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Xenicodinium reticulatum
From Fensome et al., 2019:
Xenicodinium reticulatum Hansen, 1977, p.12–13, figs.20H–J.
Holotype: Hansen, 1977, figs.20H–J. Originally Xenicodinium, subsequently Tectatodinium.
Taxonomic senior synonym: Tectatodinium pellitum, questionably according to Head (1994a, p.308), and according to Head and Nøhr-Hansen (1999, p.577).
Age: Danian.
Stratigraphical occurrence: Maastrichtian/Danian boundary
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Original description: Hansen, 1977:
Diagnosis:
Xenicodinium Klement, 1960 with a clearly reticulate surface.
Description:
Egg-shaped cysts. Wall composed of two layers, endophragm and periphragm. Endophragm smooth ca. 0.5 µm, periphragm composed of a tight reticulum of membranes (4-5 µm high) orthogonal to the surface. The reticulum thus formed has a mash-size from 4 to 10 µm. The reticulum may be orientated. In optical sections the outer margin of the reticulum is always sharp.
Archeopyle angular with (3-) 5 sides, probably precingular, situated below the less rounded pole of the cyst.
Affinities:
Xenicodinium reticulatum sp. nov. resembles Xenicodinium lubricum Morgenroth, 1968, but differs by the structure of the periphragm, which in X. lubricum is not or only weakly reticulate and possessing small cavities in the basal part of the membranes, giving rise to a more irregular surface than in X. reticulatum.
Xenicodinium reticulatum Hansen, 1977, p.12–13, figs.20H–J.
Holotype: Hansen, 1977, figs.20H–J. Originally Xenicodinium, subsequently Tectatodinium.
Taxonomic senior synonym: Tectatodinium pellitum, questionably according to Head (1994a, p.308), and according to Head and Nøhr-Hansen (1999, p.577).
Age: Danian.
Stratigraphical occurrence: Maastrichtian/Danian boundary
----------------------------------------------------------------------------------------------------------------------------------
Original description: Hansen, 1977:
Diagnosis:
Xenicodinium Klement, 1960 with a clearly reticulate surface.
Description:
Egg-shaped cysts. Wall composed of two layers, endophragm and periphragm. Endophragm smooth ca. 0.5 µm, periphragm composed of a tight reticulum of membranes (4-5 µm high) orthogonal to the surface. The reticulum thus formed has a mash-size from 4 to 10 µm. The reticulum may be orientated. In optical sections the outer margin of the reticulum is always sharp.
Archeopyle angular with (3-) 5 sides, probably precingular, situated below the less rounded pole of the cyst.
Affinities:
Xenicodinium reticulatum sp. nov. resembles Xenicodinium lubricum Morgenroth, 1968, but differs by the structure of the periphragm, which in X. lubricum is not or only weakly reticulate and possessing small cavities in the basal part of the membranes, giving rise to a more irregular surface than in X. reticulatum.