Protoperidinium bipes (Paulsen) Balech 1974 . Rev. Mus. Argent. Cienc. nat. “ B. Rivadavia ”, Hidrobiol. 4 (1): 53. (Figs. 11–12) .

References: Lebour 1925: 138, Pl. XXIX, Fig. 3 a–b (as Miniscula bipes); Schiller 1937: 194, Fig. 190 a–c; Taylor 1976: Pl. 32, Fig. 358 (as Peridinium minisculum); Kiselew 1950: 170, Fig. 272 a–v (as Peridinium bipes); Dodge 1982: 177, Fig. 19 i; Balech 1988: 82, Lam. 23, Fog. 5–6; Toriumi & Dodge 1993: 40, Fig. 12; Konovalova & Selina 2010: 128, Table XIV, 2; Krakhmalny 2011: 191, Table 76, Figs. 1–4, 6–12; Al-Yamani & Saburova 2019: 297, Pl. 163.

Basionym: Glenodinium bipes Paulsen 1904 . Plank. Investig. waters around Icel. in 1903. Medd. Komm. Havundersog., Kjobenhavn 1 (1): 21, Figs. 3–4.

Synonyms: Peridinium minisculum Pavillard 1905, Miniscula bipes (Paulsen) Lebour 1925 .

Description: Cells pentagonal, with a conical epitheca tapering into a long apical horn. The apical pore structure of Bʹ– type (Toriumi & Dodge 1993). According to the observation of Lebour (1925), the epithecal plate pattern comprises six precingular plates (6ʹʹ), three anterior intercalary plates (3a), and “meta”–”penta” combination of the 1ʹ and 2a plates. The first apical plate (1ʹ) narrow and irregularly shaped. The second anterior intercalary plate (2a) small, longitudinally elongated and five-sided, located dorsally between the third and fourth precingular plates. The cingulum median, broad, excavated, slightly ascending, bordered. The sulcus slightly broadens towards the antapex. The hypotheca with a concave posterior part and two thin antapical spines. Dimensions: 20–35 μm long and 17–21 μm wide.

Distribution: The species is widespread and often abundant in the coastal temperate waters (Al-Yamani & Saburova 2019). Data on the distribution of P. bipes are given from the GBIF.org (2022) (Fig. 78).