Dominant Species Of The Genus Protoperidinium Bergh (Peridiniales: Protoperidiniaceae) In The Black Sea Author Krakhmalnyi, Aleksandr F. Laboratory of Preservation and Biodiversity Renewal, Institute for Evolutionary Ecology of NAS of Ukraine. 37 Acad. Lebedev Str., Kiev 03143, Ukraine. Author Krakhmalnyi, Maxim A. Department of Phytoecology, Institute for Evolutionary Ecology of NAS of Ukraine. 37 Acad. Lebedev Str., Kiev 03143, Ukraine. Author Terenko, Galyna V. Department of Scientific Studies and Protection of Marine Biocenoses, Ukrainian Scientific Center of Ecology of the Sea (UkrSCES), 89 Frantsuzsky Blvd., Odessa 65009, Ukraine. & Ifremer, LITTORAL, Station de Biologie Marine, Place de la Croix, BP 40537, 29900, Concarneau CEDEX, France. Author Goncharenko, Igor V. Department of Ecological Monitoring, Institute for Evolutionary Ecology of NAS of Ukraine. 37 Acad. Lebedev Str., Kiev 03143, Ukraine. text Zootaxa 2023 2023-09-01 5339 5 427 448 http://dx.doi.org/10.11646/zootaxa.5339.5.2 journal article 265694 10.11646/zootaxa.5339.5.2 2953fa15-37a7-4c2c-9a1c-6054d4be9765 1175-5326 8309419 41EC5960-8B30-45D1-BE02-2F1C30E6F9A3 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 ).