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Impagidinium brevisulcatum
Impagidinium brevisulcatum, Michoux, 1985, p. 144-145
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Impagidinium brevisulcatum Michoux, 1985, is characterised by its large size, the reduced length of the sulcus and the particular arrangement of the parasutural septa in the apical region. The lateral borders of 1' and 4' are parallel and confer a rectangular shape upon the plates. Size: central body 78-115 µm, height of septa 5-8 µm.
Holotype: Michoux, 1985, pl.1, fig.10; Jan du Chene et al., 1986, pl.56, fig.4-6
Locus typicus: Nousse, SW France
Stratum typicum: Middle Eocene
Translation Michoux, 1985: LPP
Original description: Michoux 1985:
Diagnosis: Impagidinium species characterized by its large size, the reduced length of the sulcus and the particular arrangement of the parasutural septa in the apical region.
Description: Spherical to ovoid cyst, large (up to 155 µm in diameter), bearing parasutural septa that can be as high as 8µm, undulating or denticulate at the margins. The surface of the cyst is smooth. The cingulum is strongly helicoidal. The sulcus is short. The posterior margin of the anterior sulcal paraplate is only vague. The septa surrounding the right sulcal paraplate are often developed. 1''' is elongate and narrow. The lateral margins of 1' and 4' are parallel, giving them a rectangular form. The septum that separates them is completely or partly developed. Its posterior margin is attached to the anterior margin of 6'', and not to the anterior side of the sulcus, as it is generally the case in Impagidinium. 6'' has a trapezoidal form. The archaeopyle is precingular, formed by the loss of 3''. Tabulation: 4', 6'', 6c, 6''', 1p, ps, 1''''.
Dimensions: central body diameter: 78-115 µm; height of septa: 5-8 µm; 11 specimens measured.
Affinities:
Michoux, 1985, p. 145
I. brevisulcatum differs from all other Impagidinium species in the unusual arrangement of the parasutures of the apical regio of the cyst and in the trapezoidal form of paraplate 6'', which is generally triangular in Impagidinium.
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Impagidinium brevisulcatum Michoux, 1985, is characterised by its large size, the reduced length of the sulcus and the particular arrangement of the parasutural septa in the apical region. The lateral borders of 1' and 4' are parallel and confer a rectangular shape upon the plates. Size: central body 78-115 µm, height of septa 5-8 µm.
Holotype: Michoux, 1985, pl.1, fig.10; Jan du Chene et al., 1986, pl.56, fig.4-6
Locus typicus: Nousse, SW France
Stratum typicum: Middle Eocene
Translation Michoux, 1985: LPP
Original description: Michoux 1985:
Diagnosis: Impagidinium species characterized by its large size, the reduced length of the sulcus and the particular arrangement of the parasutural septa in the apical region.
Description: Spherical to ovoid cyst, large (up to 155 µm in diameter), bearing parasutural septa that can be as high as 8µm, undulating or denticulate at the margins. The surface of the cyst is smooth. The cingulum is strongly helicoidal. The sulcus is short. The posterior margin of the anterior sulcal paraplate is only vague. The septa surrounding the right sulcal paraplate are often developed. 1''' is elongate and narrow. The lateral margins of 1' and 4' are parallel, giving them a rectangular form. The septum that separates them is completely or partly developed. Its posterior margin is attached to the anterior margin of 6'', and not to the anterior side of the sulcus, as it is generally the case in Impagidinium. 6'' has a trapezoidal form. The archaeopyle is precingular, formed by the loss of 3''. Tabulation: 4', 6'', 6c, 6''', 1p, ps, 1''''.
Dimensions: central body diameter: 78-115 µm; height of septa: 5-8 µm; 11 specimens measured.
Affinities:
Michoux, 1985, p. 145
I. brevisulcatum differs from all other Impagidinium species in the unusual arrangement of the parasutures of the apical regio of the cyst and in the trapezoidal form of paraplate 6'', which is generally triangular in Impagidinium.