137 Nova Hedwigia Vol. 92 issue 1–2, 137–158 Stuttgart, February 2011 Article © 2011 J. Cramer in Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart, Germany www.borntraeger-cramer.de DOI: 10.1127/0029-5035/2011/0092-0137 0029-5035/2011/0092-0137 $ 5.50 Four new Luticola taxa (Bacillariophyta) from the South Shetland Islands and James Ross Island (Maritime Antarctic Region) Bart Van de Vijver 1* , Ralitsa Zidarova 2 and Myriam de Haan 1 1 National Botanic Garden of Belgium, Department of Bryophyta & Thallophyta, Domein van Bouchout, B-1860 Meise, Belgique 2 Central Laboratory of General Ecology, BASc, Yurii Gagarin Str. 2, 1113 Sofia, Bulgaria With 63 figures and 3 tables Van de Vijver, B., R. Zidarova & M. de Haan (2011): Four new Luticola taxa (Bacillariophyta) from the South Shetland Islands and James Ross Island (Maritime Antarctic Region). – Nova Hedwigia 92: 137–158. Abstract: During a revision of the genus Luticola on the South Shetland Islands and James Ross Island, four unknown Luticola species were observed. Based on detailed light microscopy and scanning electron microscopy observations, the species are described as new to science: Luticola katkae Van de Vijver & Zidarova sp. nov., Luticola vermeulenii Van de Vijver sp. nov., Luticola adelae Van de Vijver & Zidarova sp. nov. and Luticola raynae Zidarova & Van de Vijver sp. nov. Their morphology and taxonomy is discussed comparing each species with similar Luticola taxa. Notes on their ecology are added. Subsequently, the distribution of all Luticola taxa in the subantarctic and Antarctic regions is investigated resulting in a clear separation of the Subantarctic Region, the Maritime Antarctic Region and the Antarctic Continent. Key words: Luticola, Bacillariophyta, Diatoms, Antarctic, new species, morphology, biogeography. Introduction Although the non-marine diatom genus Luticola is considered one of the dominating genera in the terrestrial habitats of the Antarctic Region (Van de Vijver & Mataloni 2008) the number of species reported in published species lists from this region remained quite low. Based on Kellogg & Kellogg (2002), listing all Luticola records *Author for correspondence, e-mail: vandevijver@br.fgov.be