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Triphragmadinium demaniae
Triphragmadinium demaniae Van Simaeys et al., 2005, p.126, pl.1, figs.1–6; pl.2, figs.1–3,6–8.
Holotype: Van Simaeys et al., 2005, pl.1, figs.1–5.
Age: late Oligocene.
Original description (Van Simaeys et al., 2005);
Triphragmadinium demaniae sp. nov.
Holotype: Plate I,1–5, sample/slide: Gartow, 221 m, S-199-1-30 µm (Y-43).
Paratype: Plate II,1–3, sample/slide: Weelde, 229 m, S-209-1-30 µm (M-59/1); Plate II,6–8, sample/ slide: Weelde, 229 m, S-209-2-30 µm (Y-51); Plate I,6, sample/slide: Gartow, 221 m, S-199-1-30 µm (G-56/3).
Type occurrence: Gartow borehole, 221 m, northern Germany (sheet TK 2934 (Lenzen), R: 44 62 824, H: 58 77 250), Chattian Sand Formation, upper Eochatt, Late Oligocene.
Etymology: Named for Ellen De Man of the Royal Belgian Institute of Natural Sciences, in recognition of her micropaleontological studies of the Belgian Oligocene.
Diagnosis: A species of Triphragmadinium in which the periphragm is in contact with the endocyst both at the apical archeopyle margins and along parts of the antapical paraplate 1W boundaries.
Description: Cysts comprising endocyst and pericyst that are typically in contact only at the margins of the apical archeopyle and by a funnel-like, sickleshaped invagination of the periphragm at the posterior end (Plate I,5). Endocyst is subspherical to spherical and consists of two phragma: the inner endophragm is smooth and ca. 1–2 µm thick; the outer mesophragm is thin (<0.5 µm) and in general contact with the endophragm but separates from the latter along the paracingulum and along the paraplate boundaries (Plate I,5). This suturocavate structure, formed by an outfold of the mesophragm, demarcates the paraplate boundaries and allows the paracingulum to be easily recognised. The pericyst is subspherical to “box-shaped”, formed from a smooth to scabrate periphragm, which is typically perforated showing irregular circular claustra. The position of the funnel-like, sickle-shaped invagination suggests that the periphragm is in contact with the endocyst along parts of the antapical paraplate 1’’’’ boundaries (Plate II,2–3). A pronounced, hollow, tubular, antapical process arises from the funnel-like invagination of the periphragm. No other processes or columellae were observed. This antapical process is distally closed (Plate II,7–8). The archeopyle is apical (Type tA), and exhibits a zigzag suture; the operculum is free. The width of the pericoel is fairly constant among specimens, being ca. 50% to 60% of the endocyst length. The width of the pericoel at the antapex is variable but never exceeds more than 50% of the endocyst length.
Dimensions: Many specimens are obliquely compressed and hence are difficult to measure. In those cases we measured only the maximum endocyst and pericyst diameter. Fourteen specimens were measured. Maximum endocyst diameter 40(48)55 µm, holotype 50 µm; maximum pericyst diameter 85(90)95 µm, holotype 95 µm. The height of the suturocavate structures between endophragm and mesophragm is ca. ~4 µm.
Comparison: Triphragmadinium demaniae is most similar to fully inflated specimens of Cousteaudinium aubryae De Verteuil and Norris, 1996. However, Triphragmadinium demaniae comprises three phragma and the funnel-like, sickle-shaped invagination of the periphragm at the posterior end, indicating the antapical paraplate 1’’’’ boundaries. All other cavate Paleogene and Neogene taxa, including species of Amiculosphaera, Invertocysta, Saturnodinium, and Thalassiphora, are quite distinct from Triphragmadinium demaniae, most obviously in having a precingular archeopyle.
Stratigraphic occurrence: Latest Chattian. Evidence from Gartow borehole, 236–221 m, northern Germany; Weelde borehole, 229 m, NE Belgium; Mol Belchim borehole, 160 m, NE Belgium; Retie borehole, 153.3 m, NW Belgium; Ekeren borehole, 33.3 m, NW Belgium; Groote Heide borehole, 532–523, SE The Netherlands.
Other records: Specimens from the Lower Miocene of the Norwegian Sea illustrated by Manum et al. (1989) as Dinocyst 5, may be conspecific with Triphragmadinium demaniae, although this cannot be confirmed from the available information. The pronounced antapical horn (Manum et al., 1989, plate 8,15) and the zigzag apical archeopyle sutures (Manum et al., 1989, plate 8,14) of Dinocyst 5 favour an attribution to the genus Triphragmadinium rather than to Cousteaudinium as suggested by De Verteuil and Norris (1996, p. 114).
Remarks: Triphragmadinium demaniae occurs in deposits thought to be marginal marine, judging from the associated high concentrations of Paralecaniella indentata and Homotryblium spp.
Holotype: Van Simaeys et al., 2005, pl.1, figs.1–5.
Age: late Oligocene.
Original description (Van Simaeys et al., 2005);
Triphragmadinium demaniae sp. nov.
Holotype: Plate I,1–5, sample/slide: Gartow, 221 m, S-199-1-30 µm (Y-43).
Paratype: Plate II,1–3, sample/slide: Weelde, 229 m, S-209-1-30 µm (M-59/1); Plate II,6–8, sample/ slide: Weelde, 229 m, S-209-2-30 µm (Y-51); Plate I,6, sample/slide: Gartow, 221 m, S-199-1-30 µm (G-56/3).
Type occurrence: Gartow borehole, 221 m, northern Germany (sheet TK 2934 (Lenzen), R: 44 62 824, H: 58 77 250), Chattian Sand Formation, upper Eochatt, Late Oligocene.
Etymology: Named for Ellen De Man of the Royal Belgian Institute of Natural Sciences, in recognition of her micropaleontological studies of the Belgian Oligocene.
Diagnosis: A species of Triphragmadinium in which the periphragm is in contact with the endocyst both at the apical archeopyle margins and along parts of the antapical paraplate 1W boundaries.
Description: Cysts comprising endocyst and pericyst that are typically in contact only at the margins of the apical archeopyle and by a funnel-like, sickleshaped invagination of the periphragm at the posterior end (Plate I,5). Endocyst is subspherical to spherical and consists of two phragma: the inner endophragm is smooth and ca. 1–2 µm thick; the outer mesophragm is thin (<0.5 µm) and in general contact with the endophragm but separates from the latter along the paracingulum and along the paraplate boundaries (Plate I,5). This suturocavate structure, formed by an outfold of the mesophragm, demarcates the paraplate boundaries and allows the paracingulum to be easily recognised. The pericyst is subspherical to “box-shaped”, formed from a smooth to scabrate periphragm, which is typically perforated showing irregular circular claustra. The position of the funnel-like, sickle-shaped invagination suggests that the periphragm is in contact with the endocyst along parts of the antapical paraplate 1’’’’ boundaries (Plate II,2–3). A pronounced, hollow, tubular, antapical process arises from the funnel-like invagination of the periphragm. No other processes or columellae were observed. This antapical process is distally closed (Plate II,7–8). The archeopyle is apical (Type tA), and exhibits a zigzag suture; the operculum is free. The width of the pericoel is fairly constant among specimens, being ca. 50% to 60% of the endocyst length. The width of the pericoel at the antapex is variable but never exceeds more than 50% of the endocyst length.
Dimensions: Many specimens are obliquely compressed and hence are difficult to measure. In those cases we measured only the maximum endocyst and pericyst diameter. Fourteen specimens were measured. Maximum endocyst diameter 40(48)55 µm, holotype 50 µm; maximum pericyst diameter 85(90)95 µm, holotype 95 µm. The height of the suturocavate structures between endophragm and mesophragm is ca. ~4 µm.
Comparison: Triphragmadinium demaniae is most similar to fully inflated specimens of Cousteaudinium aubryae De Verteuil and Norris, 1996. However, Triphragmadinium demaniae comprises three phragma and the funnel-like, sickle-shaped invagination of the periphragm at the posterior end, indicating the antapical paraplate 1’’’’ boundaries. All other cavate Paleogene and Neogene taxa, including species of Amiculosphaera, Invertocysta, Saturnodinium, and Thalassiphora, are quite distinct from Triphragmadinium demaniae, most obviously in having a precingular archeopyle.
Stratigraphic occurrence: Latest Chattian. Evidence from Gartow borehole, 236–221 m, northern Germany; Weelde borehole, 229 m, NE Belgium; Mol Belchim borehole, 160 m, NE Belgium; Retie borehole, 153.3 m, NW Belgium; Ekeren borehole, 33.3 m, NW Belgium; Groote Heide borehole, 532–523, SE The Netherlands.
Other records: Specimens from the Lower Miocene of the Norwegian Sea illustrated by Manum et al. (1989) as Dinocyst 5, may be conspecific with Triphragmadinium demaniae, although this cannot be confirmed from the available information. The pronounced antapical horn (Manum et al., 1989, plate 8,15) and the zigzag apical archeopyle sutures (Manum et al., 1989, plate 8,14) of Dinocyst 5 favour an attribution to the genus Triphragmadinium rather than to Cousteaudinium as suggested by De Verteuil and Norris (1996, p. 114).
Remarks: Triphragmadinium demaniae occurs in deposits thought to be marginal marine, judging from the associated high concentrations of Paralecaniella indentata and Homotryblium spp.