Leptomyxa ambigua Smirnov et al. 2017
Diagnose: Limax-shaped amoebae are remarkably clavate in locomotion, frontal hyaline area occupies up to half of the cell. Length in locomotion 50–156 µm. The most of cells are uninucleate, but up to four nuclei are possible. Cyst single-walled, 27–50 µm in diameter usually uninucleate, some cysts have 2–4 nuclei, very rarely more. The nucleolus of the trophozoite contains numerous patches of electron-dense material, 1–2 µm across, each patch with small central lacuna.
Ecology: Leaf litter in Wandlebury Wood, Cambridgeshire, UK.
Remarks: Differs from all studied species of Leptomyxa and Rhizamoeba by the presence of characteristic patches of electron-dense material in the nucleolus. Resembles L. flabellata Goodey, 1915 but differs from this species by the cyst structure (single-walled). Resembles L. australiensis (Chakraborty et Pussard, 1985) Smirnov et al., 2017 and L. valladaresi De Obeso Fernandez Del Valle, Lorenzo-Moralez et Maciver, 2017 but differs from both these species by the locomotive morphology (clavate cells with large anterior area of the hyaloplasm versus oblong cells, vermiform or narrow-ing to the anterior end) and rarity of flattened, expanded and branched forms in cultures.