Luticola grupcei (Bacillariophyceae) - a new freshwater diatom from Mountain Baba (Macedonia) and Great Smoky Mountains National Park (USA): comparison with the type material of L. goeppertiana (Bleisch) DGMann

We provide a detailed light and electron microscopy description of Luticola grupcei sp. nov. from Mountain Baba, South-Western Macedonia and the Great Smoky Mountains National Park, U.S.A.. The species is characterized by lanceolate valves with shortly protracted ends, length 23-46 mu m and breadth 8.5-10.5 mu m. The striae are radiate throughout (15-17 in 10 mu m) and are composed of coarse arcolae (16-20 in 10 mu m). There is a single isolated stigma positioned on one side of the rectangular to somewhat panduriform central area. Luticola grupcei is morphologically comparable with the widespread, pollution-tolerant L. goeppertiana from which the new species differs with respect to shape of the valve ends, striae and areolae density, double row of puncta on the valve mantle, the elongate shape of the stigma as well as ecology. Luticola grupcei inhabits high mountain oligotraphentic waters and subaerial habitats contrary to L goeppertiana, which in Macedonia is reported for sites with high organic pollution. The type material of L. goeppertiana is used for morphological comparison. Further differences between these two species and related taxa are demonstrated through LM and SEM analyses.