Reza Safaierad thanks for your answer., Larix pollen is spherical, inaperturate and psilate. But these pollens seems to be operculate. You can see a distinct opercula in all the shown pollens.
seeing the thin exine and the rather characteristic "opercula", I would say that it is a fresh-water algae. Its actually similar to some of the disaster taxa sometimes called reduviasporonites. Best regards and good luck with your investigations! Vivi