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Cerodinium angulatum
Cerodinium angulatum, Crouch et al., 2014, p.65, pl.2, figs.1–9.
Holotype: Crouch et al., 2014, pl.2, figs.1–2.
Stratigraphic occurrence: Late Paleocene (late Teurian)–Early Eocene (Mangaorapan).
Age: late Paleocene–early Eocene.
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Original description: [Crouch et al., 2014]:
Description:
A cornucavate peridinioid cyst of intermediate size, with one apical horn and two antapical horns that are approximately of equal length. The base of the apical horn is quite narrow and the horn gently tapers to a rounded tip.
The pericyst outline in dorsal–ventral view is typically elongate and the central part of the pericyst is somewhat angular.
The periphragm is generally brown, thin, often folded and can range from a smooth to fine granulate–faintly striate appearance.
The endocyst is oval to pentagonal in most specimens, with the length of the endocyst almost equal to or slightly greater than the width. Paratabulation is indicated by the paracingulum and sometimes by the archeopyle and the parasulcal region.
The paracingulum is discernible by thickened parallel folds in the periphragm and it protrudes slightly in many specimens.
The archeopyle is intercalary Type I (2a paraplate). The operculum is free, although it often remains in position on many specimens. On these, the archeopyle outline can be difficult to determine.
Dimensions (in μm): Holotype Range:
Overall length 97 72 (90) 101
Overall width 42 35 (42) 51
Endocyst length 44 36 (42) 51
Length of apical horn 30 14 (25) 30
Length of antapical horns 26 13 (23) 35
Number of specimens measured: 11.
Affinities/Remarks:
Cerodinium angulatum sp. nov. differs from Cerodinium depressum (Morgenroth, 1966) Lentin and Williams, 1987 in having an endocyst that is slightly elongated (rather than the width being notably greater than the length), by not possessing a conical apical horn, by the central part of the pericyst being angular, and by lacking spines on the paracingulum. Cerodinium angulatum sp. nov. is smaller than Cerodinium diebelii (Alberti, 1959) Lentin and Williams, 1987 and the apical and antapical horns are not as long. Cerodinium angulatum sp. nov. differs from Cerodinium striatum (Drugg, 1967) Lentin and Williams, 1987 in being significantly smaller, having a more angular shape in the central part of the pericyst, and lacking longitudinal rows of grana on the pericyst wall. Cerodinium angulatum sp. nov. differs from Cerodinium speciosum (Alberti, 1959) Lentin and Williams, 1987 in being smaller and lacking longitudinal or tubercle ornamentation on the pericyst wall. Cerodinium angulatum sp. nov. is smaller than Cerodinium nielsii (Willumsen, 2011), the pericyst outline is more elongate and the apical and antapical horns are longer.
Holotype: Crouch et al., 2014, pl.2, figs.1–2.
Stratigraphic occurrence: Late Paleocene (late Teurian)–Early Eocene (Mangaorapan).
Age: late Paleocene–early Eocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Crouch et al., 2014]:
Description:
A cornucavate peridinioid cyst of intermediate size, with one apical horn and two antapical horns that are approximately of equal length. The base of the apical horn is quite narrow and the horn gently tapers to a rounded tip.
The pericyst outline in dorsal–ventral view is typically elongate and the central part of the pericyst is somewhat angular.
The periphragm is generally brown, thin, often folded and can range from a smooth to fine granulate–faintly striate appearance.
The endocyst is oval to pentagonal in most specimens, with the length of the endocyst almost equal to or slightly greater than the width. Paratabulation is indicated by the paracingulum and sometimes by the archeopyle and the parasulcal region.
The paracingulum is discernible by thickened parallel folds in the periphragm and it protrudes slightly in many specimens.
The archeopyle is intercalary Type I (2a paraplate). The operculum is free, although it often remains in position on many specimens. On these, the archeopyle outline can be difficult to determine.
Dimensions (in μm): Holotype Range:
Overall length 97 72 (90) 101
Overall width 42 35 (42) 51
Endocyst length 44 36 (42) 51
Length of apical horn 30 14 (25) 30
Length of antapical horns 26 13 (23) 35
Number of specimens measured: 11.
Affinities/Remarks:
Cerodinium angulatum sp. nov. differs from Cerodinium depressum (Morgenroth, 1966) Lentin and Williams, 1987 in having an endocyst that is slightly elongated (rather than the width being notably greater than the length), by not possessing a conical apical horn, by the central part of the pericyst being angular, and by lacking spines on the paracingulum. Cerodinium angulatum sp. nov. is smaller than Cerodinium diebelii (Alberti, 1959) Lentin and Williams, 1987 and the apical and antapical horns are not as long. Cerodinium angulatum sp. nov. differs from Cerodinium striatum (Drugg, 1967) Lentin and Williams, 1987 in being significantly smaller, having a more angular shape in the central part of the pericyst, and lacking longitudinal rows of grana on the pericyst wall. Cerodinium angulatum sp. nov. differs from Cerodinium speciosum (Alberti, 1959) Lentin and Williams, 1987 in being smaller and lacking longitudinal or tubercle ornamentation on the pericyst wall. Cerodinium angulatum sp. nov. is smaller than Cerodinium nielsii (Willumsen, 2011), the pericyst outline is more elongate and the apical and antapical horns are longer.