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Ovalicysta
From Williams et al., 2017:
[Ovalicysta, Bjaerke, 1980, p. 71
tax. jr. syn. of Dodekovia Döfhöfer and Davies, 1980, according to Below, 1987. Stover and Williams, 1987, and Lentin and Williams, 1989, retained Ovalicysta as a separate genus.
Type species: Ovalicysta hiata, Bjaerke, 1980 (pl.2, fig.7)]
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Original description: [Bjaerke, 1980]:
Diagnosis:
Proximate dinoflagellate cysts. Cyst wall composed of an autophragm and an ectophragm comprising radial elements producing a tectate structure. Archaeopyle intercalary, outline hexagonal with posterior and anterior angulations (geniculate) formed by one intercalary paraplate.
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Modified description:
Stover and Williams, 1987, p. 71, 169:
Synopsis:
Cysts proximate, subspherical with an apical horn; cyst wall composed of thin autophragm and thicker ectophragm; archeopyle intercalary, geniculate, usually type I, occasionally type 3I, 2a bicamerate, operculum or opercular pieces free.
Description:
Shape: Subspherical with apical horn.
Wall relationships: Autophragm thin, ectophragm thicker and composed of densely packed, sinuous ridges, which support a supposedly continuous outer layer.
Wall features: No conspicuous projecting features or markings; outer surface reported as smooth or granular.
Archeopyle: Intercalary, generally type I, less commonly type 3I, 2a bicamerate; operculum or opercular pieces free.
Paratabulation: Indicated by archeopyle and paracingulum; other indications lacking.
Paracingulum: Expressed as narrow, shallow, equatorial depression.
Parasulcus: Not indicated.
Size: Small, length about 25 to 45 µm.
Affinities:
Ovalicysta differs from Moesiodinium Antones`feu 1974, which also has a bicamerate 2a paraplate, in being acavate rather than circumcavate.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Ovalicysta Bjaerke, 1980. Stover and Williams (1987, p.169) provided the following synopsis. Cysts proximate, subspherical with an apical horn; cyst wall composed of thin autophragm and thicker ectophragm; archeopyle intercalary, geniculate, usually type I, occasionally type 3I, 2a bicamerate, operculum or opercular pieces free.
[Ovalicysta, Bjaerke, 1980, p. 71
tax. jr. syn. of Dodekovia Döfhöfer and Davies, 1980, according to Below, 1987. Stover and Williams, 1987, and Lentin and Williams, 1989, retained Ovalicysta as a separate genus.
Type species: Ovalicysta hiata, Bjaerke, 1980 (pl.2, fig.7)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Bjaerke, 1980]:
Diagnosis:
Proximate dinoflagellate cysts. Cyst wall composed of an autophragm and an ectophragm comprising radial elements producing a tectate structure. Archaeopyle intercalary, outline hexagonal with posterior and anterior angulations (geniculate) formed by one intercalary paraplate.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 71, 169:
Synopsis:
Cysts proximate, subspherical with an apical horn; cyst wall composed of thin autophragm and thicker ectophragm; archeopyle intercalary, geniculate, usually type I, occasionally type 3I, 2a bicamerate, operculum or opercular pieces free.
Description:
Shape: Subspherical with apical horn.
Wall relationships: Autophragm thin, ectophragm thicker and composed of densely packed, sinuous ridges, which support a supposedly continuous outer layer.
Wall features: No conspicuous projecting features or markings; outer surface reported as smooth or granular.
Archeopyle: Intercalary, generally type I, less commonly type 3I, 2a bicamerate; operculum or opercular pieces free.
Paratabulation: Indicated by archeopyle and paracingulum; other indications lacking.
Paracingulum: Expressed as narrow, shallow, equatorial depression.
Parasulcus: Not indicated.
Size: Small, length about 25 to 45 µm.
Affinities:
Ovalicysta differs from Moesiodinium Antones`feu 1974, which also has a bicamerate 2a paraplate, in being acavate rather than circumcavate.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Ovalicysta Bjaerke, 1980. Stover and Williams (1987, p.169) provided the following synopsis. Cysts proximate, subspherical with an apical horn; cyst wall composed of thin autophragm and thicker ectophragm; archeopyle intercalary, geniculate, usually type I, occasionally type 3I, 2a bicamerate, operculum or opercular pieces free.