorpio. The Augustan era fasti list the triumph as being held on the Kalends of March. So I guess scorpio might represent March as it is the month of Mars and Jupiter the triumph. That seems an unlikely stretch.