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Stelladinium abei
Stelladinium abei Matsuoka, 1985a, p.59–60, pl.14, figs.7–10.
Holotype: Matsuoka, 1985a, pl.14, figs.7–10.
Age: Holocene.
Original description (Matsuoka, 1985a)
Diagnosis : Cyst with pentagonal ambitus, small to intermediate in size and brown in color. Epicyst conical with one apical horn. Hypocyst rectangular with two antapical horns. Paracingulum represented by projection of autophragrn. "Cystae proximae quae habent ambitum pentagonalem dorsoventrahter sunt parvae vel intermediae in magmtudine et brunneae in colore. Epitractum est conicale cum uno cornu apicali. Hypotractum quod habet duo cornua in antapice est rectangulare. Paracingulum repraesentatur proiectione autophragmatis. Archeopyla est intercalaris. Tabulatio abest." Holotype: Slide no. SZ la-3 (81.5!34.2), PI. 14, figs. 7-10, Sample no. SZ la, Recent sediment in Senzaki Bay, West Japan.
Dimensions of figured specimen : Length of cyst 40µm, width 44µm. Description : Cyst is peridinioid in dorso-ventral view, and carries one conspicuous apical and two symmetrical and conical antapical horns. Cyst body is compressed dors0-ventrally except for the paracingular region. Cyst wall comprises two thin layers, much adpressed autophragm with microgranular to smooth surface. Paratabulation is not indicated by any feature. Paracingulum lacks any horn-like projection and represented by projected shelf of the autophragm, transversely surrounding the cyst body. Parasulcal area is suggested by moderate indentation of the autophragm. Archeopyle is apparently trapezoidal exactly with four long and two short sides, and formed by loss of the 2a paraplate, Operculum is probably free.
Remarks : This new cyst is similar to Stelladinium stellatum Reid and S. reidii Bradford in having a pentagonal ambitus and conspicuous one apical and two antapical horns. This cyst, however, differs from the latter two in lacking distinctive horns positioned at the cingular zone and a trapezoidal hypocyst.Equivalent thecate form: The thecal affinity of this cyst has been unknown, but probably correspond with a species of the genus Protoperidinium.
Holotype: Matsuoka, 1985a, pl.14, figs.7–10.
Age: Holocene.
Original description (Matsuoka, 1985a)
Diagnosis : Cyst with pentagonal ambitus, small to intermediate in size and brown in color. Epicyst conical with one apical horn. Hypocyst rectangular with two antapical horns. Paracingulum represented by projection of autophragrn. "Cystae proximae quae habent ambitum pentagonalem dorsoventrahter sunt parvae vel intermediae in magmtudine et brunneae in colore. Epitractum est conicale cum uno cornu apicali. Hypotractum quod habet duo cornua in antapice est rectangulare. Paracingulum repraesentatur proiectione autophragmatis. Archeopyla est intercalaris. Tabulatio abest." Holotype: Slide no. SZ la-3 (81.5!34.2), PI. 14, figs. 7-10, Sample no. SZ la, Recent sediment in Senzaki Bay, West Japan.
Dimensions of figured specimen : Length of cyst 40µm, width 44µm. Description : Cyst is peridinioid in dorso-ventral view, and carries one conspicuous apical and two symmetrical and conical antapical horns. Cyst body is compressed dors0-ventrally except for the paracingular region. Cyst wall comprises two thin layers, much adpressed autophragm with microgranular to smooth surface. Paratabulation is not indicated by any feature. Paracingulum lacks any horn-like projection and represented by projected shelf of the autophragm, transversely surrounding the cyst body. Parasulcal area is suggested by moderate indentation of the autophragm. Archeopyle is apparently trapezoidal exactly with four long and two short sides, and formed by loss of the 2a paraplate, Operculum is probably free.
Remarks : This new cyst is similar to Stelladinium stellatum Reid and S. reidii Bradford in having a pentagonal ambitus and conspicuous one apical and two antapical horns. This cyst, however, differs from the latter two in lacking distinctive horns positioned at the cingular zone and a trapezoidal hypocyst.Equivalent thecate form: The thecal affinity of this cyst has been unknown, but probably correspond with a species of the genus Protoperidinium.