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Subtilisphaera zawia
Subtilisphaera zawia Below, 1981
Holotype: Below, 1981, pl.9, fig.21; Fensome et al., 1991, fig.1- p.777
Locus typicus: Between Sidi Ahmed ou Rami and Tizi, southwest Morocco
Stratum typicum: Albian
Translation Below, 1981: Fensome, 1991, p. 778-779
Original diagnosis: Below, 1981, p. 129
Bicavate to cavate, dorso-ventrally flattened cyst. Endocyst pentagonal to stoutly ovoidal. Epiendocyst triangular to subtrapezoidal with straight or convex sides and a rounded apex. Hypoendocyst trapezoidal with a flattened or weakly indented antapex. Endophragm smooth. A planar, indented paracingulum divides the pericyst unequally. Epipericyst usually low, shaped like an equilateral triangle or, more
rarely, is similar to an isosceles triangle. The apical horn is not pronounced and corresponds to the tip of the epicystal triangle. The trapezoidal hypopericyst has concave or straight sides and has two antapical horns- both are symmetrically placed about the median axis. There is a short, truncate, distally rounded appendage as well as a long, tapering antapical horn, which is outwardly curved. Commonly, fine, parasutural ridges within the pandasutural bands indicate a peridinioid paratabulation. The periphragm is generally irregularly granulate. There is no archeopyle.
Original description: Below, 1981, p. 129
Typically, the endocyst and pericyst have an ideally pentagonal outline. The interior body usually fills the pericoel only ambitally in the region of the precingular and postcingular paraplates. The variants include circumcavate cysts and specimens with pericoels confined to the apical and antapical horns.
In the present material Subtilisphaera zawia and Subtilisphaera senegalensis Jain and Millepied 1973 often have a peridinioid paratabulation with fine, parasutural ridges within pandasutural bands which, in turn, separate paraplates covered with intratabular granules. However, both species are also represented by individuals without visible paratabulation and with an ornament that is irregularly distributed over the periphragm. The relationship between these two species, as indicated by their identical surface texture, also appears to be confirmed by their variation in shape. A continuous variation ranging from Subtilisphaera scabrata Jain and Millepied 1973 to Subtilisphaera senegalensis Jain and Millepied 1973 is apparent. Successive rounding of the polygonal outline results in a subpentagonal to ovoid to, finally, a spherical cyst shape ([Below, 1981a] text-figs.82-86). The reduction of the pericoel appears to be coupled with this phenomenon. On the pericyst, the paracingulum is indented as a broad band and is marked by smooth or finely echinate, thickened, anterior and posterior margins. There is no parasulcus. It was not possible to determine the archeopyle type. Frequently the pericyst splits open dorsally along the paracingulum. An (AIP) archeopyle might be expected. However, isolated cyst halves were never found, contradicting this hypothesis.
Holotype: Below, 1981, pl.9, fig.21; Fensome et al., 1991, fig.1- p.777
Locus typicus: Between Sidi Ahmed ou Rami and Tizi, southwest Morocco
Stratum typicum: Albian
Translation Below, 1981: Fensome, 1991, p. 778-779
Original diagnosis: Below, 1981, p. 129
Bicavate to cavate, dorso-ventrally flattened cyst. Endocyst pentagonal to stoutly ovoidal. Epiendocyst triangular to subtrapezoidal with straight or convex sides and a rounded apex. Hypoendocyst trapezoidal with a flattened or weakly indented antapex. Endophragm smooth. A planar, indented paracingulum divides the pericyst unequally. Epipericyst usually low, shaped like an equilateral triangle or, more
rarely, is similar to an isosceles triangle. The apical horn is not pronounced and corresponds to the tip of the epicystal triangle. The trapezoidal hypopericyst has concave or straight sides and has two antapical horns- both are symmetrically placed about the median axis. There is a short, truncate, distally rounded appendage as well as a long, tapering antapical horn, which is outwardly curved. Commonly, fine, parasutural ridges within the pandasutural bands indicate a peridinioid paratabulation. The periphragm is generally irregularly granulate. There is no archeopyle.
Original description: Below, 1981, p. 129
Typically, the endocyst and pericyst have an ideally pentagonal outline. The interior body usually fills the pericoel only ambitally in the region of the precingular and postcingular paraplates. The variants include circumcavate cysts and specimens with pericoels confined to the apical and antapical horns.
In the present material Subtilisphaera zawia and Subtilisphaera senegalensis Jain and Millepied 1973 often have a peridinioid paratabulation with fine, parasutural ridges within pandasutural bands which, in turn, separate paraplates covered with intratabular granules. However, both species are also represented by individuals without visible paratabulation and with an ornament that is irregularly distributed over the periphragm. The relationship between these two species, as indicated by their identical surface texture, also appears to be confirmed by their variation in shape. A continuous variation ranging from Subtilisphaera scabrata Jain and Millepied 1973 to Subtilisphaera senegalensis Jain and Millepied 1973 is apparent. Successive rounding of the polygonal outline results in a subpentagonal to ovoid to, finally, a spherical cyst shape ([Below, 1981a] text-figs.82-86). The reduction of the pericoel appears to be coupled with this phenomenon. On the pericyst, the paracingulum is indented as a broad band and is marked by smooth or finely echinate, thickened, anterior and posterior margins. There is no parasulcus. It was not possible to determine the archeopyle type. Frequently the pericyst splits open dorsally along the paracingulum. An (AIP) archeopyle might be expected. However, isolated cyst halves were never found, contradicting this hypothesis.