Watch List notes:

SICILY. Syracuse. Dionysios I, 405-367 BC. Litra (Silver, 12 mm, 0.92 g, 9 h). Σ-[Υ]-Ρ-[Α] Head of Athena facing, turned slightly to the left, wearing triple-crested Attic helmet and plain necklace; around and behind her neck, four dolphins. Rev. Octopus. Buceti 546a. Kreutzer, Kleinsilbermünzen, 12.1 (this coin). Rizzo pl. XLVII, 4. Very rare. Well-centered and struck from very carefully made dies. Very slightly rough surfaces, otherwise, about extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions, ex Auctiones 16, 1 October 1986, 51.

This coin type has also been dated to the period of the Third Democracy, 336-317 BC, but since the style of the present piece seems finer, the earlier date has be used here.