Pseudostaurosira cataractarum comb. nov. (Bacillariophyta): type analysis, ecology and world distribution of a former “centric” diatom

Abstract

The transfer of Melosira cataractarum Hust. to the genus Pseudostaurosira D.M. Williams & Round is presented based on a detailed analysis of the type material from Java (Malay Archipelago) using light and scanning electron microscopy. The species was initially described as a “centric” diatom within the genus Melosira C. Agardh and was later transferred to the genus Aulacoseira Thwaites. Pseudostaurosira cataractarum (Hust.) C.E. Wetzel, E. Morales & Ector comb. nov. differs from other species of the genus by its smaller size, typical radiate striae arrangement and absence of apical pore fields. We additionally propose the transfer of Fragilaria sopotensis Witkowski & Lange-Bert. to the genus Pseudostaurosira, a species that is morphologically similar to P. cataractarum.