| A new species of Triceratiaceae is described for estuarine environments of Southern Brazil. The valve of Triceratium moreirae sp. nov. is triangular with elevations bearing ocellus and a rimoportula in their basis. The valvar surface has robust pseudoloculi, circular to polygonal, each one confining a group of areolae arranged in a typical pattern. A central larger areola is surrounded by 5-8 smaller areolae, and they are poroidal with domed cribra. A septum emerges from the valvocopula, having the base reinforced by ribs and the margins folded to the innerside of the valve. The new species is compared to the closely related diatom Triceratium dubium, which has the same pattern of areolar disposition, formation of septum and pseudoloculi. The main... |
