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Crussolia
From Williams et al., 2017:
[Crussolia, Wolfard and van Erve, 1981, p. 323-325; Emendations: Smelror and Arhus, 1989, p. 39
Type species: Crussolia deflandrei, Wolfard and van Erve, 1981 (pl.1,figs.1–2)]
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Original description: [Wolfard and van Erve, 1981]:
Diagnosis:
Proximate cysts, ambitus subcircular to ellipsoidal, tapering to an apical horn; antapex rounded. Cyst wall double-layered; cysts circumcavate. Both endophragm and periphragm possessing an apical horn. Paratabulation indicated by archeopyle; sometimes a paracingulum may be present. Archeopyle is intercalary, type 3I or 5I. Apicular structures present or absent. Cyst wall ornament variable. No kalyptra present.
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Modified description:
Stover and Williams, 1987, p. 63:
Synopsis:
Cysts proximate, circumcavate; endocyst and pericyst ellipsoidal, each with an apical horn; paratabulation expressed incompletely by 3I or 5I
archeopyle only, or by archeopyle and paracingulum.
Description:
Shape: Pericyst and endocyst ellipsoidal, each with an apical horn.
Wall relationships: Cysts circumcavate.
Wall features: Endocyst ornamented with features of low relief; pericyst smooth; apicular structures may be present.
Archeopyle: Intercalary, types 3I or 5I; all or most opercular pieces free.
Paratabulation: Indicated by archeopyle only or by archeopyle and paratabulation.
Paracingulum: May be present; manner of expression not stated.
Parasulcus: Not indicated.
Size: Intermediate, overall length about 60 to 65 µm.
Affinities:
Crussolia differs from Pareodinia Deflandre 1947 emended Stover and Evitt 1978 in being cavate, and from Gochteodinia Norris 1978 in likewise being cavate and also in lacking processes.
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Emended description:
Smelor and Arhus, 1989:
Diagnosis:
Proximate dinoflagellate cysts, subcircular to ellipsoidal in outline, tapering to an apical horn, antapex rounded. Cyst wall double-layered; the cyst being circumcavate or holocavate. The relatively thick endophragm and the thin periphragm may be separated, or interconnected by slender processes or finely reticulate ridges forming meshworks. Cyst wall ornamentation is variable. Paratabulation may be indicated only by the archeopyle and accessory archeopyle structures and sometimes by a paracingulum, or may appear as more or less well expressed linear complexes on the periphragm. The tabulation pattern is basically gonyaulacoid. Archeopyle is intercalary, type 3I. Apicular structures present or absent.
[Crussolia, Wolfard and van Erve, 1981, p. 323-325; Emendations: Smelror and Arhus, 1989, p. 39
Type species: Crussolia deflandrei, Wolfard and van Erve, 1981 (pl.1,figs.1–2)]
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Original description: [Wolfard and van Erve, 1981]:
Diagnosis:
Proximate cysts, ambitus subcircular to ellipsoidal, tapering to an apical horn; antapex rounded. Cyst wall double-layered; cysts circumcavate. Both endophragm and periphragm possessing an apical horn. Paratabulation indicated by archeopyle; sometimes a paracingulum may be present. Archeopyle is intercalary, type 3I or 5I. Apicular structures present or absent. Cyst wall ornament variable. No kalyptra present.
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Modified description:
Stover and Williams, 1987, p. 63:
Synopsis:
Cysts proximate, circumcavate; endocyst and pericyst ellipsoidal, each with an apical horn; paratabulation expressed incompletely by 3I or 5I
archeopyle only, or by archeopyle and paracingulum.
Description:
Shape: Pericyst and endocyst ellipsoidal, each with an apical horn.
Wall relationships: Cysts circumcavate.
Wall features: Endocyst ornamented with features of low relief; pericyst smooth; apicular structures may be present.
Archeopyle: Intercalary, types 3I or 5I; all or most opercular pieces free.
Paratabulation: Indicated by archeopyle only or by archeopyle and paratabulation.
Paracingulum: May be present; manner of expression not stated.
Parasulcus: Not indicated.
Size: Intermediate, overall length about 60 to 65 µm.
Affinities:
Crussolia differs from Pareodinia Deflandre 1947 emended Stover and Evitt 1978 in being cavate, and from Gochteodinia Norris 1978 in likewise being cavate and also in lacking processes.
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Emended description:
Smelor and Arhus, 1989:
Diagnosis:
Proximate dinoflagellate cysts, subcircular to ellipsoidal in outline, tapering to an apical horn, antapex rounded. Cyst wall double-layered; the cyst being circumcavate or holocavate. The relatively thick endophragm and the thin periphragm may be separated, or interconnected by slender processes or finely reticulate ridges forming meshworks. Cyst wall ornamentation is variable. Paratabulation may be indicated only by the archeopyle and accessory archeopyle structures and sometimes by a paracingulum, or may appear as more or less well expressed linear complexes on the periphragm. The tabulation pattern is basically gonyaulacoid. Archeopyle is intercalary, type 3I. Apicular structures present or absent.