The new genus and species Gallaicolichen pacificus Sérus. & Lücking is described. Goniocystangia-like structures are formed with unique diaspores and we introduce the new terms peltidiangium (pl.: peltidiangia) and peltidium (pl.: peltidia) for them. Those diaspores are disc-like structures with a regular pattern of organization, made of small arms of dichotomously branched cells of Phycopeltis, all linked up to a central foot and coiled up inwards, and including a tiny, regularly arranged layer of mycobiont cells. Ascomata and conidiomata are unknown and the taxonomic position of this new genus cannot be determined. It grows on living leaves in Hawaii (type material), Australia/Queensland, New Caledonia and Vanuatu