Back
Lejeunecysta beninensis
Lejeunecysta beninensis Biffi and Grignani, 1983
Holotype: Biffi and Grignani, 1983, pl.2, fig.5
Paratypes: Biffi and Grignani, 1983
Locus typicus: Niger Delta, Nigeria
Stratum typicum: Oligocene
Original diagnosis: Biffi and Grignani, 1983, p. 128
Autocyst proximate, peridinioid, compressed dorsoventrally with a pentagonal ambitus. Conical epicyst smaller than hypocyst. Apex rounded. Hypocyst trapezoidal, with two short, conical antapical horns, sometimes ending in a sharp, solid spine. Antapical horns either divergent or convergent. Antapical depression varying from shallow to nonexistent. Autophragm laevigate. Paracingulum continuous, marked by straight transverse folds. Parasulcus not evident. Hexa archeopyle formed by loss of intercalary 2a, symmetrically situated on middorsal line, extending almost to paracingulum.
Dimensions: Holotype: autocyst length 61 Ám, breadth 58 Ám. Other specimens: autocyst length 50-70 Ám, breadth 50-65 Ám. Number of specimens measured, 15.
Affinities:
Biffi and Grignani, 1983, p. 129: Lejeunecysta beninensis differs from L. diversiforma in having the epicyst typically smaller than the hypocyst (the epicyst length is generally onethird of the hypocyst length) and having the antapical horns always very short, conical and sometimes ending in a sharp, solid spine. Morphologically, L. beninensis is close to L. sp. A Bradford, 1977 (his fig. 4, no. 8). However, detailed comparison is practically impossible, because Bradford (1977) described only one specimen. The main difference is the absence in L. beninensis of an auxiliary archeopyle in the hypocyst, termed an opisthopyle by Sarjeant (1974).
Holotype: Biffi and Grignani, 1983, pl.2, fig.5
Paratypes: Biffi and Grignani, 1983
Locus typicus: Niger Delta, Nigeria
Stratum typicum: Oligocene
Original diagnosis: Biffi and Grignani, 1983, p. 128
Autocyst proximate, peridinioid, compressed dorsoventrally with a pentagonal ambitus. Conical epicyst smaller than hypocyst. Apex rounded. Hypocyst trapezoidal, with two short, conical antapical horns, sometimes ending in a sharp, solid spine. Antapical horns either divergent or convergent. Antapical depression varying from shallow to nonexistent. Autophragm laevigate. Paracingulum continuous, marked by straight transverse folds. Parasulcus not evident. Hexa archeopyle formed by loss of intercalary 2a, symmetrically situated on middorsal line, extending almost to paracingulum.
Dimensions: Holotype: autocyst length 61 Ám, breadth 58 Ám. Other specimens: autocyst length 50-70 Ám, breadth 50-65 Ám. Number of specimens measured, 15.
Affinities:
Biffi and Grignani, 1983, p. 129: Lejeunecysta beninensis differs from L. diversiforma in having the epicyst typically smaller than the hypocyst (the epicyst length is generally onethird of the hypocyst length) and having the antapical horns always very short, conical and sometimes ending in a sharp, solid spine. Morphologically, L. beninensis is close to L. sp. A Bradford, 1977 (his fig. 4, no. 8). However, detailed comparison is practically impossible, because Bradford (1977) described only one specimen. The main difference is the absence in L. beninensis of an auxiliary archeopyle in the hypocyst, termed an opisthopyle by Sarjeant (1974).