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Pervosphaeridium
From Williams et al., 2017:
[Pervosphaeridium, Yun Hyesu, 1981, p. 26-27
Type species: originally as Hystrichosphaeridium pseudhystrichodinium, Deflandre, 1937b (pl.15 (al. pl.12), fig.3)] ; Pervosphaeridium pseudohystrichodinium, Yun, 1981
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Original description: [Yun, 1981]: (Translation: Stover and Williams, 1987, p. 176):
Diagnosis:
Chorate cysts possessing a two-walled, circular to elliptical central body with numerous, hollow, more or less similarly constructed processes and a 2P archaeopyle. Operculum released as two separated pieces. Processes are mostly simple and acuminate. More than 3 spines occur on a paraplate. The apical and antapical spines often prominently developed.
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Modified description:
Stover and Williams 1987, p. 175-176:
Synopsis:
Cysts skolochorate, body subspherical to ellipsoidal with numerous nontabular, hollow processes with mostly simple, acuminate tips; either an apical or an antapical process, or both, may be wider than the others; archeopyle precingular, type 2P, opercular pieces free.
Description:
Shape: Body subspherical to ellipsoidal.
Wall relationships: Two wall layers evidently appressed except where processes are formed, although individual layers are not apparent on illustrated specimens.
Wall features: Nontabular processes hollow and usually with simple, acuminate tips; some processes with branched tips; an apical and/or an antapical process, or both, may be wider than the others. Cyst body perforate, granulate, striate, ribbed or with small folds; striae, ribs, or folds may extend radially from the processes and connect them proximally.
Archaeopyle: Precingular, type 2P; opercular pieces free; see Comment.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large, overall diameter about 75-135 µm
Remark:
Yun (1981) neglected to state which two precingular paraplates are involved in archaeopyle formation. We suspect that they are 3`` and 4``. However, we cannot be certain because Yun failed to indicate the views or focus levels of his illustrations.
Affinities:
According to Yun (1981, p. 27) Pervosphaeridium differs from Exochosphaeridium Davey et al. 1966 in having a 2P archeopyle rather than a P archeopyle. In contrast to Kiokansium Stover and Evitt 1978 emend. Duxbury 1983, Pervosphaeridium has a two-layered central body, hollow processes, and the polar process(es) may be wider than the others.
[Pervosphaeridium, Yun Hyesu, 1981, p. 26-27
Type species: originally as Hystrichosphaeridium pseudhystrichodinium, Deflandre, 1937b (pl.15 (al. pl.12), fig.3)] ; Pervosphaeridium pseudohystrichodinium, Yun, 1981
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Yun, 1981]: (Translation: Stover and Williams, 1987, p. 176):
Diagnosis:
Chorate cysts possessing a two-walled, circular to elliptical central body with numerous, hollow, more or less similarly constructed processes and a 2P archaeopyle. Operculum released as two separated pieces. Processes are mostly simple and acuminate. More than 3 spines occur on a paraplate. The apical and antapical spines often prominently developed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams 1987, p. 175-176:
Synopsis:
Cysts skolochorate, body subspherical to ellipsoidal with numerous nontabular, hollow processes with mostly simple, acuminate tips; either an apical or an antapical process, or both, may be wider than the others; archeopyle precingular, type 2P, opercular pieces free.
Description:
Shape: Body subspherical to ellipsoidal.
Wall relationships: Two wall layers evidently appressed except where processes are formed, although individual layers are not apparent on illustrated specimens.
Wall features: Nontabular processes hollow and usually with simple, acuminate tips; some processes with branched tips; an apical and/or an antapical process, or both, may be wider than the others. Cyst body perforate, granulate, striate, ribbed or with small folds; striae, ribs, or folds may extend radially from the processes and connect them proximally.
Archaeopyle: Precingular, type 2P; opercular pieces free; see Comment.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large, overall diameter about 75-135 µm
Remark:
Yun (1981) neglected to state which two precingular paraplates are involved in archaeopyle formation. We suspect that they are 3`` and 4``. However, we cannot be certain because Yun failed to indicate the views or focus levels of his illustrations.
Affinities:
According to Yun (1981, p. 27) Pervosphaeridium differs from Exochosphaeridium Davey et al. 1966 in having a 2P archeopyle rather than a P archeopyle. In contrast to Kiokansium Stover and Evitt 1978 emend. Duxbury 1983, Pervosphaeridium has a two-layered central body, hollow processes, and the polar process(es) may be wider than the others.