Macrodomoceras is an oncocerid genus, family Polyelasmoceratidae, from the Middle Devonian of Australia. The shell of Macrodomoceras is a compressed, endogastric cyrtocone, i.e section higher than wide and curved with the ventral side concave, with a subtriangular cross section. The siphuncle is ventral, marginal, with continuous actinosiphonate lamellae. Macrodomoceras resembles Danaoceras in its subtriangular cross section, but its sutures have bluntly pointed ventral saddles.