Two new Tertiarius (Bacillariophyta, Coscinodiscophyceae) species from Mariovo Neogene basin, Macedonia

Abstract

The morphology, biostratigraphy and ecology of two new species, Tertiarius jurijlii and Tertiarius mariovensis are presented. The valve morphological variation and ultrastructure are described by light and scanning electron microscopy. Tertiarius juriljii is distinguished by the presence of hyaline area on the valve face; central area comprised of areolae arranged in single short or long radial rows; presence of small to large granules on the interstriae; and valve face fultoportulae arranged in radial rows around the valve center. Comparatively, in Tertiarius mariovensis the hyaline area around the central area is missing, and the taxon is characterized by tri– to biseriate striae in the central part of the valve face becoming uniseriate towards the valve centre and stalked rimoportula positioned between two costae inside the alveolar opening. Both species are found in nonmarine sediments of Pliocene age from Mariovo Basin, Macedonia.