From Fensome et al., 2019:
Alisogymnium sphaerocephalum, (Vozzhennikova, 1967, p.48, pl.2, fig.7; pl.3, fig.1) Lentin and Vozzhennikova, 1990, p.25.
Emendation: Lentin and Vozzhennikova, 1990, p.25–26, as Alisogymnium sphaerocephalum.
Holotype: Vozzhennikova, 1967, pl.3, fig.1; Lentin and Vozzhennikova, 1990, pl.2, figs.6,11–12; text-fig.10; Appendix A, fig.30.
Originally Gymnodinium (Appendix B), subsequently Dinogymnium, thirdly (and now) Alisogymnium.
Taxonomic junior synonym: Dinogymnium (now Alisogymnium) assamicum, according to Jain (1977a, p.133–134) — however, Lentin and Vozzhennikova (1990, p.28) retained Dinogymnium (as Alisogymnium) assamicum.
Age: Senonian.

Locus typicus: W Siberia (Yuzhno-Kolpashevsk area), Russia

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Alisogymnium sphaerocephalum, (Vozzhennikova, 1967), Lentin and Vozzhennikova, 1990

Originally Gymnodinium, subsequently Dinogymnium, thirdly (and now) Alisogymnium.
tax. sr syn. of Dinogymnium (now Alisogymnium) assamicum Jain et al., 1975, according to Jain, 1977. Lentin and Vozzhennikova, 1990, retained Dinogymnium (as Alisogymnium) assamicum as a separate species.

Holotype: Vozzhennikova, 1967, pl.3, fig.1; Lentin and Vozzhennikova, 1990, pl.2, figs.6, 11-12
Locus typicus: W Siberia (Yuzhno-Kolpashevsk area), Russia
Stratum typicum: Senonian

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Original description as Gymnodinium sphaerocephalum: [Vozzhennikova, 1967, p. 48]: (Translation: Lentin and Vozzhennikova, 1990):

Description:
Theca flask-shaped or resembling a parachute; epitheca hemispherical, hypotheca funnel-shaped with a tubular process which may be either straight or curved and is bluntly truncated at the end. Transverse furrow annulate, deep. Position of longitudinal furrow indistinct although the furrow itself is probably slit-like. Ribs run from the transverse furrow towards the poles of the theca; they extend about half way across the epitheca but do not reach the cupolar apical part, whereas on the hypotheca they extend almost to the antapex.

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Emended description:


Lentin and Vozzhennikova, 1990, p. 24-26:

Description:
Cysts elongate, epicyst long, funnel-shaped with tubular apex; hypocyst short with broadly rounded antapex; autophragm microporate, epicyst with delicate longitudinal ridges extending about 2/3 the distance from paracingulum to apex; hypocyst with delicate ridges immediately below the paracingulum, disappearing towards the antapex; archaeopyle formed by two short arcurate sutures, approximately 5 µm long, which result in the loss of a single paraplate equal to to the width of the tubular apex of the cyst; paracingulum deep, dividing the cyst into two unequal portions, the hypocyst being about 1/3 the length of the epicyst; parasulcus indicated by a shallow longitudinal depression, principally on the hypocyst, immediately below the paracingulum.

Dimensions/Size:
Holotype, 81 µm long, 33 µm wide, epitheca 48 µm long, hypotheca 30 µm long, width of the cingulum about 3 µm;
range, length 56-81 µm, width 30-33 µm.