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Spumadinium irregulare
Spumadinium irregulare Slimani and Louwye, 2013, p.15,18, pl.3, figs.1–12. Holotype: Slimani and Louwye, 2013, pl.3, figs.1–5. Age: early late Maastrichtian.
Original description (Slimani and Louwye, 2013)
Holotype: Sample Meer 895 m, slide 1, EF coordinates U44/3. Specimen dimensions: total length 75 μm, total width 62 μm, central body length 50 μm, central body width 40 μm, archaeopyle size 30 μm (Plate III, 1–5).
Paratype: Sample Turnhout 722.40 m, slide 15, EF coordinates Z29. Specimen dimensions: total length 83 μm, total width 80 μm, central body length 58 μm, central body width 57 μm, archaeopyle size 42 μm (Plate III, 7–8).
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: Lower part of the Upper Maastrichtian, Meer borehole 895 m depth.
Etymology: From medieval Latin irregularis meaning irregular, with reference to the irregular cyst wall surface.
Diagnosis: A holocavate Spumadinium species with the pericyst and endocyst irregularly separated by thin columellae or pillars, which are of different length and irregularly distributed. The two layers may be locally attached on certain restricted areas. The archaeopyle consists of a combination of precingular and anterior intercalary plates.
Description: The cyst is of intermediate to large size and has a subspherical to ovoidal endocyst that is enclosed in a larger thinner-walled pericyst. The endophragm is thick (about 1.5 to 2 μm), granulated and gives arise to thin columellae or pillars, which are of different length and are irregularly distributed. The columellae or pillars support in a non-uniform manner the very thin (less than 0.5 μm), hyaline and smooth periphragm. The periphragm bears occasionally dispersed granules. The periphragm is often expanded outwards and may be locally attached to the endophragm at the archaeopyle margin and the posterior ventral, posterior dorsal and central antapical areas. The overall cyst outline is, therefore, often irregular because of the variable bulges and undulations of the periphragm, which results from its non-uniform separation and variable distance from the endocyst. The tabulation is indicated by the archaeopyle and occasionally by fibrous or spongy thickenings that result from the local attachment of the endophragm and periphragm. The large archaeopyle displays the same margin angularities of the Spumadinium type species, and is indicative of a combination archaeopyle type 2a2P involving the release of two anterior intercalary plates (1a, 2a) and two precingular plates (3″, 4″). Individual opercular plates 3″, 4″ are observed on the holotype, the intercalary plates 1a and 2a are missing.
Discussion: Spumadinium irregulare sp. nov. is identical to the specimens figured as Membranilarnacia tenella Morgenroth, 1968 by Slimani (1995, pl. 28, fig. 12; 2000, pl. 6, fig. 12) and to Spumadinium sp. of Brinkhuis et al. (2000, pl. 4, figs. 4–6). Membranilarnacia tenella differs from the new species in having an apical archaeopyle of type (tA) consisting of a simple opercular plate rather than a combination type 2a2P of four individual opercular plates. Membranilarnacia tenella has the ectophragm connected uniformly to the central body by strong processes, while S. irregulare has a pericyst and an endocyst that are irregularly separated. Both phragma are irregularly connected by thin columellae or pillars of different length. Spumadinium felderorum Brinkhuis et al., 2000 differs from the new species through its smaller size and through its attached endophragm and periphragm, forming a completely spongeous or columellate cyst wall with a perforate outer surface ornamented with spines.
Dimensions of measured specimens: Total length 60(68)95 μm, total width 50(62)80 μm, central body length 45(54)70 μm, central body width 40(47)65 μm. Archaeopyle size 30–40 μm. 18 specimens measured.
Stratigraphic range: Upper part of the Upper Maastrichtian–Danian of Turnhout, northern Belgium ( Slimani, 1995, Slimani, 2000 and Slimani, 2001); Danian of Bunde, southern Netherlands (Brinkhuis et al., 2000); Upper part of the Upper Maastrichtian–Danian of Meer, northern Belgium (Slimani et al., 2011). Discontinuous and sporadic occurrence of this species in strata older than uppermost Maastrichtian in the Meer borehole were interpreted by Slimani et al. (2011) as the result of downhole contamination caused by drilling mud recycling.
Original description (Slimani and Louwye, 2013)
Holotype: Sample Meer 895 m, slide 1, EF coordinates U44/3. Specimen dimensions: total length 75 μm, total width 62 μm, central body length 50 μm, central body width 40 μm, archaeopyle size 30 μm (Plate III, 1–5).
Paratype: Sample Turnhout 722.40 m, slide 15, EF coordinates Z29. Specimen dimensions: total length 83 μm, total width 80 μm, central body length 58 μm, central body width 57 μm, archaeopyle size 42 μm (Plate III, 7–8).
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: Lower part of the Upper Maastrichtian, Meer borehole 895 m depth.
Etymology: From medieval Latin irregularis meaning irregular, with reference to the irregular cyst wall surface.
Diagnosis: A holocavate Spumadinium species with the pericyst and endocyst irregularly separated by thin columellae or pillars, which are of different length and irregularly distributed. The two layers may be locally attached on certain restricted areas. The archaeopyle consists of a combination of precingular and anterior intercalary plates.
Description: The cyst is of intermediate to large size and has a subspherical to ovoidal endocyst that is enclosed in a larger thinner-walled pericyst. The endophragm is thick (about 1.5 to 2 μm), granulated and gives arise to thin columellae or pillars, which are of different length and are irregularly distributed. The columellae or pillars support in a non-uniform manner the very thin (less than 0.5 μm), hyaline and smooth periphragm. The periphragm bears occasionally dispersed granules. The periphragm is often expanded outwards and may be locally attached to the endophragm at the archaeopyle margin and the posterior ventral, posterior dorsal and central antapical areas. The overall cyst outline is, therefore, often irregular because of the variable bulges and undulations of the periphragm, which results from its non-uniform separation and variable distance from the endocyst. The tabulation is indicated by the archaeopyle and occasionally by fibrous or spongy thickenings that result from the local attachment of the endophragm and periphragm. The large archaeopyle displays the same margin angularities of the Spumadinium type species, and is indicative of a combination archaeopyle type 2a2P involving the release of two anterior intercalary plates (1a, 2a) and two precingular plates (3″, 4″). Individual opercular plates 3″, 4″ are observed on the holotype, the intercalary plates 1a and 2a are missing.
Discussion: Spumadinium irregulare sp. nov. is identical to the specimens figured as Membranilarnacia tenella Morgenroth, 1968 by Slimani (1995, pl. 28, fig. 12; 2000, pl. 6, fig. 12) and to Spumadinium sp. of Brinkhuis et al. (2000, pl. 4, figs. 4–6). Membranilarnacia tenella differs from the new species in having an apical archaeopyle of type (tA) consisting of a simple opercular plate rather than a combination type 2a2P of four individual opercular plates. Membranilarnacia tenella has the ectophragm connected uniformly to the central body by strong processes, while S. irregulare has a pericyst and an endocyst that are irregularly separated. Both phragma are irregularly connected by thin columellae or pillars of different length. Spumadinium felderorum Brinkhuis et al., 2000 differs from the new species through its smaller size and through its attached endophragm and periphragm, forming a completely spongeous or columellate cyst wall with a perforate outer surface ornamented with spines.
Dimensions of measured specimens: Total length 60(68)95 μm, total width 50(62)80 μm, central body length 45(54)70 μm, central body width 40(47)65 μm. Archaeopyle size 30–40 μm. 18 specimens measured.
Stratigraphic range: Upper part of the Upper Maastrichtian–Danian of Turnhout, northern Belgium ( Slimani, 1995, Slimani, 2000 and Slimani, 2001); Danian of Bunde, southern Netherlands (Brinkhuis et al., 2000); Upper part of the Upper Maastrichtian–Danian of Meer, northern Belgium (Slimani et al., 2011). Discontinuous and sporadic occurrence of this species in strata older than uppermost Maastrichtian in the Meer borehole were interpreted by Slimani et al. (2011) as the result of downhole contamination caused by drilling mud recycling.