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Umbodinium
From Fensome et al., 2019:
Umbodinium Bint, 1983, p.173–175.
Type: Bint, 1983, pl.1, figs.1–3; text-fig.4A, as Umbodinium crustov.
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Original description: [Bint, 1983]:
Description:
Single-walled peridinioid cyst; spherical or nearly so, epicyst modified by archeopyle; no parasutural features. Epicystal paratabulation 4`, 2a, 7", indicated by archeopyle only; 3` four-sided, intercalaries hexagonal and transversely elongate; 3", 4", and 5" planate, camerate, and planate. Archeopyle combination apical and intercalary with apical series adnate ventrally across the width of 1` and both intercalary paraplates free, i.e., Type (tA)a2I; accessory sutures between precingular paraplates developed to varying extent.
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Modified description:
Stover and Williams, 1987, p. 223:
Synopsis:
Cysts proximate, subspherical, and without ridges, septa, spines, processes or horns; autocyst ornamented with features of low relief; paratabulation of epicyst known from archeopyle and accessory sutures, formula: 4`, 2a, 7"; hypocystal paratabulation not indicated; combined apical and intercalary archeopyle, type [4A]@ + 21, adnate along paraplate.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: Scabrate on only known species.
Archeopyle: Combined apical and intercalary, type [4A]@ + 21, adnate, along the midventral part of cyst at paraplate 1`; intercalary opercular pieces free.
Paratabulation: Indicated on the epicyst only, and then only by the archeopyle and accessory sutures; formula 4`, 2a, 7".
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, about 40 to 65 µm wide.
Affinities:
Ascodinium Cookson and Eisenack 1960a emended Helenes 1983 (who considered Ovoidinium Davey 1970 emended Lentin and Williams 1976 to be a junior synonym of Ascodinium) has three intercalary paraplates with 2a, when freed, representing one of two opercular pieces.
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Bint, 1983, p. 173:
Affinities:
The presence of only two intercalary paraplates sets Umbodinium apart from all other fossil peridinioid genera.
Umbodinium Bint, 1983, p.173–175.
Type: Bint, 1983, pl.1, figs.1–3; text-fig.4A, as Umbodinium crustov.
---------------------------------------------------------------------------------------------------
Original description: [Bint, 1983]:
Description:
Single-walled peridinioid cyst; spherical or nearly so, epicyst modified by archeopyle; no parasutural features. Epicystal paratabulation 4`, 2a, 7", indicated by archeopyle only; 3` four-sided, intercalaries hexagonal and transversely elongate; 3", 4", and 5" planate, camerate, and planate. Archeopyle combination apical and intercalary with apical series adnate ventrally across the width of 1` and both intercalary paraplates free, i.e., Type (tA)a2I; accessory sutures between precingular paraplates developed to varying extent.
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Modified description:
Stover and Williams, 1987, p. 223:
Synopsis:
Cysts proximate, subspherical, and without ridges, septa, spines, processes or horns; autocyst ornamented with features of low relief; paratabulation of epicyst known from archeopyle and accessory sutures, formula: 4`, 2a, 7"; hypocystal paratabulation not indicated; combined apical and intercalary archeopyle, type [4A]@ + 21, adnate along paraplate.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: Scabrate on only known species.
Archeopyle: Combined apical and intercalary, type [4A]@ + 21, adnate, along the midventral part of cyst at paraplate 1`; intercalary opercular pieces free.
Paratabulation: Indicated on the epicyst only, and then only by the archeopyle and accessory sutures; formula 4`, 2a, 7".
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, about 40 to 65 µm wide.
Affinities:
Ascodinium Cookson and Eisenack 1960a emended Helenes 1983 (who considered Ovoidinium Davey 1970 emended Lentin and Williams 1976 to be a junior synonym of Ascodinium) has three intercalary paraplates with 2a, when freed, representing one of two opercular pieces.
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Bint, 1983, p. 173:
Affinities:
The presence of only two intercalary paraplates sets Umbodinium apart from all other fossil peridinioid genera.