DIMORPHISM INCYCLOSTEPHANOS DUBIUS(BACILLARIOPHYTA) AND THE MORPHOLOGY OF INITIAL VALVES

Abstract
Analysis of the morphological variation of Cycbstephanos dubius in recent populations and subfossil sediments revealed two distinct morphotypes, characterized by the size range of the valves and the number of costae per valve. The morphotypes were found in varying abundances and often in conjunction with initial valves, indicating a possible relationship to the life cycle of this species.