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.
Liv Mariah Yarrow 
Not to take away from the Zodiacal suggestion (as there can be multiple layers of meaning), Jupiter in the quadriga can be (is?) a reference to the triumph itself (where the triumphator has his face painted red to “be” Jupiter).
For us plebeian readers please transcribe and elucidate
John Van Sickle Sicelidas@gmail.com (917) 945-9464
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Liv Mariah thanks for your scholarship; I keep following your findings and realize how far behind are we still on classical antiquity…
I have a kind of naïf question: could the medieval astrolabe continue this Zodiac, classical tradition? Astrolabes may put a date on an event that happens in a particular place. I teach in Barcelona (Technical University of Catalonia). Ever since I finished my Ph.D. in UC Berkeley, I still study L.B.Alberti’s “Descriptio urbis Romae” map; in his “De re. aedificatoria” he revived the Roman cultural heritage but reinforced some of the knowledge of classical antiquity that continued to exist throughout the Middle Ages. Thanks.
I honestly have no idea! Sorry!