Zivkovicia spectabilis

Zivkovicia spectabilis, both arrows point to the internal diaphragm.

Zivkovicia spectabilis (Penard, 1902) Ogden, 1987
Basionym: Pontigulasia spectabilis Penard, 1902

Diagnosis: test pyriform, circular in oral view, with a clear broad neck; test covered with sand- or quartz-grains arranged on an organic matrix; aperture circular; internally at the junction of the neck with a perforated diaphragm, with two holes.

Dimensions: Penard (1902): length of shell 125-170 µm; Todorov and Bankov (2019): Length 102-131 µm; my measurements: Length 110-200 µm.

Ecology: In sediment of mesotrophic water bodies and in Sphagnum.

Remarks: It’s difficult to get a clear view of the diaphragm. Most often the diaphragm is obscured by debris in the neck.

Zivkovicia spectabilis, from Penard, 1902.

Zivkovicia spectabilis, 123 µm, Tirol – Austria

Diaphragm, with two holes. The same image but now manipulated so that the two holes are better visible.

This specimen was found within a rich population of Difflugia urceolata, in a shallow sphagnumpool with Utricularia minor near the village of Kortenhoef, the Netherlands. The test has a distinct incision between neck and posterior end. The neck is remarkably hyaline compared to the fundus. Through the outer wall two holes are visible in the diaphragm. Length 110 µm.