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Cribroperidinium sepimentum
Cribroperidinium sepimentum Neale and Sarjeant, 1962, p.443-444, pl.19, fig.4; text-figs.3a-b.
Holotype: Neale and Sarjeant, 1962, pl.19, fig.4; text-fig.3a-b; Jan du Chêne et al., 1986a, pl.19, fig.4. N.I.A.
Locus typicus: Speeton Clay, Heslerton, England
Age: Hauterivian.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cribroperidinium sepimentum Neale and Sarjeant, 1962. From the diagnosis of Neale and Sarjeant (1962), A species of Cribroperidinium having a rounded-polygonal cyst with a strong spiral horn and an antapical process formed by an outgrowth of crests at the antapex. The cyst is perforate, the perforations being of variable size and irregular arrangements. The crests are strong and show lines of perforations sometimes intersecting the outer margin to form slits; these produce a fibrous appearance. Cingulum narrow, laevorotatory; sulcus broad, confined to the central half of the ventral surface. Tabulation 6', 4-?5a, 8", 9"’, 1p, 2pv, ?6-7pc. Size: holotype, overall length 139 µm, width 96 µm, length of horn 32 µm.
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Original diagnosis: Neale and Sarjeant, 1962, p. 443
A species of Cribroperidinium having a rounded-polygonal theca with a strong spiral horn and an antapical process formed by an outgrowth of crests at the antapex. The theca is perforate, the perforations being of variable size and irregular arrangements. The crests are strong and show lines of perforations sometimes intersecting the outer margin to form slits; these produce a fibrous appearance.
Transverse furrow narrow, laevo-rotatory; longitudinal furrow broad, confined to the central half of the ventral surface. Tabulation 6', 4-?5a, 8'', 9''', 1p, 2pv, 6-?7pc.
Original description: Neale and Sarjeant, 1962, p. 443-444
Theca deep yellowish-brown in colour; crests chesnutbrown. Apical tabulation complex; all plates forming part of the surface of the apical horn are here designated apical plates. On this basis, there are six apical plates; plate 1' forming the anterior prolongation of the longitudinal furrow. Either four or five anterior intercalary plates, the supposed boundary between plates 2a and 3" not being confirmed. Eight pre-equatorial plates; plate 8" very reduced. Transverse furrow forming a laevo-rotatory spiral whose two ends differ in antero-posterior position by the furrow's breadth; it is divided by low ridges into sections. Longitudinal furrow short, broad, with two posterior ventral plates situated posterior to it. Nine postequatorial plates, plates 1''' and 9''' being reduced. One posterior intercalary plate, polygonal, situated posterior to plate 1'''. Either six or seven plates forming a posterior circle; these plates might be designated antapical plates, but since the antapex itself is occupied by a tuft of spines they are here termed 1-7pc. The presence of plate 3pc was not confirmed.
Lines of spines on plates 6'' and 7" and a partly developed crest on plate 6''' suggest that a process of increase or reduction in plate number is in progress. Isolated spines with closed tips, simple or bifurcate, are present on plates 5''' (two), 7''' and 8'''. A crest is certainly present separating plates 6''' and 4pc, but its course was not determined.
Dimensions: Overall length 139 Ám, breadth 96 Ám, length of horn 32 Ám.
Affinities:
Neale and Sarjeant, 1962, p. 444: This species differs from all described dinoflagellates in its combination of perforate theca, tabulation and crest character.
Holotype: Neale and Sarjeant, 1962, pl.19, fig.4; text-fig.3a-b; Jan du Chêne et al., 1986a, pl.19, fig.4. N.I.A.
Locus typicus: Speeton Clay, Heslerton, England
Age: Hauterivian.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cribroperidinium sepimentum Neale and Sarjeant, 1962. From the diagnosis of Neale and Sarjeant (1962), A species of Cribroperidinium having a rounded-polygonal cyst with a strong spiral horn and an antapical process formed by an outgrowth of crests at the antapex. The cyst is perforate, the perforations being of variable size and irregular arrangements. The crests are strong and show lines of perforations sometimes intersecting the outer margin to form slits; these produce a fibrous appearance. Cingulum narrow, laevorotatory; sulcus broad, confined to the central half of the ventral surface. Tabulation 6', 4-?5a, 8", 9"’, 1p, 2pv, ?6-7pc. Size: holotype, overall length 139 µm, width 96 µm, length of horn 32 µm.
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Original diagnosis: Neale and Sarjeant, 1962, p. 443
A species of Cribroperidinium having a rounded-polygonal theca with a strong spiral horn and an antapical process formed by an outgrowth of crests at the antapex. The theca is perforate, the perforations being of variable size and irregular arrangements. The crests are strong and show lines of perforations sometimes intersecting the outer margin to form slits; these produce a fibrous appearance.
Transverse furrow narrow, laevo-rotatory; longitudinal furrow broad, confined to the central half of the ventral surface. Tabulation 6', 4-?5a, 8'', 9''', 1p, 2pv, 6-?7pc.
Original description: Neale and Sarjeant, 1962, p. 443-444
Theca deep yellowish-brown in colour; crests chesnutbrown. Apical tabulation complex; all plates forming part of the surface of the apical horn are here designated apical plates. On this basis, there are six apical plates; plate 1' forming the anterior prolongation of the longitudinal furrow. Either four or five anterior intercalary plates, the supposed boundary between plates 2a and 3" not being confirmed. Eight pre-equatorial plates; plate 8" very reduced. Transverse furrow forming a laevo-rotatory spiral whose two ends differ in antero-posterior position by the furrow's breadth; it is divided by low ridges into sections. Longitudinal furrow short, broad, with two posterior ventral plates situated posterior to it. Nine postequatorial plates, plates 1''' and 9''' being reduced. One posterior intercalary plate, polygonal, situated posterior to plate 1'''. Either six or seven plates forming a posterior circle; these plates might be designated antapical plates, but since the antapex itself is occupied by a tuft of spines they are here termed 1-7pc. The presence of plate 3pc was not confirmed.
Lines of spines on plates 6'' and 7" and a partly developed crest on plate 6''' suggest that a process of increase or reduction in plate number is in progress. Isolated spines with closed tips, simple or bifurcate, are present on plates 5''' (two), 7''' and 8'''. A crest is certainly present separating plates 6''' and 4pc, but its course was not determined.
Dimensions: Overall length 139 Ám, breadth 96 Ám, length of horn 32 Ám.
Affinities:
Neale and Sarjeant, 1962, p. 444: This species differs from all described dinoflagellates in its combination of perforate theca, tabulation and crest character.