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Epelidosphaeridia
From Fensome et al., 2019:
Epelidosphaeridia, Davey, 1969a, p.142.
Emendation: Nøhr-Hansen et al., 2017, p.368.
Type: Cookson and Hughes, 1964, pl.8, fig.8, as Epelidosphaeridia spinosa.
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Original description: [Davey, 1969]:
Diagnosis:
Shell subpolygonal; epitract conical with small apical protuberance, hypotract polygonal with small antapical horn on one side. Shell wall two layered, periphragm giving rise to a moderate number of spines, truncated or forked distally. Cingulum and sulcus outlined by spines. Cingulum slightly laevo-rotatory. Apical archeopyle.
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Modified description:
Stover and Evitt 1978, p. 46:
Synopsis:
Cysts proximochorate, lenticular to compressed peridinioid; autophragm spinose, paratabulation indicated mainly by paracingulum; archeopyle apical, type uncertain.
Description:
Shape: Lenticular to compressed peridinioid, in the latter case with a short apical horn and two antapical horns, of which one may be reduced or absent.
Wall relationships: Autophragm only.
Wall features: Parasutural features virtually lacking except along margins of paracingulum and parasulcus. Periphragm sparsely to densely spinose.
Paratabulation: Generally not expressed, formula unknown. Grouping or alignment of processes suggests that it may be possible to decipher
the paratabulation.
Archeopyle: Apical, type uncertain; margin in dorsal-ventral view gently curved to nearly straight and may have a wide, generally shallow cutout in middorsal area, which may be deeper on one side than the other. Presence of cutout suggests intercalary paraplates may be involved also in archeopyle formation; operculum free.
Paracingulum: Vaguely to clearly indicated by transverse alignment of spines.
Parasulcus: Indicated as a slightly depressed area almost devoid of spines.
Size: Small to intermediate
Affinities:
Epelidosphaeridia differs from Spinidinium in having an apical rather than an intercalary archeopyle. Although the exact type of archeopyle on Epelidosphaeridia is unknown, it is assuredly in the apical area. The unanswered question is whether apical paraplates alone or apical and intercalary paraplates together form the archeopyle.
Epelidosphaeridia, Davey, 1969a, p.142.
Emendation: Nøhr-Hansen et al., 2017, p.368.
Type: Cookson and Hughes, 1964, pl.8, fig.8, as Epelidosphaeridia spinosa.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Davey, 1969]:
Diagnosis:
Shell subpolygonal; epitract conical with small apical protuberance, hypotract polygonal with small antapical horn on one side. Shell wall two layered, periphragm giving rise to a moderate number of spines, truncated or forked distally. Cingulum and sulcus outlined by spines. Cingulum slightly laevo-rotatory. Apical archeopyle.
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Modified description:
Stover and Evitt 1978, p. 46:
Synopsis:
Cysts proximochorate, lenticular to compressed peridinioid; autophragm spinose, paratabulation indicated mainly by paracingulum; archeopyle apical, type uncertain.
Description:
Shape: Lenticular to compressed peridinioid, in the latter case with a short apical horn and two antapical horns, of which one may be reduced or absent.
Wall relationships: Autophragm only.
Wall features: Parasutural features virtually lacking except along margins of paracingulum and parasulcus. Periphragm sparsely to densely spinose.
Paratabulation: Generally not expressed, formula unknown. Grouping or alignment of processes suggests that it may be possible to decipher
the paratabulation.
Archeopyle: Apical, type uncertain; margin in dorsal-ventral view gently curved to nearly straight and may have a wide, generally shallow cutout in middorsal area, which may be deeper on one side than the other. Presence of cutout suggests intercalary paraplates may be involved also in archeopyle formation; operculum free.
Paracingulum: Vaguely to clearly indicated by transverse alignment of spines.
Parasulcus: Indicated as a slightly depressed area almost devoid of spines.
Size: Small to intermediate
Affinities:
Epelidosphaeridia differs from Spinidinium in having an apical rather than an intercalary archeopyle. Although the exact type of archeopyle on Epelidosphaeridia is unknown, it is assuredly in the apical area. The unanswered question is whether apical paraplates alone or apical and intercalary paraplates together form the archeopyle.