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Uvatodinium nasutum

Uvatodinium nasutum Vozzhennikova, 1963, p.182; text-figs.13a-b.; Emendation: Lentin and Vozzhennikova, 1990, p.71-72.

Taxonomic junior synonym: Uvatodinium marginatum, according to Lentin and Vozzhennikova (1990, p.71).

Holotype: Vozzhennikova, 1963, text-figs.13a-b; Vozzhennikova, 1967, pl.8, fig.5; lost according to Lentin and Vozzhennikova (1990, p.71).
Lectotype: Lentin and Vozzhennikova, 1990, pl.12, figs.1-2; text-fig.38, designated by Lentin and Vozzhennikova (1990, p.71).
Age: Paleocene.
Locus typicus: W Siberia, Russia
Translation Vozzhennikova, 1963: Lentin and Vozzhennikova, 1990

Original description: Vozzhennikova, 1963, p.182
Theca almost spherical. Epitheca somewhat larger than hypotheca, with a projecting apical horn. Hypotheca hemispherical without a projecting process, or sometimes with a horn to the antapex. Transverse furrow annulate, shallow, relatively wide. Longitutinal furrow confined to the hypovalve and not extending as far as the antapex. Surface of theca with a coarsely cellular pattern and with spinules on the margins of the cellular areas.

Emended descrpition: Lentin and Vozzhennikova, 1990, p.71-72
Cysts oval with a single long, narrow, distally rounded apical horn; periphragm expanded in area of paracingulum providing short lateral extensions; hypocyst broadly rounded, without antapical horns; endophragm oval, may be closely appressed to periphragm on the epicyst except in the area of the apical horn and paracingulum; endophragm and periphragm more or less separate on hypocyst; cornucavate to circumcavate. Periphragm ornamented with randomly distributed fine reticulum with small coni arising at the junctions of the reticulum; endophragm finely granulose. Paratabulation indicated by archeopyle and paracingulum only; peridinioid. Archeopyle identical in both wall layers, small standard hexa formed by the loss of the 2a intercalary paraplate, operculum free. Paracingulum indicated by a shallow depression at the lateral margins. Parasulcus not indicated.
Size: Lectotype, length 152 µm, width 133 µm; Range, length 97-160 µm, width 78-138 µm.
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