Protoperidinium subinerme (Paulsen) Loebl. III 1969

Krakhmalnyi, Aleksandr F., Krakhmalnyi, Maxim A., Terenko, Galyna V. & Goncharenko, Igor V., 2023, Dominant Species Of The Genus Protoperidinium Bergh (Peridiniales: Protoperidiniaceae) In The Black Sea, Zootaxa 5339 (5), pp. 427-448 : 442-443

Protoperidinium subinerme (Paulsen) Loebl. III 1969 . Proc. North–Am. Paleontol. Conv., Chicago: 905. ( Figs. 53–54 ).

References: Lebour 1925: 114, Pl. XXII, 2 a-f; Schiller 1937: 243, Fig. 244 a–o; Kiselew 1950: 200, Fig. 338 a–b, 342 a–g; Wood 1968: 108, Fig. 330 (as Peridinium subinermis ); Dodge 1982: 189, Fig. 21 I-K; Pl. V f; Dodge 1985: 66; Okolodkov 2008: 126, Pl. 8: 5–8; Konovalova & Selina 2010: 145, Table XXI, 8 a–b; Krakhmalnyi 2011: 208, Table 92, Figs. 1–13 ; Al-Yamani & Saburova 2019: 330, Pl. 183.

Basionym: Peridinium subinermis Paulsen 1904 . Medd. Hav. Kbhvn. Ser. Plankton 1 (1): 24, Fig. 10 .

Description: Cells broadly rhomboid. The epitheca broadly conical with a flat apex. The apical pore structure of Aʹ– type ( Toriumi & Dodge 1993). The epithecal plate pattern comprises seven precingular plates (7ʹʹ), four apical plates (4ʹ), three anterior intercalary plates (3a), 1ʹ plate – “ortho”, 2a – “hexa”. Thecal plates reticulated, with pores and microspines. The cingulum median, deeply excavated, bordered. The sulcus deeply immersed, broadens towards the antapex, extends posteriorly to the center of the hypotheca, with two lists giving the appearance of small antapical spines in ventral view. The cytoplasm pale pink. Dimensions: 43–53 μm long and 47–50 μm wide.

Nomenclatural note: The species can be confused with Protoperidinium punctulatum (Paulsen) Balech , which was once considered a variety of this species. Protoperidinium punctulatum is characterized by the following features: more broadly pentagonal shape with a rounded, truncate antapex; papillae or broad-based short spines on the surface; more excavated ventral area; 2a – typically “penta” but could be “hexa”; sulcus extending to antapex and not expanding posteriorly ( Steidinger & Tangen 1997).

Distribution: Coastal and open water, in temperate to tropical waters; cosmopolitan ( Steidinger & Tangen 1997). Data on the distribution of P. subinerme are given from the GBIF.org (2022) ( Fig. 98 ).

Figures

FIGURES 47–58. Protoperidinium of the Black Sea. 47–52—P. pellucidum; 53–54—P. subinerme; 55—P. solidicorne; 56– 57—P. pyriforme; 58—P. pentagonum. Designations: 1ʹ—first apical plate, 2a—second intercalary plate. Hypothecal pore in plate 1ʹʹʹ is marked with an arrow (47, 50). 47–49—DIC; 50–52, 56–58—epifluorescence; 53–55—transmitted light. Scale bars: 47–54 = 10 µm; 55–58 = 20 µm.

FIGURES 11–22. Protoperidinium of the Black Sea. 11–12—P. bipes; 14–15—P. brochii; 13, 16—P. crassipes; 17–19—P. claudicans; 20–22—P. depressum. Designations: 1ʹ—first apical plate, 2a—second intercalary plate. 11, 13, 15–16—DIC; 12, 14, 18–19, 22—epifluorescence; 17, 20–21—transmitted light. Scale bars: 11–12, 14–15 = 10 µm; 13, 16–22 = 20 µm.

FIGURES 1–10. Protoperidinium of the Black Sea. 1–2—P. achromaticum; 3–4, 7—P. brevipes; 5, 10—P. quadrioblongum; 6, 8–9—P. excentricum. Designations: 1ʹ—first apical plate, 2a—second intercalary plate. 4, 6–9—epifluorescence; 5, 10— transmitted light. Scale bars: 10 µm.

FIGURES 95–98. Global distribution maps of some Protoperidinium species. 95—P. oblongum; 96—P. solidicorne; 97—P. steinii; 98—P. subinerme.