Protoperidinium depressum (Bailey) Balech 1974

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 : 434

Protoperidinium depressum (Bailey) Balech 1974 . Rev. Mus. Argent. Cienc. Nat. “ B. Rivadavia ”, Hydrobiologia 4 (1): 57. ( Figs. 20–22 ) .

References: Lebour 1925: 119, Pl. XXIII, Figs. a–f; Schiller 1937: 250, Fig. 251 a–t; Kiselew 1950: 203, Fig. 340 a–v, 344 a–b; Wood 1968: 100, Fig. 295 a, b; Taylor 1976: 160, Pl. 34: 383; Pl. 45: 526 (as Peridinium depressum ); Dodge 1982: 176, Fig. 20 A ; Pl. V: e; Dodge 1985: 50; Balech 1988: 87, Lam. 25, 4–8; Steidinger & Tangen 1997: 538, Pl. 52; Evagelopoulos 2002: 42, Figs. 2–3 , 34 ; Okolodkov 2008: 118, Pl. 6, 1–3; Hoppenrath et al. 2009: 151, Fig. 61 d-h; Krakhmalny 2011: 195, Table 79, Figs. 10–14 ; Phan-Tan et al. 2017: 134, Fig. 3 a–g ; Al-Yamani & Saburova 2019: 306, Pl. 169.

Basionym: Peridinium depressum Bailey 1854 . Smithson. Contr. Knowl. 7: 12, Figs. 33–34 .

Description: Cells large, pentagonal, dorsoventrally compressed, asymmetrical. The apical horn elongated. The apical pore structure of Bʹ– type ( Toriumi & Dodge 1993). The epithecal plate pattern comprises seven precingular plates (7ʹʹ), four apical plates (4ʹ), three anterior intercalary plates (3a), 1ʹ and 2a plates of “ortho”–”quadra” type. Thecal plates reticulate. The cingulum median, descending (displaced by 1.0 cingular width), bordered. The sulcus deep, with narrow sulcal lists. The hypotheca with sharp diverging antapical horns. The cellular contents pink or brown-red. Dimensions: 96.2–129.8 μm long and 82.2–97.7 μm wide.

Distribution: Coastal and oceanic, even forms blooms in warm water estuaries. Temperate to tropical waters; cosmopolitan ( Steidinger & Tangen 1997). Data on the distribution of P. depressum are given from the GBIF.org (2022) ( Fig. 84 ).

Figures

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 23–34. Protoperidinium of the Black Sea. 23–31—P. divergens; 32—P. conicum; 33—P. knipowitschii; 34—P. granii. Designations: 1ʹ—first apical plate, 2a—second intercalary plate. 24, 34—DIC; 25–28—epifluorescence; 29–31—FE- SEM; 23, 32–33—transmitted light. Scale bars: 20 µm.

FIGURES 59–64. Protoperidinium of the Black Sea. 59–64—P. mediterraneum. Designations: 1ʹ—first apical plate. 59–63— DIC; 64—epifluorescence. Scale bars: 10 µm.

FIGURES 77–85. Global distribution maps of some Protoperidinium species. 77—Protoperidinium achromaticum; 78—P. bipes; 79—P. brevipes; 80—P. brochii; 81—P. claudicans; 82—P. conicum; 83—P. crassipes; 84—P. depressum; 85—P. divergens.