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Cribroperidinium tensiftense
Cribroperidinium tensiftense Below, 1981
Holotype: Below, 1981, pl.1, fig.10; Jan du Chene 1986 pl.19, fig.8; Fensome et al., 1991, fig.1-p.757
Paratype: Below, 1981, pl.1, fig.11 and Jan du Chene 1986 pl.19, fig.9
Locus typicus: Chichaoua I borehole, Chichaoua, Morocco
Stratum typicum: Barremian-Albian
Translation Below, 1981: Fensome, 1991, p. 758-759
Original diagnosis: Below, 1981, p. 41
Proximate cyst, spheroidal, elongate-oval or rhomboidal in outline. Epicyst with short, pyramid-shaped, broad-based apical horn. Hypocyst of the same size. Both halves separated by the spiral, equatorial hexatabulate paracingulum. Parasulcus straight, subdivided. Paraplates marked by low, distally irregularly dentate ridges and distributed according to the scheme 4", 6", 6c, 6""", pc, l"""" as, ra, rs, ps, ls. Equally developed intratabular pseudosutures are present. The thick wall is twolayered. It consists of a smooth endophragm and a thin periphragm with very fine perforations, on its outer surface, the periphragm bears short pila, bacula or tubercula. The space between the two layers is filled with a dense supporting lattice. The archeopyle is of type P(3"").
Original description: Below, 1981, p. 41-42
A characteristic, rather constant feature of the species is the short triangular, broad-based apical horn which surmounts the weakly elongate-oval or rhomboid body. This is the essential differentiating characteristic from Cribroperidinium orthoceras (Eisenack 1958) Davey 1969, which has a long, narrow, in part parallel-sided, apical appendage. In contrast to those of the latter species, the parasutures are developed as delicate ridges or rows of denticles. The same applies to the numerous fine surface ornaments which vary in form and density. The paratabulatio.l - a reconstruction of which can be seen in [Below, 1981a] text-fig.24 - follows the scheme previously determined by Gocht for Cribroperidinium ventriosum (O.Wetzel 1933) Lentin and Williams 1973 emend. Gocht 1979. The arrangement of intratabular pseudosutures is somewhat modified, whereas the torsion of the hypocyst towards the epicyst is realized in the same manner.
Two peculiarities of the wall structure, although evident only in well preserved populations, will be pointed out here. The endophragm and periphragm are separated by a scaffolding of densely placed supporting elements ([Below, 1981a] pl.l3, fig.5). On the ridge between 1" and 4", approximately halfway between the tip of the apical hom and the anterior end of 6", a round or elongate "pore" occurs ([Below, 1981a] pl.13, fig.3d).
Size.
Holotype: length (without apical horn) 92 Ám, width 86 Ám, length of apical horn 20 Ám. Range of other specimens Iength 100(116)133 Ám, width 81(95)108 Ám.
Holotype: Below, 1981, pl.1, fig.10; Jan du Chene 1986 pl.19, fig.8; Fensome et al., 1991, fig.1-p.757
Paratype: Below, 1981, pl.1, fig.11 and Jan du Chene 1986 pl.19, fig.9
Locus typicus: Chichaoua I borehole, Chichaoua, Morocco
Stratum typicum: Barremian-Albian
Translation Below, 1981: Fensome, 1991, p. 758-759
Original diagnosis: Below, 1981, p. 41
Proximate cyst, spheroidal, elongate-oval or rhomboidal in outline. Epicyst with short, pyramid-shaped, broad-based apical horn. Hypocyst of the same size. Both halves separated by the spiral, equatorial hexatabulate paracingulum. Parasulcus straight, subdivided. Paraplates marked by low, distally irregularly dentate ridges and distributed according to the scheme 4", 6", 6c, 6""", pc, l"""" as, ra, rs, ps, ls. Equally developed intratabular pseudosutures are present. The thick wall is twolayered. It consists of a smooth endophragm and a thin periphragm with very fine perforations, on its outer surface, the periphragm bears short pila, bacula or tubercula. The space between the two layers is filled with a dense supporting lattice. The archeopyle is of type P(3"").
Original description: Below, 1981, p. 41-42
A characteristic, rather constant feature of the species is the short triangular, broad-based apical horn which surmounts the weakly elongate-oval or rhomboid body. This is the essential differentiating characteristic from Cribroperidinium orthoceras (Eisenack 1958) Davey 1969, which has a long, narrow, in part parallel-sided, apical appendage. In contrast to those of the latter species, the parasutures are developed as delicate ridges or rows of denticles. The same applies to the numerous fine surface ornaments which vary in form and density. The paratabulatio.l - a reconstruction of which can be seen in [Below, 1981a] text-fig.24 - follows the scheme previously determined by Gocht for Cribroperidinium ventriosum (O.Wetzel 1933) Lentin and Williams 1973 emend. Gocht 1979. The arrangement of intratabular pseudosutures is somewhat modified, whereas the torsion of the hypocyst towards the epicyst is realized in the same manner.
Two peculiarities of the wall structure, although evident only in well preserved populations, will be pointed out here. The endophragm and periphragm are separated by a scaffolding of densely placed supporting elements ([Below, 1981a] pl.l3, fig.5). On the ridge between 1" and 4", approximately halfway between the tip of the apical hom and the anterior end of 6", a round or elongate "pore" occurs ([Below, 1981a] pl.13, fig.3d).
Size.
Holotype: length (without apical horn) 92 Ám, width 86 Ám, length of apical horn 20 Ám. Range of other specimens Iength 100(116)133 Ám, width 81(95)108 Ám.