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Pterodinium premnon
From Fensome et al., 2019:
Pterodinium premnon Duxbury, 1980, p.131, pl.3, figs.1–2. Holotype: Duxbury, 1980, pl.3, figs.1–2; Jan du Chêne et al., 1986a, pl.87, figs.9–10. Taxonomic junior synonym: Impagidinium phlyctaena, according to Duxbury (2019, p.201). NIA. Age: middle Barremian.
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Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Barremian
Original diagnosis: Duxbury, 1980, p. 131:
An ovoidal to ellipsoidal dinoflagellate cyst bearing a short, parallel-sided, flat-ended apical horn. Typically gonyaulacacean paratabulation is outlined by high parasutural crests which are minutely perforate and distally bear numerous, very short denticles. Hollow, broad-based, paraplate-centred projections are present, one per paraplate area and these taper and are distally closed and convex. The archeopyle is precingular (3"). Observed Dimensions: Holotype 58 x 55 µm. Overall 61 (59) 58 x 58 (57) 55 µm.
Affinities:
Duxbury, 1980, p.131: The combination of high, minutely perforate parasutural crests and plate-centred projections renders P. premnos distinct from all other species.
Pterodinium premnon Duxbury, 1980, p.131, pl.3, figs.1–2. Holotype: Duxbury, 1980, pl.3, figs.1–2; Jan du Chêne et al., 1986a, pl.87, figs.9–10. Taxonomic junior synonym: Impagidinium phlyctaena, according to Duxbury (2019, p.201). NIA. Age: middle Barremian.
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Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Barremian
Original diagnosis: Duxbury, 1980, p. 131:
An ovoidal to ellipsoidal dinoflagellate cyst bearing a short, parallel-sided, flat-ended apical horn. Typically gonyaulacacean paratabulation is outlined by high parasutural crests which are minutely perforate and distally bear numerous, very short denticles. Hollow, broad-based, paraplate-centred projections are present, one per paraplate area and these taper and are distally closed and convex. The archeopyle is precingular (3"). Observed Dimensions: Holotype 58 x 55 µm. Overall 61 (59) 58 x 58 (57) 55 µm.
Affinities:
Duxbury, 1980, p.131: The combination of high, minutely perforate parasutural crests and plate-centred projections renders P. premnos distinct from all other species.