Moved to species page.

ID'd with the help of Phillip Harpootlian. Punctate elytral striae exclude Geotrupes semiopacus. G. blackburnii and G. splendidus have their sutural striae ending at the scutelum, as compared to G.balyi and G.hornii which have their sutural striae bending and wrapping around the scutelum (hard to see on this photo, but it is there if you look closely). Also, the antennal clubs of G.balyi and G.hornii tend to be light brown as opposed to dark brown or black. G.balyi differs from G.hornii in that the former always has some blue, green, or purple iridescence (albeit subtle in this photo) while the latter is pure anthracite black.