P. Aelius Paetus. 138 BC. AR Denarius (3.57 gm). 

Head of Roma right, X behind head. 
The Dioscuri riding right, each holding spear.
P PAETVS below, ROMA in exergue.

Crawford 233/1; Aelia 3; Syd. 455

With permission of cngcoins.com, auction 61, Lot: 1204, Sept 2002.