New and interesting species in the genus Luticola D.G.!Mann (Bacillariophyta) from Deception Island (South Shetland Islands)

During a survey of the terrestrial diatom flora of Deception Island (South Shetland Islands, southern Atlantic Ocean), 10 taxa belonging to the genus Luticola were observed. Five of these, namely Luticola gigamuticopsis sp. nov., L. caubergsii sp. nor., L. quadriscrobiculata sp. nov., L. nelidae sp. nor. and L. australomutica sp. nov., are described as new species using light and scanning electron microscopy. Comments are made on their systematic position and on differences and similarities with other species. The morphology and taxonomy of the five other Luticola taxa, including Luticola muticopsis and two related forms, are also discussed. The high number of Luticola taxa on Deception Island is remarkable but not unusual for oceanic islands. From the biogeographical point of view, there is a clear separation between the sub-Antarctic localities in the southern Indian Ocean and the islands in the southern Atlantic Ocean with several species showing a restricted biogeography.