Three new cymbelloid species in the genera Cymbella, Cymbopleura and Delicatophycus from the mineral spring Crvena Voda near Skopje, Republic of North Macedonia

Mineral springs are unique habitats frequently inhabited by specific diatom species with restricted distributions. In the mineral spring Crvena Voda near Skopje, three cymbelloid taxa were observed, whose morphological characteristics differ from already known taxa. They are described here as: Cymbella parahelvetica sp. nov., Cymbopleura angustilanceolata sp. nov. and Delicatophycus fontinalis sp. nov. Cymbella parahelvetica sp. nov. is characterized by the absence of an apical pore field at the valve ends and by very densely arranged striae. Cymbopleura angustilanceolata sp. nov. can be distinguished from other Cymbopleura species by the valve outline, the shape of the central area and the stria density. Delicatophycus fontinalis sp. nov. can be differentiated from similar species by its strongly arched dorsal margin, its valve width and stria density.