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Phelodinium africanum
Phelodinium africanum Biffi and Grignani, 1983
Holotype: Biffi and Grignani, 1983, pl.6, fig.4
Paratypes: 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, pentagonal in ambitus. Short apical horn sometimes well developed, broad or very reduced, truncate to slightly acuminate. Antapical horns conical, acuminate. Pericoels more or less developed, commonly restricted to antapical horns. Cyst sides convex to straight. Periphragm wrinkled. Cingulum indicated by transverse, parallel ridges. Periarcheopyle formed by loss of intercalary 2a, symmetrically situated on middorsal line.
Dimensions: Holotype: pericyst length 105 µm; breadth 104 µm. Other specimens: pericyst length 85-110 µm; breadth 80-110 µm. Number of specimens measured, 30.
Affinities:
Biffi and Grignani, 1983, p. 140: The genus Phelodinium was established by Stover and Evitt (1978) to separate the cornucavate specimens, previously placed in Lejeunia, from those forms possessing an autophragm only. Phelodinium africanum differs from P. magnificum (Stanley) Stover and Evitt,1978 in having shorter, broad antapical horns, a wrinkled periphragm, and in being more distinctly cornucavate. Some specimens of P. africanum (pl. 6, figs. 1-2) seem to be superficially similar to L. hyalina, but the constant presence of a horn pericoel (more than 50 specimens collected in the studied intervals) confirms the separation between the two species at the generic level. Phelodinium africanum differs from P. nigencum in having more developed pericoels at the antapical horns and a thin endophragm.
Holotype: Biffi and Grignani, 1983, pl.6, fig.4
Paratypes: 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, pentagonal in ambitus. Short apical horn sometimes well developed, broad or very reduced, truncate to slightly acuminate. Antapical horns conical, acuminate. Pericoels more or less developed, commonly restricted to antapical horns. Cyst sides convex to straight. Periphragm wrinkled. Cingulum indicated by transverse, parallel ridges. Periarcheopyle formed by loss of intercalary 2a, symmetrically situated on middorsal line.
Dimensions: Holotype: pericyst length 105 µm; breadth 104 µm. Other specimens: pericyst length 85-110 µm; breadth 80-110 µm. Number of specimens measured, 30.
Affinities:
Biffi and Grignani, 1983, p. 140: The genus Phelodinium was established by Stover and Evitt (1978) to separate the cornucavate specimens, previously placed in Lejeunia, from those forms possessing an autophragm only. Phelodinium africanum differs from P. magnificum (Stanley) Stover and Evitt,1978 in having shorter, broad antapical horns, a wrinkled periphragm, and in being more distinctly cornucavate. Some specimens of P. africanum (pl. 6, figs. 1-2) seem to be superficially similar to L. hyalina, but the constant presence of a horn pericoel (more than 50 specimens collected in the studied intervals) confirms the separation between the two species at the generic level. Phelodinium africanum differs from P. nigencum in having more developed pericoels at the antapical horns and a thin endophragm.