Protoperidinium knipowitschii (Usachev) Balech 1974 . Rev. Mus. Argent. Cienc. Nat. “ B. Rivadavia ”, Hydrobiologia 4 (1): 68. (Fig. 33) .

References: Kiselew 1950: 203, Fig. 341 (as Peridinium knipowitschii); Krakhmalnyi 2011: 200, Table 82, 12–15.

Basionym: Peridinium knipowitschii Usachev 1927 . Zborn. chest prof. Knipovicha: 405, Fig. 2 A–D.

Description: Cells subpentagonal. The epitheca conical, with concave sides. Apical and antapical horns relatively long and thin. The cingulum median, slightly ascending, bordered. The sulcus straight, bears lists, left sulcal list emerges in a way that it can be confused with a spine. Yellow and reddish inclusions are sometimes visible in the cytoplasm. Dimensions: 50.3–59.0 μm long and 39.0–44.3 μm wide.

Nomenclatural note: Taxon of a questionable validity (Gómez 2005: 199). Morphologically insufficiently studied species. Identification is based on the characteristic pentagonal star-shape and size.

Distribution: Black Sea, Sea of Azov (Krakhmalnyi 2011; Fig. 88).