Watch List notes:

The Roman Republic

Marcus Antonius with M. Silanus. Denarius, mint moving with M. Antonius 33, AR 3.89 g. ANTON·AVG· IMP·III·COS·DES·III·III ·V·R·P·C Head of M. Antonius r.; behind ear, signature (?) P. Rev. M·SILANVS· AVG / Q·PRO·COS. Babelon Antonia 97. C 71. Sydenham 1208. Sear Imperators 346. RBW –. Crawford 542/1.
Rare and in exceptional condition for the issue. A bold portrait and an
attractive old cabinet tone, extremely fine
Ex Leu 17, 1977, Nicolas, 877 and NAC 70, 2013, 197 sales.
According to Crawford the P, which is clearly visible behind the ear of M. Antonius, is a signature of an unknown artist.