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Microdinium marheineckii
Microdinium marheineckei Slimani, 1994, p.36–37, pl.6, figs.16–17,24–25.
Holotype: Slimani, 1994, pl.6, figs.16–17,24–25.
Age: late Maastrichtian–earliest Danian.
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Original description (Slimani, 1994) (translated from French):
Microdinium marheineckii sp. nov. (P1.6, Fig.16,17,24,25)
Name derivation: In honor of Dr. Uwe MARHEINECKE, Geol. Paleont. Inst. U. Mus., Hamburg, Germany.
Horizon: Turnhout -759.89 m, preparation 5, E.F. coord. R28.
Type locality: Turnhout -759.89 m.
Type horizon: Upper Maastrichtian
Synonymy:
1992: Phanerodinium sp. 2 - MARHEINECKE, p. 111, pl. 25, fig. 5, 6.
Diagnosis: Small, proximal, subspheroidal to ovoid cyst with an epicyst slightly smaller than the hypocyst. The paratabulation is of the partiform gonyaulacoid type: lpr, 4', 4a, 6", 6c, 5 - 6"', lp, 1"", 4 - 5s; it is indicated by islands of parasutural furrows devoid of ornamentation and delimited by low penitabular ridges. The intratabular surfaces bear numerous granules or rigid projections. The archaeopyle is apical and intercalary of type (tAtl)a with a ventrally adnate operculum.
Dimensions: Holotype. Maximum diameter: 24 µm. Variations: Maximum diameter: 20 - 28 µm.
Number of specimens measured: 7.
Material: 8 specimens.
Description: The autophragm (about 1 pm thick) is rigid, smooth, and bears numerous granules or projections that can reach up to 4 µm in height. These ornaments are solid and rigid, giving a slightly granulated appearance in superior view. Paratabulation is indicated by parasutural furrows that are narrow, devoid of ornamentation, and bordered by fine penitabular ridges that separate them from the intratabular ornamentation. The height of these structures is constant in the same individual, but slightly variable intraspecifically. The arrangement of the hypocystal paraplates is partiform; the antapical paraplate is hexagonal and larger than the posterior intercalary paraplate. The parasulcus is composed of 4 to 5 paraplates, the posterior of which is wider and omega-shaped. The segmented paracingulum (4 to 5 µm wide) is very weakly laevogyre. The operculum is composed of 9 small paraplates: 4 apical, 4 anterior intercalary, and 1 preapical.
Note and comparison: Microdinium marheineckii sp. nov. is characterized by parasutural grooves devoid of ornamentation and by penitabular ridges that separate these grooves from the intratabular ornamentation. Fibradinium densibaculatum (BELOW. 1987b) LENTIN and WILLIAMS (1989) is the closest to this species, mainly due to the presence of parasutural grooves devoid of ornamentation, but it is distinguished by its much denser ornamentation and the absence of penitabular ridges. Specimens of Phanerodinium sp. Two specimens depicted by MARHEINECKE (1992: pl. 25, fig. 5, 6) are similar to the species studied.
Stratigraphic distribution: Turnhout: -795.24 to -759.89 m, upper part of the Upper Maastrichtian - early Danian. MARHEINECK E (1992), Upper Maastrichtian, Hemmoor, Germany.
Holotype: Slimani, 1994, pl.6, figs.16–17,24–25.
Age: late Maastrichtian–earliest Danian.
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Original description (Slimani, 1994) (translated from French):
Microdinium marheineckii sp. nov. (P1.6, Fig.16,17,24,25)
Name derivation: In honor of Dr. Uwe MARHEINECKE, Geol. Paleont. Inst. U. Mus., Hamburg, Germany.
Horizon: Turnhout -759.89 m, preparation 5, E.F. coord. R28.
Type locality: Turnhout -759.89 m.
Type horizon: Upper Maastrichtian
Synonymy:
1992: Phanerodinium sp. 2 - MARHEINECKE, p. 111, pl. 25, fig. 5, 6.
Diagnosis: Small, proximal, subspheroidal to ovoid cyst with an epicyst slightly smaller than the hypocyst. The paratabulation is of the partiform gonyaulacoid type: lpr, 4', 4a, 6", 6c, 5 - 6"', lp, 1"", 4 - 5s; it is indicated by islands of parasutural furrows devoid of ornamentation and delimited by low penitabular ridges. The intratabular surfaces bear numerous granules or rigid projections. The archaeopyle is apical and intercalary of type (tAtl)a with a ventrally adnate operculum.
Dimensions: Holotype. Maximum diameter: 24 µm. Variations: Maximum diameter: 20 - 28 µm.
Number of specimens measured: 7.
Material: 8 specimens.
Description: The autophragm (about 1 pm thick) is rigid, smooth, and bears numerous granules or projections that can reach up to 4 µm in height. These ornaments are solid and rigid, giving a slightly granulated appearance in superior view. Paratabulation is indicated by parasutural furrows that are narrow, devoid of ornamentation, and bordered by fine penitabular ridges that separate them from the intratabular ornamentation. The height of these structures is constant in the same individual, but slightly variable intraspecifically. The arrangement of the hypocystal paraplates is partiform; the antapical paraplate is hexagonal and larger than the posterior intercalary paraplate. The parasulcus is composed of 4 to 5 paraplates, the posterior of which is wider and omega-shaped. The segmented paracingulum (4 to 5 µm wide) is very weakly laevogyre. The operculum is composed of 9 small paraplates: 4 apical, 4 anterior intercalary, and 1 preapical.
Note and comparison: Microdinium marheineckii sp. nov. is characterized by parasutural grooves devoid of ornamentation and by penitabular ridges that separate these grooves from the intratabular ornamentation. Fibradinium densibaculatum (BELOW. 1987b) LENTIN and WILLIAMS (1989) is the closest to this species, mainly due to the presence of parasutural grooves devoid of ornamentation, but it is distinguished by its much denser ornamentation and the absence of penitabular ridges. Specimens of Phanerodinium sp. Two specimens depicted by MARHEINECKE (1992: pl. 25, fig. 5, 6) are similar to the species studied.
Stratigraphic distribution: Turnhout: -795.24 to -759.89 m, upper part of the Upper Maastrichtian - early Danian. MARHEINECK E (1992), Upper Maastrichtian, Hemmoor, Germany.