I could not find the etymology of the surname Dumenigo in any of my references. If I was to take a wild guess I would think that its roots are in the word "domingo". Spain's white telephone pages only show one person with that surname in all of Spain, in Santa Cruz de Tenerife. The US white telephone pages show 54 listings. There are two Cuban composers named Moises Hernandez Dumenigo and Samuel Hernandez Dumenigo. Saludos, Jorge