A consideration of Epithemia reicheltii (Rhopalodiales, Bacillariophyceae) and the description of two new species of the genus

We present light and scanning electron microscopical observations of two species from North America that resemble the original concept of Epithemia reicheltii Fricke. We review the history of that taxon, its similarity with Epithemia cistula, and present data to suggest the two North American species considered herein, which are sympatric in their distribution in Douglas Lake, Michigan, are different from one another. One of those species is described as new, Epithemia lacusdouglasi sp. nov. and we discuss the possibility of sympatric speciation in this locality. Epithemia reicheltii has also been reported from South Africa, and we review that report with original material. Based on our observations of the size diminution series of the taxon, we propose E. schoemanii sp. nov. and discuss its systematic position based on its valve morphology.