Grammatophora ornata (Fragilariophyceae: Grammatophoraceae), a new species with areolate valvocopulae, from a coral reef

Abstract

A new extant species of Grammatophora is distinguished by elaborately areolate valvocopulae. It was collected on blue coral in Apra Harbor, Guam. Valves were narrowly to linear-elliptical, 22–77 µm long by 5–6 µm wide, with transapical striae 19–20 in 10 µm. In these characters valves are very similar to those of G. oceanica and G. marina. The valve is asymmetrical in the apical plane, having a slightly deeper mantle at one end. Valvocopulae were remarkably different from other species in having elongate areolae closed by vela, 11–12 in 10 µm, throughout the valvocopula. Septa were planar, inclined towards the center of the cell. Live cells were not observed but spines on both apices suggest that this species may not form the zigzag colonies typical of common Grammatophora species.