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Vallodinium nigeriaense
Vallodinium nigeriaense (Jan du Chêne and Adediran, 1985, p.31,33, pl.7, figs.1–6; pl.8, figs.1–6; pl.9, figs.1–5) Williams et al., 2015, p.316.
Originally Wilsonidium, subsequently (and now) Vallodinium.
Holotype: Jan du Chêne and Adediran, 1985, pl.9, figs.1-2
Locus typicus: Benin-Ore Highway, Km 41, Nigeria
Stratum typicum: Late Palaeocene-Early Eocene
Original description: Jan du Chêne and Adediran, 1985, p. 31
Pentagonal, comucavate cyst with one apical, two lateral and two antapical horns, which all are well developed. The two lateral horns and the two antapical horns are symmetrically located and generally equal in length, the left antapical being sometimes slightly longer. The endocyst is generally circular to pentagonal with broadly rounded angles. The surface of the periphragm is ornamented by parasutural ridges supporting numerous short processes typically distally unified by a undulose fringe. These ridges and processes define a Peridiniacean-type paratabulation of 4", 3a, 7", xc, 5""", 2"""", ps. Intratabular ornamentation is generally absent, but a few dispersed granulae or verrucae may occur on some specimens. The trapezoidal archeopyle corresponds to the 2a paraplate. The operculum is free. The parasulcus is easily observable. Boundaries of the sulcal paraplates are suggested (in some specimens) by isolated processes. The lower ridges of the paracingulum is generally better defined than the upper ridge.
Dimensions: Range Length of the pericyst including apical and antapical horns 123-90 µm. Width of the pericyst including lateral horns 110-93 µm. Diameter of the endocyst 78-58 µm x 75-63 µm. Length of the apical horn 20-15 µm. Length of the lateral horns 20-13 µm. Length of the antapical horns 23-20 µm. Height of the processes including parasutural ridges and undulose fringe up to 8 µm. Number of specimens measured: 23.
Affinities:
Jan du Chêne and Adediran, 1985, p. 31: Wilsonidium nigeriaense differs from other Wilsonidium species by having distally interconnected parasutural processes (text-fig. 10). In Wilsonidium echinosuturatum the peritabular processes are not connected distally and the horns are much shorter. Consequently the cyst has a more rounded pentagonal outline. Wilsonidium ornatum is much bigger than Wilsonidium nigeriaense.
Originally Wilsonidium, subsequently (and now) Vallodinium.
Holotype: Jan du Chêne and Adediran, 1985, pl.9, figs.1-2
Locus typicus: Benin-Ore Highway, Km 41, Nigeria
Stratum typicum: Late Palaeocene-Early Eocene
Original description: Jan du Chêne and Adediran, 1985, p. 31
Pentagonal, comucavate cyst with one apical, two lateral and two antapical horns, which all are well developed. The two lateral horns and the two antapical horns are symmetrically located and generally equal in length, the left antapical being sometimes slightly longer. The endocyst is generally circular to pentagonal with broadly rounded angles. The surface of the periphragm is ornamented by parasutural ridges supporting numerous short processes typically distally unified by a undulose fringe. These ridges and processes define a Peridiniacean-type paratabulation of 4", 3a, 7", xc, 5""", 2"""", ps. Intratabular ornamentation is generally absent, but a few dispersed granulae or verrucae may occur on some specimens. The trapezoidal archeopyle corresponds to the 2a paraplate. The operculum is free. The parasulcus is easily observable. Boundaries of the sulcal paraplates are suggested (in some specimens) by isolated processes. The lower ridges of the paracingulum is generally better defined than the upper ridge.
Dimensions: Range Length of the pericyst including apical and antapical horns 123-90 µm. Width of the pericyst including lateral horns 110-93 µm. Diameter of the endocyst 78-58 µm x 75-63 µm. Length of the apical horn 20-15 µm. Length of the lateral horns 20-13 µm. Length of the antapical horns 23-20 µm. Height of the processes including parasutural ridges and undulose fringe up to 8 µm. Number of specimens measured: 23.
Affinities:
Jan du Chêne and Adediran, 1985, p. 31: Wilsonidium nigeriaense differs from other Wilsonidium species by having distally interconnected parasutural processes (text-fig. 10). In Wilsonidium echinosuturatum the peritabular processes are not connected distally and the horns are much shorter. Consequently the cyst has a more rounded pentagonal outline. Wilsonidium ornatum is much bigger than Wilsonidium nigeriaense.