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Heibergella asymmetrica
From Fensome et al., 2019:
Heibergella asymmetrica Bujak and Fisher, 1976, p.54,56, pl.8, figs.1–8; text-figs.4A–B. Holotype: Bujak and Fisher, 1976, pl.8, figs.1–2. Age: Norian.
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Paratype: Bujak and Fisher, 1976
Locus typicus: Drake Point F-16, core 3722"; Queen Elizabeth Islands, arctic Canada
Stratum typicum: Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.54
Apparently single-walled cysts typically compressed dorsoventrally. Epitract of subtriangular outline modified by presence of apical horn. Hypotract of semicircular to bulbous outline. Antapical horns typically absent or poorly defined, although a single, pointed antapical horn may rarely be present. Wall of cyst thin, outer surface scabrate or smooth and variably folded. Cingulum laevo-rotary, delimited by distally smooth or undulate crests, interrupted by sulcus which is absent or poorly defined on epitract, but defined on hypotract by crests similar to those bordering cingulum. Archeopyle anterior intercalary, formed by loss or displacement of portion of wall probably corresponding to single plate.
Dimensions: Holotype, length 61 µm, breadth 56 µm. Observed range, length 53-70 µm, breadth 44-60 µm.
Heibergella asymmetrica Bujak and Fisher, 1976, p.54,56, pl.8, figs.1–8; text-figs.4A–B. Holotype: Bujak and Fisher, 1976, pl.8, figs.1–2. Age: Norian.
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Paratype: Bujak and Fisher, 1976
Locus typicus: Drake Point F-16, core 3722"; Queen Elizabeth Islands, arctic Canada
Stratum typicum: Carnian-Norian
Original diagnosis: Bujak and Fisher, 1976, p.54
Apparently single-walled cysts typically compressed dorsoventrally. Epitract of subtriangular outline modified by presence of apical horn. Hypotract of semicircular to bulbous outline. Antapical horns typically absent or poorly defined, although a single, pointed antapical horn may rarely be present. Wall of cyst thin, outer surface scabrate or smooth and variably folded. Cingulum laevo-rotary, delimited by distally smooth or undulate crests, interrupted by sulcus which is absent or poorly defined on epitract, but defined on hypotract by crests similar to those bordering cingulum. Archeopyle anterior intercalary, formed by loss or displacement of portion of wall probably corresponding to single plate.
Dimensions: Holotype, length 61 µm, breadth 56 µm. Observed range, length 53-70 µm, breadth 44-60 µm.