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Vozzhennikovia rotunda
Vozzhennikovia rotunda (Wilson, 1967) Lentin and Williams, 1976
Originally Spinidinium, subsequently (and now) Vozzhennikovia, thirdly Dioxya.
Morgan, 1977, transferred this species to Dioxya Cookson and Eisenack, 1958. Lentin and Williams, 1981, retained it in Vozzhennikovia.
Holotype: Wilson, 1967, fig.6
Locus typicus: Erratics on Black Island, McMurdo Sound, Antarctica
Stratum typicum: Eocene
Original diagnosis: Wilson, 1967, p.64: Spinidinium rotundum
Shell circular or near-circular, single-layered; surface covered with numerous smali spines. Apical horn relatively large (8-11 µm) rectangular; right antapical horn small, Pointed (4-5 µm); left antapical horn absent. Transverse girdle faintly defined by a double row of spine-bearing ridges which are usually discontinuous. Wide longitudinal furrow. Intercalary archeopyle wide, hexagonal, located on dorsal epitheca; operculum free. Atabulate.
Dimensions: Holotype: l=65 µm, b=58 µm. Range: l=55 (66) 72 µm, b=47 (52) 58 µm.
Originally Spinidinium, subsequently (and now) Vozzhennikovia, thirdly Dioxya.
Morgan, 1977, transferred this species to Dioxya Cookson and Eisenack, 1958. Lentin and Williams, 1981, retained it in Vozzhennikovia.
Holotype: Wilson, 1967, fig.6
Locus typicus: Erratics on Black Island, McMurdo Sound, Antarctica
Stratum typicum: Eocene
Original diagnosis: Wilson, 1967, p.64: Spinidinium rotundum
Shell circular or near-circular, single-layered; surface covered with numerous smali spines. Apical horn relatively large (8-11 µm) rectangular; right antapical horn small, Pointed (4-5 µm); left antapical horn absent. Transverse girdle faintly defined by a double row of spine-bearing ridges which are usually discontinuous. Wide longitudinal furrow. Intercalary archeopyle wide, hexagonal, located on dorsal epitheca; operculum free. Atabulate.
Dimensions: Holotype: l=65 µm, b=58 µm. Range: l=55 (66) 72 µm, b=47 (52) 58 µm.