It could be Caligula and Germanicus. When I read your post, I remembered this coin that took me exactly one year to attribute and lots of pictures and turning the coin with different lighting to see the lettering, until I was able to decipher it. Attaching mine for comparison (weight and diameter are different): 16 x 18 mm, 5.07 g; Crete, Knossos 37 – 41 AD, moneyers Pulcher and Varius Ref.: RPC 995- 996; Obverse: C CAESAR AV (GERMAN)ICVS laureate head of Caligula right Reverse: GER CAESAR PVLCHRO III VARIO IIVIR laureate head of Germanicus right, star in front