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Lacunodinium
From Williams et al., 2017:
[Lacunodinium, He Chengquan, 1984a, p. 768
Type Species: Lacunodinium foveolatum, He Chengquan, 1984a (pl.1, figs.2a–b)]
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Original description: [He Cheng-quan, 1984]: (Translation: Fensome et al., 1991, p. 311):
Diagnosis:
Proximate dinoflagellate cysts, subspherical or elliptical in shape, without apical and antapical horns. Cingulum or sulcus lacking. Cyst wall thicker, composed of appressed periphragm and endophragm. Surface foveolate.
Paratabulation indicated only by archaeopyle.
Archaeopyle precingular, Type P (3`` only); operculum free.
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Modified description:
Chen et al., 1988, p.16-17:
Synopsis:
Cysts proximate, subspherical to broadly ellipsoidal, surface pitted to microreticulate, paratabulation expressed solely by precingular type P archeopyle, operculum free.
Description:
Shape: Subspherical to broadly ellipsoidal.
Wall Relationships: Wall composed of appressed periphragm and endophragm.
Wall features: Surface finely pitted (punctate) to microreticulate.
Archeopyle: Precingular, type P, (3" only); operculum free.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus; Not indicated.
Size: Intermediate, about 70 µm long and 55 µm to 65 µm wide.
Affinities:
Lacunodinium differs from the following genera, all of which have type P (3") precingular archeopyles, in being finely pitted to microreticulate; Pyxidinopsis Habib 1976 is imperfectly reticulate, Tectatodinium Wall 1967 is thick walled and has a smooth or faintly ornamented outer surface. Cerebrocysta Bujak in Bujak et al. 1980 has interspersed short, discontinuous ridges and granules, Operculodinium Wall 1967 is spinate, Chytroeisphaeridia (Sarjeant 1962) Downie and Sarjeant 1965 emended Davey 1979 is thin walled and smooth or scabrate, and Filisphaera Bujak 1984 has a periphragm composed of radiating fibers.
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GSC: (provisional translation: courtesy R. Fensome):
In this genus, the shell wall is 3 to 4 µm thick and foveal ornamentation is fairly close, resulting in a somewhat finely reticulate appearance. In its finely foveate surface, the new genus differs from Pyxidinopsis (rugose to incompletely reticulate), Tectatodinium (smooth or with indistinct decoration), Cerebrocysta (rugose), Operculodinium (spinate), Tapeinosphaeridium (thin-walled, smooth or granulate). In its surface decoration and lack of cingulum, it also differs from Ellipsodinium.
[Lacunodinium, He Chengquan, 1984a, p. 768
Type Species: Lacunodinium foveolatum, He Chengquan, 1984a (pl.1, figs.2a–b)]
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Original description: [He Cheng-quan, 1984]: (Translation: Fensome et al., 1991, p. 311):
Diagnosis:
Proximate dinoflagellate cysts, subspherical or elliptical in shape, without apical and antapical horns. Cingulum or sulcus lacking. Cyst wall thicker, composed of appressed periphragm and endophragm. Surface foveolate.
Paratabulation indicated only by archaeopyle.
Archaeopyle precingular, Type P (3`` only); operculum free.
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Modified description:
Chen et al., 1988, p.16-17:
Synopsis:
Cysts proximate, subspherical to broadly ellipsoidal, surface pitted to microreticulate, paratabulation expressed solely by precingular type P archeopyle, operculum free.
Description:
Shape: Subspherical to broadly ellipsoidal.
Wall Relationships: Wall composed of appressed periphragm and endophragm.
Wall features: Surface finely pitted (punctate) to microreticulate.
Archeopyle: Precingular, type P, (3" only); operculum free.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus; Not indicated.
Size: Intermediate, about 70 µm long and 55 µm to 65 µm wide.
Affinities:
Lacunodinium differs from the following genera, all of which have type P (3") precingular archeopyles, in being finely pitted to microreticulate; Pyxidinopsis Habib 1976 is imperfectly reticulate, Tectatodinium Wall 1967 is thick walled and has a smooth or faintly ornamented outer surface. Cerebrocysta Bujak in Bujak et al. 1980 has interspersed short, discontinuous ridges and granules, Operculodinium Wall 1967 is spinate, Chytroeisphaeridia (Sarjeant 1962) Downie and Sarjeant 1965 emended Davey 1979 is thin walled and smooth or scabrate, and Filisphaera Bujak 1984 has a periphragm composed of radiating fibers.
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GSC: (provisional translation: courtesy R. Fensome):
In this genus, the shell wall is 3 to 4 µm thick and foveal ornamentation is fairly close, resulting in a somewhat finely reticulate appearance. In its finely foveate surface, the new genus differs from Pyxidinopsis (rugose to incompletely reticulate), Tectatodinium (smooth or with indistinct decoration), Cerebrocysta (rugose), Operculodinium (spinate), Tapeinosphaeridium (thin-walled, smooth or granulate). In its surface decoration and lack of cingulum, it also differs from Ellipsodinium.