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Rhombodinium translucidum
Rhombodinium translucidum Michoux, 1988
Holotype: Michoux, 1988, pl.4, fig.4
Locus typicus: "Marnes a discocyclines" Louer section, France
Stratum typicum: Early Eocene
Original diagnosis: Michoux, 1988, p.31
Circumcavate peridinioid cyst, dorsoventrally compressed, without processes. Paratabulation indicated by the intercalary (I/2a) archeopyle and by faint, irregular, subparallel folds underlining the paracingulum. Archeopyle of the Wetzeliella meckelfeldensis type, operculum free.
Original description: Michoux, 1988, p. 31
Peridinioid dinoflagellate cyst, pentagonal to rhomboidal in outline, depending on the degree of reduction of the right antapical horn. The epicyst may show lateral expansions of the periphragm, somewhat reminiscent, although much less prominent, of the shoulders exhibited by members of the genus Chatangiella (see Plate 4, figs. 3, 8). The paracingulum is weakly indicated by irregular, subparallel folds of the periphragm, extending between the lateral horns. The endophragm is subcircular to ellipsoidal, separated from the periphragm by a continuous pericoel. Both phragma are thin and smooth. The archeopyle is trapezoidal, typically as long as it is wide (see Plate 4, fig. 2), with the endoarcheopyle shorter than the periarcheopyle. This typical shape is often modified by folding of the delicate endophragm.
Dimensions. Pericyst. Length: 126 (138) 151 µm. Width: 130 (139) 149 µm. Holotype: 126 x 135 µm. Archeopyle. Length: 29 (33) 37 µm. Width: 30 (33) 36 µm. Holotype: 34 x 33 µm.
Affinities:
Michoux, 1988, p. 32: Rhombodinium translucidum is similar to R. glabrum (Cookson) Vozzhennikova in shape and archeopyle type. R. glabrum, however, has a thicker endophragm and wider pericoel. R. rugosum bears more conspicuous parasutural folds, and has a relatively wider and shorter archeopyle. Wetzeliella unicaudalis Caro differs in having more pointed horns, more elongated lateral horns, a pentagonal endophragm, and scattered spines over the periphery of the cyst.
Holotype: Michoux, 1988, pl.4, fig.4
Locus typicus: "Marnes a discocyclines" Louer section, France
Stratum typicum: Early Eocene
Original diagnosis: Michoux, 1988, p.31
Circumcavate peridinioid cyst, dorsoventrally compressed, without processes. Paratabulation indicated by the intercalary (I/2a) archeopyle and by faint, irregular, subparallel folds underlining the paracingulum. Archeopyle of the Wetzeliella meckelfeldensis type, operculum free.
Original description: Michoux, 1988, p. 31
Peridinioid dinoflagellate cyst, pentagonal to rhomboidal in outline, depending on the degree of reduction of the right antapical horn. The epicyst may show lateral expansions of the periphragm, somewhat reminiscent, although much less prominent, of the shoulders exhibited by members of the genus Chatangiella (see Plate 4, figs. 3, 8). The paracingulum is weakly indicated by irregular, subparallel folds of the periphragm, extending between the lateral horns. The endophragm is subcircular to ellipsoidal, separated from the periphragm by a continuous pericoel. Both phragma are thin and smooth. The archeopyle is trapezoidal, typically as long as it is wide (see Plate 4, fig. 2), with the endoarcheopyle shorter than the periarcheopyle. This typical shape is often modified by folding of the delicate endophragm.
Dimensions. Pericyst. Length: 126 (138) 151 µm. Width: 130 (139) 149 µm. Holotype: 126 x 135 µm. Archeopyle. Length: 29 (33) 37 µm. Width: 30 (33) 36 µm. Holotype: 34 x 33 µm.
Affinities:
Michoux, 1988, p. 32: Rhombodinium translucidum is similar to R. glabrum (Cookson) Vozzhennikova in shape and archeopyle type. R. glabrum, however, has a thicker endophragm and wider pericoel. R. rugosum bears more conspicuous parasutural folds, and has a relatively wider and shorter archeopyle. Wetzeliella unicaudalis Caro differs in having more pointed horns, more elongated lateral horns, a pentagonal endophragm, and scattered spines over the periphery of the cyst.