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Microdinium minutum
Microdinium minutum Louwye, 1997, p.151, pl.1, figs.14–16; pl.2, fig.5.
This name was not validly published in Slimani (1994, p.41), since no description was provided.
Holotype: Louwye, 1997, pl.1, figs.14–16; pl.2, fig.5.
Age: latest Cenomanian–Santonian.
Original description (Louwye 1997):
Microdinium minutum n.sp. Pl. 1: 14-16, Pl. 2: 5
Synonymy.
1974 Histiocysta palla Davey 1969 - Faucher, p. 130, pl. 3, figs. 5, 6, Late Turonian, France.
1975 H. palla Davey 1969 - Foucher, pl. 1, fig. 2, Turanian, France.
Derivatio nominis. <>, latin: small.
Holotype. Keiem well 36E135, -211.6 m, P.1, coord. E.F. V-41.4 (Pl. 1, figs. 14-16, P1.2, fig. 5), reposito¬ry: collection of the Laboratory of Paleontology, Uni¬versity of Ghent.
Locus typicus and stratum typicum. Keiem, West Flanders, Belgium, well no. 36E135, -211.6 m, Tu¬ranian (Coniacian?).
Dimensions. Holotype: total length, 31 µm; total width, 27 µm. Variation: total length, 28 - 36 µm; total width, 22-31 µm. Number of measured specimens: 12.
Diagnosis. The small, proximate and suturocavate cyst has an ellipsoidal silhouette. The cyst is circular in equatorial view. The maximum width is situated near the posterior end of the paracingulum. The endophragm is scabrate while the periphragm is hyaline and in optical section only recognizable as a thin line. The endophragm and periphragm are appressed except in the parasutural areas where discrete, cavate parasutures are developed which reflect the paratabulation. The barely visible parasutural ridges give the impression of unornamented parasutural strips. The sparse, intratabular ornamentation consists of isolated granules and irregular crests. The slightly offset paracingulum divides the cyst in a hypocyst which is roughly twice as large as the epicyst. Paratabulation: 4 apicals, 4 anterior intercalaries, 6 precingulars, 6 paracingulars and 6 postcingulars, X and Y in partiform hypocystal arrangement, the exact arrangement of the parasulcal plates could not be determined. The precingular paraplate 2 is distinctively triangular. The apical archeopyle is of type (tAtI). An adherent operculum was observed in a few cases.
Comparison. Microdinium granocarinatum (Below, 1987) Lentin & Williams, 1989 (Late Campanian) differs by the higher parasutural crests and the den¬se granular, intratabular ornamentation. M. densi¬granulatum (Below, 1987) Lentin & Williams, 1989 (MiddleAlbian) is acavate and densely ornamented with granules.
Remarks. The cavate parasutures are discrete, gi-ving the impression of unornamented parasutural strokes bordered with penitabular crests.
Occurrence. apart from the Turanian occurrences reported by Faucher (1974 & 1975), the species is encountered at Keiem: -211.6 m (Turanian), at Nieuwkerke, -103.0 m (Santonian) and at Oostduin-kerke, -254.5 m (Cenomanian).
This name was not validly published in Slimani (1994, p.41), since no description was provided.
Holotype: Louwye, 1997, pl.1, figs.14–16; pl.2, fig.5.
Age: latest Cenomanian–Santonian.
Original description (Louwye 1997):
Microdinium minutum n.sp. Pl. 1: 14-16, Pl. 2: 5
Synonymy.
1974 Histiocysta palla Davey 1969 - Faucher, p. 130, pl. 3, figs. 5, 6, Late Turonian, France.
1975 H. palla Davey 1969 - Foucher, pl. 1, fig. 2, Turanian, France.
Derivatio nominis. <
Holotype. Keiem well 36E135, -211.6 m, P.1, coord. E.F. V-41.4 (Pl. 1, figs. 14-16, P1.2, fig. 5), reposito¬ry: collection of the Laboratory of Paleontology, Uni¬versity of Ghent.
Locus typicus and stratum typicum. Keiem, West Flanders, Belgium, well no. 36E135, -211.6 m, Tu¬ranian (Coniacian?).
Dimensions. Holotype: total length, 31 µm; total width, 27 µm. Variation: total length, 28 - 36 µm; total width, 22-31 µm. Number of measured specimens: 12.
Diagnosis. The small, proximate and suturocavate cyst has an ellipsoidal silhouette. The cyst is circular in equatorial view. The maximum width is situated near the posterior end of the paracingulum. The endophragm is scabrate while the periphragm is hyaline and in optical section only recognizable as a thin line. The endophragm and periphragm are appressed except in the parasutural areas where discrete, cavate parasutures are developed which reflect the paratabulation. The barely visible parasutural ridges give the impression of unornamented parasutural strips. The sparse, intratabular ornamentation consists of isolated granules and irregular crests. The slightly offset paracingulum divides the cyst in a hypocyst which is roughly twice as large as the epicyst. Paratabulation: 4 apicals, 4 anterior intercalaries, 6 precingulars, 6 paracingulars and 6 postcingulars, X and Y in partiform hypocystal arrangement, the exact arrangement of the parasulcal plates could not be determined. The precingular paraplate 2 is distinctively triangular. The apical archeopyle is of type (tAtI). An adherent operculum was observed in a few cases.
Comparison. Microdinium granocarinatum (Below, 1987) Lentin & Williams, 1989 (Late Campanian) differs by the higher parasutural crests and the den¬se granular, intratabular ornamentation. M. densi¬granulatum (Below, 1987) Lentin & Williams, 1989 (MiddleAlbian) is acavate and densely ornamented with granules.
Remarks. The cavate parasutures are discrete, gi-ving the impression of unornamented parasutural strokes bordered with penitabular crests.
Occurrence. apart from the Turanian occurrences reported by Faucher (1974 & 1975), the species is encountered at Keiem: -211.6 m (Turanian), at Nieuwkerke, -103.0 m (Santonian) and at Oostduin-kerke, -254.5 m (Cenomanian).