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Phelodinium nigericum
Phelodinium nigericum Biffi and Grignani, 1983
Holotype: Biffi and Grignani, 1983, pl.3, fig.3
Paratype: Biffi and Grignani, 1983
Locus typicus: Niger Delta, Nigeria
Stratum typicum: Oligocene
Original diagnosis: Biffi and Grignani, 1983, p. 140
Pericyst proximate, cornucavate, peridinioid, compressed dorsoventrally with pentagonal ambitus. Length and breadth of cyst approximately equal. Apical horn short, truncated. Antapical horns well separated, short, pointed. Antapical depression not prominent. Cyst flanks straight to slightly concave or convex. Endocyst wall thick (2-3 µm). Periphragm very thin; pericoels evident usually at level of antapical horns, but sometimes visible on cyst flanks (pl. 3, fig. 3). Periphragm laevigate and endophragm laevigate to slightly chagrinate. Pericingulum delimited by transverse ridges or folds, appearing generally straight and slightly excavate. Periarcheopyle formed by loss of intercalary 2a. Endoarcheopyle more evident than periarcheopyle due to thin periphragm.
Dimensions: Holotype: pericyst length 115 µm, breadth 114 µm. Other specimens: pericyst length 95-120 µm, breadth 90-115 µm. Number of specimens measured, 10.
Affinities:
Biffi and Grignani, 1983, p. 140: Phelodinium nigericum differs from P. africanum in having less developed pericoels at the antapical horns, which are more acuminate. Also, the species has a different stratigraphic range.
Holotype: Biffi and Grignani, 1983, pl.3, fig.3
Paratype: Biffi and Grignani, 1983
Locus typicus: Niger Delta, Nigeria
Stratum typicum: Oligocene
Original diagnosis: Biffi and Grignani, 1983, p. 140
Pericyst proximate, cornucavate, peridinioid, compressed dorsoventrally with pentagonal ambitus. Length and breadth of cyst approximately equal. Apical horn short, truncated. Antapical horns well separated, short, pointed. Antapical depression not prominent. Cyst flanks straight to slightly concave or convex. Endocyst wall thick (2-3 µm). Periphragm very thin; pericoels evident usually at level of antapical horns, but sometimes visible on cyst flanks (pl. 3, fig. 3). Periphragm laevigate and endophragm laevigate to slightly chagrinate. Pericingulum delimited by transverse ridges or folds, appearing generally straight and slightly excavate. Periarcheopyle formed by loss of intercalary 2a. Endoarcheopyle more evident than periarcheopyle due to thin periphragm.
Dimensions: Holotype: pericyst length 115 µm, breadth 114 µm. Other specimens: pericyst length 95-120 µm, breadth 90-115 µm. Number of specimens measured, 10.
Affinities:
Biffi and Grignani, 1983, p. 140: Phelodinium nigericum differs from P. africanum in having less developed pericoels at the antapical horns, which are more acuminate. Also, the species has a different stratigraphic range.