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Operculodinium xanthium
From Fensome et al., 2019:
Operculodinium xanthium (Benedek, 1972, p.27–28, pl.9, fig.8; text-fig.9) Stover and Evitt, 1978, p.179. Emendation: Benedek and Sarjeant, 1981, p.342–343, as Lingulodinium xanthium. Holotype: Benedek, 1972, pl.9, fig.8; Benedek and
Sarjeant, 1981, fig.9, no.5. Originally Cordosphaeridium, subsequently (and now) Operculudinium, thirdly Lingulodinium. Stover and Hardenbol (1994, p.33) retained this species in Operculodinium. Age: middle–Late
Oligocene.
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Original description: [Benedek, 1972] (translated from German):
Cordosphaeridium xanthium n. sp.
Derivation nominis: xanthion gr. = burdock.
Holotype: The specimen preserved in specimen 559/116 and illustrated on Plate 9, Fig. 8.
Paratypes: 534/116, 587/116.
Typical location: Tönisberg, Lower Rhine.
Typical stratum: Upper Oligocene (Upper Grafenberg beds).
Diagnosis: A species of the genus Cordosphaeridium, whose capsule surface has a net-like structure composed of tough fibers, from which numerous small, pointed processes emerge.
Description: The spherical, sometimes ellipsoidal capsule has a two-layered structure. The inner layer is smooth, the outer layer is fibrous and thus has a net-like pattern. Fiber bundles extend into the processes. These form small, proximally broad, fairly uniform appendages, the length of which varies slightly. All specimens examined have a large, elliptical pyloma.
Remarks: C. xanthium differs from previously known species of this genus in its numerous short, simply pointed appendages. A certain similarity exists only with one species described by GOCHT (1969) but still unknown (Gen. et sp. indet. 3), although significant differences can be observed in the specific formation of the appendages. The appendages of C. xanthium n. sp. have neither knob-like thickenings nor forking distally.
Assignment to the broad genus Cordosphaeridium was strictly based on diagnosis. Presumably, this combines genetically inconsistent features. This applies to many of the problematic dinoflagellate cysts and will only change once the fine structures of the shells are more precisely known.
Dimensions: capsule Ø μ (76μ/100μ), process length 6μ/12μ, wall thickness up to 4μ, pylome Ø 30μ/40μ (10 measurements). Number of specimens examined: 31.
Operculodinium xanthium (Benedek, 1972, p.27–28, pl.9, fig.8; text-fig.9) Stover and Evitt, 1978, p.179. Emendation: Benedek and Sarjeant, 1981, p.342–343, as Lingulodinium xanthium. Holotype: Benedek, 1972, pl.9, fig.8; Benedek and
Sarjeant, 1981, fig.9, no.5. Originally Cordosphaeridium, subsequently (and now) Operculudinium, thirdly Lingulodinium. Stover and Hardenbol (1994, p.33) retained this species in Operculodinium. Age: middle–Late
Oligocene.
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Original description: [Benedek, 1972] (translated from German):
Cordosphaeridium xanthium n. sp.
Derivation nominis: xanthion gr. = burdock.
Holotype: The specimen preserved in specimen 559/116 and illustrated on Plate 9, Fig. 8.
Paratypes: 534/116, 587/116.
Typical location: Tönisberg, Lower Rhine.
Typical stratum: Upper Oligocene (Upper Grafenberg beds).
Diagnosis: A species of the genus Cordosphaeridium, whose capsule surface has a net-like structure composed of tough fibers, from which numerous small, pointed processes emerge.
Description: The spherical, sometimes ellipsoidal capsule has a two-layered structure. The inner layer is smooth, the outer layer is fibrous and thus has a net-like pattern. Fiber bundles extend into the processes. These form small, proximally broad, fairly uniform appendages, the length of which varies slightly. All specimens examined have a large, elliptical pyloma.
Remarks: C. xanthium differs from previously known species of this genus in its numerous short, simply pointed appendages. A certain similarity exists only with one species described by GOCHT (1969) but still unknown (Gen. et sp. indet. 3), although significant differences can be observed in the specific formation of the appendages. The appendages of C. xanthium n. sp. have neither knob-like thickenings nor forking distally.
Assignment to the broad genus Cordosphaeridium was strictly based on diagnosis. Presumably, this combines genetically inconsistent features. This applies to many of the problematic dinoflagellate cysts and will only change once the fine structures of the shells are more precisely known.
Dimensions: capsule Ø μ (76μ/100μ), process length 6μ/12μ, wall thickness up to 4μ, pylome Ø 30μ/40μ (10 measurements). Number of specimens examined: 31.