Back
Sverdrupiella raiaformis
Sverdrupiella raiaformis Bujak and Fisher, 1976
Holotype: Bujak and Fisher, 1976, pl.3, fig.4-5; text-fig.2D
Locus typicus: Jameson Bay C-31, cuttings 3500-3590", Queen Elizabeth Islands, arctic Canada
Stratum typicum: ?Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.50
Cavate cysts, capsule ovoidal to rhomboidal and often obscured by thick periphragm and ornament. Periphragm comprising rounded conical to almost hemispherical epitract, which is shorter than hypotract, without apical horn, and acutely conical hypotract tapering to single, pointed antapical horn. Outer surface of periphragm covered by baculate to clavate and occasionally acuminate spines which are often densely arranged. Cingulum laevo-rotary, sulcus restricted to hypotract. Cingular and sulcal margins defined either by crests bearing baculate to clavate spines or by rows of spines distinguishable from remainder of spines on periphragm by their alignment and slightly larger size. Archeopyle formed by displacement of two, or more commonly three, anterior intercalary plates which remain attached along posterior margins. Mode of archeopyle formation in capsule unknown.
Dimensions: Holotype, periphragm length 77 µm, periphragm breadth 68 µm, length and breadth of capsule unknown. Observed range, periphragm length 62-87 µm, periphragm breadth 55-75 µm, capsule length 33-54 µm, capsule breadth 49-53 µm.
Holotype: Bujak and Fisher, 1976, pl.3, fig.4-5; text-fig.2D
Locus typicus: Jameson Bay C-31, cuttings 3500-3590", Queen Elizabeth Islands, arctic Canada
Stratum typicum: ?Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.50
Cavate cysts, capsule ovoidal to rhomboidal and often obscured by thick periphragm and ornament. Periphragm comprising rounded conical to almost hemispherical epitract, which is shorter than hypotract, without apical horn, and acutely conical hypotract tapering to single, pointed antapical horn. Outer surface of periphragm covered by baculate to clavate and occasionally acuminate spines which are often densely arranged. Cingulum laevo-rotary, sulcus restricted to hypotract. Cingular and sulcal margins defined either by crests bearing baculate to clavate spines or by rows of spines distinguishable from remainder of spines on periphragm by their alignment and slightly larger size. Archeopyle formed by displacement of two, or more commonly three, anterior intercalary plates which remain attached along posterior margins. Mode of archeopyle formation in capsule unknown.
Dimensions: Holotype, periphragm length 77 µm, periphragm breadth 68 µm, length and breadth of capsule unknown. Observed range, periphragm length 62-87 µm, periphragm breadth 55-75 µm, capsule length 33-54 µm, capsule breadth 49-53 µm.