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Lunnomidinium scaniense
Lunnomidinium *scaniense Lindström, 2002, p.255-258, pl.1, figs.1-12; pl.2, figs.1-12; pl.3, figs1-12; pl.4, figs.1-6; text-figs.4a-d.
Holotype: Lindström, 2002, pl.1, figs.1-6; text-figs.4a-b.
Age: Rhaetian.
Original description (Lindström, 2002)
Holotype: Plate I (1–6), LO8267T, sample LU-14, slide 2, England Finder coordinates X29/1 (Fig. 4).
Paratypes: (1) Plate I (7–12), LO8268t, sample LU-14, slide 2, England Finder coordinates O40/3 (Fig. 4); (2) Plate II (1–2), LO8269t, sample LU-04, slide 1, England Finder coordinates N21/2; (3) Plate II (10), LO8275t, sample LU-04, slide 2, England Finder coordinates Z29/4; (4) Plate III (1–2), LO8278t, sample LU-14, slide 1, England Finder coordinates K27/2.
Repository: Department of Geology, Lund University, Sweden.
Type locality: Lunnom Coal and Clay Pit, Scania, Sweden.
Type occurrence: Sample LU-14, 1.90 m below the reference level ( Fig. 3); the bottom of coal seam B, within a sandstone layer (−1.85 to −2.10 m).
Etymology: After Scania, the English name for Skåne, the southernmost province of Sweden, where the type locality is situated.
Diagnosis: A species of Lunnomidinium with a subpentagonal outline in dorso-ventral view, and intratabular ornamentation in the apical, precingular, postcingular, and parts of the posterior intercalary and antapical paraplate series.
Description: Proximate to proximochorate, acavate, small (<50 μm) to intermediate (50–100 μm) sized dinoflagellate cysts. Outline subpentagonal in dorso-ventral view. Generally slightly flattened dorso-ventrally. Epicyst with one apical lobe, domed to bottleneck-shaped. Hypocyst slightly longer than epicyst. Antapex concave, divided into two antapical lobes. Autophragm of low relief; granulate or scabrate to punctate or fossulate, rarely almost smooth, surmounted by intratabular protuberances and/or ornamentation (grana or spines) in some, but not all of the paraplate series. Anterior intercalary paraplates, paracingulum, parasulcus, and concave antapical area, generally devoid of intratabular ornamentation. Protuberances hollow, commonly prominent, occasionally ill-defined or flattened, and often topped with grana or short spines ( Plate II, 1–2). Ill-defined protuberances may appear to have been replaced by small groups of grana or spines (Plate II, 5). Paratabulation indicated by low parasutural ridges or sutures, and by the intratabular protuberances. Paracingulum always evident as a broad transverse constriction. Parasulcus apparent as a ventral groove/indented area disrupting the intratabular ornamentation of the precingular, cingular and postcingular series. Paratabulation divided into seven or eight paraplate series (Fig. 4). Paraplates usually pentagonal, hexagonal or heptagonal in shape, occasionally quadrangular. Paratabulation formula: 0–1pr, 7–9′, 9–10a, 12–15″, 7c, 10–15‴, 10–13p, 6⁗ and Xs. Archeopyle epicystal, type {tAtItP}. Principal archeopyle suture immediately anterior to the paracingulum. Operculum adnate ventrally in the parasulcal area. Occasionally detached epicysts (Plate II, 7–9) and hypocysts (Plate III, 10–12; Plate IV, 5) are found; isolated epicysts usually oriented laterally, isolated hypocysts commonly oriented dorso-ventrally. Archeopyle margin straight; with a sulcal notch on isolated hypocysts Plate III, 12; Plate IV, 5).
Remarks: There appear to be two varieties of cysts. (1) Variety α: small sized (<50 μm), delicate cysts with scabrate/granulate autophragm ( Plate I, 1–6; Plate II, 1–5, 10; Plate IV, 1–4). (2) Variety β: basically intermediate sized (50–100 μm), more robust cysts with punctate/fossulate autophragm (Plate I, 7–12; Plate II, 6–9, 11–12; Plate III, 1–12; Plate IV, 5–6).
A quantitative plot of overall length vs. hypocyst width in 141 dorso-ventrally oriented specimens reveals a division into two fairly distinct clusters, which appear to correspond to the two different varieties (Fig. 5a). Total length vs. hypocyst width plots for different samples show that the two varieties occur in varying frequencies in the samples (Fig. 5b–i); e.g. within the thin muddy layer in the coal seam in the Lunnom section (sample LU-04, see Fig. 3). Cysts assigned to var. α make up almost 5% of the palynoflora, but only two specimens assigned to var. β were found in that sample. Specimens assigned to var. β are generally not as common as var. α. Histograms of the total length and the hypocyst width also show a possible division into two slightly overlapping groups (Fig. 6).
Dimensions Number of specimens measured Total length (µm) Hypocyst width (µm)
Holotype 1 35 34
Range 141 33 (47) 72 30 (42) 60
Range var. α 98 33 (42) 57 30 (38) 52
Range var. β 43 46 (57) 72 38 (50) 60
Stratigraphic occurrence: −2.20 to 0.25 m in the Lunnom section (bottom of coal seam is reference level; 0 m). Rhaetian, Vallåkra and Bjuv Members of the Höganäs Formation, Scania, southern Sweden.
Holotype: Lindström, 2002, pl.1, figs.1-6; text-figs.4a-b.
Age: Rhaetian.
Original description (Lindström, 2002)
Holotype: Plate I (1–6), LO8267T, sample LU-14, slide 2, England Finder coordinates X29/1 (Fig. 4).
Paratypes: (1) Plate I (7–12), LO8268t, sample LU-14, slide 2, England Finder coordinates O40/3 (Fig. 4); (2) Plate II (1–2), LO8269t, sample LU-04, slide 1, England Finder coordinates N21/2; (3) Plate II (10), LO8275t, sample LU-04, slide 2, England Finder coordinates Z29/4; (4) Plate III (1–2), LO8278t, sample LU-14, slide 1, England Finder coordinates K27/2.
Repository: Department of Geology, Lund University, Sweden.
Type locality: Lunnom Coal and Clay Pit, Scania, Sweden.
Type occurrence: Sample LU-14, 1.90 m below the reference level ( Fig. 3); the bottom of coal seam B, within a sandstone layer (−1.85 to −2.10 m).
Etymology: After Scania, the English name for Skåne, the southernmost province of Sweden, where the type locality is situated.
Diagnosis: A species of Lunnomidinium with a subpentagonal outline in dorso-ventral view, and intratabular ornamentation in the apical, precingular, postcingular, and parts of the posterior intercalary and antapical paraplate series.
Description: Proximate to proximochorate, acavate, small (<50 μm) to intermediate (50–100 μm) sized dinoflagellate cysts. Outline subpentagonal in dorso-ventral view. Generally slightly flattened dorso-ventrally. Epicyst with one apical lobe, domed to bottleneck-shaped. Hypocyst slightly longer than epicyst. Antapex concave, divided into two antapical lobes. Autophragm of low relief; granulate or scabrate to punctate or fossulate, rarely almost smooth, surmounted by intratabular protuberances and/or ornamentation (grana or spines) in some, but not all of the paraplate series. Anterior intercalary paraplates, paracingulum, parasulcus, and concave antapical area, generally devoid of intratabular ornamentation. Protuberances hollow, commonly prominent, occasionally ill-defined or flattened, and often topped with grana or short spines ( Plate II, 1–2). Ill-defined protuberances may appear to have been replaced by small groups of grana or spines (Plate II, 5). Paratabulation indicated by low parasutural ridges or sutures, and by the intratabular protuberances. Paracingulum always evident as a broad transverse constriction. Parasulcus apparent as a ventral groove/indented area disrupting the intratabular ornamentation of the precingular, cingular and postcingular series. Paratabulation divided into seven or eight paraplate series (Fig. 4). Paraplates usually pentagonal, hexagonal or heptagonal in shape, occasionally quadrangular. Paratabulation formula: 0–1pr, 7–9′, 9–10a, 12–15″, 7c, 10–15‴, 10–13p, 6⁗ and Xs. Archeopyle epicystal, type {tAtItP}. Principal archeopyle suture immediately anterior to the paracingulum. Operculum adnate ventrally in the parasulcal area. Occasionally detached epicysts (Plate II, 7–9) and hypocysts (Plate III, 10–12; Plate IV, 5) are found; isolated epicysts usually oriented laterally, isolated hypocysts commonly oriented dorso-ventrally. Archeopyle margin straight; with a sulcal notch on isolated hypocysts Plate III, 12; Plate IV, 5).
Remarks: There appear to be two varieties of cysts. (1) Variety α: small sized (<50 μm), delicate cysts with scabrate/granulate autophragm ( Plate I, 1–6; Plate II, 1–5, 10; Plate IV, 1–4). (2) Variety β: basically intermediate sized (50–100 μm), more robust cysts with punctate/fossulate autophragm (Plate I, 7–12; Plate II, 6–9, 11–12; Plate III, 1–12; Plate IV, 5–6).
A quantitative plot of overall length vs. hypocyst width in 141 dorso-ventrally oriented specimens reveals a division into two fairly distinct clusters, which appear to correspond to the two different varieties (Fig. 5a). Total length vs. hypocyst width plots for different samples show that the two varieties occur in varying frequencies in the samples (Fig. 5b–i); e.g. within the thin muddy layer in the coal seam in the Lunnom section (sample LU-04, see Fig. 3). Cysts assigned to var. α make up almost 5% of the palynoflora, but only two specimens assigned to var. β were found in that sample. Specimens assigned to var. β are generally not as common as var. α. Histograms of the total length and the hypocyst width also show a possible division into two slightly overlapping groups (Fig. 6).
Dimensions Number of specimens measured Total length (µm) Hypocyst width (µm)
Holotype 1 35 34
Range 141 33 (47) 72 30 (42) 60
Range var. α 98 33 (42) 57 30 (38) 52
Range var. β 43 46 (57) 72 38 (50) 60
Stratigraphic occurrence: −2.20 to 0.25 m in the Lunnom section (bottom of coal seam is reference level; 0 m). Rhaetian, Vallåkra and Bjuv Members of the Höganäs Formation, Scania, southern Sweden.