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Adnatosphaeridium membraniphorum
Adnatosphaeridium? membraniphorum, Jan du Chêne and Adediran, 1985
Stancliffe and Sarjeant, 1990, considered this to be a provisionally accepted species of Adnatosphaeridium.
Holotype: Jan du Chêne and Adediran, 1985, pl.20, fig.1-3
Locus typicus: Benin-Ore Highway Km 41, Nigeria
Stratum typicum: Late Palaeocene-Early Eocene
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Original description: [Jan du Chêne and Adediran, 1985, p. 10]:
Description:
Cyst skolochorate with a subspherical body bearing intratabular process complexes united distally by redundant trabeculae.
The process stacks are simple, sometimes branched, arranged as intratabular, irregularly-shaped complexes. Individual complexes are covered distally by a reticulate or perforate membrane, thus each membrane corresponds to a paraplate. In addition, each membrane is joined to the immediately adjacent membranes by narrow trabeculae.
The archeopyle is apical, type tA.
The basal part of the operculum supports four irregularly shaped process complexes which are interpreted as representing four apical paraplates. The paratabulation is indicated by the archeopyle and occasionally by accessory sutures between precingular paraplates. The distribution of the irregularly-shaped complexes of processes and the corresponding perforate membranes allow to define apical, precingular and postcingular paraplates in most of the specimens observed.
Dimensions:
Range Diameter of the central body 56-68 µm; Length of the processes 20-36 µm
Number of specimens measured: 22.
Affinities:
Without a close study of the distribution of the irregular complexes of processes, the generic attribution of this dinoflagellate species is difficult. Hemisphaeridium Bujak, 1980 (type species: Hemisphaeridium fenestratum Bujak, 1980) has an epicystal archeopyle. Glaphyrocysta Stover and Evitt, 1978, with the species G. exuberans (Deflandre and Cookson, 1955) Stover and Evitt, 1978, G. pastielsii (Deflandre and Cookson, 1955) Stover and Evitt, 1978, G. texta (Bujak, 1976) Stover and Evitt, 1978 or G. microfenestrata (Bujak, 1976) Stover and Evitt, 1978 do not have processes complexes in midventral and middorsal areas. Glaphyrocysta also has a lenticular body.
Stancliffe and Sarjeant, 1990, considered this to be a provisionally accepted species of Adnatosphaeridium.
Holotype: Jan du Chêne and Adediran, 1985, pl.20, fig.1-3
Locus typicus: Benin-Ore Highway Km 41, Nigeria
Stratum typicum: Late Palaeocene-Early Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Jan du Chêne and Adediran, 1985, p. 10]:
Description:
Cyst skolochorate with a subspherical body bearing intratabular process complexes united distally by redundant trabeculae.
The process stacks are simple, sometimes branched, arranged as intratabular, irregularly-shaped complexes. Individual complexes are covered distally by a reticulate or perforate membrane, thus each membrane corresponds to a paraplate. In addition, each membrane is joined to the immediately adjacent membranes by narrow trabeculae.
The archeopyle is apical, type tA.
The basal part of the operculum supports four irregularly shaped process complexes which are interpreted as representing four apical paraplates. The paratabulation is indicated by the archeopyle and occasionally by accessory sutures between precingular paraplates. The distribution of the irregularly-shaped complexes of processes and the corresponding perforate membranes allow to define apical, precingular and postcingular paraplates in most of the specimens observed.
Dimensions:
Range Diameter of the central body 56-68 µm; Length of the processes 20-36 µm
Number of specimens measured: 22.
Affinities:
Without a close study of the distribution of the irregular complexes of processes, the generic attribution of this dinoflagellate species is difficult. Hemisphaeridium Bujak, 1980 (type species: Hemisphaeridium fenestratum Bujak, 1980) has an epicystal archeopyle. Glaphyrocysta Stover and Evitt, 1978, with the species G. exuberans (Deflandre and Cookson, 1955) Stover and Evitt, 1978, G. pastielsii (Deflandre and Cookson, 1955) Stover and Evitt, 1978, G. texta (Bujak, 1976) Stover and Evitt, 1978 or G. microfenestrata (Bujak, 1976) Stover and Evitt, 1978 do not have processes complexes in midventral and middorsal areas. Glaphyrocysta also has a lenticular body.