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Druggidium discretum
Druggidium discretum Slimani and Louwye, 2011, p.43. pl.1, figs.1–15.
Holotype: Slimani and Louwye, 2011, pl.1, figs.1–4.
Age: latest Maastrichtian.
Original description (Slimani and Louwye, 2011):
Druggidium discretum sp. nov. (Plate I, 1–15)
In press Druggidium? sp. C of Slimani et al., table 1, fig. 8i.
Holotype: Slide Meer 848 m, preparation 1, EF V34/1 (Plate I, 1–4).
Repository: Botanical collection of the National Herbarium (RAB), Scientific Institute, Mohammed V-Agdal University, Rabat, Morocco.
Type locality: Meer (Antwerp province, northern Belgium), well no. 007E0205 of the Geological Survey of Belgium.
Stratigraphic horizon: Uppermost Maastrichtian, Meer 848 m borehole depth.
Etymology: Latin, discretus, discreet, with reference to the discreet indication of tabulation.
Diagnosis: An ovoidal species of Druggidium characterized by a finely spongeous wall with a discreet indication of tabulation, except for the cingulum and the sulcus, which are delimited by very low crests. The archeopyle is formed by the release of one or more precingular plates or consists of a combination involving apical, anterior intercalary and precingular plates.
Description: This small proximate dinoflagellate cyst has an ovoidal shape. The hypocyst length comprises about 2/3 of the total cyst length, the rest is shared equally by the cingulum and epicyst. The cyst wall is composed of two closely adpressed layers. The endophragm is smooth and has a maximum thickness of 1 μm. The periphragm has a finely spongeous structure and a maximum thickness of 2 μm. The cingulum is indicated by an unsegmented transverse depression limited by 2 parallel low ridges. The cingulum is slightly laevorotatory and has a maximum width of 6 μm. The sulcus presents a flagellar scar and a large postcingular omega-shaped area. Apart from the unsegmented cingulum and sulcus, the cyst wall surface does not show clear tabulation. The archeopyle may be precingular of type P with a free monoplacoid operculum (plate 3″) or 2P with a compound biplacoid operculum formed by plates 3″ and 4″, both free or one of them attached adcingularly. The archeopyle may also be a combination of type 2P(AI)a with a compound operculum consisting of one ventrally-attached part (apical and anterior intercalary plates) and two free plates (3″ and 4″).
Discussion: The finely spongeous periphragm with a weak indication of tabulation, plus the characteristic unsegmented cingulum distinguishes Druggidium discretum sp. nov. from all other Druggidium species. Specimens of the new species with a precingular archeopyle of type P are similar to Tectatodinium pellitum Wall, 1967 in the possession of a spongeous periphram, but differ distinctly in being smaller and in having a cingulum and sulcus. The new species is conspecific with Druggidium? sp. C of Slimani et al. (2011).
Dimensions: Holotype length 30 μm, width 25 μm. Range: length 30 (31)33 μm, width 25(27)30 μm. Number of specimens measured: 10.
Stratigraphic occurrence: Uppermost Maastrichtian of Turnhout (personal observation in prepared microscope slides, H. Slimani) and Meer (Slimani et al., 2011), northern Belgium.
Holotype: Slimani and Louwye, 2011, pl.1, figs.1–4.
Age: latest Maastrichtian.
Original description (Slimani and Louwye, 2011):
Druggidium discretum sp. nov. (Plate I, 1–15)
In press Druggidium? sp. C of Slimani et al., table 1, fig. 8i.
Holotype: Slide Meer 848 m, preparation 1, EF V34/1 (Plate I, 1–4).
Repository: Botanical collection of the National Herbarium (RAB), Scientific Institute, Mohammed V-Agdal University, Rabat, Morocco.
Type locality: Meer (Antwerp province, northern Belgium), well no. 007E0205 of the Geological Survey of Belgium.
Stratigraphic horizon: Uppermost Maastrichtian, Meer 848 m borehole depth.
Etymology: Latin, discretus, discreet, with reference to the discreet indication of tabulation.
Diagnosis: An ovoidal species of Druggidium characterized by a finely spongeous wall with a discreet indication of tabulation, except for the cingulum and the sulcus, which are delimited by very low crests. The archeopyle is formed by the release of one or more precingular plates or consists of a combination involving apical, anterior intercalary and precingular plates.
Description: This small proximate dinoflagellate cyst has an ovoidal shape. The hypocyst length comprises about 2/3 of the total cyst length, the rest is shared equally by the cingulum and epicyst. The cyst wall is composed of two closely adpressed layers. The endophragm is smooth and has a maximum thickness of 1 μm. The periphragm has a finely spongeous structure and a maximum thickness of 2 μm. The cingulum is indicated by an unsegmented transverse depression limited by 2 parallel low ridges. The cingulum is slightly laevorotatory and has a maximum width of 6 μm. The sulcus presents a flagellar scar and a large postcingular omega-shaped area. Apart from the unsegmented cingulum and sulcus, the cyst wall surface does not show clear tabulation. The archeopyle may be precingular of type P with a free monoplacoid operculum (plate 3″) or 2P with a compound biplacoid operculum formed by plates 3″ and 4″, both free or one of them attached adcingularly. The archeopyle may also be a combination of type 2P(AI)a with a compound operculum consisting of one ventrally-attached part (apical and anterior intercalary plates) and two free plates (3″ and 4″).
Discussion: The finely spongeous periphragm with a weak indication of tabulation, plus the characteristic unsegmented cingulum distinguishes Druggidium discretum sp. nov. from all other Druggidium species. Specimens of the new species with a precingular archeopyle of type P are similar to Tectatodinium pellitum Wall, 1967 in the possession of a spongeous periphram, but differ distinctly in being smaller and in having a cingulum and sulcus. The new species is conspecific with Druggidium? sp. C of Slimani et al. (2011).
Dimensions: Holotype length 30 μm, width 25 μm. Range: length 30 (31)33 μm, width 25(27)30 μm. Number of specimens measured: 10.
Stratigraphic occurrence: Uppermost Maastrichtian of Turnhout (personal observation in prepared microscope slides, H. Slimani) and Meer (Slimani et al., 2011), northern Belgium.