This coin is not listed in RIC and S. Estiot has only 2 other examples listed.
TACITUS AE22mm 3.75g Antoninian/Aurelian (VF)
AV: IMP C M CL TACITVS AVG; Bust right, radiate, cuirassed and draped with paludamentum
REV: CLEMENTIA TEMP; Mars in military dress stg. (or walking) l., holding olive branch in r. hand, spear and shield which rests on ground in l. hand.
EXE: XXI inverted Z
REF: LV 250, unlisted in RIC RIC Online #3512 very rare, just 2 other specs known, 1 in La Venera Hoard, 7th officina, Rome mint, nov-dec. 275AD.