Acanthocystis amura Zlatogursky, Gerasimova et Plotnikov, 2016
Diagnosis: Cell diameter 9.1 to 14.2 µm. Spine scales of two types. Type 1 spine scales 1.3–4.8 µm with four small hooks on the tip. Type 2 spine scales 1.0–3.6 µm with four, sometimes three or five teeth on the tip. Plate scales oval, 1.2–2.6 x 1.0–1.8 µm, with axial thickening and thickened border.
Ecology: Freshwater. Type locality. The Amur River, the Far East of Russia, the sandy bank. N 50°15’5” 35 E 127°32’51”. Collected in August of 2012.
Remarks: The morphology of Acanthocystis amura resembles that of Acanthocystis quadrifurca. They both have similar spine scales but their plate scales are completely different. A. valdiviense differs from the new species in absence of hook-bearing scales. Molecular phylogeny based on 18S rDNA consistently placed A. amura into A. nichollsi/A. costata clade, but relationships between those three species were not resolved. Morphology of another centrohelid strain from another location (the South Urals) has been compared with that of the original strain and few minor differences in size characteristics of the scales have been revealed.