AbstractTouwia laticostatais proposed as a new genus and species of the Neckeraceae, subfamily Thamnobryoideae. It is an aquatic moss characterized by very small, lanceolate to oblong-Ianceolate, erect-spreading to spreading leaves with very strong, percurrent costa that occupies almost⅓the width of the lamina and lamina cells rhomboidal above and becoming elongate towards the base.