Back
Pentadinium imaginatum
Pentadinium imaginatum (Benedek, 1972, p.43–44, pl.2, figs.11a–b; pl.6, figs.9a–b) Stover and Hardenbol, 1994, p.33.
Originally Pentadinium laticinctum subsp. imaginatum, subsequently (and now) Pentadinium imaginatum.
Taxonomic senior synonym: Pentadinium taeniagerum subsp. imaginatum (as Toenisbergia imaginatum), according to Benedek et al. (1982, p.279) — however, Lentin and Williams (1985, p.279) retained Pentadinium imaginatum (as Pentadinium laticinctum subsp. imaginatum).
Holotype: Benedek, 1972, pl.6, figs.9a–b; Benedek et al., 1982, figs.6A,C,E,8A–B.
Age: late Oligocene.
Original diagnosis: Benedek 1972, p. 43: Pentadinium laticinctum imaginatum
A sub-species of the P. laticinctum GERLACH , the capsule-envelope of which shows no tabulation.
Original description: Benedek 1972, p. 43,44: Pentadinium laticinctum imaginatum
The dark yellow, thick-walled internal capsule is spherical and is enveloped by a thin-walled, transparent, non-tabulate external envelope. In the apical region and in the antapical on, the internal capsule is solidly intergrown with the external envelope. In place of sutures, the location of the transversal furrow is indicated by slight constrictions. A pylome shows up in the place of the precingular plate 3" .
Remarks: Benedek 1972, p. 43,44
In size and in outline, this equals the P. laticinctum GERLACH (1961); however, as far as the Tönisberg material is concerned, the form here in question can not be distinguished with 100% certainty from said P. laticinctum GERLACH (1961) and from other sub-species, due to the absence of a tabulation.Most specimens are characterized by open pylomes. It should be pointed out, that Plate 2 figure 11 illustrates the exceptional case in which the pylome cover is still present in situ. The dimensions of this specimen (capsule diameter 52/62 microns), remain below the ones of the open P. laticinctum. The rarity of the appearance of the closed stages or their absence in the hitherto examined Eocene and Oligocene samples, which frequently contain sizable quantities of Pentadiniae, can be explained therewith, that normally the "mature stages" had been attained. Some factors have possibly interrupted the developmental cycle and, in the present case, had delivered a non-mature cyst to prosterity.
Dimensions:
Capsule diameter 65 µm (63/70 µm), specimen diameter 97µm (95/100 µm), holotype diameter 65 µm, specimen [not further specified] 98/100 µm
Number of examined specimens: 10
Originally Pentadinium laticinctum subsp. imaginatum, subsequently (and now) Pentadinium imaginatum.
Taxonomic senior synonym: Pentadinium taeniagerum subsp. imaginatum (as Toenisbergia imaginatum), according to Benedek et al. (1982, p.279) — however, Lentin and Williams (1985, p.279) retained Pentadinium imaginatum (as Pentadinium laticinctum subsp. imaginatum).
Holotype: Benedek, 1972, pl.6, figs.9a–b; Benedek et al., 1982, figs.6A,C,E,8A–B.
Age: late Oligocene.
Original diagnosis: Benedek 1972, p. 43: Pentadinium laticinctum imaginatum
A sub-species of the P. laticinctum GERLACH , the capsule-envelope of which shows no tabulation.
Original description: Benedek 1972, p. 43,44: Pentadinium laticinctum imaginatum
The dark yellow, thick-walled internal capsule is spherical and is enveloped by a thin-walled, transparent, non-tabulate external envelope. In the apical region and in the antapical on, the internal capsule is solidly intergrown with the external envelope. In place of sutures, the location of the transversal furrow is indicated by slight constrictions. A pylome shows up in the place of the precingular plate 3" .
Remarks: Benedek 1972, p. 43,44
In size and in outline, this equals the P. laticinctum GERLACH (1961); however, as far as the Tönisberg material is concerned, the form here in question can not be distinguished with 100% certainty from said P. laticinctum GERLACH (1961) and from other sub-species, due to the absence of a tabulation.Most specimens are characterized by open pylomes. It should be pointed out, that Plate 2 figure 11 illustrates the exceptional case in which the pylome cover is still present in situ. The dimensions of this specimen (capsule diameter 52/62 microns), remain below the ones of the open P. laticinctum. The rarity of the appearance of the closed stages or their absence in the hitherto examined Eocene and Oligocene samples, which frequently contain sizable quantities of Pentadiniae, can be explained therewith, that normally the "mature stages" had been attained. Some factors have possibly interrupted the developmental cycle and, in the present case, had delivered a non-mature cyst to prosterity.
Dimensions:
Capsule diameter 65 µm (63/70 µm), specimen diameter 97µm (95/100 µm), holotype diameter 65 µm, specimen [not further specified] 98/100 µm
Number of examined specimens: 10