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Microdinium inornatum
From Fensome et al., 2019:
Microdinium inornatum Slimani, 1994, p.34–36, pl.4, fig.13; pl.6, figs.5–8,14–15,22–23. Holotype: Slimani, 1994, pl.6, figs.5–8, 22–23. Taxonomic junior synonym: Microdinium glabrum Wilson (name not validly published), according to Slimani (2001a, p.193). Age: early Campanian–late Maastrichtian.
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Original description (Slimani, 1994):
Microdinum inornatum sp. nov. (P1.4, Fig. 13; P1.6, Figs. 5-8, 14, 15, 22, 23)
Name derivation: Latin: inornatus, unornamented; refers to the cyst's surface, which is devoid of ornamentation.
Holiday: Turnhout -775.01 m, preparation 6, E.F. coord. Q36/3.
Paratype: Turnhout -933 m. preparation 3, E.F. coord. P30.
Type locality: Turnhout -775.01 m.
Type horizon: Maastrichtian.
Synonymy:
?1974: Microdinium glabrum in WILSON, pp. 259-260, pl. 14, fig. 4-6.
?1992: Phanerodinium cf. Ph. squamosum BELOW, 1987b - MARHEINECKE, p. 109, pl. 24, fig. 13-20.
Diagnosis: Ovoid to subspheroidal cyst with a hypocyst twice as long as the epicyst. It has a glabrous surface and bears prominent parasutural ridges indicating complete paratabulation of the gonyaulacoid type and conforms to the formula: 1 pr, 4', 4a, 6", 6c, 6" M p. 1 "' \ 5s. The archaeopyle is apical and intercalary, type (tAtl)a, with a small operculum attached to its ventral margin.
Dimensions: Holotype: maximum diameter: 34 µm. Variations: maximum diameter: 26-40 µm.
Number of specimens measured: 10.
Material: 23 specimens.
Description: The endophragm is thick (1 to 1.5 µm) and smooth. The periphragm is very thin, smooth, transparent, and completely in contact with the endophragm or slightly distinct on the margins of the intratabular surfaces. The parasutural ridges (average height of 4 µm) are smooth, transparent, and accentuated proximally by their thick, dense bases. Paraplate 1 is hexagonal, while paraplate 1p is smaller and pentagonal. The hypocystal configuration is partiform. The parasulcus is segmented into 5 paraplates; the posterior sulcal paraplate is wider and subomegaform. The paracingulum is wide (8 to 10 µm) and very slightly laevorotatory or non-spiral. The archaeopyle is 8 to 10 µm wide; The attached operculum is composed of 9 paraplates: 1 preapical, 4 apical and 4 anterior intercalary.
Comparison: Microdinium inornatum sp. nov. is possibly comparable to Microdinium glabrum by WILSON (1974) in his Ph.D. work (unpublished). It is distinguished from Microdinium crctaceum sp. nov. and Microdinium sonciniae (MARHEINECKE, 1992) comb. nov., by its cyst lacking intratabular ornamentation. The specimens listed under the name Phanerodinium cf. Ph. squamosum by MARHEINECKE (1992) resemble the studied species especially by their fairly developed crests and also by the absence of intratabular ornamentation. M. glabrum COOKSON and EISENACK (1974) and Microdinium squamosum (BELOW, 1987b) LENTIN and WILLIAMS (1989) are also species without ornamentation but their smooth crests are lower.
Stratigraphic distribution: Beutenaken: sample 1 to 5, Halembaye: ex. 4 to 27; Lower Campanian - Upper Campanian. (Zone with G. quadrata - Zone with B. mucronata). Turnhout: -978 to -775.01 m, Upper Campanian. - Maastrichtian upper. In WILSON (1974), Maastrichtian inf. (occidentalis and lanceolata Zone - occidentalis Zone), Denmark. MARHEINECKE (1992), Maastrichtian, Hemmoor, Germany.
Microdinium inornatum Slimani, 1994, p.34–36, pl.4, fig.13; pl.6, figs.5–8,14–15,22–23. Holotype: Slimani, 1994, pl.6, figs.5–8, 22–23. Taxonomic junior synonym: Microdinium glabrum Wilson (name not validly published), according to Slimani (2001a, p.193). Age: early Campanian–late Maastrichtian.
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Original description (Slimani, 1994):
Microdinum inornatum sp. nov. (P1.4, Fig. 13; P1.6, Figs. 5-8, 14, 15, 22, 23)
Name derivation: Latin: inornatus, unornamented; refers to the cyst's surface, which is devoid of ornamentation.
Holiday: Turnhout -775.01 m, preparation 6, E.F. coord. Q36/3.
Paratype: Turnhout -933 m. preparation 3, E.F. coord. P30.
Type locality: Turnhout -775.01 m.
Type horizon: Maastrichtian.
Synonymy:
?1974: Microdinium glabrum in WILSON, pp. 259-260, pl. 14, fig. 4-6.
?1992: Phanerodinium cf. Ph. squamosum BELOW, 1987b - MARHEINECKE, p. 109, pl. 24, fig. 13-20.
Diagnosis: Ovoid to subspheroidal cyst with a hypocyst twice as long as the epicyst. It has a glabrous surface and bears prominent parasutural ridges indicating complete paratabulation of the gonyaulacoid type and conforms to the formula: 1 pr, 4', 4a, 6", 6c, 6" M p. 1 "' \ 5s. The archaeopyle is apical and intercalary, type (tAtl)a, with a small operculum attached to its ventral margin.
Dimensions: Holotype: maximum diameter: 34 µm. Variations: maximum diameter: 26-40 µm.
Number of specimens measured: 10.
Material: 23 specimens.
Description: The endophragm is thick (1 to 1.5 µm) and smooth. The periphragm is very thin, smooth, transparent, and completely in contact with the endophragm or slightly distinct on the margins of the intratabular surfaces. The parasutural ridges (average height of 4 µm) are smooth, transparent, and accentuated proximally by their thick, dense bases. Paraplate 1 is hexagonal, while paraplate 1p is smaller and pentagonal. The hypocystal configuration is partiform. The parasulcus is segmented into 5 paraplates; the posterior sulcal paraplate is wider and subomegaform. The paracingulum is wide (8 to 10 µm) and very slightly laevorotatory or non-spiral. The archaeopyle is 8 to 10 µm wide; The attached operculum is composed of 9 paraplates: 1 preapical, 4 apical and 4 anterior intercalary.
Comparison: Microdinium inornatum sp. nov. is possibly comparable to Microdinium glabrum by WILSON (1974) in his Ph.D. work (unpublished). It is distinguished from Microdinium crctaceum sp. nov. and Microdinium sonciniae (MARHEINECKE, 1992) comb. nov., by its cyst lacking intratabular ornamentation. The specimens listed under the name Phanerodinium cf. Ph. squamosum by MARHEINECKE (1992) resemble the studied species especially by their fairly developed crests and also by the absence of intratabular ornamentation. M. glabrum COOKSON and EISENACK (1974) and Microdinium squamosum (BELOW, 1987b) LENTIN and WILLIAMS (1989) are also species without ornamentation but their smooth crests are lower.
Stratigraphic distribution: Beutenaken: sample 1 to 5, Halembaye: ex. 4 to 27; Lower Campanian - Upper Campanian. (Zone with G. quadrata - Zone with B. mucronata). Turnhout: -978 to -775.01 m, Upper Campanian. - Maastrichtian upper. In WILSON (1974), Maastrichtian inf. (occidentalis and lanceolata Zone - occidentalis Zone), Denmark. MARHEINECKE (1992), Maastrichtian, Hemmoor, Germany.