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Omatia
From Williams et al., 2017:
[Omatia, Cookson and Eisenack, 1958, p. 60; Emendations: Wiggins, 1969, p. 150; Stover and Helby, 1987b, p. 149, 152
Tax. sr. syn. of Herendeenia Wiggins, 1969, according to Stover and Evitt, 1978. Stover and Helby, 1987, retained Herenddenia as a separate genus.
Type species: Omatia montgomeryi, Cookson and Eisenack, 1958 (pl.8, fig.8)] ; emend. Wiggins, 1969; emend. Stover and Helby, 1987
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Original description: [Cookson and Eisenack, 1958]:
Description:
Shell more or less fusiform, partially or completely covered by delicate fin-like membrane.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Emended descriptions:
Wiggins, 1969:
Description:
The cyst is fusiform in outline, with the tabulation 3`, 6``, 7c, 6```, lp, 1````. The archeopyle is precingular and is formed by the 3`` plate. The apical, precingular, postcingular, and posterior intercalary plates are either completely or partially delineated by fin-like membranes.
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Stover and Helby, 1987:
Synopsis:
Cysts proximate, elongate ellipsoidal with a short apical protrusion; autophragm and ectophragm separated over all or most of cyst ectophragm supported by processes which may occur in longitudinal rows, as local groups, and/or as isolated structures; paratabulation indicated mainly by rows of processes; formula: 4`, 4", Xc, 5```, 1p, 1````; no definitive archeopyle.
Description:
Shape: Autocyst elongate ellipsoidal with short, apical protrusion and generally truncate antapical margin; shape of ectocyst more or less follows that of autocyst.
Wall relationships: Autophragm and ectophragm separated over all or most of cyst; ectophragm supported by processes.
Wall features: Autophragm surface ornamented with features of low relief and with relatively short, generally simple processes; processes isolated, in closely spaced groups, or in longitudinal rows. Ectophragm smooth.
Archeopyle: No definitive archeopyle; rupture and separation of one portion from another may occur almost anywhere on the cyst.
Paratabulation: Indicated mainly by parasutural features; formula 4`, 4", Xc, 5```, 1p, 1````; paratabulation consistently reduced ventrally from the `standard` gonyaulacacean pattern.
Paracingulum: Generally not indicated; when discernible, limits defined by equatorial terminations of parasutural features; occasionally expressed by transverse folds or thickenings of the ectophragm, undivided.
Parasulcus: Generally not indicated; posterior limit inferred from configuration of adjacent paraplates.
Size: intermediate to large, generally greater than 100 µm.
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Modified description:
Stover and Evitt, 1978, p. 177-178:
Synopsis:
Cysts proximochorate, elongate ellipsoidal, with short apical projection; paratabulation gonyaulacacean, indicated completely or partly by parasutural ridges or septa; archeopyle precingular, Type P.
Description:
Shape: Body elongate ellipsoidal; cyst with short apical protrusion and generally truncate antapical margin.
Wall relationships: Autophragm only, or autophragm and ectophragm.
Wall features: Parasutural ridges or septa complete or interrupted, solid to perforate; additionally, narrow longitudinal trabeculae connect the distal ends of slender projections. Parasutural features may increase in height toward the poles.
Paratabulation: Indicated completely or partly by parasutural features; gonyaulacacean, formula: 3`, 6``, 0-6c, 6```, 1p, 1````, O-ls.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six subrectangular paraplates, or not indicated.
Parasulcus: Indicated by bordering parasutural features, generally at extremities only.
Size: Intermediate to large.
Affinities:
Omatia differs from Boreocysta, to which it is similar in shape, in having parasutural ridges or septa and a precingular archeopyle. Boreocysta is cavate, lacks parasutural features, and has an apical archeopyle.
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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.
Omatia Cookson and Eisenack, 1958, emend. Wiggins, 1969, emend. Stover and Helby, 1987b. Omatia differs from Herendeenia in having the two wall layers separated over most of the cyst, whereas in Herendeenia the two layers are appressed. The processes in Omatia are mainly parasutural but can also be isolated and in small groups. Herendeenia does not have processes. There is no definite archeopyle in Omatia whereas Herendeenia has a single plate 3" archeopyle. Omatia has four precingular plates and a smooth autophragm and ectophragm; Herendeenia has five or six precingular plates and an ornamented periphragm. Boreocysta has nontabular processes, generally more numerous in the polar regions and an apical archeopyle.
[Omatia, Cookson and Eisenack, 1958, p. 60; Emendations: Wiggins, 1969, p. 150; Stover and Helby, 1987b, p. 149, 152
Tax. sr. syn. of Herendeenia Wiggins, 1969, according to Stover and Evitt, 1978. Stover and Helby, 1987, retained Herenddenia as a separate genus.
Type species: Omatia montgomeryi, Cookson and Eisenack, 1958 (pl.8, fig.8)] ; emend. Wiggins, 1969; emend. Stover and Helby, 1987
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1958]:
Description:
Shell more or less fusiform, partially or completely covered by delicate fin-like membrane.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Emended descriptions:
Wiggins, 1969:
Description:
The cyst is fusiform in outline, with the tabulation 3`, 6``, 7c, 6```, lp, 1````. The archeopyle is precingular and is formed by the 3`` plate. The apical, precingular, postcingular, and posterior intercalary plates are either completely or partially delineated by fin-like membranes.
-----------------------------------------
Stover and Helby, 1987:
Synopsis:
Cysts proximate, elongate ellipsoidal with a short apical protrusion; autophragm and ectophragm separated over all or most of cyst ectophragm supported by processes which may occur in longitudinal rows, as local groups, and/or as isolated structures; paratabulation indicated mainly by rows of processes; formula: 4`, 4", Xc, 5```, 1p, 1````; no definitive archeopyle.
Description:
Shape: Autocyst elongate ellipsoidal with short, apical protrusion and generally truncate antapical margin; shape of ectocyst more or less follows that of autocyst.
Wall relationships: Autophragm and ectophragm separated over all or most of cyst; ectophragm supported by processes.
Wall features: Autophragm surface ornamented with features of low relief and with relatively short, generally simple processes; processes isolated, in closely spaced groups, or in longitudinal rows. Ectophragm smooth.
Archeopyle: No definitive archeopyle; rupture and separation of one portion from another may occur almost anywhere on the cyst.
Paratabulation: Indicated mainly by parasutural features; formula 4`, 4", Xc, 5```, 1p, 1````; paratabulation consistently reduced ventrally from the `standard` gonyaulacacean pattern.
Paracingulum: Generally not indicated; when discernible, limits defined by equatorial terminations of parasutural features; occasionally expressed by transverse folds or thickenings of the ectophragm, undivided.
Parasulcus: Generally not indicated; posterior limit inferred from configuration of adjacent paraplates.
Size: intermediate to large, generally greater than 100 µm.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 177-178:
Synopsis:
Cysts proximochorate, elongate ellipsoidal, with short apical projection; paratabulation gonyaulacacean, indicated completely or partly by parasutural ridges or septa; archeopyle precingular, Type P.
Description:
Shape: Body elongate ellipsoidal; cyst with short apical protrusion and generally truncate antapical margin.
Wall relationships: Autophragm only, or autophragm and ectophragm.
Wall features: Parasutural ridges or septa complete or interrupted, solid to perforate; additionally, narrow longitudinal trabeculae connect the distal ends of slender projections. Parasutural features may increase in height toward the poles.
Paratabulation: Indicated completely or partly by parasutural features; gonyaulacacean, formula: 3`, 6``, 0-6c, 6```, 1p, 1````, O-ls.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six subrectangular paraplates, or not indicated.
Parasulcus: Indicated by bordering parasutural features, generally at extremities only.
Size: Intermediate to large.
Affinities:
Omatia differs from Boreocysta, to which it is similar in shape, in having parasutural ridges or septa and a precingular archeopyle. Boreocysta is cavate, lacks parasutural features, and has an apical archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Omatia Cookson and Eisenack, 1958, emend. Wiggins, 1969, emend. Stover and Helby, 1987b. Omatia differs from Herendeenia in having the two wall layers separated over most of the cyst, whereas in Herendeenia the two layers are appressed. The processes in Omatia are mainly parasutural but can also be isolated and in small groups. Herendeenia does not have processes. There is no definite archeopyle in Omatia whereas Herendeenia has a single plate 3" archeopyle. Omatia has four precingular plates and a smooth autophragm and ectophragm; Herendeenia has five or six precingular plates and an ornamented periphragm. Boreocysta has nontabular processes, generally more numerous in the polar regions and an apical archeopyle.