A new species of brown algae, Taonia abbottiana D.S. Littler et M.M. Littler, is described from the tropical western Atlantic. To date, this is the only member of the genus reported from the region. Taonia abbottiana differs from other species of the genus in having (1) sporangia raised above the surface layer on a stalk composed of two cells, and (2) in addition having a surface cortical layer of differentiated cells that are smaller than those of the medullary layers. Taonia abbottiana has often been confused with Stypopodium zonale, but the two differ anatomically in the development of cells directly behind the growing margin and, when living at similar depths, T. abbottiana consistently has light colored concentric lines, while S. zonale has dark concentric lines.