Couldn't get this due to recent wife fury, that moneyer's mark I honestly had not noticed before. Was that a bird or insect? Any idea when this coin was struck, or by whom? Depiction of the horses also differed from the usual, halted by the driver instead of galloping.
From Wildwinds: Roman Republic, Anonymous Denarius. Circa 179-170 BC. Helmeted head of Roma right, X behind / Diana with crescent on head driving biga right, fly below, ROMA in ex. Cr159/2; Syd 322; RSC 22b
I happened to be searching Roman Republicans for something else and was already on the correct wildwinds page (Roman Republic, Anonymous). Rather than using Wildwind's search function it is often easier to do a "find on page" search. In this case I tried "bee" (no hits) and then "fly". Bingo