| Summary: | A new species of araphid diatoms with bilobate ends is described as Staurosirella tigris sp. nov. It was found in mid-Miocene glacial-lacustrine sediments in the Friis Hills, Antarctica. The new diatom is placed in Staurosirella because it has striae composed of apically-oriented lineolae, separated by long, thin vimines, and it lacks rimoportulae. It can be easily distinguished by its rectangular valve shape with bilobate ends, differing from Staurosirella grunowii, another four-lobed Miocene species, by having a rectangular central portion to its valves instead of being cross-shaped with the four lobes arising from a common central area. Also, the distribution of the new species is different, to date only being found in Antarctica, while S. grunowii is restricted to the Northern Hemisphere.
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