Dolphin, the trident of Poseidon, it might be? Over dolphin letters MY Apparently this small coin Phoenicia? Or Fonika?
Myus, Ionia, AE11 mm, 400-300 BC. 1.2g. Laureate head of Zeus right. MY, dolphin swimming right, trident below. Weber 6699; SNG von Aulock 8183 and 2114; Imhoof-Blumer KM p. 90, 5; Mionnet III p. 23, 134; Waddington 1337; SNG Copenhagen 1022; SNG Tuebingen 3112. Rare coin and rare mint. Note: The attribution of this coin to Myus is the subject of some discussion in coin catalogs. Mygissos (Caria) has also been suggested. However, the place that this coin was discovered makes Myus more probable. Contributed by Ars-Aeterna / David Suter, Switzerland, September, 2011