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Sentusidinium separatum
Sentusidinium separatum (McIntyre and Brideaux, 1980) Lentin and Williams, 1981
Originally Cleistosphaeridium, subsequently (and now) Sentusidinium.
Holotype: McIntyre and Brideaux, 1980, pl.6, figs.4-5
Taxonomic junior synonym: Sentusidinium cuculliforme, according to Courtinat in Fauconnier and Masure (2004, p.486).
Locus typicus: District of Mackenzie, Canada
Age: Valanginian.
Original diagnosis: McIntyre and Brideaux, 1980, p. 19-20: Cleistosphaeridium separatum
Shape: Pericyst - Complete pericyst not observed, the remaining portion nearly hemispherical; antapex rounded. Dorsoventral compression. Endocyst - Commonly obscure, closely appressed to the pericyst. Pericoels - Not observed. Phragma: Periphragm - About 0.5 µm thick; surface sculpture of fine granulate to echinate elements less than 0.5 µm high; processes arising from periphragm closed, distally bifid to finely branched, 2-8 µm long (typically 4-7 µm) and about 1 µm wide; in places on some specimens, processes concentrated in penetabular position on paraplates and reduced in density or absent in the interior of paraplates; 15-20 processes per paraplate. Endophragm - Commonly obscure, less than 0.5 µm thick; presumably smooth. Paratabulation. Pericyst - Marked development of accessory parasutures in the vicinity of the archeopyle and penetabular concentration of processes denote an epiparatabulation of 4", 0a, 6" and ?c; less pronounced penetabular concentration of processes denotes a hypoparatabulation of ? (5"""-6""", 1"""", ?p). Endocyst - Paratabulation not observed. Pericingulum - Not observed. Perisulcus - Present on one specimen, position denoted by distinct sulcal notch; parasulcal processes discrete and apparently parasutural, denoting an anterior sulcal paraplate and one or more sulcal paraplates.
Archeopyle: Apical, Type A(1"-4"). Operculum free and? simple.
Dimensions: Pericyst length - 23-42 µm (archeopyle developed); width - 30-52 µm.
Affinities:
McIntyre and Brideaux, 1980, p. 20: Cleistosphaeridium separatum
Cleistosphaeridium separatum differs from Cleistosphaeridium huguoniotii in possessing marked accessory parasutures and narrower processes which are commonly penetabular.
Originally Cleistosphaeridium, subsequently (and now) Sentusidinium.
Holotype: McIntyre and Brideaux, 1980, pl.6, figs.4-5
Taxonomic junior synonym: Sentusidinium cuculliforme, according to Courtinat in Fauconnier and Masure (2004, p.486).
Locus typicus: District of Mackenzie, Canada
Age: Valanginian.
Original diagnosis: McIntyre and Brideaux, 1980, p. 19-20: Cleistosphaeridium separatum
Shape: Pericyst - Complete pericyst not observed, the remaining portion nearly hemispherical; antapex rounded. Dorsoventral compression. Endocyst - Commonly obscure, closely appressed to the pericyst. Pericoels - Not observed. Phragma: Periphragm - About 0.5 µm thick; surface sculpture of fine granulate to echinate elements less than 0.5 µm high; processes arising from periphragm closed, distally bifid to finely branched, 2-8 µm long (typically 4-7 µm) and about 1 µm wide; in places on some specimens, processes concentrated in penetabular position on paraplates and reduced in density or absent in the interior of paraplates; 15-20 processes per paraplate. Endophragm - Commonly obscure, less than 0.5 µm thick; presumably smooth. Paratabulation. Pericyst - Marked development of accessory parasutures in the vicinity of the archeopyle and penetabular concentration of processes denote an epiparatabulation of 4", 0a, 6" and ?c; less pronounced penetabular concentration of processes denotes a hypoparatabulation of ? (5"""-6""", 1"""", ?p). Endocyst - Paratabulation not observed. Pericingulum - Not observed. Perisulcus - Present on one specimen, position denoted by distinct sulcal notch; parasulcal processes discrete and apparently parasutural, denoting an anterior sulcal paraplate and one or more sulcal paraplates.
Archeopyle: Apical, Type A(1"-4"). Operculum free and? simple.
Dimensions: Pericyst length - 23-42 µm (archeopyle developed); width - 30-52 µm.
Affinities:
McIntyre and Brideaux, 1980, p. 20: Cleistosphaeridium separatum
Cleistosphaeridium separatum differs from Cleistosphaeridium huguoniotii in possessing marked accessory parasutures and narrower processes which are commonly penetabular.