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Prolixosphaeridium spissum
Prolixosphaeridium? spissum (McIntyre and Brideaux, 1980) Lentin and Williams, 1981
NOW Prolixosphaeridiopsis (acritarch). Originally Cleistosphaeridium, subsequently Prolixosphaeridium?, thirdly (and now) Prolixosphaeridiopsis (acritarch). At the time of the transfer, Lentin and Williams, 1981 questionably included this species in Prolixosphaeridium.
Holotype: McIntyre and Brideaux, 1980, pl.7, fig.1-4
Locus typicus: "Grizzly Gorge", District of Mackenzie, Canada
Stratum typicum: Valanginian
Original diagnosis: McIntyre and Brideaux, 1980, p. 20: Cleistosphaeridium spissum
Shape: Pericyst - Ambitus ovoid, elongate, length/width ratio greater than 1.0; apical and antapical horns absent; dorsoventral compression. Endocyst - Ambitus as for pericyst; closely appressed throughout. Pericoels - Absent.
Phragma: Periphragm - Less than 0.5 µm thick; bearing hundreds of densely distributed processes of two main types: the most common type, very thin walled, tubular but flattened, wider basally, tapering slightly distally; distally trifurcate with stout aculei, partly open or? closed, in places distinctly connected basally by a
reticulate network of very low ridges, in places apparently discrete; a second less common type, observed along what are interpreted as cingular parasutures, thin-columned, acuminate or distally slightly clavate, closed, joined basally by a system of low ridges. Length of all types, from 5-15 µm, typically 7-10 µm.
Endophragm - Indistinct, very thin, smooth.
Paratabulation: Pericyst - paratabulation indeterminate. Endocyst - Paratabulation absent. Pericingulum - On some specimens, rows of acuminate processes, seemingly connected basally, may represent pericingular parasutures. Perisulcus - Not observed.
Archeopyle: Not observed.
Dimensions: Maximum pericyst diameter - 30-110 µm, maximum width - 19-83 µm.
Variation: Orientation of many specimens uncertain; some smaller specimens may be orientated in the apical-antapical view, maximum dimensions thus representing
compressed widths and depths.
NOW Prolixosphaeridiopsis (acritarch). Originally Cleistosphaeridium, subsequently Prolixosphaeridium?, thirdly (and now) Prolixosphaeridiopsis (acritarch). At the time of the transfer, Lentin and Williams, 1981 questionably included this species in Prolixosphaeridium.
Holotype: McIntyre and Brideaux, 1980, pl.7, fig.1-4
Locus typicus: "Grizzly Gorge", District of Mackenzie, Canada
Stratum typicum: Valanginian
Original diagnosis: McIntyre and Brideaux, 1980, p. 20: Cleistosphaeridium spissum
Shape: Pericyst - Ambitus ovoid, elongate, length/width ratio greater than 1.0; apical and antapical horns absent; dorsoventral compression. Endocyst - Ambitus as for pericyst; closely appressed throughout. Pericoels - Absent.
Phragma: Periphragm - Less than 0.5 µm thick; bearing hundreds of densely distributed processes of two main types: the most common type, very thin walled, tubular but flattened, wider basally, tapering slightly distally; distally trifurcate with stout aculei, partly open or? closed, in places distinctly connected basally by a
reticulate network of very low ridges, in places apparently discrete; a second less common type, observed along what are interpreted as cingular parasutures, thin-columned, acuminate or distally slightly clavate, closed, joined basally by a system of low ridges. Length of all types, from 5-15 µm, typically 7-10 µm.
Endophragm - Indistinct, very thin, smooth.
Paratabulation: Pericyst - paratabulation indeterminate. Endocyst - Paratabulation absent. Pericingulum - On some specimens, rows of acuminate processes, seemingly connected basally, may represent pericingular parasutures. Perisulcus - Not observed.
Archeopyle: Not observed.
Dimensions: Maximum pericyst diameter - 30-110 µm, maximum width - 19-83 µm.
Variation: Orientation of many specimens uncertain; some smaller specimens may be orientated in the apical-antapical view, maximum dimensions thus representing
compressed widths and depths.