A new species of centrohelid heliozoans Acanthocystis amura from the Amur River, the Far East of Russia was studied with light- and electron microscopy. Acanthocystis costata has simple oval plate scales (1.3 – 4.8 x 1.0 – 3.6 µm) with an axial thickening and a thin border and two types of spine scales. Type 1 spine scales are longer 1.3 – 4.8 µm and have four small hooks on its tip, while type 2 spine scales are shorter: 1.0 – 3.6 µm and end with four teeth. Acanthocystis amura and Acanthocystis quadrifurca are similar in morphology of spine scales but their plate scales are completely different. A. valdiviense is different from the new species by absence of hook-bearing scales. Molecular phylogeny based on 18S rDNA strongly place A. amura into A. nichollsi/A. costata clade, but relationships between those three species are not resolved. A strain from different location (the South Urals) was compared morphologically to the type one and expressded some minor differences in size characteristics of the scales.