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Wilsonidium rugosum
From Fensome et al., 2019:
Wilsonidinium? rugosum (Stanley, 1965) Lentin and Williams, 1976
Originally Wetzeliella, subsequently Wilsonidium?, thirdly Wetzeliella?, fourthly (and now) Spinidinium.
At the time of the transfer, Lentin and Williams, 1976, questionably included this species in Wilsonidium.
Stover and Evitt, 1978, questionably transferred this species to Wetzeliella Eisenack, 1938, and Costa and Downie, 1979, transferred the species to Spinidinium Cookson and Eisenack, 1962. Lentin and Williams, 1981, questionably retained it in Wilsonidium.
Holotype: Stanley, 1965, pl.21, fig.10-11
Locus typicus: South Dakota, USA
Stratum typicum: Paleocene
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Original description: Stanley, 1965, p.222-223: Wetzeliella rugosa
Outer cyst rhomboidal to subrhomboidal in outline with the length being either slightly longer or slightly shorter than the width. Length varies between 50-60 µm whereas the width also varies between 50-60 µm. Outer cyst membrane thin and almost always irregularly folded or crumpled; membrane bears spinelike sculpture elements that have a length of about 1.5 to 2 µm. Apical horn about 3-5 µm in length; antapical horns two in number; the left one being well developed with a length of about 5 µm whereas the right one is poorly developed. Girdle indistinct but does appear to be bordered on both edges by a row of spinelike processes. Interior cyst thin-walled and more or less completely fills the outer cyst.
Affinities:
Stanley, 1965, p.223: Wetzeliella rugosa
Wetzeliella rugosa is differentiated from W. pilata, by ist spinlike sculpture elements that lach any expansion at their distal ends.
Wilsonidinium? rugosum (Stanley, 1965) Lentin and Williams, 1976
Originally Wetzeliella, subsequently Wilsonidium?, thirdly Wetzeliella?, fourthly (and now) Spinidinium.
At the time of the transfer, Lentin and Williams, 1976, questionably included this species in Wilsonidium.
Stover and Evitt, 1978, questionably transferred this species to Wetzeliella Eisenack, 1938, and Costa and Downie, 1979, transferred the species to Spinidinium Cookson and Eisenack, 1962. Lentin and Williams, 1981, questionably retained it in Wilsonidium.
Holotype: Stanley, 1965, pl.21, fig.10-11
Locus typicus: South Dakota, USA
Stratum typicum: Paleocene
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Original description: Stanley, 1965, p.222-223: Wetzeliella rugosa
Outer cyst rhomboidal to subrhomboidal in outline with the length being either slightly longer or slightly shorter than the width. Length varies between 50-60 µm whereas the width also varies between 50-60 µm. Outer cyst membrane thin and almost always irregularly folded or crumpled; membrane bears spinelike sculpture elements that have a length of about 1.5 to 2 µm. Apical horn about 3-5 µm in length; antapical horns two in number; the left one being well developed with a length of about 5 µm whereas the right one is poorly developed. Girdle indistinct but does appear to be bordered on both edges by a row of spinelike processes. Interior cyst thin-walled and more or less completely fills the outer cyst.
Affinities:
Stanley, 1965, p.223: Wetzeliella rugosa
Wetzeliella rugosa is differentiated from W. pilata, by ist spinlike sculpture elements that lach any expansion at their distal ends.