Description: The cells are 6–15 times longer than they are wide, uniformly curved, and narrower towards the ends. These are narrowly rounded with a small end pore and a few crystals in the vacuoles. The cell wall is smooth, with no girdle bands. In contrast to the similar Closterium dianae, the shape of Closterium parvulum is noticeably more stocky.

Dimension: Length (75)–90–130–(160) µm, width (9)–10–15–(18) µm.

Occurrence:  Widely distributed in ponds, pools, silting zones and the like, sometimes even in large numbers.

Left: Original graphic by Prof. Lenzenweger.
Right: Photomicrograph by Prof. Lenzenweger. For microphotography, the microscope illumination was adjusted in such a way that as many features as possible that are important for species identification are prominently displayed.

Copyright by Prof. Rupert Lenzenweger, Ried im Innkreis, Austria.