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Pterodinium circumsutum
Pterodinium circumsutum Morgenroth, 1966
Now Pentadinium?. Originally Pterodinium, subsequently (and now) Pentadinium?.
Holotype: Morgenroth, 1966, pl.1, fig.3
Age: Early Oligocene
Original description Morgenroth, 1966
Derivatio nominis: circumsucre Latin = to hem around.
Holotype: The one in Slide H17 preserved specimen shown on Plate 1, Fig. 3. Paratypoid: H2, H15, H18.
Locus typicus: Leopold'sche Ziegelei (south of Helmstedt).
Strahum typicum: Lower Oligocene.
Diagnosis: A species of the genus Pterodinium with broad, usually weakly toothed edges as field boundaries. Instead of a belt furrow, there is only a simple left-handed spiral margin, which is interrupted ventrally by an undivided, broad transverse furrow.
Description: The clearly oval capsule has a granulated surface. Approximately 14µ high, mostly serrated edges rise from the field boundaries. - The apical pole is designated by an approximately square field. Below this are 3 large trapezoidal fields, of which the middle one has broken off in all specimens to form a pylom. A transverse furrow is not formed. In its place there is a simple left-handed spiral border, which is interrupted ventrally by a wide, undivided longitudinal furrow. This is often limited on both sides by low seams, but in some specimens there is no clear demarcation. The hypotheca is followed by 3 trapezoidal fields. The antapex - like the apical pole - is formed by a trapezoidal field.
Dimensions:
Cyst length: 57µ (50µ–62µ)
Cyst width: 49µ (42µ–50µ)
Hem width: 11–14 µ
(20 measurements)
Number of specimens measured: 21.
Comparison: Pterodinium circumsutum differs from all previously found species in this genus mainly due to the lack of a true belt groove.
Remarks: So far the genus with 3 species has only been recorded in the Albian and Aptian. A possible rearrangement of the specimens found from chalk layers can be ruled out, as no other microfossils known only from chalk were found in the samples.
Now Pentadinium?. Originally Pterodinium, subsequently (and now) Pentadinium?.
Holotype: Morgenroth, 1966, pl.1, fig.3
Age: Early Oligocene
Original description Morgenroth, 1966
Derivatio nominis: circumsucre Latin = to hem around.
Holotype: The one in Slide H17 preserved specimen shown on Plate 1, Fig. 3. Paratypoid: H2, H15, H18.
Locus typicus: Leopold'sche Ziegelei (south of Helmstedt).
Strahum typicum: Lower Oligocene.
Diagnosis: A species of the genus Pterodinium with broad, usually weakly toothed edges as field boundaries. Instead of a belt furrow, there is only a simple left-handed spiral margin, which is interrupted ventrally by an undivided, broad transverse furrow.
Description: The clearly oval capsule has a granulated surface. Approximately 14µ high, mostly serrated edges rise from the field boundaries. - The apical pole is designated by an approximately square field. Below this are 3 large trapezoidal fields, of which the middle one has broken off in all specimens to form a pylom. A transverse furrow is not formed. In its place there is a simple left-handed spiral border, which is interrupted ventrally by a wide, undivided longitudinal furrow. This is often limited on both sides by low seams, but in some specimens there is no clear demarcation. The hypotheca is followed by 3 trapezoidal fields. The antapex - like the apical pole - is formed by a trapezoidal field.
Dimensions:
Cyst length: 57µ (50µ–62µ)
Cyst width: 49µ (42µ–50µ)
Hem width: 11–14 µ
(20 measurements)
Number of specimens measured: 21.
Comparison: Pterodinium circumsutum differs from all previously found species in this genus mainly due to the lack of a true belt groove.
Remarks: So far the genus with 3 species has only been recorded in the Albian and Aptian. A possible rearrangement of the specimens found from chalk layers can be ruled out, as no other microfossils known only from chalk were found in the samples.