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Selenopemphix nephroides
Selenopemphix nephroides Benedek, 1972, p.47–48, pl.11, fig.13; pl.16, figs.1–4. Emendations: Bujak in Bujak et al., 1980, p.84; Benedek and Sarjeant, 1981, p.333–334,336 — however, see Head (1993, p.36).
Taxonomic junior synonym: Lejeunia (now Lejeunecysta) psilodora, according to Benedek and Sarjeant (1981, p.333) — however, Lentin and Williams (1985, p.217) and Head (1993, p.36) retained Lejeunia (as Lejeunecysta) psilodora.
Motile equivalent: Protoperidinium subinerme (Paulsen, 1904) Loeblich III, 1970, according to Harland (1982, p.396) — however, see Head (1993, p.36; 1996b, p.1215).
Holotype: Benedek, 1972, pl.11, fig.13; Benedek and Sarjeant, 1981, fig.8, nos.5–6; Head, 1993, fig.20, no.12.
Stratum typicum: Middle-late Oligocene
Locus typicus: Toenisberg, Lower Rhine Area, Germany
Translation Benedek, 1972: LPP, GSC
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Original diagnosis: Benedek 1972, p. 47-48: Selenopemphix nephroides
Same as for genus.
Original description: Benedek 1972, p. 48: Selenopemphix nephroides
the thin-walled, kidney-shaped capsule is flattened dorso-ventrally and is provided with two large rounded-off antapical proturberances. The envelope which displays frequent folds is of a brown coloration and is slightly granular. All specimens possessed a trapezoidal opening below the apical region. The non-tabulated Dinoflagellate envelope, which neither displays a longitudinal furrow nor a transversal furrow, possesses apical and antapical regions which likewise deviate from those of known genera.
Findings of studies with the electron microscope: Among the numerous sectional preparations, the ones illustrated in Plate 16 were chosen as being characteristic for the species here under discussion.
In its middle portion, the wall of the dorso-ventrally (?) flattened envelope has a thickness of 0.15 microns; at the sides its thickness increases up to 0.6 microns. Despite the different thicknesses, the wall is constructed uniformly. Three layers can be distinguished. The internal and external layer are of equal thicknesses (0.05 microns), and moreover, it is less permeable with respect to the electron beam, so that it appears much darker in the ultra-thin-section.
From the thin external layer, small proturberances with club-like outlines arise.
Dimensions: Capsule-length: 52 microns (42/60 microns), capsule breadth 59 microns (43/76 microns), pylome diameter 28/16 microns [shown as such] (10 measurements). Number of examined specimens: 42.
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Emended description: Bujak in Bujak et al., 1980, p. 84-86.
Autocyst compression polar. Apex rounded, sometimes prolonged into a small rounded horn. Antapex rounded or prolonged into two small rounded horns of approximately equal size. Autophragm laevigate to chagrinate, without spines or perforations. Paracingular margins denoted distally entire, raised ridges devoid of spines. Parasulcus may be defined by a shallow indentation. Archaeopyle intercalary, rounded resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. It is always asymmetrically located relative to the middorsal line. The operculum is free or remains attached along the posterior parasuture. Dimensions: Autocyst thickness 28-56 µm, breadth 36-56 µm. 21 specimens measured.
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Emended description: Benedek and Sarjeant, 1981, p. 333-336.
Cyst proximate, rotundly pentagonal in ambitus and kidney-shaped in polar view, with a broadly conical apical prominence and two rounded antapical projections, that at left longer and broader than that at right. Epitract larger than hypotract and having the form of a rounded cone. Paracingulum not indented but faintly indicated by lines on the surface: parasulcus only very faintly marked: paratabulation otherwise not indicated. Archaeopyle formed by loss of a single, very large intercalary paraplate (Type I), situated asymmetrically, with its longest portion to the left of the mid-dorsal line. Archaeopyle index between 0.5 and 0.7.
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Supplemental description: Head, 1993, p.36
Cyst light brown and biphragmal, with polar compression and circular to subcircular ambitus. Endophragm thin walled (less than 0.5 µm thick), light brown, with smooth surface. Periphragm much thinner than endophragm, essentially colorless, smooth surface. Periphragm, separated by up to 3.0 µm at ambitus, may also be seen elsewhere as fine folds over endocyst. Paracingulum clearly developed, margins marked distally by a line of slight thickening on endophragm. Parasulcus moderately incised. Apical and antapical horns weakly developed and usually obscured by folding on polar surface. Archeopyle 2a intercalary, large and rounded.
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Taxonomic junior synonym: Lejeunia (now Lejeunecysta) psilodora, according to Benedek and Sarjeant (1981, p.333) — however, Lentin and Williams (1985, p.217) and Head (1993, p.36) retained Lejeunia (as Lejeunecysta) psilodora.
Motile equivalent: Protoperidinium subinerme (Paulsen, 1904) Loeblich III, 1970, according to Harland (1982, p.396) — however, see Head (1993, p.36; 1996b, p.1215).
Holotype: Benedek, 1972, pl.11, fig.13; Benedek and Sarjeant, 1981, fig.8, nos.5–6; Head, 1993, fig.20, no.12.
Stratum typicum: Middle-late Oligocene
Locus typicus: Toenisberg, Lower Rhine Area, Germany
Translation Benedek, 1972: LPP, GSC
---------------------------------------
Original diagnosis: Benedek 1972, p. 47-48: Selenopemphix nephroides
Same as for genus.
Original description: Benedek 1972, p. 48: Selenopemphix nephroides
the thin-walled, kidney-shaped capsule is flattened dorso-ventrally and is provided with two large rounded-off antapical proturberances. The envelope which displays frequent folds is of a brown coloration and is slightly granular. All specimens possessed a trapezoidal opening below the apical region. The non-tabulated Dinoflagellate envelope, which neither displays a longitudinal furrow nor a transversal furrow, possesses apical and antapical regions which likewise deviate from those of known genera.
Findings of studies with the electron microscope: Among the numerous sectional preparations, the ones illustrated in Plate 16 were chosen as being characteristic for the species here under discussion.
In its middle portion, the wall of the dorso-ventrally (?) flattened envelope has a thickness of 0.15 microns; at the sides its thickness increases up to 0.6 microns. Despite the different thicknesses, the wall is constructed uniformly. Three layers can be distinguished. The internal and external layer are of equal thicknesses (0.05 microns), and moreover, it is less permeable with respect to the electron beam, so that it appears much darker in the ultra-thin-section.
From the thin external layer, small proturberances with club-like outlines arise.
Dimensions: Capsule-length: 52 microns (42/60 microns), capsule breadth 59 microns (43/76 microns), pylome diameter 28/16 microns [shown as such] (10 measurements). Number of examined specimens: 42.
------------------------------------------
Emended description: Bujak in Bujak et al., 1980, p. 84-86.
Autocyst compression polar. Apex rounded, sometimes prolonged into a small rounded horn. Antapex rounded or prolonged into two small rounded horns of approximately equal size. Autophragm laevigate to chagrinate, without spines or perforations. Paracingular margins denoted distally entire, raised ridges devoid of spines. Parasulcus may be defined by a shallow indentation. Archaeopyle intercalary, rounded resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. It is always asymmetrically located relative to the middorsal line. The operculum is free or remains attached along the posterior parasuture. Dimensions: Autocyst thickness 28-56 µm, breadth 36-56 µm. 21 specimens measured.
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Emended description: Benedek and Sarjeant, 1981, p. 333-336.
Cyst proximate, rotundly pentagonal in ambitus and kidney-shaped in polar view, with a broadly conical apical prominence and two rounded antapical projections, that at left longer and broader than that at right. Epitract larger than hypotract and having the form of a rounded cone. Paracingulum not indented but faintly indicated by lines on the surface: parasulcus only very faintly marked: paratabulation otherwise not indicated. Archaeopyle formed by loss of a single, very large intercalary paraplate (Type I), situated asymmetrically, with its longest portion to the left of the mid-dorsal line. Archaeopyle index between 0.5 and 0.7.
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Supplemental description: Head, 1993, p.36
Cyst light brown and biphragmal, with polar compression and circular to subcircular ambitus. Endophragm thin walled (less than 0.5 µm thick), light brown, with smooth surface. Periphragm much thinner than endophragm, essentially colorless, smooth surface. Periphragm, separated by up to 3.0 µm at ambitus, may also be seen elsewhere as fine folds over endocyst. Paracingulum clearly developed, margins marked distally by a line of slight thickening on endophragm. Parasulcus moderately incised. Apical and antapical horns weakly developed and usually obscured by folding on polar surface. Archeopyle 2a intercalary, large and rounded.
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