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Sverdrupiella
From Williams et al., 2017:
[Sverdrupiella, Bujak and Fischer, 1976, p. 45-48
Type species: Sverdrupiella septentrionalis, Bujak and Fischer, 1976 (pl.1, figs.1–2; text-fig.2A)]
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Original description: [Bujak and Fisher, 1976]
Diagnosis:
Cavate to bicavate dinoflagellate cyst, ovoidal to polygonal in shape, with or without one apical and one or two antapical horns. Outer surface of periphragm smooth or granular, with or without spines or verrucae. Reflected tabulation absent or rarely weakly defined by peritabular arrangement of ornament. Cingulum and sulcus well or poorly defined. Archaeopyle typically formed by loss or displacement of one to three anterior intercalary plates in periphragm. Occasionally, some or all remaining epitractal plates may also be displaced or lost. Opening in capsule usually consisting of simple split.
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Modified description:
Stover and Evitt 1978, p. 126-127:
Synopsis:
Cysts proximate, generally bicavate, polygonal to broadly rounded; apical and antapical ends narrowly or broadly rounded; periphragm smooth or variously ornamented with nontabular features of low to moderate relief; paratabulation indicated by archaeopyle and paracingulum; archaeopyle typically intercalary, Types I, 2I, or 3I; additional epicystal paraplates may be released as well.
Description:
Shape: Polygonal to biconical with pointed to broadly rounded apical and antapical ends.
Wall relationships: Cysts generally bicavate, endocyst circular to oval; occasional specimen may lack endocyst.
Wall features: No parasutural features. Pericyst smooth to variously ornamented with scattered to dense nontabular spines or verrucae. Paratabulation: Indicated by archaeopyle and paracingulum; other indications very rare and faint. Archaeopyle: Typically intercalary, Types I, 2I, or 3I; operculum normally free, occasionally adherent; pieces of compound operculae separate or remain together. Additional epicystal paraplates may be involved in archaeopyle formation, and some specimens lack indications of an archaeopyle.
Paracingulum: Indicated by parallel, transverse, equatorial ridges or rows of spines or verrucae.
Parasulcus: Delimited mainly on hypocyst by ridges or rows of spines or verrucae.
Size: intermediate to large.
Affinities:
The variety of shapes displayed by the species of Sverdrupiella makes it difficult to compare it with a single other genus. In shape, several species are similar to Scriniodinium and Tubotuberella, which have precingular rather than intercalary archaeopyles. The biconical species of Sverdrupiella are similar to Palaeocystodinium from which they differ in having a compound archaeopyle and a nearly equidimensional endocyst instead of an ellipsoidal endocyst.
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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.
Sverdrupiella Bujak and Fisher, 1976. Diagnosis from Bujak and Fisher (1976, p.46), Cavate to bicavate dinoflagellate cysts, ovoidal to polygonal in shape, with or without one apical and one or two antapical horns. Outer surface of periphragm smooth or granular, with or without spines or verrucae. Reflected tabulation absent or rarely weakly defined by peritabular arrangement of ornament. Cingulum and sulcus well or poorly defined. Archeopyle typically formed by loss or displacement of one to three anterior intercalary plates in periphragm. Occasionally, some or all remaining epitractal plates may also be displaced or lost. Opening in capsule usually consisting of simple split.
[Sverdrupiella, Bujak and Fischer, 1976, p. 45-48
Type species: Sverdrupiella septentrionalis, Bujak and Fischer, 1976 (pl.1, figs.1–2; text-fig.2A)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Bujak and Fisher, 1976]
Diagnosis:
Cavate to bicavate dinoflagellate cyst, ovoidal to polygonal in shape, with or without one apical and one or two antapical horns. Outer surface of periphragm smooth or granular, with or without spines or verrucae. Reflected tabulation absent or rarely weakly defined by peritabular arrangement of ornament. Cingulum and sulcus well or poorly defined. Archaeopyle typically formed by loss or displacement of one to three anterior intercalary plates in periphragm. Occasionally, some or all remaining epitractal plates may also be displaced or lost. Opening in capsule usually consisting of simple split.
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Modified description:
Stover and Evitt 1978, p. 126-127:
Synopsis:
Cysts proximate, generally bicavate, polygonal to broadly rounded; apical and antapical ends narrowly or broadly rounded; periphragm smooth or variously ornamented with nontabular features of low to moderate relief; paratabulation indicated by archaeopyle and paracingulum; archaeopyle typically intercalary, Types I, 2I, or 3I; additional epicystal paraplates may be released as well.
Description:
Shape: Polygonal to biconical with pointed to broadly rounded apical and antapical ends.
Wall relationships: Cysts generally bicavate, endocyst circular to oval; occasional specimen may lack endocyst.
Wall features: No parasutural features. Pericyst smooth to variously ornamented with scattered to dense nontabular spines or verrucae. Paratabulation: Indicated by archaeopyle and paracingulum; other indications very rare and faint. Archaeopyle: Typically intercalary, Types I, 2I, or 3I; operculum normally free, occasionally adherent; pieces of compound operculae separate or remain together. Additional epicystal paraplates may be involved in archaeopyle formation, and some specimens lack indications of an archaeopyle.
Paracingulum: Indicated by parallel, transverse, equatorial ridges or rows of spines or verrucae.
Parasulcus: Delimited mainly on hypocyst by ridges or rows of spines or verrucae.
Size: intermediate to large.
Affinities:
The variety of shapes displayed by the species of Sverdrupiella makes it difficult to compare it with a single other genus. In shape, several species are similar to Scriniodinium and Tubotuberella, which have precingular rather than intercalary archaeopyles. The biconical species of Sverdrupiella are similar to Palaeocystodinium from which they differ in having a compound archaeopyle and a nearly equidimensional endocyst instead of an ellipsoidal endocyst.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Sverdrupiella Bujak and Fisher, 1976. Diagnosis from Bujak and Fisher (1976, p.46), Cavate to bicavate dinoflagellate cysts, ovoidal to polygonal in shape, with or without one apical and one or two antapical horns. Outer surface of periphragm smooth or granular, with or without spines or verrucae. Reflected tabulation absent or rarely weakly defined by peritabular arrangement of ornament. Cingulum and sulcus well or poorly defined. Archeopyle typically formed by loss or displacement of one to three anterior intercalary plates in periphragm. Occasionally, some or all remaining epitractal plates may also be displaced or lost. Opening in capsule usually consisting of simple split.