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Spinidinium densispinatum
Spinidinium densispinatum Stanley, 1965
Tax. sr. synonym of Spinidinium microceratum Stanley, 1965, according to Stone, 1973.
Holotype: Stanley, 1965, pl.21, fig.1-3
Locus typicus: South Dakota, USA
Stratum typicum: Paleocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Spinidinium densispinatum Stanley, 1965. According to diagnosis of Stanley (1965, p.226-227), Spinidinium densispinatum has a subpentagonal pericyst in dorso-ventral view; epicyst is larger than hypocyst. Periphragm thin and usually folded, ornamented with short, rodlike, clublike, spinelike or grapple-like processes that are about 2-3 µm long. Apical horn short, conelike with a broad base and a distal pore (?); horn length 4-5 µm. Antapical horns two in number with the right one weakly developed whereas the left horn is well developed, but short; length of the latter horn is about 4-5 µm. Endocyst thin-walled, more or less circular in outline and almost fills pericyst. Often two nuclei-like bodies that are 7-8 µm in diameter are present inside the inner cyst. Cingulum distinct, border with row of spinelike appendages. Furrow wide, usually indistinct. Archeopyle when present usually polygonal. This species differs from S.styloniferum by its shorter apical horn and by its subcircular outline in dorso-ventral view. Size: pericyst length 50-65 µm, width 40-50 µm.
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Original description: Stanley, 1965, p.226
Outer cyst subpentagonal in dorso-ventral view: length 50 µm, width 40-50 µm, epitheca larger than hypotheca. Outer cyst membrane thin and usually badly folded; ornamented with short rodlike, clublike, spinelike or grapple-like appendages that are about 2-3 µm long. Apical horn short, conelike with a broad base and a distal pore (?); horn length 4-5 µm. Antapical horns two in number with the right one weakly developed whereas the left horn is well developed, but short; length of the latter horn is about 4-5. Inner cyst thin-walled, more or less circular in outline and almost fills outer cyst. Often two nuclei-like bodies that are 7-8 µm in diameter are present inside the inner cyst. Girdle distinct; girdle border fringed by a row of spinelike appandages. Furrow wide, usually indistinct. Archeopyle, when present, usually polygonal in outline.
Affinities:
Stanley, 1965, p.227: Spinidinium densispinatum is readily differentiated from S. microceratum by its more or less subcircular outline in dorso-ventral view and by its more densely spinate membrane. Spinidinium densispinatum differs from S. styliferum Cookson and Eisenack by its shorter apical horn and by its subcircular outline in dorso-ventral view.
Tax. sr. synonym of Spinidinium microceratum Stanley, 1965, according to Stone, 1973.
Holotype: Stanley, 1965, pl.21, fig.1-3
Locus typicus: South Dakota, USA
Stratum typicum: Paleocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Spinidinium densispinatum Stanley, 1965. According to diagnosis of Stanley (1965, p.226-227), Spinidinium densispinatum has a subpentagonal pericyst in dorso-ventral view; epicyst is larger than hypocyst. Periphragm thin and usually folded, ornamented with short, rodlike, clublike, spinelike or grapple-like processes that are about 2-3 µm long. Apical horn short, conelike with a broad base and a distal pore (?); horn length 4-5 µm. Antapical horns two in number with the right one weakly developed whereas the left horn is well developed, but short; length of the latter horn is about 4-5 µm. Endocyst thin-walled, more or less circular in outline and almost fills pericyst. Often two nuclei-like bodies that are 7-8 µm in diameter are present inside the inner cyst. Cingulum distinct, border with row of spinelike appendages. Furrow wide, usually indistinct. Archeopyle when present usually polygonal. This species differs from S.styloniferum by its shorter apical horn and by its subcircular outline in dorso-ventral view. Size: pericyst length 50-65 µm, width 40-50 µm.
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Original description: Stanley, 1965, p.226
Outer cyst subpentagonal in dorso-ventral view: length 50 µm, width 40-50 µm, epitheca larger than hypotheca. Outer cyst membrane thin and usually badly folded; ornamented with short rodlike, clublike, spinelike or grapple-like appendages that are about 2-3 µm long. Apical horn short, conelike with a broad base and a distal pore (?); horn length 4-5 µm. Antapical horns two in number with the right one weakly developed whereas the left horn is well developed, but short; length of the latter horn is about 4-5. Inner cyst thin-walled, more or less circular in outline and almost fills outer cyst. Often two nuclei-like bodies that are 7-8 µm in diameter are present inside the inner cyst. Girdle distinct; girdle border fringed by a row of spinelike appandages. Furrow wide, usually indistinct. Archeopyle, when present, usually polygonal in outline.
Affinities:
Stanley, 1965, p.227: Spinidinium densispinatum is readily differentiated from S. microceratum by its more or less subcircular outline in dorso-ventral view and by its more densely spinate membrane. Spinidinium densispinatum differs from S. styliferum Cookson and Eisenack by its shorter apical horn and by its subcircular outline in dorso-ventral view.