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Cerodinium markovae

Cerodinium markovae, (Vozzhennikova, 1967), Lentin and Williams, 1987

Originally Ceratiopsis (an illegitimate generic name), subsequently Deflandrea, thirdly (and now) Cerodinium.

Holotype: Vozzhennikova, 1967, pl.120, fig.2; Lentin and Vozzhennikova, 1990, pl.3, figs.7-8, text-fig.16
Locus typicus: Tomsk region, W Siberia, Russia
Stratum typicum: Paleocene-Eocene

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Original description as Ceratiopsis markovae: [Vozzhennikova, 1967, p. 159]: (Translation: Lentin and Vozzhennikova, 1990):

Description:
Epitheca larger than hypotheca with outline conical or more rarely funnel-shaped. The apical horn is short, bluntly rounded or pointed, slightly tapering or not tapering. Hypotheca smaller than epitheca with short triangular apical horns. Transverse furrow shallow, annulate, displaced towards the hinder end of the theca. Longitudinal furrow extends to the antapex. Internal body large, ovoid, its surface finely granular and colored bright yellow or pale brown. Theca closely appressed to the internal body, thin-walled, transparent, delicate. Surface of theca smooth or finely tuberculate. Pylome large, round-trapeziform and situated near the transverse furrow or, more rarely, nearer to the apex.

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Expanded description:

Lentin and Vozzhennikova, 1990, p.38:

Description:
Cyst shape peridinioid with one short, conical apical horn and two nearly equal, short antapical horns; endocyst elongate oval; apical pericoel well developed, antapical pericoel poorly developed, not extending to paracingular area.
Periphragm extremely thin With delicate intratabular granules, very delicate ridges on the periphragm produce longitudinal striae; endophragm finely granulose.
Paratabulation expressed by the archeopyle, and paracingulum only.
Archeopyle large standard hexa (iso-deltaform) formed by the loss of the 2a paraplate in both wall layers.
Paracingulum is shallow, indistinct to d1stinct, occasionally bordered with crenulations caused by the striae, displaced towards the antapex. The perisulcus is shallow and expressed only as a depression on the hypocyst.

Dimensions:
Holotype, length 132 µm, breadth 73 µm; length of endocyst 62 µm, breadth 48 µm; width of paracingulum 5.5 µm.
Range, length 120 - 132 µm, width 54 - 73 µm.
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