Contribution to the genus Diploneis (Bacillariophyta): Twelve species from Holarctic freshwater habitats proposed as new to science

Abstract

Numerous questionable extant populations of Diploneis with cribrate areolae are morphologically compared (in LM and SEM) to resembling established taxa. In most of these examinations the types are available and documented in the literature by several authors during the last forty years. All taxa in question belong ecologically to the minority of Diploneis that live exclusively in freshwater. As main result twelve species from Europe and one from Florida, U.S.A., are selected and proposed as new to science. These are: D. abscondita, D. calcilacustris, D. hinziae, D. lusatica, D. modicahassiaca, D. oblongellopsis, D. praetermissa, D. puellafallax, D. tirolensis, all from Central Europe (Austria, Germany, Switzerland); D. nanofontanella and D. tundra from European Arctic Russia; and D. parahinziae from Florida. After critical examination, D. arctica stat. nov., D. ladogensis stat. nov., and D. dilatata stat. nov. are proposed to be transferred from infraspecific to species rank.