This is a representation of the genius of the Roman people. The attributes are indisputable: foot on a globe, scepter, cornucopia, curule chair, crowned by victory. But what the heck is he wearing? Notice the drapery over and around the head. This is just not typical. Is it supposed to be a toga over the head for piety? I can’t think of another similarly dressed seated figure. Also notice below that the fabric comes around the arm and billows outward. I’d originally thought of this as fillets tided to the scepter, but I think not now. It seems to all be meant as one single garment.
We can compare the earlier full body representation of the genius of the Roman people on a rather poorly carved type:
CRRO Links 329/1 and 397/1. Links to illustrated specimens (here and here).
The closest seated bare chested figure with drapery over the head I can find is the Tiberius in the Vatican (if it has not been overly restored, that is):