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Catastomocystis
From Williams et al., 2017:
[Catastomocystis, Singh, 1983, p. 151
Type species: Catastomocystis spinosa, Singh, 1983 (pl.55, figs.1–2)]
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Original description: [Singh, 1983]:
Description:
Proximate to proximochorate, camocavate dinoflagellate cysts with subpentagonal to ellipsoidal outline; apex rounded to somewhat angular,
without an apical horn; antapex truncated; pericyst with a large, oval, antapical pericoelar opening (opisthopyle); endocyst ellipsoidal to spherical;
periphragm and endophragm dorsally appressed and widely separated elsewhere; paratabulation partially outlined on the pericyst by vestigial gonal and intergonal processes devoid of stalks and represented only by their distal spines and by discontinuous parasutural crests or by low parasutural crests only; paratabulation gonyaulacacean, incompletely expressed in varying degree of clarity, possible formula: 3-4`, 6", 6c, 5-6```,1````; paracingulum delineated by parallel, transverse, equatorial ridges, and subdivided into rectangular paraplates; archeopyle precingular, type P (3" only); operculum
free.
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Modified description:
Stover ans Williams, 1987, p. 51:
Synopsis:
Cysts proximate, camocavate; endocyst spherical to ellipsoidal, pericyst more or less ellipsoidal, outline modified by truncated antapical margin where a large pericoelar opening is formed; endophragm and periphragm appressed dorsally, separated elsewhere; periphragm (as seen in dorsal-ventral view) with short essentially peripheral spines, or with discontinuous parasutural ridges, or with both; paratabulation incompletely expressed, possible formula: 3-4`, 6", 6c, 5-6```, 1````; archeopyle precingular, type P, 3" only.
Description:
Shape: Pericyst more or less ellipsoidal; outline may be modified by a nearly straight (truncated) antapical margin.
Wall relationships: Cysts camocavate, somewhat ellipsoidal periphragm appressed to ellipsoidal endophragm dorsally, separated elsewhere.
Wall features: Periphragm, as seen in dorsal-ventral view, with short spines along or near the periphery, or with discontinuous parasutural crests, or with both (see comment below); a large opening occurs in the antapical margin of the hypopericyst.
Archeopyle: Precingular, type P, 3" only; operculum free.
Paratabulation: Expressed incompletely by ornamentation and parasutural features; possible formula: 3-4`, 6", 6c, 5-6```,1````.
Paracingulum: Delineated by six subrectangular paraplates.
Parasulcus: Not indicated.
Size: Small to intermediate, about 45 to 70 μm in overall length.
Affinities:
Catastomocystis differs from Hystrichostrogylon Agelopoulos 1964 emended Stover and Evitt 1978 in having an antapical opening in the pericoel and in lacking Spiniferites-type processes. Thalassiphora Eisenack and Gocht 1960 emended Benedek and Gocht 1981, in which the endophragm and periphragm are appressed dorsally, has a large ventral opening rather than an antapical opening and lacks short periphragmal projections. Separation of the two wall layers in Stephodinium Deflandre 1936a emended Davey 1970 is confined to the dorsal precingular and cingular areas.
[Catastomocystis, Singh, 1983, p. 151
Type species: Catastomocystis spinosa, Singh, 1983 (pl.55, figs.1–2)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Singh, 1983]:
Description:
Proximate to proximochorate, camocavate dinoflagellate cysts with subpentagonal to ellipsoidal outline; apex rounded to somewhat angular,
without an apical horn; antapex truncated; pericyst with a large, oval, antapical pericoelar opening (opisthopyle); endocyst ellipsoidal to spherical;
periphragm and endophragm dorsally appressed and widely separated elsewhere; paratabulation partially outlined on the pericyst by vestigial gonal and intergonal processes devoid of stalks and represented only by their distal spines and by discontinuous parasutural crests or by low parasutural crests only; paratabulation gonyaulacacean, incompletely expressed in varying degree of clarity, possible formula: 3-4`, 6", 6c, 5-6```,1````; paracingulum delineated by parallel, transverse, equatorial ridges, and subdivided into rectangular paraplates; archeopyle precingular, type P (3" only); operculum
free.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover ans Williams, 1987, p. 51:
Synopsis:
Cysts proximate, camocavate; endocyst spherical to ellipsoidal, pericyst more or less ellipsoidal, outline modified by truncated antapical margin where a large pericoelar opening is formed; endophragm and periphragm appressed dorsally, separated elsewhere; periphragm (as seen in dorsal-ventral view) with short essentially peripheral spines, or with discontinuous parasutural ridges, or with both; paratabulation incompletely expressed, possible formula: 3-4`, 6", 6c, 5-6```, 1````; archeopyle precingular, type P, 3" only.
Description:
Shape: Pericyst more or less ellipsoidal; outline may be modified by a nearly straight (truncated) antapical margin.
Wall relationships: Cysts camocavate, somewhat ellipsoidal periphragm appressed to ellipsoidal endophragm dorsally, separated elsewhere.
Wall features: Periphragm, as seen in dorsal-ventral view, with short spines along or near the periphery, or with discontinuous parasutural crests, or with both (see comment below); a large opening occurs in the antapical margin of the hypopericyst.
Archeopyle: Precingular, type P, 3" only; operculum free.
Paratabulation: Expressed incompletely by ornamentation and parasutural features; possible formula: 3-4`, 6", 6c, 5-6```,1````.
Paracingulum: Delineated by six subrectangular paraplates.
Parasulcus: Not indicated.
Size: Small to intermediate, about 45 to 70 μm in overall length.
Affinities:
Catastomocystis differs from Hystrichostrogylon Agelopoulos 1964 emended Stover and Evitt 1978 in having an antapical opening in the pericoel and in lacking Spiniferites-type processes. Thalassiphora Eisenack and Gocht 1960 emended Benedek and Gocht 1981, in which the endophragm and periphragm are appressed dorsally, has a large ventral opening rather than an antapical opening and lacks short periphragmal projections. Separation of the two wall layers in Stephodinium Deflandre 1936a emended Davey 1970 is confined to the dorsal precingular and cingular areas.