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Sverdrupiella downiei
Sverdrupella downiei Bujak and Fisher, 1976
Taxonomic senior synonym: Sverdrupiella septentrionalis, according to Below (1987a, p.101).
Holotype: Bujak and Fisher, 1976, pl.6, fig.1-2; text-fig.21
Locus typicus: Skybattle Bay C-15, cuttings 8020-8080"; Queen Elizabeth Islands, arctic Canada
Stratum typicum: ?Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.51-52
Bicavate cysts, capsule ovoidal to rhomboidal. Periphragm longer than broad and compressed dorsoventrally, forming apical horn and delimiting tapering antapical pericoel. Posterior margin of antapical pericoel sometimes irregularly convex or concave, often defining small protuberance which is offset with respect to the middorsal line and probably reflects left antapical horn. Cingulum laevo-rotary and often strongly helicoid, defined by two undulate to crenulate crests, which sometimes bear a few short spines. Sulcus not defined on epitract, delimited on hypotract by two continuous or discontinuous crests similar to those on cingular margins. Remainder of periphragm sparsely to densely covered by echinate, baculate, clavate, or bifid spines.
Archeopyle formed by displacement of up to two anterior intercalary plates in periphragm attached along their posterior margins. In occasional specimens some or all apical, intercalary, and precingular plates absent. Mode of archeopyle formation in capsule unknown.
Dimensions: Holotype, periphragm length 102 µm, periphragm breadth 60 µm, capsule length 48 µm, capsule breadth 55 µm. Observed range, periphragm length 88-102 µm, periphragm breadth 49-62 µm, capsule length 48-53 µm, capsule breadth 47-55 µm.
Taxonomic senior synonym: Sverdrupiella septentrionalis, according to Below (1987a, p.101).
Holotype: Bujak and Fisher, 1976, pl.6, fig.1-2; text-fig.21
Locus typicus: Skybattle Bay C-15, cuttings 8020-8080"; Queen Elizabeth Islands, arctic Canada
Stratum typicum: ?Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.51-52
Bicavate cysts, capsule ovoidal to rhomboidal. Periphragm longer than broad and compressed dorsoventrally, forming apical horn and delimiting tapering antapical pericoel. Posterior margin of antapical pericoel sometimes irregularly convex or concave, often defining small protuberance which is offset with respect to the middorsal line and probably reflects left antapical horn. Cingulum laevo-rotary and often strongly helicoid, defined by two undulate to crenulate crests, which sometimes bear a few short spines. Sulcus not defined on epitract, delimited on hypotract by two continuous or discontinuous crests similar to those on cingular margins. Remainder of periphragm sparsely to densely covered by echinate, baculate, clavate, or bifid spines.
Archeopyle formed by displacement of up to two anterior intercalary plates in periphragm attached along their posterior margins. In occasional specimens some or all apical, intercalary, and precingular plates absent. Mode of archeopyle formation in capsule unknown.
Dimensions: Holotype, periphragm length 102 µm, periphragm breadth 60 µm, capsule length 48 µm, capsule breadth 55 µm. Observed range, periphragm length 88-102 µm, periphragm breadth 49-62 µm, capsule length 48-53 µm, capsule breadth 47-55 µm.