CIMRM 545 - Aion, Museo Gregoriano Profano, Vatican Museums.

This link says it is in the Museo Gregoriano Profano, Vatican Museums, and is 2nd century. This link has most detail.

CIMRM entry

545. White marble statue (H. 1.55 Br. 0.37 base). Formerly in the Villa Albani; nowadays in the Vatican Musea, near the entrance of the former Library. Raffei, Diss., 130 and Pl. III, 2; K Q. Visconti, Mus. Pio Clem., II, Pl. XIX; Clarac, Mus. Sculpt., Pl. 560, 1192 and. 1192 A (before and after the restorations) and IV, 26; Millin, Gall. Myth., cf. 66; Zoega, Abh., 203f No 5; Lajard, Pl. LXXII; MMM II 214f No. 37 and figs. 43-44; RRS I 296, 4; Leipoldt, XVI and fig. 38; Alinari, 35667. See fig. 153. A naked trunk in three coils of a serpent. Four signs of the zodiac, two on the breast (Aries and Libra) and one on each thigh (Cancer and Capricornus). Added are: lion's head, two wings, the arms and legs with two coils of the serpent, and finally the cloak, on which Aion is standing.