Choanocystidae Cavalier-Smith and von der Heyden, 2007
Diagnosis: Periplast with two contrasting types of siliceous scales, oval or bilobed tangential basal plate-scales (margin not hollow and inrolled) and outer bipartite radial spine-scales consisting of a vertical stalk, sometimes curved or branched but lacking lateral wings, emanating from near a strong indentation on one side of a flat horizontal basal disc. Funnel-shaped scales absent.
Type genus: Choanocystis Penard 1904
Main cell body Haplomyxa spec. Description: The cell had a cylindrical flattened body from which numerous granuloreticulopodia emerged. The common shape was more or less
V. delicatula, after Valkanov, 1962 Genus Valkanovia Tappan, 1966 Diagnosis: Shell ovoid, oblate, elliptical in cross-section, composed of elongated elliptical hyaline scales arranged in a
Gocevia pontica, after Valkanov, 1934 Gocevia pontica Valkanov, 1934 Diagnosis: Clearly addressed bipolarity. Body covered by a weakly flexible tectum covered with foreign bodies. The
N. brevis, after Snegovaya and Alekperov, 2009 Genus Nabranella Snegovaya and Alekperov, 2009 Diagnosis: Shell oval or spherical shape without neck. Apical top flat and
Genus Armipyxis Dekhtiar, 2009 Genus Armipyxis was created by Dekhtiar (2009) to accommodate all species with internal struts. However, C. aculeata may also have struts, although
N. pseudolimnetica, after Penard, 1902 Netzelia pseudolimnetica Ogden and Meisterfeld, 1989 Synonym Difflugia limnetica (Levander, 1900) Penard, 1902. D. limnetica – Pejler, 1962, Oikos, 12,
C. hiraethogii, after Ogden. 1983 Cylindrifflugia hiraethogii (Ogden, 1983) González-Miguéns et al., 2022 Diagnosis: the shell is light yellow or transparent, thin pyriform with a distinct
C. bacillariarum, 103 – 114 µm – Fochteloërveen, Netherlands Cylindrifflugia bacillariarum (Perty, 1849) n. comb. González-Miguéns et al., 2022 Diagnosis: shell transparent, colorless or
C. elegans, length 84-102 µm, Gaasterland Cylindrifflugia elegans (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia elegans Penard, 1890 Diagnosis: shell outline rough, pyriform
C. lanceolata, shells 153-169 µm long, nuclei 23-26 µm (Naardermeer, Netherlands) Cylindrifflugia lanceolata (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia lanceolata Penard,