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Lophocysta
From Williams et al., 2017:
[Lophocysta, Manum, 1979, p. 238
Type species: Lophocysta sulcolimbata, Manum, 1979 (pl.1, figs.4–6; text-figs.1A–B)]
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Original description: [Manum, 1979]:
Description:
Dinoflagellate cysts with apparent gonyaulacacean paratabulation; archeopyle pentagonal, precingular. Prominent periphragm expansion restricted to midventral area and with ribs indicating paratabulation. Dorsal face with inconspicuous processes in gonal positions.
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Modified description:
Stover and Williams, 1987, p. 151:
Synopsis:
Cysts camocavate, endocyst subspherical to ellipsoidal; periphragm appressed to endocyst dorsally, widely separated ventrally to form a sac-like structure, paratabulation gonyaulacacean, indicated dorsally by gonal projections and elsewhere by parasutural ribs on the periphragm; archeopyle precingular, type P, operculum free.
Description:
Shape: Endocyst subspherical to ellipsoidal; periphragm forms ventral, sac-like extension.
Wall relationships: Cysts camocavate; periphragm appressed to endophragm dorsally, separated elsewhere, amount of separation greatest ventrally.
Wall features: Endophragm smooth; periphragm smooth dorsally or with scattered gonal projections, elsewhere the periphragm is finely ornamented and has low, parasutural ridges (ribs). Consistent ventrally located openings may occur in the periphragm.
Archeopyle: Precingular, type P (3" only); operculum free.
Paratabulation: Indicated dorsally by gonal projections and the archeopyle, elsewhere by parasutural ridges; gonyaulacacean, formula: 4`, 6", 6c,
6```, 1 p, 1````, 6s.
Paracingulum: Paraplates 1c-5c indicated by gonal projections, paraplate 6c by parasutural ridges.
Parasulcus: Paraplates indicated by parasutural ridges.
Size: Small to intermediate; overall length about 45 to 75 µm.
Affinities:
Hystrichostrogylon Agelopoulos 1964 emended Stover and Evitt 1978 is constructed similarly to Lophocysta, but possesses processes of the Spiniferites-type. On Thalassiphora Eisenack and Gocht 1960 emended Benedek and Gocht 1981, the dorsal area of the periphragm-endophragm contact is considerably less than that in Lophocysta; the latter genus also lacks a ventral opening, that is present on Thalassiphora. In Amiculosphaera Harland 1979b, the periphragm is appressed to the endocyst in the antapical area only and the genus
has a funnel-shaped apical structure.
[Lophocysta, Manum, 1979, p. 238
Type species: Lophocysta sulcolimbata, Manum, 1979 (pl.1, figs.4–6; text-figs.1A–B)]
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Original description: [Manum, 1979]:
Description:
Dinoflagellate cysts with apparent gonyaulacacean paratabulation; archeopyle pentagonal, precingular. Prominent periphragm expansion restricted to midventral area and with ribs indicating paratabulation. Dorsal face with inconspicuous processes in gonal positions.
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Modified description:
Stover and Williams, 1987, p. 151:
Synopsis:
Cysts camocavate, endocyst subspherical to ellipsoidal; periphragm appressed to endocyst dorsally, widely separated ventrally to form a sac-like structure, paratabulation gonyaulacacean, indicated dorsally by gonal projections and elsewhere by parasutural ribs on the periphragm; archeopyle precingular, type P, operculum free.
Description:
Shape: Endocyst subspherical to ellipsoidal; periphragm forms ventral, sac-like extension.
Wall relationships: Cysts camocavate; periphragm appressed to endophragm dorsally, separated elsewhere, amount of separation greatest ventrally.
Wall features: Endophragm smooth; periphragm smooth dorsally or with scattered gonal projections, elsewhere the periphragm is finely ornamented and has low, parasutural ridges (ribs). Consistent ventrally located openings may occur in the periphragm.
Archeopyle: Precingular, type P (3" only); operculum free.
Paratabulation: Indicated dorsally by gonal projections and the archeopyle, elsewhere by parasutural ridges; gonyaulacacean, formula: 4`, 6", 6c,
6```, 1 p, 1````, 6s.
Paracingulum: Paraplates 1c-5c indicated by gonal projections, paraplate 6c by parasutural ridges.
Parasulcus: Paraplates indicated by parasutural ridges.
Size: Small to intermediate; overall length about 45 to 75 µm.
Affinities:
Hystrichostrogylon Agelopoulos 1964 emended Stover and Evitt 1978 is constructed similarly to Lophocysta, but possesses processes of the Spiniferites-type. On Thalassiphora Eisenack and Gocht 1960 emended Benedek and Gocht 1981, the dorsal area of the periphragm-endophragm contact is considerably less than that in Lophocysta; the latter genus also lacks a ventral opening, that is present on Thalassiphora. In Amiculosphaera Harland 1979b, the periphragm is appressed to the endocyst in the antapical area only and the genus
has a funnel-shaped apical structure.