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Phthanoperidinium crenulatum
From Fensome et al., 2019:
Phthanerodinium crenulatum (de Coninck, 1975, p.96, pl.17, figs.5–7,12–15) Lentin and Williams, 1977b, p.131. Emendation: Heilmann-Clausen, 1985, p.24–25, as Phthanoperidinium crenulatum. Holotype: de Coninck, 1975, pl.17, figs.12–13. Originally Peridinium, subsequently (and now) Phthanoperidinium. Age: Early Eocene (Ypresian).
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Original description (De Conick, J. 1975) Not yet translated from French.
Holotype: Kallo - 329.5 m. Preparation 1; coord. 33.7 - 122.2 PI.XVII, fig.12-13.
Diagnosis: The body profile is rounded pentagonal. The archaeopyle is intercalary. Serrated crests (Latin: crenulatus) mark the tabulation. I saw 7 precingulate and 5 postcingulate plates. The girdle is relatively wide and helical; the distance between its ends is about one time its width. The longitudinal fossa is wider than the girdle. The apex bears a short horn on which the serrated crests rise. At the antapex, the crests become higher and suggest two weakly developed antapical horns. Body dimensions: approximately 35 µm to 40 µm. Apical horn height: about 5µm. Ridge height: up to about 2.5µm. Total wingspan: about 42 to 50µm.
Remarks: The species superficially resembles Gonyaulacysta serrata (Cookson & Eisenack, 1958) and G. tenuiceras (Eisenack, 1958), which have similar general shape and plate margins; however, the dimensions of these species are larger, while their tabulation has either remained undetermined or is different. In addition, the presence of an intercalary archaeopyle in our organisms is in contradiction with the definition of the genus Gonyaulacysta.
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Emended description: Heilmann-Clausen, 1985, p. 24
The outline of the cyst in dorsoventral view is rounded-pentagonal. An apical horn, and usually one or two small antapical horns, are present. Small pericoels are developed beneath horns, or cysts may be circumcavate. The periphragm is smooth. Denticulate crests outline most paraplates. The crests are usually in a parasutural position, however, in the mid-dorsal part of the precingular series they are penitabular in some specimens (pl. 2, fig. 7; text-hg. 10) and parasutural in others (pl. 2, fig. 5). The paratabulation is 4', 3a, 7", Xc, 5''', 2'''', Xs. The paracingulum is moderately helicoidal; the parasulcus expands towards the antapex. The archaeopyle is intercalary, type 3I.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Phthanoperidinium crenulatum (de Coninck, 1975) Lentin and Williams, 1977b. As emended by Heilmann-Clausen (1985, p.24-25), the outline of the cyst in dorso-ventral view is rounded-pentagonal. An apical horn, and usually one or two small antapical horns, are present. Small pericoels are developed beneath horns, or cysts may be circumcavate. The periphragm is smooth. Denticulate crests outline most paraplates. The crests are usually in a parasutural position, however, in the mid-dorsal part of the precingular series they are penitabular in some specimens and parasutural in others. The paratabulation is standard peridinioid. The paracingulum is moderately helicoidal; the parasulcus expands towards the antapex. The archeopyle is intercalary type 3I. Size: body 35-40 µm, height of apical horn ca. 5 µm, height of crests ca 2.5 µm, overall 42-50 µm
Phthanerodinium crenulatum (de Coninck, 1975, p.96, pl.17, figs.5–7,12–15) Lentin and Williams, 1977b, p.131. Emendation: Heilmann-Clausen, 1985, p.24–25, as Phthanoperidinium crenulatum. Holotype: de Coninck, 1975, pl.17, figs.12–13. Originally Peridinium, subsequently (and now) Phthanoperidinium. Age: Early Eocene (Ypresian).
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Original description (De Conick, J. 1975) Not yet translated from French.
Holotype: Kallo - 329.5 m. Preparation 1; coord. 33.7 - 122.2 PI.XVII, fig.12-13.
Diagnosis: The body profile is rounded pentagonal. The archaeopyle is intercalary. Serrated crests (Latin: crenulatus) mark the tabulation. I saw 7 precingulate and 5 postcingulate plates. The girdle is relatively wide and helical; the distance between its ends is about one time its width. The longitudinal fossa is wider than the girdle. The apex bears a short horn on which the serrated crests rise. At the antapex, the crests become higher and suggest two weakly developed antapical horns. Body dimensions: approximately 35 µm to 40 µm. Apical horn height: about 5µm. Ridge height: up to about 2.5µm. Total wingspan: about 42 to 50µm.
Remarks: The species superficially resembles Gonyaulacysta serrata (Cookson & Eisenack, 1958) and G. tenuiceras (Eisenack, 1958), which have similar general shape and plate margins; however, the dimensions of these species are larger, while their tabulation has either remained undetermined or is different. In addition, the presence of an intercalary archaeopyle in our organisms is in contradiction with the definition of the genus Gonyaulacysta.
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Emended description: Heilmann-Clausen, 1985, p. 24
The outline of the cyst in dorsoventral view is rounded-pentagonal. An apical horn, and usually one or two small antapical horns, are present. Small pericoels are developed beneath horns, or cysts may be circumcavate. The periphragm is smooth. Denticulate crests outline most paraplates. The crests are usually in a parasutural position, however, in the mid-dorsal part of the precingular series they are penitabular in some specimens (pl. 2, fig. 7; text-hg. 10) and parasutural in others (pl. 2, fig. 5). The paratabulation is 4', 3a, 7", Xc, 5''', 2'''', Xs. The paracingulum is moderately helicoidal; the parasulcus expands towards the antapex. The archaeopyle is intercalary, type 3I.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Phthanoperidinium crenulatum (de Coninck, 1975) Lentin and Williams, 1977b. As emended by Heilmann-Clausen (1985, p.24-25), the outline of the cyst in dorso-ventral view is rounded-pentagonal. An apical horn, and usually one or two small antapical horns, are present. Small pericoels are developed beneath horns, or cysts may be circumcavate. The periphragm is smooth. Denticulate crests outline most paraplates. The crests are usually in a parasutural position, however, in the mid-dorsal part of the precingular series they are penitabular in some specimens and parasutural in others. The paratabulation is standard peridinioid. The paracingulum is moderately helicoidal; the parasulcus expands towards the antapex. The archeopyle is intercalary type 3I. Size: body 35-40 µm, height of apical horn ca. 5 µm, height of crests ca 2.5 µm, overall 42-50 µm