A new species of the genus Mallomonas from section Marsupiales from Viet Nam

A new species of the genus Mallomonas from Viet Nam is described in this paper. The description was based on the scale morphology, which was studied using scanning and transmission electron microscopy. The new species, Mallomonas arenosa sp. nov., was characterized by small rhombic scales with a small dome, rectangular or polygonal reticulation on the shield with pits inside, and struts radiating from the arms of the anterior submarginal rib to the anterior flanges. Based on the ultrastructure of the scales, the new species should be assigned to the section Marsupiales. This is only the third species in this section. Mallomonas arenosa has only been found in two nearby localities.