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Cribroperidinium intricatum
Cribroperidinium ?intricatum Davey, 1969a, p.125-128, pl.2, figs.1-3; text-figs.11a-b-12a-b.
Originally Cribroperidinium, subsequently (and now) Cribroperidinium?. Questionable assignment: Helenes (1984, p.125) as a problematic species.
Holotype: Davey, 1969a, pl.2, fig.1; text-figs.11a,12a; Jan du Chêne et al., 1986a, pl.24, figs.10-11.
Paratype: Davey, 1969, pl.2, fig.2-3
Locus typicus: Saskatchewan, Canada
Age: Albian.
Original diagnosis: Davey, 1969, p. 126
Shell subspherical, epitract and hypotract of similar size. Apical horn of moderate length, subconical. Shell wall moderately thick, granular and bears a few, randomly arranged tubercles. Crests usually in form of low ridges, well defined, sometimes membranous, delimiting a large number of plates on shell surface. Sutural spines absent. Plate II"' crossed diagonally by low crest. Operculum possessing semi-circular crest. Sulcus possessing posterior ventral plates. Cingulum narrow, plates not defined.
Original description: Davey, 1969, p. 126
The shell wall is 1 to 1,5 Á in thickness and densely granular. The crests are typically low thickenings of the periphragm (2-3 Á wide), but in the antapical region, and occasionally elsewhere, the crests take the form of high flanges. The latter (up to 6 ~ in height) are membranous, thin and always perforate. The number of apical plates always appears to be six. Plate 1', equivalent to the first apical plate, is elongate and abuts against the anterior end of the sulcus. The crest arrangement on the ventral surface appears to be practically constant and is characteristic of this species. The crests limiting the plates I', I", II", III", IV", VII" and VIII" are always constant in position. Plates I''' and II''' are reduced due to the presence of a posterior intercalary plate. Plate II''' always possesses a crest passing diagonally across it and the crest between plates III''' and IV''' is of a characteristic right angle shape. The positions of the crests on the dorsal surface of the epitract are fairly constant, only varying in minor details. The large plate V" is usually detached in archaeopyle formation and possesses a semi-circular crest from which radiate a small number of other crests (Pl. 2, fig. 3). These pass over the boundary of plate V" to continue on adjacent parts of the epitract. The positions of the crests on the dorsal surface of the hypotract appear to be less constant in position. Their predominent direction is parallel to the longitudinal axis of the shell, sometimes a series of posterior circle plates may be present. Antapical plates, if present at all, are very reduced and obscured by the crestal membranes.
The cingulum is narrow (c. 6 Ám in width), slightly laevo-rotatory, and tends to possess a thicker wall than is usual for the remainder of the shell. The sulcus only projects onto the epitract for a short distance, being considerably larger and wider on the hypotract. It is always divided into a number of posterior ventral plates by reduced crests.
Supplemental description (of a well preserved specimen) Brideaux, 1971, p.84
Length, 140 Ám; width, 105 Ám; apical horn length, 35 Ám. Main cyst rounded-pentagonal in shape; relatively long, tapering apical horn; antapex rounded, slightly flattened at the antapical axis. Epitract including apical horn longer than the hypotract. Cingulum 4.5 Ám wide, marked by thicker wall layer, showing irregular, small foveae along its interior course, helicoid, sinistral, displacement about one and one-half cingulum widths (12 Ám). Sulcus elongate, slightly curved, extending onto the epitract and narrowing; sulcul plates outlined by low sutures, the sulcus course by higher ridges; sulcus terminated antapically by plate ?I'''', apically by plates of the apical series. Tabulation outlined by thick irregular ledges or crests, 1-2 Ám wide and 1-2 Ám high. Tabulation complex, complicated by irregular intertabular ridges which often fuse with sutures outlining the larger plates. A partial determination of the tabulation on this specimen is V--?VI', VII"?, 0 c, ?VII''', I''''?, 5s, ?Ipv. The numbering of the plates depends on interpretation of certain sutures as representing actual reflected plate boundaries. Scattered knobs and granules are present on intratabular regions. The archeopyle is precingular and formed by the loss of a trianguloid plate numbered ?IV" on this specimen.
General Description: Brideaux, 1971, p. 84
Originally Cribroperidinium, subsequently (and now) Cribroperidinium?. Questionable assignment: Helenes (1984, p.125) as a problematic species.
Holotype: Davey, 1969a, pl.2, fig.1; text-figs.11a,12a; Jan du Chêne et al., 1986a, pl.24, figs.10-11.
Paratype: Davey, 1969, pl.2, fig.2-3
Locus typicus: Saskatchewan, Canada
Age: Albian.
Original diagnosis: Davey, 1969, p. 126
Shell subspherical, epitract and hypotract of similar size. Apical horn of moderate length, subconical. Shell wall moderately thick, granular and bears a few, randomly arranged tubercles. Crests usually in form of low ridges, well defined, sometimes membranous, delimiting a large number of plates on shell surface. Sutural spines absent. Plate II"' crossed diagonally by low crest. Operculum possessing semi-circular crest. Sulcus possessing posterior ventral plates. Cingulum narrow, plates not defined.
Original description: Davey, 1969, p. 126
The shell wall is 1 to 1,5 Á in thickness and densely granular. The crests are typically low thickenings of the periphragm (2-3 Á wide), but in the antapical region, and occasionally elsewhere, the crests take the form of high flanges. The latter (up to 6 ~ in height) are membranous, thin and always perforate. The number of apical plates always appears to be six. Plate 1', equivalent to the first apical plate, is elongate and abuts against the anterior end of the sulcus. The crest arrangement on the ventral surface appears to be practically constant and is characteristic of this species. The crests limiting the plates I', I", II", III", IV", VII" and VIII" are always constant in position. Plates I''' and II''' are reduced due to the presence of a posterior intercalary plate. Plate II''' always possesses a crest passing diagonally across it and the crest between plates III''' and IV''' is of a characteristic right angle shape. The positions of the crests on the dorsal surface of the epitract are fairly constant, only varying in minor details. The large plate V" is usually detached in archaeopyle formation and possesses a semi-circular crest from which radiate a small number of other crests (Pl. 2, fig. 3). These pass over the boundary of plate V" to continue on adjacent parts of the epitract. The positions of the crests on the dorsal surface of the hypotract appear to be less constant in position. Their predominent direction is parallel to the longitudinal axis of the shell, sometimes a series of posterior circle plates may be present. Antapical plates, if present at all, are very reduced and obscured by the crestal membranes.
The cingulum is narrow (c. 6 Ám in width), slightly laevo-rotatory, and tends to possess a thicker wall than is usual for the remainder of the shell. The sulcus only projects onto the epitract for a short distance, being considerably larger and wider on the hypotract. It is always divided into a number of posterior ventral plates by reduced crests.
Supplemental description (of a well preserved specimen) Brideaux, 1971, p.84
Length, 140 Ám; width, 105 Ám; apical horn length, 35 Ám. Main cyst rounded-pentagonal in shape; relatively long, tapering apical horn; antapex rounded, slightly flattened at the antapical axis. Epitract including apical horn longer than the hypotract. Cingulum 4.5 Ám wide, marked by thicker wall layer, showing irregular, small foveae along its interior course, helicoid, sinistral, displacement about one and one-half cingulum widths (12 Ám). Sulcus elongate, slightly curved, extending onto the epitract and narrowing; sulcul plates outlined by low sutures, the sulcus course by higher ridges; sulcus terminated antapically by plate ?I'''', apically by plates of the apical series. Tabulation outlined by thick irregular ledges or crests, 1-2 Ám wide and 1-2 Ám high. Tabulation complex, complicated by irregular intertabular ridges which often fuse with sutures outlining the larger plates. A partial determination of the tabulation on this specimen is V--?VI', VII"?, 0 c, ?VII''', I''''?, 5s, ?Ipv. The numbering of the plates depends on interpretation of certain sutures as representing actual reflected plate boundaries. Scattered knobs and granules are present on intratabular regions. The archeopyle is precingular and formed by the loss of a trianguloid plate numbered ?IV" on this specimen.
General Description: Brideaux, 1971, p. 84