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Apteodinium spiridoides

Apteodinium spiridoides, Benedek, 1972

Tax. sr. synonym of Apteodinium tectatum Piasecki, 1980, according to Lucas-Clark, 1987. Benedek and Sarjeant, 1981, transferred this species to Emslandia; however, Jan du Chêne et al., 1986, retained it in Apteodinium.

Holotype: Benedek, 1972, pl.2, fig.1; Benedek and Sarjeant, 1981, fig.2, no.1-3; Jan du Chêne et al., 1986, pl.11, fig.6-9.
Paratypes: Benedek, 1972
Locus typicus: Tonisberg, Niederrhein, Germany
Stratum typicum: Middle Oligocene

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Original description: [Benedek, 1972, p. 5]: (Translation: LPP):

Diagnosis:
An Apteodinium species with the following features: the rounded ovoidal, in outline diamond-shaped shell, has an up to 5 µm thick, apparently strongly granulate wall. The veined wall seems to be patterned with white stains.

Description:
yellow-brownish membrane, epitheca and hypotheca are separated by a narrow, hardly indented, sometimes not visible girdle-furrow. There is only an indication of a longitudinal furrow. Apical and antapical processes are not observed. All specimens possess a rounded trapezoidal opening in precingular position.

Dimensions:
shell length 76 (72-78) µm, width 72-74 µm, pylome 30x40 µm, wall 5 µm.

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Emended description as Emslandia spiridoides:

Benedek and Sarjeant, 1981, p. 319:

Diagnosis:
Cyst proximate, subglobular to broadly subpolygonal. Epitract in the form of a rounded and trucated cone, crowned by a broad, low apical prominence: hypotract hemispherical. Phragma thick, two-layered; endophragm quite thin, periphragm roughly twelve to fifteen times thicker (total thickness c. 5 µm) and perforated by an irregular pattern of cavities and canals, sometimes opening to the exterior.
Paracingulum well marked by an indentation of the periphragm surface and bordered by narrow ridges; its two ends are only slightly offset. Parasulcus similarly marked and extending for a short distance anterior, and a greater distance posterior, to the paracingulum.
Surface of periphragm granulate to finely scabrate.
Archaeopyle single-plate precingular, Type P.

Dimensions:
Holotype: length 76 µm, breadth 73 µm, thickness of wall 5 µm.
Range of Dimensions: Length 72-78 µm, breadth 72-74 µm, thickness of wall 5 µm. Material: 7 specimens.

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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Apteodinium spiridoides Benedek, 1972, emend. Benedek and Sarjeant, 1981. Benedek and Sarjeant (1981, p.319) Cyst proximate, subglobular to broadly polygonal. Epicyst in the form of a rounded and truncated cone, crowned by a broad, low apical prominence; hypocyst hemispherical. Phragma thick, two-layered; endophragm thin, periphragm roughly twelve to fifteen times thicker (total thickness ca 5 µm) and perforated by an irregular pattern of cavities and canals, sometimes opening to the exterior. Surface of periphragm granulate to finely scabrate.
Size: length 72-78 µm, width 72-74 µm, wall 5 µm.
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