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Rhombodinium porosum
Rhombodinium porosum Bujak, 1979
Holotype: Bujak, 1979, pl.1, figs.5-6; Bujak et al., 1980, pl.20, fig.8
Locus typicus: Whitecliff Bay, Isle of Wight, England
Age: Late Eocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhombodinium porosum Bujak, 1979. Diagnosis according toBujak (1979, 314-315), Pericyst ambitus rhomboidal. Apical and left antapical horns rounded to conical, right antapical horn strongly reduced or absent, lateral horns tapering, rectangular or flared. Endocyst ambitus rounded rhomboidal. Periphragm smooth with perforations of varying size and shape. Perforations largest and most common near the ambital periphery and on the pericingulum; also present but reduced in size and number on the mid-dorsal and mid-ventral areas. Paracingulum defined by 2 folds in the periphragm. Endophragm without perforations but with strong granulations apically, antapically and laterally, and with weaker granulation on the remaining ambital periphery and the paracingulum. Archeopyle intercalary, soleiform, resulting from the displacement of paraplate 2a, trapezoidal with side Q3 longer than side Q1. Perioperculum and endoperculum adjacent and remaining attached to the cyst along side Q1. Size: pericyst length 105-150 µm, width 115-175 µm, endocyst length 75-115 µm, width 75-120 µm. The perforations in R.porosum can be up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm.
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Original diagnosis: Bujak, 1979, p. 314
Pericyst ambitus rhomboidal. Apical and left antapical horns rounded to conical, right antapical horn strongly reduced or absent, lateral horns tapering, rectangular or flared. Endocyst ambitus rounded rhomboidal. Periphragm smooth with perforations of varying size and shape. Perforations largest and most common near the ambital periphery and on the pericingulum; also present but reduced in size and number on the mid-dorsal and mid-ventral areas. Paracingulum defined by 2 folds in the periphragm. Endophragm without perforations but with strong granulation apically, antapically and laterally, and with weaker granulation on the remaining ambital periphery and the paracingulum. Archeopyle intercalary, soleiform, resulting from the displacement of paraplate 2a, trapezoidal with side Q3 longer than side Q1. Perioperculum and endoperculum adjacent and remaining attached to the cyst along side Q1.
Dimensions. Pericyst length 105-150 µm, breadth 115-175 µm. Endocyst length 75-115 µm, breadth 75-120 µm (n = 20)
Remarks: The perforations in R. porosum are oval or circular and of varying size up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm. The perforations are largest and most common along the pericingulum and around the ambital periphery of the periphragm, always smaller on the mid-dorsal and mid-ventral areas. The outline of the periphragm is frequently interrupted by perforations seen in side view.
Remarks Bujak, 1979, p.314:
The perforations in R. porosum are oval or circular and of varying size up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm. The perforations are largest and most common along the pericingulum and around the ambital periphery of the periphragm, always smaller on the mid-dorsal and mid-ventral areas. The outline of the periphragm is frequently interrupted by perforations seen in side view.
Holotype: Bujak, 1979, pl.1, figs.5-6; Bujak et al., 1980, pl.20, fig.8
Locus typicus: Whitecliff Bay, Isle of Wight, England
Age: Late Eocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhombodinium porosum Bujak, 1979. Diagnosis according toBujak (1979, 314-315), Pericyst ambitus rhomboidal. Apical and left antapical horns rounded to conical, right antapical horn strongly reduced or absent, lateral horns tapering, rectangular or flared. Endocyst ambitus rounded rhomboidal. Periphragm smooth with perforations of varying size and shape. Perforations largest and most common near the ambital periphery and on the pericingulum; also present but reduced in size and number on the mid-dorsal and mid-ventral areas. Paracingulum defined by 2 folds in the periphragm. Endophragm without perforations but with strong granulations apically, antapically and laterally, and with weaker granulation on the remaining ambital periphery and the paracingulum. Archeopyle intercalary, soleiform, resulting from the displacement of paraplate 2a, trapezoidal with side Q3 longer than side Q1. Perioperculum and endoperculum adjacent and remaining attached to the cyst along side Q1. Size: pericyst length 105-150 µm, width 115-175 µm, endocyst length 75-115 µm, width 75-120 µm. The perforations in R.porosum can be up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm.
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Original diagnosis: Bujak, 1979, p. 314
Pericyst ambitus rhomboidal. Apical and left antapical horns rounded to conical, right antapical horn strongly reduced or absent, lateral horns tapering, rectangular or flared. Endocyst ambitus rounded rhomboidal. Periphragm smooth with perforations of varying size and shape. Perforations largest and most common near the ambital periphery and on the pericingulum; also present but reduced in size and number on the mid-dorsal and mid-ventral areas. Paracingulum defined by 2 folds in the periphragm. Endophragm without perforations but with strong granulation apically, antapically and laterally, and with weaker granulation on the remaining ambital periphery and the paracingulum. Archeopyle intercalary, soleiform, resulting from the displacement of paraplate 2a, trapezoidal with side Q3 longer than side Q1. Perioperculum and endoperculum adjacent and remaining attached to the cyst along side Q1.
Dimensions. Pericyst length 105-150 µm, breadth 115-175 µm. Endocyst length 75-115 µm, breadth 75-120 µm (n = 20)
Remarks: The perforations in R. porosum are oval or circular and of varying size up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm. The perforations are largest and most common along the pericingulum and around the ambital periphery of the periphragm, always smaller on the mid-dorsal and mid-ventral areas. The outline of the periphragm is frequently interrupted by perforations seen in side view.
Remarks Bujak, 1979, p.314:
The perforations in R. porosum are oval or circular and of varying size up to 5 µm in diameter. They often join to form irregularly shaped, compound perforations with a long diameter up to 15 µm. The perforations are largest and most common along the pericingulum and around the ambital periphery of the periphragm, always smaller on the mid-dorsal and mid-ventral areas. The outline of the periphragm is frequently interrupted by perforations seen in side view.