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Valvaeodinium groenlandicum
Valvaeodinium groenlandicum (Smelror, 1988) Smelror, 1988
Originally Ellipsoidictyum, subsequently (and now) Valvaeodinium, thirdly Valensiella (combination not validly published).
Holotype: Smelror, 1988, pl.8, figs.5-6
Age: Early Oxfordian
Original description (Smelror, 1988)":
1972 Aff. Valensiella Sarjeant, pp.47-48, pl.6, fig.5.
Description: Dinoflagellate cyst, elongate ovoidal in outline, with gently rounded antapex and apex (when operculum in place). A raised reticulum, supported by slender processes up to 5 µm high and enclosing the whole central body. Autophragm otherwise smooth. The open reticulum consists of simple, slender strands interconnected at triple junctions, and forming a polygonal meshwork. However, the general size and outline of the meshes varies considerably. The height of the reticulum above the surface of the central body is in general relatively uniform, but as the slender reticulum is easily folded or torn, there are great variations among the least well preserved specimens. In some specimens depressions in the reticulum appear to be present over the supposed paracingular region, but this is not a consistent feature. The archaeopyle is apical and possibly of type 2A (i.e. formed by loss of the paraplates 3' and 4'). Paratabulation in addition to the archeopyle and accessory archeopyle sutures is not expressed.
Dimensions: Length of central body (including the reticulum) 37-45 µm, width 29-33 µm (8 specimens measured). Holotype: length 44 µm, width 30 µm.
Etymology: From East Greenland from which the species was first recorded and unformally described.
Holotype: S-14/48-1: $48/1, Plate VIII, 5, 6.
Paratype: S-14/47-1: N50/3, Plate VIII, 3.
Type stratum and locality: Kong Karls Land, Hhrfagrehaugen section, Retziusfjellet Member 24.4 m above base.
Occurrence: Hhrfagrehaugen section, Retziusfjellet Member 22.4-24.4 m above base (Lower Oxfordian).
Remarks: Ellipsoidictyum groenlandicum n. sp. is similar to the specimens described as aft. Valensiella sp. from the Upper Vardekloft Formation of Jameson Land (East Greenland) by Sarjeant (1972). Sarjeant reported that the raised reticulum seems to arranged into larger, roughly oval to rectangular, groups which may suggest paratabulation. No such configuration is, however, evident in the present examined material from Kong Karls Land. There is no evidence that the reticulum is generally least high at the antapex as described by Sarjeant (1972).
Ellipsoidictyum groenlandicum n. sp. is here tentatively placed in the genus Ellipsoidictyum because this genus is characterized by interconnected septa forming a surface reticulum, and has previously not included species with a raised reticulum. Ellipsoidictyum groenlandicum n. sp. is conspecific with the species illustrated as Ellipsoidictyum sp. cf. E. cincture Klement 1960 by Davies (1983).
Originally Ellipsoidictyum, subsequently (and now) Valvaeodinium, thirdly Valensiella (combination not validly published).
Holotype: Smelror, 1988, pl.8, figs.5-6
Age: Early Oxfordian
Original description (Smelror, 1988)":
1972 Aff. Valensiella Sarjeant, pp.47-48, pl.6, fig.5.
Description: Dinoflagellate cyst, elongate ovoidal in outline, with gently rounded antapex and apex (when operculum in place). A raised reticulum, supported by slender processes up to 5 µm high and enclosing the whole central body. Autophragm otherwise smooth. The open reticulum consists of simple, slender strands interconnected at triple junctions, and forming a polygonal meshwork. However, the general size and outline of the meshes varies considerably. The height of the reticulum above the surface of the central body is in general relatively uniform, but as the slender reticulum is easily folded or torn, there are great variations among the least well preserved specimens. In some specimens depressions in the reticulum appear to be present over the supposed paracingular region, but this is not a consistent feature. The archaeopyle is apical and possibly of type 2A (i.e. formed by loss of the paraplates 3' and 4'). Paratabulation in addition to the archeopyle and accessory archeopyle sutures is not expressed.
Dimensions: Length of central body (including the reticulum) 37-45 µm, width 29-33 µm (8 specimens measured). Holotype: length 44 µm, width 30 µm.
Etymology: From East Greenland from which the species was first recorded and unformally described.
Holotype: S-14/48-1: $48/1, Plate VIII, 5, 6.
Paratype: S-14/47-1: N50/3, Plate VIII, 3.
Type stratum and locality: Kong Karls Land, Hhrfagrehaugen section, Retziusfjellet Member 24.4 m above base.
Occurrence: Hhrfagrehaugen section, Retziusfjellet Member 22.4-24.4 m above base (Lower Oxfordian).
Remarks: Ellipsoidictyum groenlandicum n. sp. is similar to the specimens described as aft. Valensiella sp. from the Upper Vardekloft Formation of Jameson Land (East Greenland) by Sarjeant (1972). Sarjeant reported that the raised reticulum seems to arranged into larger, roughly oval to rectangular, groups which may suggest paratabulation. No such configuration is, however, evident in the present examined material from Kong Karls Land. There is no evidence that the reticulum is generally least high at the antapex as described by Sarjeant (1972).
Ellipsoidictyum groenlandicum n. sp. is here tentatively placed in the genus Ellipsoidictyum because this genus is characterized by interconnected septa forming a surface reticulum, and has previously not included species with a raised reticulum. Ellipsoidictyum groenlandicum n. sp. is conspecific with the species illustrated as Ellipsoidictyum sp. cf. E. cincture Klement 1960 by Davies (1983).