Diagnosis: Surface in locomotion with some longitudinal dorsal folds; outline in locomotion oblong; hyaloplasm usually in a broad anterior region; nucleus elongated oblong, sausage shaped, with a single elongated oblong nucleolus of homogeneous texture; single contractile vacuole.
Dimensions: Length ca. 42 µm, length: nucleus c. 10 µm long, 3.7 µm broad (n = 1).
Ecology: Freshwater, dune lake, the Netherlands.
I found another species with more or less the same nucleus in sediment of a small river in the Ordesa valley in Nothern Spain (see below)