This issue of Cosa imitates Rome’s first didrachm (RRC 13/1). It’s date post 273BC (the founding date of Cosa) has sometimes been used to try to draw down the date of Rome’s first didrachm, the idea being that iconographic borrow would be unlikely over a gap of some 40-50 years. The gap doesn’t bother me.
I was just intrigued by the dolphin addition to the design. Buttery says its there “bronze to identify Cosa as a port” (p. 22). Need this be true? I’m just recalling the dolphin neck terminus we find on the obverse of the coins of Signia:
Segni is most certainly not on the sea. And as I mentioned in passing in another post, Mercury isn’t particularly associated with nautical imagery and dolphins. I’m wondering it is not a design element considered aesthetically pleasing at the bottom of a protome to ease the transition. Two examples an argument does not make. I’ll keep my eye out for more.