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Cepadinium
From Williams et al., 2017:
[Cepadinium, Duxbury, 1983, p. 58;
Type species: Cepadinium variabile, Duxbury, 1983 (pl.9, fig.8; text-figs.27A–E)]
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Original description: [Duxbury, 1983]:
Diagnosis:
Proximo-cavate, peridiniacean dinoflagellate cysts which are dorsoventrally flattened with a slight ventral concavity. Three horns are usually present, consisting of one apical, one well-developed left-antapical and one reduced right-antapical. Three or four body layers are usually present, in which case an ornament of granules and/or coni may be present on the second layer in. As few as two layers may be seen and in this case, the granules and/or coni are present on the external surface. A laevo-rotatory paracingulum is present, and, laterally, a paracingular notch may be observed which becomes increasingly pronounced with an increasing number of body layers.
The archeopyle is of a 3A(2`-4`)3I type and the operculum usually remains attached ventrally.
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Modified description:
Stover and Williams, 1987, p. 53:
Synopsis:
Cysts proximate, compressed dorso-ventrally, peridinioid in shape with an apical horn and one or two antapical horns; cysts cavate, with two, three or four(?) wall layers; archeopyle combined apical and intercalary, type [3A31]@, operculum usually remains attached ventrally.
Description:
Shape: Compressed peridinioid with an apical horn and one or two antapical horns; right antapical horn may be reduced or absent.
Wall relationships: Cavate, with two, three, or four(?) wall layers; cavation varies from cornucavate to circumcavate depending on which wall layers are involved.
Wall features: Granules and/or cones on periphragm on two-layered cysts, on mesophragm on three-layered cysts, or on the second wall layer from the outside on supposedly fourlayered cysts.
Archeopyle: Combined apical and intercalary, type [3A31]@; operculum usually remains attached ventrally; single opercular piece evidently contains paraplates 2`-4` and 1 a-3a.
Paratabulation: Indicated by archeopyle margin and by the paracingulum.
Paracingulum: Indicated by subparallel, transverse folds and by indentations at the lateral equatorial margins.
Parasulcus: Possibly indicated by a ventral depression.
Size: Small to intermediate, length about 45 μm to 85μm.
Affinities:
Cepadinium differs from Ascodinium Cookson and Eisenack 1960a emended Helenes 1983 in having three of the four apical paraplates involved in archeopyle formation (paraplate 1` remains with the rest of the cyst), whereas in Ascodinium, all four apical paraplates are part of the free operculum.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cepadinium Duxbury, 1983, has one apical, one left antapical and one reduced right antapical horn. There are three to four body layers.
[Cepadinium, Duxbury, 1983, p. 58;
Type species: Cepadinium variabile, Duxbury, 1983 (pl.9, fig.8; text-figs.27A–E)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Duxbury, 1983]:
Diagnosis:
Proximo-cavate, peridiniacean dinoflagellate cysts which are dorsoventrally flattened with a slight ventral concavity. Three horns are usually present, consisting of one apical, one well-developed left-antapical and one reduced right-antapical. Three or four body layers are usually present, in which case an ornament of granules and/or coni may be present on the second layer in. As few as two layers may be seen and in this case, the granules and/or coni are present on the external surface. A laevo-rotatory paracingulum is present, and, laterally, a paracingular notch may be observed which becomes increasingly pronounced with an increasing number of body layers.
The archeopyle is of a 3A(2`-4`)3I type and the operculum usually remains attached ventrally.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 53:
Synopsis:
Cysts proximate, compressed dorso-ventrally, peridinioid in shape with an apical horn and one or two antapical horns; cysts cavate, with two, three or four(?) wall layers; archeopyle combined apical and intercalary, type [3A31]@, operculum usually remains attached ventrally.
Description:
Shape: Compressed peridinioid with an apical horn and one or two antapical horns; right antapical horn may be reduced or absent.
Wall relationships: Cavate, with two, three, or four(?) wall layers; cavation varies from cornucavate to circumcavate depending on which wall layers are involved.
Wall features: Granules and/or cones on periphragm on two-layered cysts, on mesophragm on three-layered cysts, or on the second wall layer from the outside on supposedly fourlayered cysts.
Archeopyle: Combined apical and intercalary, type [3A31]@; operculum usually remains attached ventrally; single opercular piece evidently contains paraplates 2`-4` and 1 a-3a.
Paratabulation: Indicated by archeopyle margin and by the paracingulum.
Paracingulum: Indicated by subparallel, transverse folds and by indentations at the lateral equatorial margins.
Parasulcus: Possibly indicated by a ventral depression.
Size: Small to intermediate, length about 45 μm to 85μm.
Affinities:
Cepadinium differs from Ascodinium Cookson and Eisenack 1960a emended Helenes 1983 in having three of the four apical paraplates involved in archeopyle formation (paraplate 1` remains with the rest of the cyst), whereas in Ascodinium, all four apical paraplates are part of the free operculum.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cepadinium Duxbury, 1983, has one apical, one left antapical and one reduced right antapical horn. There are three to four body layers.