CYCLOTELLA ELYMAEA, A NEW FOSSIL SPECIES FROM THE NEOGENE BASIN OF KOZANI-AEANI-SERVIA, NORTHERN GREECE

Abstract

A new fossil species of Cyclotella, C. elymaea, has been studied by LM and SEM. It was dominant in Neogene deposits of the Kozani-Aeani-Servia basin, northern Greece, accompanied by numerous hemispherical valves which are assumed to be or derive from initial cells. Analysis of morphometric parameters revealed significant variation in valve structure, mostly related to the degree of silicification of the frustules and the decrease in valve diameter resulting from cell division. This comprised variation in the pattern of ornamentation in the central zone, in the density of the marginal fultoportulae and in the structure of the striae. However, since the general characteristics of the valve are constant throughout C. elymaea and transitional forms can be recognized between the variants, it is suggested that the morphotypes are all part of the same life cycle. In the informal subdivision of Cyclotella that has been proposed, C. elymaea would fall within the “andancensis” group.