References: Lebour 1925: 134, Pl. XXVIII, Fig. 1 a–d; Schiller 1937: 209, Fig. 206 a–m; Kiselew 1950: 188, Fig. 313 a–v; Wood 1968: 106, Fig. 318 (as Peridinium pallidum); Krakhmalnyi 2011: 203, Table 85: 1–15.
Basionym: Peridinium pallidum Ostenfeld 1899. Plankton i 1898, Jagttagelser etc., Kbhvn.: 60.
Description: Cells rhomboid or pentagonal, slightly dorsally compressed, with straight lateral sides. 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 plate – “para”, 2a – “hexa”. The thecal surface reticulated. The cingulum median, ascending (displaced by 1.0 cingular width), bordered. The hypotheca with two short slightly divergent antapical spines. The plate 1ʹʹʹ bears the hypothecal pore (Abé 1981; Dodge 1987; Okolodkov 2003). The sulcus broad, expanding, left sulcal list larger, protruding at the base of the left antapical spine. The cells contents pink. Dimensions: 51.1–96.7 μm long and 33.0–88.9 μm wide.
Distribution: Coastal and oceanic from cold temperate to warm temperate waters; worldwide distribution (Steidinger & Tangen 1997). Data on the distribution of P. pallidum are given from the GBIF.org (2022) (Fig. 91).