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Ovoidinium implanum
From Fensome et al., 2019:
Ovoidinium implanum Davey, 1979b, p.558–559, pl.5, figs.7–9,11–12. Holotype: Davey, 1979b, pl.5, figs.7,11. Originally (and now) Ovoidinium, subsequently Ascodinium. Lentin and Williams (1989, p.269) retained this species in Ovoidinium. Age: late Albian.
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Original description (Davey, 1979):
Ovoidinium implanum sp. nov. (Plate 5, Figures 7-9, 11, 12)
Derivation of name: Latin, implanus, uneven — with reference to the rough wall of the cyst.
Diagnosis: A subspherical to ovoid species of Ovoidinium composed of endophragm and periphragm both of moderate thickness; the apical region is broadly subconical. The periphragm is closely adpressed to the endophragm except at the antapex where a small pericoel is usually present and at the apex where occasionally an apical pericoel exists. The periphragm is strongly ornamented and all gradations exist from coarse irregularly shaped pits (fossulate-foveolate ornamentation) to a dense, fine intraperforation. A pericingulum and antapically widening perisulcus are usually noticeable. The combination archeopyle (type 4A31) is always developed and the operculum often remains attached.
Holotype: MPK 1668, DSDP Leg 48, Hole 400A, Sample 62-4, 111-113 cm. Albian, northern Bay of Biscay.
Dimensions: Holotype [Range]:
Overall length (complete specimen) 54 µm [40 (49) 56 µm].
Overall length (operculum detached) [c. 40 µm]
Width 46 µm [40 (44) 48 µm]
Height of antapical pericoel 5 µm [0-5 µm]
Description: The wall layers are each of about 0.5 µm in thickness. The endophragm appears to be smooth whereas the periphragm has a characteristically strong ornamentation and, although some positive elements may occasionally be detected around the lateral margins of the cyst, it appears most probably that a negative ornamentation is typical. The antapical periphragm extension when present, may either be almost symmetrical (see holotype) or may be more strongly developed on the left side.
Remarks: The reduced pericoels and the structure of the periphragm distinguishes O. implanum sp. nov. from all previously described species. This distinctive species only occurred in Section 62-4 where it was common.
Ovoidinium implanum Davey, 1979b, p.558–559, pl.5, figs.7–9,11–12. Holotype: Davey, 1979b, pl.5, figs.7,11. Originally (and now) Ovoidinium, subsequently Ascodinium. Lentin and Williams (1989, p.269) retained this species in Ovoidinium. Age: late Albian.
---------------------------------------------------------------------------------------------------
Original description (Davey, 1979):
Ovoidinium implanum sp. nov. (Plate 5, Figures 7-9, 11, 12)
Derivation of name: Latin, implanus, uneven — with reference to the rough wall of the cyst.
Diagnosis: A subspherical to ovoid species of Ovoidinium composed of endophragm and periphragm both of moderate thickness; the apical region is broadly subconical. The periphragm is closely adpressed to the endophragm except at the antapex where a small pericoel is usually present and at the apex where occasionally an apical pericoel exists. The periphragm is strongly ornamented and all gradations exist from coarse irregularly shaped pits (fossulate-foveolate ornamentation) to a dense, fine intraperforation. A pericingulum and antapically widening perisulcus are usually noticeable. The combination archeopyle (type 4A31) is always developed and the operculum often remains attached.
Holotype: MPK 1668, DSDP Leg 48, Hole 400A, Sample 62-4, 111-113 cm. Albian, northern Bay of Biscay.
Dimensions: Holotype [Range]:
Overall length (complete specimen) 54 µm [40 (49) 56 µm].
Overall length (operculum detached) [c. 40 µm]
Width 46 µm [40 (44) 48 µm]
Height of antapical pericoel 5 µm [0-5 µm]
Description: The wall layers are each of about 0.5 µm in thickness. The endophragm appears to be smooth whereas the periphragm has a characteristically strong ornamentation and, although some positive elements may occasionally be detected around the lateral margins of the cyst, it appears most probably that a negative ornamentation is typical. The antapical periphragm extension when present, may either be almost symmetrical (see holotype) or may be more strongly developed on the left side.
Remarks: The reduced pericoels and the structure of the periphragm distinguishes O. implanum sp. nov. from all previously described species. This distinctive species only occurred in Section 62-4 where it was common.