This coin is not in RIC 5, but since it is woefully outdated, that is not saying much. It is listed on the site which is working on an update to RIC V--
http://www.ric.mom.fr/en/coin/3414This coin is known from two obverse dies. The RIC V temp page describes this coin as “Medusa-head on cuirass†though I don’t see a Medusa head.
Tacitus
A.D. 275- 276
Silvered Antoninianus
21mm 4.0gm
IMP C M CL TACITVS P F AVG; radiate and cuirassed bust left.
MARTI PACIF; Mars advancing left, holding branch, spear and shield.
In ex. S
RIC V Ticinum --