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Leptodinium membranigerum
Leptodinium membranigerum Gerlach, 1961; emend. Sarjeant, 1984
Originally (and now) Leptodinium, subsequently Impagidinium?.
Holotype: Gerlach, 1961, pl.26, figs.1-3 (lost according to Sarjeant, 1984)
Lectotype: Gerlach, 1961, pl.26, fig.7, text-fig.5; Sarjeant, 1984, pl.1, fig.1,3, text-figs.1A-B; Jan du Chêne et al., 1986, pl.67, figs.17-18 (designated by Sarjeant, 1984)
Locus typicus: Emsb³ren boring no. 7, NW Germany
Stratum typicum: Late Oligocene
Translation Gerlach, 1961: Sarjeant, 1984
Original diagnosis: Gerlach, 1961, p. 162-163
A species of the genusLeptodinium with oval theca. Tabulation formula as given in the generic diagnosis; 4", 6", 5""", 1p and 1"""". Epitheca larger and more elongate than the rounded hypotheca. Girdle furrow spiral, formed of six plates. Offset of its ends somewhat more than a furrow breadth. Longitudinal furrow wholly undifferentiated. Sutures of plates marked by low hyaline crests, shell membrane appearing to bear a thornlike point at the position of convergence of two crests. Plates finely granulate, membrane relatively thin.
Emended diagnosis: Sarjeant, 1984, p. 75-76
Cyst proximate, holotabulate, and acavate; relatively thin but composed of two closely appressed wall layers. Ambitus broadly ovoidal, with epitract markedly larger than hypotract. Low crests, undulate to irregularly scalloped or echinate distally, define the paratabulation 4", 6", 6c, 6""", 2p, 1"""", ?6s. Paraplate 4" is quite large and asymmetrically pentagonal, having a fairly long boundary with a quadrate 6"; this boundary intersects that of 1" in a position anterior to that of 1" with the sulcus. All precingular paraplates are larger than their postcingular equivalents. The right boundary of the small, elongate paraplate 1""" is poorly marked; for this reason the sulcus, which broadens posteriorly, may appear to have the form of an inverted, broad-hafted axe with its blade to the right. Faint lines divide the sulcus into one anterior, at least four median and one (or two?) posterior paraplates. Two posterior intercalary paraplates of similar size separate the sulcus from the rather small antapical paraplate. The cingulum is of moderate breadth, forming a feeble laevorotatory spiral such that its two ends differ in anteroposterior position only by the cingulum"s breadth. Surface of phragma uniformly granulate.
Archaeopyle single-plate precingular (type P) formed by the opening or loss of paraplate 3""".
Dimensions: Holotype (in lateral view): length 55 Ám, breadth 47 Ám. Lectotype (in slightly oblique dorsoventral view and slightly flattened): length 74 Ám, breadth 66 Ám . Paratype (in lateral view): length 63 Ám, breadth 53 Ám. Range of dimensions: length 55-74 Ám), breadth 47-63 Ám (near 51 Ám). Material: 10 specimens.
Originally (and now) Leptodinium, subsequently Impagidinium?.
Holotype: Gerlach, 1961, pl.26, figs.1-3 (lost according to Sarjeant, 1984)
Lectotype: Gerlach, 1961, pl.26, fig.7, text-fig.5; Sarjeant, 1984, pl.1, fig.1,3, text-figs.1A-B; Jan du Chêne et al., 1986, pl.67, figs.17-18 (designated by Sarjeant, 1984)
Locus typicus: Emsb³ren boring no. 7, NW Germany
Stratum typicum: Late Oligocene
Translation Gerlach, 1961: Sarjeant, 1984
Original diagnosis: Gerlach, 1961, p. 162-163
A species of the genusLeptodinium with oval theca. Tabulation formula as given in the generic diagnosis; 4", 6", 5""", 1p and 1"""". Epitheca larger and more elongate than the rounded hypotheca. Girdle furrow spiral, formed of six plates. Offset of its ends somewhat more than a furrow breadth. Longitudinal furrow wholly undifferentiated. Sutures of plates marked by low hyaline crests, shell membrane appearing to bear a thornlike point at the position of convergence of two crests. Plates finely granulate, membrane relatively thin.
Emended diagnosis: Sarjeant, 1984, p. 75-76
Cyst proximate, holotabulate, and acavate; relatively thin but composed of two closely appressed wall layers. Ambitus broadly ovoidal, with epitract markedly larger than hypotract. Low crests, undulate to irregularly scalloped or echinate distally, define the paratabulation 4", 6", 6c, 6""", 2p, 1"""", ?6s. Paraplate 4" is quite large and asymmetrically pentagonal, having a fairly long boundary with a quadrate 6"; this boundary intersects that of 1" in a position anterior to that of 1" with the sulcus. All precingular paraplates are larger than their postcingular equivalents. The right boundary of the small, elongate paraplate 1""" is poorly marked; for this reason the sulcus, which broadens posteriorly, may appear to have the form of an inverted, broad-hafted axe with its blade to the right. Faint lines divide the sulcus into one anterior, at least four median and one (or two?) posterior paraplates. Two posterior intercalary paraplates of similar size separate the sulcus from the rather small antapical paraplate. The cingulum is of moderate breadth, forming a feeble laevorotatory spiral such that its two ends differ in anteroposterior position only by the cingulum"s breadth. Surface of phragma uniformly granulate.
Archaeopyle single-plate precingular (type P) formed by the opening or loss of paraplate 3""".
Dimensions: Holotype (in lateral view): length 55 Ám, breadth 47 Ám. Lectotype (in slightly oblique dorsoventral view and slightly flattened): length 74 Ám, breadth 66 Ám . Paratype (in lateral view): length 63 Ám, breadth 53 Ám. Range of dimensions: length 55-74 Ám), breadth 47-63 Ám (near 51 Ám). Material: 10 specimens.