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Xenicodinium reticulatum
Xenicodinium reticulatum, Hansen, 1977, p. 12
Holotype: Hansen, 1977, figs.20D-G
Locus typicus: TUBA 13, Copenhagen, Denmark
Stratum typicum: Xenicodium lubricum Zonule (Danian)
Age: Danian
Stratigraphical occurrence: Maastrichtian/Danina 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.
Holotype: Hansen, 1977, figs.20D-G
Locus typicus: TUBA 13, Copenhagen, Denmark
Stratum typicum: Xenicodium lubricum Zonule (Danian)
Age: Danian
Stratigraphical occurrence: Maastrichtian/Danina 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.