An overlooked genus 'Olifantiella C. Riaux- Gobin & Compère'. expanding biogeography with new species and ultrastructure observations

The small-sized marine diatom genus Olifantiella was originally described from the tropical waters of Réunion Island as Olifantiella mascarenica C. Riaux-Gobin & Compère. Later, more species were found from the South Pacific and Indo-Pacific and from Port of Antwerp, Belgium expanding the biogeopraphy. Genus Olifantiella have some distinct characters ; single row of areola (macroareola), trumpet like structure “buciniportula” in internal valve and broad perforated girdle. It is easily overlooked, according to Giffen after ultrastructure examination of Navicula species, some were found to share the same characters. Navicula infirmitata was described from South Africa by Giffen and Navicula supralitoralis described by Aleem & Hustedt from southern England. These two taxa were also reported from the Baltic Sea under the genus name “Navicula”. These species are proposed for transfer into Olifantiella in terms of possessing macroareola and buciniportula. In addition, LM and SEM studies revealed new Olifantiella taxa in scrapes from loggerhead sea turtle (Caretta caretta Linnaeus, 1758) carapaces sampled from the Turkish coast nesting grounds. Here, we introduce two epizoic species new to science. More Olifantiella species have been recorded with ultrastructure examination and Ion beam fabrication. O. pseudobiremis is recorded from Black Sea coasts, whilst O. mascarenica is recorded in Aegean Sea and Adriatic Sea for the first time. These results expand the distribution of Olifantiella from tropical to temperate waters. This research has been funded by Polish Research Centre in Cracow by the research grant no. 2012/04/A/ ST10/00544 (MK, AW), 2012/07/N/NZ8/02359 (AC).