A new licmosphenioid, Licmophora complanata (Bacillariophyta: Fragilariophycidae), from Majuro Atoll, Central Pacific

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A new Licmophora with an apical window and additional perforations in the septum was discovered in a sample from Majuro Atoll, Marshall Islands. Valves are so narrow that they almost always present in girdle view, when they appear triangular, the mantle comprising most of the valve surface. A eucentric stage was used to tilt specimens up to 80° to see the shape in valve view and to see rimoportulae. Valves were 92–140 µm long, 8 µm wide, with three expanded areas, the broadest in the middle. The areolae were elongated in the apical axis but separated by wide virgae and vimines, unlike the narrow and closely spaced areolae in Licmophora cf. abbreviata, but with essentially similar vela. The morphology of Licmophora complanata is most like Licmophora peragallioides and Licmophora clevei in having a moderately long and wide rostrum with a moderately large apical window in the septum.