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Rhombodinium perforatum
Rhombodinium perforatum (Jan du Chene and Chateauneuf, 1975) Lentin and Williams, 1977
Originally Wetzeliella subgen. Rhombodinium, subsequently (and now) Rhombodinium.
Holotype: Jan du Chene and Chateauneuf, 1975, pl.1, fig.8-9
Locus typicus: Les Voirons, Haute-Savaoie, France
Stratum typicum: Middle Eocene: Lutetian
Translation Jan du Chene and Chateauneuf, 1975: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhombodinium perforatum (Jan du Chêne and Châteauneuf, 1975) Lentin and Williams, 1977b. According to Jan du Chêne and Chateauneuf (1975, p.30-31), Rhombodinium perforatum has a pentagonal pericyst with horns at each angle. The apical horn is short and pointed. Its base is marked by an angle with the pericyst margin. The two antapical horns are distinctive and pointed. The left antapical horn is the longer. The two lateral horns are long, and bear folds reflecting the position of the cingulum. Tabulation cannot be discerned. The periphragm is finely and regularly perforate over all its surface. The width of the periphragm is greater than its length. The margins of the periphragm are straight between the horns. The endophragm is smooth ovoidal to quadrangular. It follows the outline of the periphragm between the horns. Size: periphragm length 80-114 µm, width 88-120 µm, apical horn 12-20 µm, antapical horn 6-20 µm, lateral horns 10-26 µm, endocyst length 60-90 µm, width 60-86 µm.
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Jan du Chene and Chateauneuf, 1975, p. 30-31: Wetzeliella (Rhombodinium) perforata.
Diagnosis: the outline of the periphragm is pentagonal, with a horn at each corner. The apical horn is short and pointed. Its base is marked by an angle on the sides of the periphragm. The two antapical horns are distinct and pointed. The left antapical horn is longer than the right antapical horn. The two lateral horns are long, reinforces by folds which indicate the trace of the transverse furrow. No tabulation can be distinguished. The periphragm is finely and regularly perforate on its entire surface. The width of the periphragm exceeds the length. The sides of the periphragm are straight between the corners. The endophragm is smooth, ovoidal to quadrangular. Between the corners, it follows the outline of the periphragm.
Trapezoidal, intercalary archaeopyle.
Dimensions:
Holotype. Periphragm: length 94 µm, width 120 µm, apical horn 12 µm, left antapical horn 10 µm, right antapical horn 6 µm, lateral horns 22 µm. Inner body: length 70 µm, width 84 µm.
Variations (10 specimens): Periphragm: length 80(97)114 µm, width 88(101)120 µm, apical horn 12(15)20 µm, antapical horns 6(11)20 µm, lateral horns 10(16)26 µm. Inner body: length 60(71)90 µm, width 60(73)86 µm.
Affinities.
Jan du Chene and Chateauneuf 1975, p. 31
W. perforata differs from all described Wetzeliella species by its finely perforate periphragm. Only Wetzeliella (Rhombodinium) waipawaensis has a punctate periphragm, which may correspond to a negative ornamentation, according to Sarjeant (1974). W. waipawaensis differs from W. perforata by its circular endophragm.
Originally Wetzeliella subgen. Rhombodinium, subsequently (and now) Rhombodinium.
Holotype: Jan du Chene and Chateauneuf, 1975, pl.1, fig.8-9
Locus typicus: Les Voirons, Haute-Savaoie, France
Stratum typicum: Middle Eocene: Lutetian
Translation Jan du Chene and Chateauneuf, 1975: LPP
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhombodinium perforatum (Jan du Chêne and Châteauneuf, 1975) Lentin and Williams, 1977b. According to Jan du Chêne and Chateauneuf (1975, p.30-31), Rhombodinium perforatum has a pentagonal pericyst with horns at each angle. The apical horn is short and pointed. Its base is marked by an angle with the pericyst margin. The two antapical horns are distinctive and pointed. The left antapical horn is the longer. The two lateral horns are long, and bear folds reflecting the position of the cingulum. Tabulation cannot be discerned. The periphragm is finely and regularly perforate over all its surface. The width of the periphragm is greater than its length. The margins of the periphragm are straight between the horns. The endophragm is smooth ovoidal to quadrangular. It follows the outline of the periphragm between the horns. Size: periphragm length 80-114 µm, width 88-120 µm, apical horn 12-20 µm, antapical horn 6-20 µm, lateral horns 10-26 µm, endocyst length 60-90 µm, width 60-86 µm.
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Jan du Chene and Chateauneuf, 1975, p. 30-31: Wetzeliella (Rhombodinium) perforata.
Diagnosis: the outline of the periphragm is pentagonal, with a horn at each corner. The apical horn is short and pointed. Its base is marked by an angle on the sides of the periphragm. The two antapical horns are distinct and pointed. The left antapical horn is longer than the right antapical horn. The two lateral horns are long, reinforces by folds which indicate the trace of the transverse furrow. No tabulation can be distinguished. The periphragm is finely and regularly perforate on its entire surface. The width of the periphragm exceeds the length. The sides of the periphragm are straight between the corners. The endophragm is smooth, ovoidal to quadrangular. Between the corners, it follows the outline of the periphragm.
Trapezoidal, intercalary archaeopyle.
Dimensions:
Holotype. Periphragm: length 94 µm, width 120 µm, apical horn 12 µm, left antapical horn 10 µm, right antapical horn 6 µm, lateral horns 22 µm. Inner body: length 70 µm, width 84 µm.
Variations (10 specimens): Periphragm: length 80(97)114 µm, width 88(101)120 µm, apical horn 12(15)20 µm, antapical horns 6(11)20 µm, lateral horns 10(16)26 µm. Inner body: length 60(71)90 µm, width 60(73)86 µm.
Affinities.
Jan du Chene and Chateauneuf 1975, p. 31
W. perforata differs from all described Wetzeliella species by its finely perforate periphragm. Only Wetzeliella (Rhombodinium) waipawaensis has a punctate periphragm, which may correspond to a negative ornamentation, according to Sarjeant (1974). W. waipawaensis differs from W. perforata by its circular endophragm.