A shaft-tomb funerary culture at Jacona, Michoacán, in west Mexico. Its tombs, radiocarbon-dated to roughly 1600 BC, are the oldest formal burial complexes known in Mesoamerica, contemporary with early Olmec development and predating the nearby Capacha culture and (later) Chupícuaro.
Known almost entirely from its funerary complex; no associated settlement has been excavated. Its distinctive shaft-and-chamber tomb style anticipates the wider West Mexican shaft-tomb tradition (Colima, Nayarit, Jalisco) of the following two millennia, and its antiquity has been used to question the Olmec's status as Mesoamerica's sole 'mother culture.'
Standard survey of West Mexican shaft-tomb cultures (El Opeño, Capacha, Colima/Nayarit/Jalisco) that situates El Opeño as the tradition's earliest known expression.
Regional synthesis covering the west Mexican Formative, including El Opeño's place relative to Capacha and other early complexes.