Back
Pentadinium laticinctum ssp. laticinctum
Pentadinium laticinctum ssp. Iaticinctum
Autonym.
Holotype: Gerlach, 1961, pl.26, fig.5-6, text-figs. 6-7; Benedek et al, 1982, fig.3E-F; Jan du Chene et al, 1986, pl.80, fig.3
Locus typicus: Emsb³ren, Northwest Germany
Stratum typicum: Middle Oligocene-middle Miocene
Translation Gerlach, 1961: LPP
Original diagnosis: Gerlach 1961, p. 165.
A species in the genus Pentadinium with the next particular features: Theca spherical-polyhedric, and at the apex and antapex distinctly blunt.
Tabulation formula: 1', 5'', 5''' and 1''''. Membrane granulate.
Additions (shortened): The representatives of this genus consist of two wall layers. A strong, dark coloured capsule is enveloped by a clear, soft outer layer. The tabulation exists of an apical plate, five precingular plates, five postcingular plates and an antapical plate. The apical and antapical plate show a median polar orientation and a polygonal outline. Epitheca and hypotheca border always five pre- and postcingular plates respectively. 2'', 3'' and 4'' are of equal size, 1'' and 5'' are a little smaller.
Pylome is not rarely observed at the middorsal 3''. Sometimes the 3''is located in the inner capsule, which will be lifted during the excystment of the protoplasm. All plates are enclosed by irregular running broad margins. The girdle furrow, dividing the epitheca and hypotheca in two almost equally sized parts, is helicoidal. This is flanked on both sides by a wide membranoid border. The girdle furrow is interrupted by a longitudinal furrow, which is probably extending from apex to antapex and is smooth deepened. Like the precingular plates the postcingular plates are trapezoid. 2''', 3''' and 4''' appear particularly large, while 1''' and 5''' remain smaller. The plates 2''', 3''' and 4''' construct the dorsal turn, while 1''' and 5''' are ventrally situated. The outer membrane is distinct granulat. The colour is yellowish-brown.
Dimensions:
Range: 85-89 µm. 10 specimens measured.
--------------------------------------------------------------------------
Emended description: Benedek et al., 1982, p. 269-272
Cyst proximate to proximochorate. Central body almost spherical, without horns; phragma two-layered, suturocavate, the latter feature imparting to the cyst a subpolygonal appearance in polar or lateral view. Paratabulation 4', 6'', ?6c, 5''', 1p, 1pv, 1''''. The boundaries between some paraplates are incompletely expressed by sutural outgrowths. Mid-ventral region occupied by a greatly widened sulcus, paraplate 6'' being displaced towards the apex and the sulcus separated from the antapex by two small paraplates (1pv, 1p). Surface of phragma granular and with a few, irregularly spaced verrucae, especially on the ventral surface. Height of sutural cavations between one-sixth and one-eighth of the diameter of the central body. Archaeopyle single plate precingular (Type P), formed by loss of paraplate 3''.
Description: The apical region is occupied by what has, in the past, been taken to be a single paraplate, since it is incompletely subdivided by sutural outgrowths. However, such outgrowths are regularly to be seen projecting into the area of supposed 'single paraplate' and, in favourable specimens, lines or very low ridges on the surface of the periphragm outline boundaries which show this region to be actually occupied by four apical paraplates (see in particularly Fig. 1 and 3C). Greatest difficulty was encountered in determining the exact shape of paraplate 1'; in our reconstruction (Fig.1) this appears shorter than usual, but its boundary with the sulcus may have been misplaced. Paraplates 2'-4' are more clearly defined, the latter being smallest. Six precingular paraplates are present, not five as earlier reported. However, the last of the series (6'') is displaced towards the apex by a widening of the more posterior end of the cingulum: moreover, though this paraplate is marked by sutural outgrowths on three sides, its boundary with the sulcus is not always completely thus demarcated. Paraplates 1'' and 6'' are smaller than the others in this series. Five postcingular paraplates are present (though the line of the posterior left-hand margin of the sulcus suggests derivation from earlier forms with six). Paraplate 1''' is the smallest of the series, separated from the antapex by the posterior intercalary paraplate (1p), but paraplate 5''' is also somewhat reduced. A single large, polygonal paraplate (1'''') occupies the antapex. Because of the rotundity of these forms and the flange formed by the sutural outgrowths surrounding the cingulum, specimens are more commonly seen in polar than in lateral view. Where the latter view is presented, it may be seen that the ventral region is occupied largely by a sulcus that is greatly expanded in its central and posterior parts. Verrucae are concentrated on this region of the surface (on the sulcus itself and near the sulcal margins of adjacent paraplates), though they may also be present elsewhere on the periphragm surface. The sulcus is separated from the antapex by a clearly marked posterior ventral paraplate (1pv). The cingulum forms a laevorotatory spiral whose two ends do not differ in anteroposterior position, only because of a great widening of its more posterior end, but for this expansion, they would differ roughly by its width. Folds of the high sutural cavations emarcating it make the number of cingular paraplates hard to determine: at least five, probably six, are present.
Autonym.
Holotype: Gerlach, 1961, pl.26, fig.5-6, text-figs. 6-7; Benedek et al, 1982, fig.3E-F; Jan du Chene et al, 1986, pl.80, fig.3
Locus typicus: Emsb³ren, Northwest Germany
Stratum typicum: Middle Oligocene-middle Miocene
Translation Gerlach, 1961: LPP
Original diagnosis: Gerlach 1961, p. 165.
A species in the genus Pentadinium with the next particular features: Theca spherical-polyhedric, and at the apex and antapex distinctly blunt.
Tabulation formula: 1', 5'', 5''' and 1''''. Membrane granulate.
Additions (shortened): The representatives of this genus consist of two wall layers. A strong, dark coloured capsule is enveloped by a clear, soft outer layer. The tabulation exists of an apical plate, five precingular plates, five postcingular plates and an antapical plate. The apical and antapical plate show a median polar orientation and a polygonal outline. Epitheca and hypotheca border always five pre- and postcingular plates respectively. 2'', 3'' and 4'' are of equal size, 1'' and 5'' are a little smaller.
Pylome is not rarely observed at the middorsal 3''. Sometimes the 3''is located in the inner capsule, which will be lifted during the excystment of the protoplasm. All plates are enclosed by irregular running broad margins. The girdle furrow, dividing the epitheca and hypotheca in two almost equally sized parts, is helicoidal. This is flanked on both sides by a wide membranoid border. The girdle furrow is interrupted by a longitudinal furrow, which is probably extending from apex to antapex and is smooth deepened. Like the precingular plates the postcingular plates are trapezoid. 2''', 3''' and 4''' appear particularly large, while 1''' and 5''' remain smaller. The plates 2''', 3''' and 4''' construct the dorsal turn, while 1''' and 5''' are ventrally situated. The outer membrane is distinct granulat. The colour is yellowish-brown.
Dimensions:
Range: 85-89 µm. 10 specimens measured.
--------------------------------------------------------------------------
Emended description: Benedek et al., 1982, p. 269-272
Cyst proximate to proximochorate. Central body almost spherical, without horns; phragma two-layered, suturocavate, the latter feature imparting to the cyst a subpolygonal appearance in polar or lateral view. Paratabulation 4', 6'', ?6c, 5''', 1p, 1pv, 1''''. The boundaries between some paraplates are incompletely expressed by sutural outgrowths. Mid-ventral region occupied by a greatly widened sulcus, paraplate 6'' being displaced towards the apex and the sulcus separated from the antapex by two small paraplates (1pv, 1p). Surface of phragma granular and with a few, irregularly spaced verrucae, especially on the ventral surface. Height of sutural cavations between one-sixth and one-eighth of the diameter of the central body. Archaeopyle single plate precingular (Type P), formed by loss of paraplate 3''.
Description: The apical region is occupied by what has, in the past, been taken to be a single paraplate, since it is incompletely subdivided by sutural outgrowths. However, such outgrowths are regularly to be seen projecting into the area of supposed 'single paraplate' and, in favourable specimens, lines or very low ridges on the surface of the periphragm outline boundaries which show this region to be actually occupied by four apical paraplates (see in particularly Fig. 1 and 3C). Greatest difficulty was encountered in determining the exact shape of paraplate 1'; in our reconstruction (Fig.1) this appears shorter than usual, but its boundary with the sulcus may have been misplaced. Paraplates 2'-4' are more clearly defined, the latter being smallest. Six precingular paraplates are present, not five as earlier reported. However, the last of the series (6'') is displaced towards the apex by a widening of the more posterior end of the cingulum: moreover, though this paraplate is marked by sutural outgrowths on three sides, its boundary with the sulcus is not always completely thus demarcated. Paraplates 1'' and 6'' are smaller than the others in this series. Five postcingular paraplates are present (though the line of the posterior left-hand margin of the sulcus suggests derivation from earlier forms with six). Paraplate 1''' is the smallest of the series, separated from the antapex by the posterior intercalary paraplate (1p), but paraplate 5''' is also somewhat reduced. A single large, polygonal paraplate (1'''') occupies the antapex. Because of the rotundity of these forms and the flange formed by the sutural outgrowths surrounding the cingulum, specimens are more commonly seen in polar than in lateral view. Where the latter view is presented, it may be seen that the ventral region is occupied largely by a sulcus that is greatly expanded in its central and posterior parts. Verrucae are concentrated on this region of the surface (on the sulcus itself and near the sulcal margins of adjacent paraplates), though they may also be present elsewhere on the periphragm surface. The sulcus is separated from the antapex by a clearly marked posterior ventral paraplate (1pv). The cingulum forms a laevorotatory spiral whose two ends do not differ in anteroposterior position, only because of a great widening of its more posterior end, but for this expansion, they would differ roughly by its width. Folds of the high sutural cavations emarcating it make the number of cingular paraplates hard to determine: at least five, probably six, are present.