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Maduradinium pentagonum ssp. ovale
Maduradinium pentagonum subsp. ovale (Cookson and Eisenack, 1982, p.34, pl.1, figs.15-16) Lentin and Williams, 1985, p.230.
Holotype: Cookson and Eisenack, 1982, pl.1, fig.16.
Originally Maduradinium pentagonum var. ovale, subsequently (and now) Maduradinium pentagonum subsp. ovale. Age: Senonian
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Original description: [Cookson and Eisenack, 1982] (translated from German):
Maduradinium pentagonum COOKS. & EIS. 1970, var. ovale n. var.
Plate 1, Figs. 15-16
Type: The specimen shown on Plate 1, Fig. 16, preserved in specimen Madura 1.
Diagnosis: Shell oval, unlaminated, apparently single-layered, thick-walled, particularly at the poles, thinning towards the equator, with a granular structure and surface, with a short, broad, and full apical and antapical horn. Girdle (cingulum) equatorial, slightly spiral, fairly broad, bordered by low but strong ridges.
Archaeopyle precingular, broadly trapezoidal.
Material and Dimensions: One specimen, shell without horns approx. 95 x 89 μm, with horns and girdle approx. 125 x 92 μm; Girdle approx. 5 and below.
Remarks: The anta-apical horn is not in the plane of symmetry, but is shifted slightly to the right.
Occurrence: Madura 1 Bore, at 966-988 ft.
Additions: In addition to the described specimen, a second, even more deviating specimen
of the same bore sample occurs. It is almost spherical, its apical horn is greatly reduced. The anta-apical horn is also
shifted slightly to the right; a second anta-apical horn could just be seen in a faint bulge of the shell.
A girdle is also just visible, although no longer delimited by ridges.
Noteworthy is a recapitulation of the flagellar pore (flagellar mark) on the ventral side, where the ends of the girdle are expected (cf. COOKSON & EISENACK 1970: 153).
Both specimens belong to the vicinity of Maduradinium or are perhaps extreme members, although they differ significantly from the type. They occur in the same drill sample as the specimens illustrated in 1970. One see 1970, Plate 10, Fig. 13-16. In Fig. 17, which is similar to our current specimens, a similar member is present. The specimens illustrated in COOKSON & EISENACK 1970, Plate 10, Figs. 13-16 must henceforth be called Maduradinium pentagonum var. pentagonale.
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Remarks and transfer by Lentin and Williams, 1985:
MADURADINIUM Cookson and Eisenack, 1970a, p.150.
*pentagonum Cookson and Eisenack, 1970a, p.150, p1.10, fig.13-17. Senonian.
subsp. ovale (Cookson and Eisenack, 1982) stat. nov.
1982 Maduradinium pentagonum var. ovale Cookson and Eisenack, p.34, p1.1, fig.15-16. Senonian.
Holotype: Cookson and Eisenack, 1982, pl.1, fig.16.
Originally Maduradinium pentagonum var. ovale, subsequently (and now) Maduradinium pentagonum subsp. ovale. Age: Senonian
--------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1982] (translated from German):
Maduradinium pentagonum COOKS. & EIS. 1970, var. ovale n. var.
Plate 1, Figs. 15-16
Type: The specimen shown on Plate 1, Fig. 16, preserved in specimen Madura 1.
Diagnosis: Shell oval, unlaminated, apparently single-layered, thick-walled, particularly at the poles, thinning towards the equator, with a granular structure and surface, with a short, broad, and full apical and antapical horn. Girdle (cingulum) equatorial, slightly spiral, fairly broad, bordered by low but strong ridges.
Archaeopyle precingular, broadly trapezoidal.
Material and Dimensions: One specimen, shell without horns approx. 95 x 89 μm, with horns and girdle approx. 125 x 92 μm; Girdle approx. 5 and below.
Remarks: The anta-apical horn is not in the plane of symmetry, but is shifted slightly to the right.
Occurrence: Madura 1 Bore, at 966-988 ft.
Additions: In addition to the described specimen, a second, even more deviating specimen
of the same bore sample occurs. It is almost spherical, its apical horn is greatly reduced. The anta-apical horn is also
shifted slightly to the right; a second anta-apical horn could just be seen in a faint bulge of the shell.
A girdle is also just visible, although no longer delimited by ridges.
Noteworthy is a recapitulation of the flagellar pore (flagellar mark) on the ventral side, where the ends of the girdle are expected (cf. COOKSON & EISENACK 1970: 153).
Both specimens belong to the vicinity of Maduradinium or are perhaps extreme members, although they differ significantly from the type. They occur in the same drill sample as the specimens illustrated in 1970. One see 1970, Plate 10, Fig. 13-16. In Fig. 17, which is similar to our current specimens, a similar member is present. The specimens illustrated in COOKSON & EISENACK 1970, Plate 10, Figs. 13-16 must henceforth be called Maduradinium pentagonum var. pentagonale.
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Remarks and transfer by Lentin and Williams, 1985:
MADURADINIUM Cookson and Eisenack, 1970a, p.150.
*pentagonum Cookson and Eisenack, 1970a, p.150, p1.10, fig.13-17. Senonian.
subsp. ovale (Cookson and Eisenack, 1982) stat. nov.
1982 Maduradinium pentagonum var. ovale Cookson and Eisenack, p.34, p1.1, fig.15-16. Senonian.