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Trichodinium discus
From Fensome et al., 2019:
Trichodinium discus Harding, 1990b, p.38, pl.18, figs.7–13 ex Harding in Williams et al. 1998, p.615.
Holotype: Harding, 1990b, pl.18, fig.7.
NOW Elimatia. Originally Trichodinium, subsequently (and now) Elimatia. This name was not validly published in Harding (1990b) since the lodgement of the holotype was not specified (ICN Article 40.7). NIA.
Age: early Barremian.
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Barremian
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Original diagnosis: Harding, 1990, p. 38
Shape: Ambitus cubcircular to prolate ovoidal. Greatest width across posterior of paracingulum. Epicyst generally shorter than hypocyst (may be only 1/2 the length in exceptional circumstances). Strong dorso-ventral compression.
Phragma: Differentiated autophragm -- µm thick. Distal surface composed of pseudoreticulum of sporopollenin fibres which anastomose to form acuminate tubercles up to 4 µm long. Tubercles are evenly distributed save for bald areas corresponding to paraplate IV and the parasulcus. Occasionally the parasutures are indicated by low ridges, usually along the paracingulum. No apical process.
Paratabulation: Obscure, consistent with L-type sexiform gonyaulacoid in as far as can be determined.
Archaeopyle: Type P4 - free, monoplacoid operculum, anterior archaeopyle margin is distinctly rounded.
Paracingulum: Occasionally defined by aligned tubercles. Laevorotatory, displaced by 1-1/2 cingulum widths.
Parasulcus: L-type. Area of reduced tuberculation. Flagellar scar pronounced.
Dimensions: Length (63) 57.5 (51) µm. Width (60) 56.0 (47) µm. Specimens = 15 (10).
Affinities:
Harding, 1990, p.38: Trichodinium discus is probably the form recorded by previous workers on Barremian dinocysts as T. castanea. However, this new species is clearly not the same as the latter named species, due to its lack of an apical prominence and its more circular ambitus. The lack of an apical horn and the character of the tuberculation serve to differentiate this new species from the other members of the genus.
Trichodinium discus Harding, 1990b, p.38, pl.18, figs.7–13 ex Harding in Williams et al. 1998, p.615.
Holotype: Harding, 1990b, pl.18, fig.7.
NOW Elimatia. Originally Trichodinium, subsequently (and now) Elimatia. This name was not validly published in Harding (1990b) since the lodgement of the holotype was not specified (ICN Article 40.7). NIA.
Age: early Barremian.
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Barremian
---------------------------------------------------------------------------------------------------
Original diagnosis: Harding, 1990, p. 38
Shape: Ambitus cubcircular to prolate ovoidal. Greatest width across posterior of paracingulum. Epicyst generally shorter than hypocyst (may be only 1/2 the length in exceptional circumstances). Strong dorso-ventral compression.
Phragma: Differentiated autophragm -- µm thick. Distal surface composed of pseudoreticulum of sporopollenin fibres which anastomose to form acuminate tubercles up to 4 µm long. Tubercles are evenly distributed save for bald areas corresponding to paraplate IV and the parasulcus. Occasionally the parasutures are indicated by low ridges, usually along the paracingulum. No apical process.
Paratabulation: Obscure, consistent with L-type sexiform gonyaulacoid in as far as can be determined.
Archaeopyle: Type P4 - free, monoplacoid operculum, anterior archaeopyle margin is distinctly rounded.
Paracingulum: Occasionally defined by aligned tubercles. Laevorotatory, displaced by 1-1/2 cingulum widths.
Parasulcus: L-type. Area of reduced tuberculation. Flagellar scar pronounced.
Dimensions: Length (63) 57.5 (51) µm. Width (60) 56.0 (47) µm. Specimens = 15 (10).
Affinities:
Harding, 1990, p.38: Trichodinium discus is probably the form recorded by previous workers on Barremian dinocysts as T. castanea. However, this new species is clearly not the same as the latter named species, due to its lack of an apical prominence and its more circular ambitus. The lack of an apical horn and the character of the tuberculation serve to differentiate this new species from the other members of the genus.