Watch List notes:

Q. Marius Libo. 148 BC. AE as (32.4 mm, 20.44 g, 1 h). Rome mint. Laureate head of Janus; I above / Q. MARC above, LIBO before, ROMA below, prow of galley right. Crawford 215/2a; Sydenham 396c. Fine, sandy patina. Scarce. 

Ex RBW Collection (not in previous sales); purchased privately from Tom Cederland (August, 1995).