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Apteodinium indicosum
Apteodinium? indicosum, (Brideaux, 1971, nom. subst. pro Palaeoperidinium granulatum C. Singh, 1964), Stover and Evitt, 1978
Originally Palaeoperidinium granulatum, subsequently Gonyaulacysta indicosa, thirdly (and now) Apteodinium? indicosum.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Apteodinium.
Holotype: Singh, 1964, Plate 18, fig. 2,3
Locus typicus: Fort Augustus no. 1 well, Manville Group, East Central Alberta
Stratum typicum: Grand Rapids Formation
Distribution: Middle Albian. Common in the shale member of the Clearwater Formation and the lower grand Rapids Formation.
Age: Middle-Late Albian
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Original description as Paleoperidinium granulatum: [Singh 1964, p. 135]:
Description:
Test nearly cingular, approximately as long as broad; apical horn averaging 1/5 of the total length, solid to partly solid, short and conical, arising abruptly from the epitheca; a spirally winding membraneous structure commonly present on the apical horn; body distinctly granulose, the equatorial girdle in the middle marked by two prominent lines bearing longer spinules; no plates or longitudinal furrow visible; one longitudinal fold and two horizontal folds, one on each surface usually present.
Dimensions/Size range:
Total length (including apical horn) 96 to 115 µm (Holotype 100 µm)
Length of the test 80 to 89 µm (Holotype 82 µm)
Breadth of the test 80 to 88 µm (Holotype 83 µm)
Length of the apical horn 16 to 26 µm (Holotype 18 µm)
Affinities/Remarks:
Palaeoperidinium nudum DOWNIE, 1957, can be distinguished from P. granulatum n. sp. by its longer apical horn, which is 1/3 of the total length of the body, elongated test, and smooth transparent wall. P. ventriosum DEFLANDRE, 1935, has a much smaller apical horn compared with the size of the body and has over-all dimensions smaller than P. granulatum n. sp.
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Supplemental description as Gonyaulacysta indicosa:
Brideaux 1971, p. 83:
Discussion :
The new specific epithet is necessary to avoid creating a junior homonym of Gonyaulacysta granulata (KLEMENT) SARJEANT 1969, P. 9. Gonyaulacysta indicosa nom. nov. resembles the generic concept of Gonyaulacysta in shape, possession of a precingular archeopyle, and a faint, although not clearly definable, tabulation referable to that genus.
Dimensions:
On 2 measured specimens respectively: length, 80 µm and 119 µm; width, 84 µm and 112 µm; length of apical horn, 7 µm and 14 µm
Distribution:
specimens recorded here from the Joli Fou Formation, Battle Lake well: Late Albian.
Originally Palaeoperidinium granulatum, subsequently Gonyaulacysta indicosa, thirdly (and now) Apteodinium? indicosum.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Apteodinium.
Holotype: Singh, 1964, Plate 18, fig. 2,3
Locus typicus: Fort Augustus no. 1 well, Manville Group, East Central Alberta
Stratum typicum: Grand Rapids Formation
Distribution: Middle Albian. Common in the shale member of the Clearwater Formation and the lower grand Rapids Formation.
Age: Middle-Late Albian
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Original description as Paleoperidinium granulatum: [Singh 1964, p. 135]:
Description:
Test nearly cingular, approximately as long as broad; apical horn averaging 1/5 of the total length, solid to partly solid, short and conical, arising abruptly from the epitheca; a spirally winding membraneous structure commonly present on the apical horn; body distinctly granulose, the equatorial girdle in the middle marked by two prominent lines bearing longer spinules; no plates or longitudinal furrow visible; one longitudinal fold and two horizontal folds, one on each surface usually present.
Dimensions/Size range:
Total length (including apical horn) 96 to 115 µm (Holotype 100 µm)
Length of the test 80 to 89 µm (Holotype 82 µm)
Breadth of the test 80 to 88 µm (Holotype 83 µm)
Length of the apical horn 16 to 26 µm (Holotype 18 µm)
Affinities/Remarks:
Palaeoperidinium nudum DOWNIE, 1957, can be distinguished from P. granulatum n. sp. by its longer apical horn, which is 1/3 of the total length of the body, elongated test, and smooth transparent wall. P. ventriosum DEFLANDRE, 1935, has a much smaller apical horn compared with the size of the body and has over-all dimensions smaller than P. granulatum n. sp.
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Supplemental description as Gonyaulacysta indicosa:
Brideaux 1971, p. 83:
Discussion :
The new specific epithet is necessary to avoid creating a junior homonym of Gonyaulacysta granulata (KLEMENT) SARJEANT 1969, P. 9. Gonyaulacysta indicosa nom. nov. resembles the generic concept of Gonyaulacysta in shape, possession of a precingular archeopyle, and a faint, although not clearly definable, tabulation referable to that genus.
Dimensions:
On 2 measured specimens respectively: length, 80 µm and 119 µm; width, 84 µm and 112 µm; length of apical horn, 7 µm and 14 µm
Distribution:
specimens recorded here from the Joli Fou Formation, Battle Lake well: Late Albian.